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Scientific American Supplement No. 822 - Volume XXXII, Number 822. Issue Date October 3, 1891
Author: Various
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It may, therefore, be supposed that the decomposition of carbonic acid by leaves brings about the formation of starch through the following transformations: (1) The decomposition of the carbonic acid with emission of oxygen and production of methylic aldehyde; (2) polymerization of methylic aldehyde and formation of glucose; (3) combination of several molecules of glucose with elimination of water; formation of starch.

Starch is thus the first stable product of chlorophylian activity. Is there, in fact, starch in leaves? It is easy to reveal its presence by the blue coloration that it assumes in contact with iodine in a leaf bleached by boiling alcohol.

Mr. Deherain has devised a nice method of demonstrating that this formation of starch, and consequently the decomposition of carbonic acid, can occur only under the influence of sunlight. He pointed it out to us in his course of lectures at the School of Grignon, and asked us to repeat the experiment. We succeeded, and now make the modus operandi known to our readers.

The leaf that gave the best result was that of the Aristolochia Sipho. The leaf, adherent to the plant, is entirely inclosed between two pieces of perfectly opaque black paper. That which corresponds to the upper surface of the limb bears cut-out characters, which are here the initials of Mr. Deherain. The two screens are fastened to the leaf by means of a mucilage of gum arabic that will easily cede to the action of warm water at the end of the experiment.

The exposure is made in the morning, before sunrise. At this moment, the leaf contains no starch; that which was formed during the preceding day has emigrated during the night toward the interior of the plant.

After a few hours of a good insolation, the leaf is picked off. Then the gum which holds the papers together is dissolved by immersion in warm water. The decolorizing is easily effected through boiling alcohol, which dissolves the chlorophyl and leaves the leaf slightly yellowish and perfectly translucent.

There is nothing more to do then but dip the leaf in tincture of iodine. If the insolation has been good, and if the screens have been well gummed so that no penumbra has been produced upon the edge of the letters, a perfectly sharp image will be instantly obtained. The excess of iodine is removed by washing with alcohol and water, and the leaf is then dried and preserved between the leaves of a book.

It is well before decolorizing the leaf to immerse it in a solution of potassa; the chlorophylian starch then swells and success is rendered easier.—Lartigue and Malpeaux, in La Nature.

* * * * *



STANDARDS AND METHODS FOR THE POLARIMETRIC ESTIMATION OF SUGARS.[1]

[Footnote 1: Report to the United States Internal Revenue Department by C.A. Crampton, Chemist of U.S. Internal Revenue; H.W. Wiley, Chief Chemist of U.S. Department of Agriculture; and O.H. Tittmann, Assistant in Charge of Weights and Measures, U.S. Coast and Geodetic Survey.]

Section 1, paragraph 231, of the act entitled "An act to reduce revenue and equalize duties on imports and for other purposes," approved October 1, 1890, provides:

"231. That on and after July 1, eighteen hundred and ninety-one, and until July 1, nineteen hundred and five, there shall be paid, from any moneys in the Treasury not otherwise appropriated, under the provisions of section three thousand six hundred and eighty-nine of the Revised Statutes, to the producer of sugar testing not less than ninety degrees by the polariscope, from beets, sorghum, or sugar cane grown within the United States, or from maple sap produced within the United States, a bounty of two cents per pound; and upon such sugar testing less than ninety degrees by the polariscope, and not less than eighty degrees, a bounty of one and three-fourth cents per pound, under such rules and regulations as the Commissioner of Internal Revenue, with the approval of the Secretary of the Treasury, shall prescribe."

It is the opinion of this Commission that the expression "testing ... degrees by the polariscope," used with reference to sugar in the act, is to be considered as meaning the percentage of pure sucrose the sugar contains, as ascertained by polarimetric estimation.

It is evident that a high degree of accuracy is necessary in the examination of sugars by the Bureau of Internal Revenue, under the provisions of this act, inasmuch as the difference of one-tenth of one per cent. in the amount of sucrose contained in a sugar may, if it is on the border line of 80 deg., decide whether the producer is entitled to a bounty of 13/4 cents per pound (an amount nearly equivalent to the market value of such sugar) or to no bounty whatever. It is desirable, therefore, that the highest possible degree of accuracy should be secured in the work, for while many sugars will doubtless vary far enough from either of the two standard percentages fixed upon in the act, viz., 80 deg. and 90 deg., to admit of a wide margin of error without material consequences, yet a considerable proportion will approximate to them so closely that a difference of a few tenths of a degree in the polarization will change the classification of the sugar.

A very high degree of accuracy may be obtained in the optical estimation of sugars, if the proper conditions are observed. Such conditions are (1) accurately graded and adjusted instruments, weights, flasks, tubes, etc.; (2) skilled and practiced observers; (3) a proper arrangement of the laboratories in which the work is performed; and (4) a close adherence to the most approved methods of manipulation.

On the other hand, if due observance is not paid to these conditions, the sources of error are numerous, and inaccurate results inevitable.

We will endeavor to point out in this report the best means of meeting the proper conditions for obtaining the highest degree of accuracy consistent with fairly rapid work. It would be manifestly impossible to observe so great a refinement of accuracy in this work as would be employed in exact scientific research.

This would be unnecessary for the end in view, and impossible on account of the amount of time that would be required.

I.—INSTRUMENTS AND APPARATUS.

It is of the greatest importance that the polariscopes and all apparatus used in the work shall be carefully and accurately adjusted and graduated, and upon a single and uniform system of standardization. Recent investigations of the polarimetric work done in the customs branch of the Treasury Department have shown that a very considerable part of the want of agreement in the results obtained at the different ports was due to a lack of uniformity in the standardization of the instruments and apparatus.

(a.) The Polariscope.—There are many different forms of this instrument used. Some are adapted for use with ordinary white light, and some with monochromatic light, such as sodium ray. They are graduated and adjusted upon various standards, all more or less arbitrary. Some, for example, have their scales based upon the displacement of the polarized ray produced by a quartz plate of a certain thickness; others upon the displacement produced by an arbitrary quantity of pure sucrose, dissolved and made up to a certain volume and polarized in a certain definite length of column. It would be very desirable to have an absolute standard set for polariscopic measurements, to which all instruments could be referred, and in the terms of which all such work could be stated. This commission has information that an investigation is now in progress under the direction of the German imperial government, having for its end and purpose the determination of such data as will serve for the establishment of an absolute standard. When this is accomplished it can easily be made a matter of international agreement, and all future forms of instruments be based upon it. This commission would suggest that the attention of the proper authorities should be called to the desirability of official action by this government with a view to co-operation with other countries for the adoption of international standards for polarimetric work. Until this is done, however, it will be necessary for the Internal Revenue Bureau to adopt, provisionally, one of the best existing forms of polariscope, and by carefully defining the scale of this instrument, establish a basis for its polarimetric work which will be a close approximation to an absolute standard, and upon which it can rely in case of any dispute arising as to the results obtained by the officers of the bureau.

For the instrument to be provisionally adopted by the Internal Revenue Bureau, this commission would recommend the "half shadow" instrument made by Franz Schmidt & Haensch, Berlin. This instrument is adapted for use with white light illumination, from coal oil or gas lamps. It is convenient and easy to read, requiring no delicate discrimination of colors by the observer, and can be used even by a person who is color blind.

This form of instrument is adjusted to the Ventzke scale, which, for the purposes of this report, is defined to be such that 1 deg. of the scale is the one hundredth part of the rotation produced in the plane of polarization of white light in a column 200 mm. long by a standard solution of chemically pure sucrose at 17.5 deg. C. The standard solution of sucrose in distilled water being such as to contain, at 17.5 deg. C. in 100 c.c., 26.048 grms. of sucrose.

In this definition the weights and volumes are to be considered as absolute, all weighings being referred to a vacuum.

The definition should properly be supplemented with a statement of the equivalent circular rotation in degrees, minutes, and seconds that would be produced by the standard solution of sugar used to read 100 deg. on the scale. This constant is now a matter of investigation, and it is thought best not to give any of the hitherto accepted values. When this is established, it is recommended that it be incorporated in a revision of the regulations of the internal revenue relative to sugar, in order to make still more definite and exact the official definition of the Ventzke scale.

The instruments should be adjusted by means of control quartz plates, three different plates being used for complete adjustment, one reading approximately 100 deg. on the scale, one 90 deg., and one 80 deg..

These control quartz plates should have their exact values ascertained in terms of the Ventzke scale by the office of weights and measures by comparison with the standard quartz plates in possession of that office, in strict accordance with the foregoing definition, and should also be accompanied by tables giving their values for temperatures from 10 deg. to 35 deg..

(b.) Weights.—The weights used should be of solid brass, and should be standardized by the office of weights and measures.

(c.) Flask.—The flasks used should be of such a capacity as to contain at 17.5 deg. C. 100.06 cubic centimeters, when filled in such a manner that the lowest point of the meniscus of the surface of the liquid just touches the graduation mark. The flasks will be standardized to contain this volume in order that the results shall conform to the scale recommended for adoption without numerical reduction of the weighings to vacuo. They should be calibrated by the office of weights and measures.

(d.) Tubes.—The tubes used should be of brass or glass, 200 and 100 millimeters in length, and should be measured by the office of weights and measures.

(e.) Balances.—The balances used should be sensitive to at least one milligramme.

II.—SKILLED OBSERVERS.

The commission recommends that the work of polarizing sugars be placed in the hands of chemists, or at least of persons who are familiar with the use of the polariscope and have some knowledge of the theory of its construction and of chemical manipulations. To this end we would suggest that applicants for positions where such work is to be done should be obliged to undergo a competitive examination in order to test their fitness for the work that is to be required of them.

III.—ARRANGEMENT OF LABORATORIES.

The arrangement of the rooms in which polarizations are performed has an important bearing upon the accuracy of the results obtained.

Polariscopic observations are made more readily and accurately if the eye of the observer is screened from diffused light; therefore, a partial darkening of the room, which may be accomplished by means of curtains or hangings, is an advantage. On the other hand, the temperature at which the observation is made has a very considerable influence upon the results obtained, so that the arrangements for darkening the room must not be such as will interfere with its proper ventilation. Otherwise the heat from the lamps used, if confined within a small room, will cause considerable variations in the temperature of the room from time to time.

The proper conditions will best be met, in our opinion, by placing the lamps either in a separate room from that in which the instruments are, and perforating the wall or partition between the two rooms for the light to reach the end of the instruments, or in a ventilated hood with the walls perforated in a like manner. By lining the wall or partition on both sides with asbestos paper, and inserting a plate of plane glass in the aperture through which the light passes, the increase of temperature from the radiation of the lamp will be still further avoided. With the lamps separated from the instruments in this manner, the space in which the instruments are contained is readily darkened without much danger of its temperature being unduly raised.

Some light, of course, is necessary for reading the scales, and if artificial light is employed for this purpose, the sources chosen should be such that as little heat as possible will be generated by them. Small incandescent electric lights are best for such purpose. Refinements of this kind cannot always be used, of course, but the prime requisite with reference to the avoidance of temperature errors is that all operations—filling the flasks and tubes, reading the solutions, controlling the instrument with standard quartz plates, etc.—should be done at one and the same temperature, and that this temperature be a constant one, that is, not varying greatly at different hours of the day. For example, the room should not be allowed to become cold at night, so that it is at low temperature in the morning when work is begun, and then rapidly heated up during the day. The polariscope should not be exposed to the direct rays of the sun during part of the day, and should not be near artificial sources of heat, such as steam boilers, furnaces, flues, etc.

The tables upon which the instruments stand should be level.

IV.—METHODS OF MANIPULATION.

The methods of manipulation used in the polarization of sugar are of prime importance. They consist in weighing out the sugar, dissolving it, clarifying the solution, making it up to standard volume, filtering, filling the observation tube, regulating the illumination, and making the polariscopic reading.

The proper conduct of these processes, in connection with the use of accurately graduated apparatus, is the only surety against the numerous sources of error which may be encountered. Different sugars require different treatment in clarification, and much must necessarily be left to the judgment and experience of the operator.

The following directions are based upon various official procedures such as the one used in the United States custom houses, the method prescribed by the German government, etc. They embody also the result of recent research in regard to sources of error in polarimetric estimation of sugar:

DIRECTIONS FOR THE POLARIZATION OF SUGAR.

1.—Description of Instrument and Manner of Using.

The instrument employed is known as the half shadow apparatus of Schmidt and Haensch. It is shown in the following cut.



The tube N contains the illuminating system of lenses and is placed next to the lamp; the polarizing prism is at O, and the analyzing prism at H. The quartz wedge compensating system is contained in the portions of the tube marked F, E, G, and is controlled by the milled head M. The tube J carries a small telescope, through which the field of the instrument is viewed, and just above is the reading tube K, which is provided with a mirror and magnifying lens for reading the scale.

The tube containing the sugar solution is shown in position in the trough between the two ends of the instrument. In using the instrument the lamp is placed at a distance of at least 200 mm. from the end; the observer seats himself at the opposite end in such a manner as to bring his eye in line with the tube J. The telescope is moved in or out until the proper focus is secured, so as to give a clearly defined image, when the field of the instrument will appear as a round, luminous disk, divided into two halves by a vertical line passing through the center, and darker on one half of the disk than on the other. If the observer, still looking through the telescope, will now grasp the milled head M and rotate it, first one way and then the other, he will find that the appearance of the field changes, and at a certain point the dark half becomes light, and the light half dark. By rotating the milled head delicately backward and forward over this point he will be able to find the exact position of the quartz wedge operated by it, in which the field is neutral, or of the same intensity of light on both halves.



The three different appearances presented by the field are best shown in the above diagram. With the milled head set at the point which gives the appearance of the middle disk as shown, the eye of the observer is raised to the reading tube, K, and the position of the scale is noted. It will be seen that the scale proper is attached to the quartz wedge, which is moved by the milled head, and attached to the other quartz wedge is a small scale called a vernier which is fixed, and which serves for the exact determination of the movable scale with reference to it. On each side of the zero line of the vernier a space corresponding to nine divisions of the movable scale is divided into ten equal parts. By this device the fractional part of a degree indicated by the position of the zero line is ascertained in tenths; it is only necessary to count from zero, until a line is found which makes a continuous line with one on the movable scale.

With the neutral field as indicated above, the zero of the movable scale should correspond closely with the zero of the vernier unless the zero point is out of adjustment.

If the observer desires to secure an exact adjustment of the zero of the scale, or in any case if the latter deviates more than one-half of a degree, the zero lines are made to coincide by moving the milled head and securing a neutral field at this point by means of the small key which comes with the instrument, and which fits into a nipple on the left hand side of F, the fixed quartz wedge of the compensating system. This nipple must not be confounded with a similar nipple on the right hand side of the analyzing prism, H, which it fits as well, but which must never be touched, as the adjustment of the instrument would be seriously disturbed by moving it. With the key on the proper nipple it is turned one way or the other until the field is neutral. Unless the deviation of the zero be greater than 0.5 deg., it will not be necessary to use the key, but only to note the amount of the deviation, and for this purpose the observer must not be content with a single setting, but must perform the operation five or six times, and take the mean of these different readings. If one or more of the readings show a deviation of more than 0.3 deg. from the general average, they should be rejected as incorrect. Between each observation the eye should be allowed 10 to 20 seconds of rest.

The "setting" of the zero having been performed as above, the determination of the accurate adjustment of the instrument by means of the "control" quartz plates is proceeded with. Three such plates will be furnished with each polariscope, which have "sugar values" respectively approximating 80 deg., 90 deg., and 100 deg.. These values may vary with the temperature, and tables are furnished with them which give their exact value at different temperatures, from 10 deg. to 35 deg. C.

One of these plates is placed in the instrument, and the field observed; it will be seen that the uniform appearance of the field is changed. The milled head is turned to the right until the exact point of neutrality is re-established, just as described above in setting the zero. The scale is read, the observation repeated, the reading taken again, and so on until five or six readings have been made. The average is taken, readings being rejected which show a divergence of more than 0.3, and the result corrected for the deviation of the zero point, if any was found, the deviation being added if it was to the left, and subtracted if to the right. If the adjustment of the instrument be correct, the result should be the value of the control plate used, as ascertained from the table, for the temperature of 20 deg.. Each of the three plates is read in the instrument in this way. A variation of 0.3 from the established values may be allowed for errors of observation, temperature, etc., but in the hands of a careful observer a deviation greater than this with one of the three plates, after a careful setting of the zero, shows that the instrument is not accurately adjusted.

The complete verification of the accurate adjustment of the polariscope by means of three control plates, as given above, should be employed whenever it is set up for the first time by the officer using it, whenever it has sustained any serious shock or injury, and whenever it has been transported from one place to another. It should also be done at least once a week while the instrument is in active use.

After the complete verification has been performed as described, further checking of the instrument is done by means of one control plate alone, the one approximating 90 deg., and the setting of the zero point is dispensed with, the indication of the scale for sugar solutions being corrected by the amount of deviation shown in the reading of the 90 deg. control plate from its established value as ascertained from the table, at the temperature of the room.

For example: A sugar solution polarizes 80.5; the control plate just before had given a polarization of 91.4, the temperature of the room during both observations being 25 deg. C. According to the table the value of the control plate at 25 deg. C. is 91.7; the reading is, therefore, 0.3 too low, and 0.3 is added to the reading of the sugar solution, making the corrected result 80.8. The temperature of the room should be ascertained from a standardized thermometer placed close to the instrument and in such a position as to be subject to the same conditions.

PREPARATION OF THE SUGAR SOLUTION FOR POLARIZATION.

If the sample is not entirely uniform it must be thoroughly mixed before weighing out, after all the lumps are broken up, best with a mortar and pestle. Then 26.048 grammes are weighed out on the balance in the tared German silver dish furnished for this purpose. Care must be taken that the operations of mixing and weighing out are not unduly prolonged, otherwise the sample may easily suffer considerable loss of moisture, especially in a warm room. The portion of sugar weighed out is washed by means of a jet from a wash bottle into a 100 c.c. flask, the dish being well rinsed three or four times and the rinsings added to the contents of the flask. The water used must be either distilled water or clear water which has been found to have no optical activity. After the dish has been thoroughly rinsed, enough water is added to bring the contents of the flask to about 80 c.c. and it is gently rotated until all the sugar has dissolved. The flask should be held by the neck with the thumb and finger, and the bulb not handled during this operation. Care must be taken that no particle of the sugar or solution is lost. To determine if all the sugar is dissolved, the flask is held above the level of the eye, in which position any undissolved crystals can be easily seen at the bottom. The character of the solution is now observed. If it be colorless or of a very light straw color, and not opalescent, so that it will give a clear transparent liquid on filtration through paper, the volume is made up directly with water to the 100 c.c. mark on the flask. Most sugar solutions, however, will require the addition of a clarifying or decolorizing agent in order to render them sufficiently clear and colorless to polarize. In such case, before making up to the mark, a saturated solution of subacetate of lead is added.

The quantity of this agent required will vary according to the quality of the sugar; for sugar which has been grained in the strike pan and washed in the centrifugals, from 3 to 15 drops will be required; for sugar grained in the strike pan but not well washed in the centrifugals, that is, sugar intended for refining purposes, from 15 to 30 drops will be required; for sugar not grained in the strike pan, that is, "wagon" or "string sugar," "second sugar," etc., from 1 to 3 c.c. will be required. After adding the solution of subacetate of lead the flask must be gently shaken, so as to mix it with the sugar solution. If the proper amount has been added, the precipitate will usually subside rapidly, but if not, the operator may judge of the completeness of the precipitation by holding the flask above the level of the eye and allowing an additional drop of subacetate of lead to flow down the side of the flask into the solution; if this drop leaves a clear track along the glass through the solution it indicates that the precipitation is complete; if, on the other hand, all traces of the drop are lost on entering the solution, it indicates that an additional small quantity of the subacetate of lead is required. The operator must learn by experience the point where the addition should cease; a decided excess of subacetate of lead solution should never be used.

The use of subacetate of lead should, in all cases, be followed by the addition of "alumina cream" (aluminic hydrate suspended in water)[2] in about double the volume of the subacetate solution used, for the purpose of completing the clarification, precipitating excess of lead, and facilitating filtration. In many cases of high grade sugars, especially beet sugars, the use of alumina alone will be sufficient for clarification without the previous addition of subacetate of lead.

[Footnote 2: Prepared as follows: Shake up powdered commercial alum with water at ordinary temperature until a saturated solution is obtained. Set aside a little of the solution, and to the residue add ammonia, little by little, stirring between additions, until the mixture is alkaline to litmus paper. Then drop in additions of the portion left aside, until the mixture is just acid to litmus paper. By this procedure a cream of aluminum hydroxide is obtained suspended in a solution of ammonium sulphate, the presence of which is not at all detrimental for sugar work when added after subacetate of lead, the ammonium sulphate precipitating whatever excess of lead may be present.]

The solution is now made up to the mark by the addition of distilled water in the following manner. The flask, grasped by the neck between the thumb and finger, is held before the operator in an upright position, so that the mark is at the level of the eye, and distilled water is added drop by drop from a siphon bottle or wash bottle, until the lowest point of the curve or meniscus formed by the surface of the liquid just touches the mark. If bubbles hinder the operation, they may be broken up by adding a single drop of ether, or a spray from an ether atomizer, before making up to the mark. The mouth of the flask is now tightly closed with the thumb, and the contents of the flask are thoroughly mixed by turning and shaking. The entire solution is now poured upon the filter, using for this purpose a funnel large enough to contain all the 100 c.c. at once, and a watch glass is placed over the funnel during filtration to prevent a concentration of the solution by evaporation.

The funnel and vessel used to receive the filtrate must be perfectly dry. The first portion of the filtrate, about 20 to 30 c.c., should be rejected entirely, as its concentration may be affected by a previous hygroscopic moisture content of the filter paper. It may also be necessary to return subsequent portions to the filter until the liquid passes through perfectly clear.

If a satisfactory clarification has not been obtained, the entire operation must be repeated, since only with solutions that are entirely clear and bright can accurate polarimetric observations be made.

When a sufficient quantity of the clear liquid has passed through the filter, the 200 mm. observation tube is filled with it. The 100 mm. tube should never be used except in rare cases, when notwithstanding all the means used to effect the proper decolorization of the solution, it is still too dark to polarize in the 200 mm. tube. In such cases the shorter tube may be used, and its reading multiplied by two. The zero deviation must then be determined and applied to the product. This will give the reading which would have been obtained if a 200 mm. tube could have been used, and it only remains to apply the correction determined by the use of the control plate as previously described.

Example:

Solution reads in 100 mm. tube 47.0 Multiplied by 2 2.0 —— Product 94.0 Zero reads plus 0.3 0.3 —— Solution would read in 200 mm. tube 93.7

Reading of control plate 90.4 Sugar value of control plate 90.5 —— Instrument too low by 0.1 Add 0.1 to 93.7 —— Correct polarization of solution 93.8

Before filling the tube it must either be thoroughly dried by pushing a plug of filter paper through it, or it must be rinsed several times with the solution itself. The cover glasses must also be clean and dry, and without serious defects or scratches. Unnecessary warming of the tube by the hand during filling should be avoided; it is closed at one end with the screw cap and cover glass, and grasped by the other end with the thumb and finger. The solution is poured into it until its curved surface projects slightly above the opening, the air bubbles allowed time to rise, and the cover glass pushed horizontally over the end of the tube in such a manner that the excess of liquid is carried over the side, leaving the cover glass exactly closing the tube with no air bubbles beneath it, and with no portion of the liquid upon its upper surface. If this result is not attained, the operation must be repeated, the cover glass being rubbed clean and dry, and the solution again brought up over the end by adding a few more drops. The cover glass being in position, the tube is closed by screwing on the cap. The greatest care must be observed in screwing down the caps that they do not press too tightly upon the cover glasses; by such pressure the glasses themselves may become optically active, and cause erroneous readings when placed in the instrument. It should therefore be ascertained that the rubber washers are in position over the cover glasses, and the caps should be screwed on lightly. It must also be remembered that a cover glass, once compressed, may part with its acquired optical activity very slowly, and some time must be allowed to elapse before it is used again.

The polariscopic reading may now be taken, an observation on the 90 deg. control plate having been made immediately before as previously described. Then without altering the position of the instrument relative to the light, or changing the character of the latter in any way, the tube filled with the sugar solution is substituted for the control plate. The telescope is adjusted, if necessary, so as to give a sharply defined field, which must appear round and clear. (This condition must be fulfilled before the observation is performed, as it is essential to accuracy.) The milled head is turned until the neutral point is found, and the reading is taken exactly as previously described, the operation repeated five or six times, the average taken with the rejection of aberrant readings, the average figure corrected for the deviation shown by the control observation from the sugar value of the control plate at the temperature of observation as given in the table, and the result taken as the polarization of the sugar. When a series of successive polarizations is made under the same conditions as regards temperature, position of the instrument with relation to the high intensity, of the light, etc., the control observation need not be made before each polarization, one such observation being sufficient for the entire series. The control must be repeated at least once an hour, however, and oftener when the operator has reason to think that any of the factors indicated above have been altered, for any such alteration of conditions may change the zero point of the instrument.

In the polarization of the quartz plates, as also in the polarization of very white sugars, difficulty may be experienced in obtaining a complete correspondence of both halves of the field. With a little practice this may be overcome and the neutral point found, but when it cannot, the ordinary telescope of the instrument may be replaced by another, which is furnished with the polariscope and which carries a yellow plate. This removes the difficulty and renders it possible, even for one not well accustomed to the instrument, to set it at the exact point of neutrality.

SUMMARIZED SOURCES OF ERROR.

The following principal sources of error must be especially guarded against:

1. Drying out of sample during weighing.

2. Excess of subacetate of lead solution in clarification.

3. Incomplete mixing of solution after making up to mark.

4. Imperfect clarification or filtration.

5. Concentration of solution by evaporation during filtration.

6. Undue compression of the cover glass.

7. Alteration of the temperature of room, position of instrument, or intensity of light while the observation or control observation is being performed.

8. Performances of polarization with a cloudy, dim, or not completely round or sharply defined field.

In closing this report the members of this commission hereby signify their intention to promote uniformity and accuracy by adopting and using the standards and general plan of procedure recommended in this report in the polarimetric determinations over which, in their respective branches of government work, they have control.

* * * * *



THE GRAND FALLS OF LABRADOR.

Hamilton Inlet, or Ionektoke, as the Esquimaus call it, is the outlet to the largest river on the Labrador Peninsula, and of great importance to commerce, Rigolet, the headquarters of the Hudson Bay Company in this region, being situated on its shores. This inlet is the great waterway to Central Labrador, extending into the interior for nearly 200 miles.

This immense basin is undoubtedly of glacial origin, evidences of ice erosion being plainly seen. It is divided into two general basins, connected by the "narrows," a small strait, through which the water rushes with frightful rapidity at each tide. Into the head of the inlet flows the Hamilton, or Grand River, an exploration of which, though attended with the greatest danger and privation, has enticed many men to these barren shores. Perhaps the most successful expedition thus far was that of Mr. Holme, an Englishman, who, in the summer of 1888, went as far as Lake Waminikapon, where, by failure of his provisions, he was obliged to turn back, leaving the main object of the trip, the discovery of the Grand Falls, wholly unaccomplished.

It has been left for Bowdoin College to accomplish the work left undone by Mr. Holme, to do honor to herself and her country by not only discovering, measuring, and photographing the falls, but making known the general features of the inland plateau, the geological structure of the continent, and the course of the river.

On Sunday, July 26, a party of the Bowdoin expedition, consisting of Messrs. Cary, Cole, Young, and Smith, equipped with two Rushton boats and a complement of provisions and instruments, left the schooner at the head of the inlet for a five weeks' trip into the interior, the ultimate object being the discovery of the Grand Falls. The mouth of the river, which is about one mile wide, is blockaded by immense sand bars, which have been laid down gradually by the erosive power of the river. These bars extend far out into Goose Bay, at the head of Lake Melville, and it is impossible to approach the shores except in a small boat. Twenty-five miles up the river are the first falls, a descent of the water of twenty-five feet, forming a beautiful sight. Here a cache of provisions was made, large enough to carry the party back to the appointed meeting place at Northwest River. The carry around the first falls is about one and a half miles in length, and very difficult on account of the steep sides of the river.

From the first falls to Gull Island Lake, forty miles above, the river is alternately quick and dead water. Part of it is very heavy rapids, over which it was necessary to track, and in some places to double the crews. Each boat had a tow line of fifty feet, and in tracking the end was taken ashore by one of the crew of two, while the boat was kept off the bank by the other man with an oar. At the Horseshoe Rapids, ten miles above Gull Island Lake, an accident happened which threatened to put a stop to further progress of the expedition. While tracking around a steep point in crossing these rapids the boat which Messrs. Cary and Smith were tracking was overturned, dumping barometer, shotgun, and ax into the river, together with nearly one-half the total amount of provisions. In the swift water of the rapids all these things were irrevocably lost, a very serious loss at this stage in the expedition. On this day so great was the force of the water that only one mile was made, and that only with the greatest difficulty.

Just above the mouth of the Nimpa River, which enters the Grand River twenty-five miles above Gull Island Lake, a second cache of provisions was made, holding enough to carry the party to their first cache at the first falls. One of the boats was now found to be leaking badly, and a stop was made to pitch the cracks and repair her, making necessary the loss of a few hours. From Nimpa River to the Mouni Rapids, at the entrance to Lake Waminikapon, the water was found to be fairly smooth, and good progress was made. The change in the scenery, too, is noticeable, becoming more magnificent and grand. The mountains, which are bolder and more barren, approach much nearer to each other on each side of the river, and at the base of these grim sentinels the river flows silvery and silently. The Mouni Rapids, through which the water passes from Lake Waminikapon, presented the next obstacle to further progress, but the swift water here was soon passed, and well repaid the traveler with the sight here presented almost unexpectedly to his view.

The lake was entered about 4 o'clock in the afternoon, and, as the narrow entrance was passed, the sun poured its full rich light on rocky mountains stretching as far away as the eye could reach, on each side of the lake, and terminating in rocky cliffs from 600 to 800 feet in perpendicular height, which formed the shores or confines of the lake. Across Lake Waminikapon, which is, more properly speaking, not a lake at all, but rather a widening of the river bed, the progress was very good, the water having no motion to retard the boats, and forty miles were made during the day.

Here a misfortune, which had been threatening for several days, came upon the party. Mr. Young's arm was so swollen, from the shoulder to finger tips, that he could scarcely move it, the pain being excessive. It had been brought on doubtless by cold and exposure. Seeing that he could be of no further use to the party, it was decided to divide forces, Mr. Smith returning with the sick man to Rigolet for medical assistance. The separation took place August 8, when the party had been on the river eleven days. The party were very sorry to return at this point, since from the best information which they could get in regard to the distance, the falls were but fifty miles above them. Under the circumstances, however, there was no help for it. So Smith and Young, bidding their friends good fortune, started on their return trip. The mouth of the river was reached in three days, a little less than one-third the time consumed in going up, and that, too, with only one man to handle the boat.

On the way down the river another party, composed of Messrs. Bryant and Kenaston of Philadelphia, was met, who were on the same business as the Bowdoin party, the discovery of the falls. Mr. Bryant handed to Mr. Young a twenty-five pound can of flour, which, he said, he had found in the whirlpool below the first falls. It had been in the boat which was overturned in the Horseshoe Rapids, and had made the journey to the first falls, a distance of over fifty miles, without denting or injuring the can in any way. It was a great relief to the Bryant party to learn the cause of the mishap, as they had feared a more serious calamity.

After the departure of the other two, Messrs. Cary and Cole encountered much rapid water, so that their progress was necessarily slow. On the third day, when they had proceeded sixty-five miles above Lake Waminikapon, and had seen no indications of any falls, the rapidity of the current forced them to leave the river and make any further progress on foot. The boat was cached at this point, together with all that was left of provisions and instruments except the compass and food for six days. They left just enough provisions to carry them to their last cache at Ninipi River, and hoped, by careful use of the remainder, to find the object of their search. If they had not enough provisions, then they must turn back, leaving reports of falls as destitute of confirmation as ever.

The land bordering the river at this point was heavily wooded, and in places where the river shore could not be followed on account of the cliffs, their progress was necessarily slow. Finding an elevation of land at no great distance from them, they ascended it for a general survey of the country. Far away in the distance could be seen the current of the Grand River flowing sluggishly but majestically on its course to the sea. Lakes on all sides were visible, most of them probably of glacial origin. Descending from this mountain, which the explorers christened Mount Bowdoin, a course was laid on the river bank, where camp was made that night. Being now somewhat weak from hard labor and insufficient food, their progress was slow through the thick wood, but on the next night camp was made on the edge of the plateau or table land of Labrador.

After proceeding a short distance on the next day, Aug. 13, a loud roar was heard in the distance, and a course was laid for the river at the nearest point. The river at this point, about one mile above the falls, was 500 yards wide, narrowing to fifty yards a short distance below, where great clouds of spray floating in the air warned the weary travelers that their object had been attained. Quickly they proceeded to the scene, and a magnificent sight burst upon their view.

Grand Falls, though not approaching the incredible height attributed to it by legendary accounts of the Indians, is a grand fall of water. Its total descent is accomplished in a series of falls aggregating nearly 500 feet. The greatest perpendicular descent is not over 200 feet. The half dozen falls between this grand descent and the bed of the river on the plateau vary from ten to twenty-five feet, adding to the majesty and grandeur of the scene. It was with great difficulty that the bottom of the falls was reached and a photograph of the scene taken.

After leaving the plateau and plunging over the falls, the waters enter an immense canon or gorge, nearly 40 miles long and 300 yards wide, the perpendicular sides of which rise to a height of from 300 to 500 feet. The sides of this canon show it to be hollowed out of solid Archaean rock. Through this canon the water rushes with terrific rapidity, making passage by boat wholly impossible. Many erroneous stories have been told in regard to the height of these falls, all of them greatly exaggerating the descent of the water. The Indians of this locality of the tribe of the Nascopee or the race of Crees have long believed the falls to be haunted by an evil spirit, who punished with death any one who might dare to look upon them. The height of land or plateau which constitutes the interior of the Labrador peninsula is from 2,000 to 2,500 feet above the sea level, fairly heavily wooded with spruce, fir, hackmatack, and birch, and not at all the desolate waste it has been pictured by many writers. The barrenness of Labrador is confined to the coast, and one cannot enter the interior in any direction without being struck by the latent possibilities of the peninsula were it not for the abundance of flies and mosquitoes. Their greed is insatiable, and at times the two men were weakened from the loss of blood occasioned by these insects.

The object of the expedition being attained, the return trip was begun, and the sight of the cached boat and provisions eagerly watched for. On Aug. 15 the camp was sighted, but to their horror they saw smoke issuing from the spot. It at once flashed upon their minds what had taken place, and when they arrived they found that their fears had been all too truly realized. Charred remains of the boat, a burned octant, and a few unexploded cartridges were all that remained of the meager outfit upon which they depended to take them to the mouth of the river, a distance of over 250 miles. The camp fire, not having been completely extinguished, had burned the boat and destroyed all their provisions.

It was truly a hard outlook for them, but no time must be lost if provisions were to be obtained. Hastily a raft was constructed, the logs being bound together with spruce roots. In this way, by alternately walking and rafting, the mouth of the river was reached Aug. 29. On the way down the river five rafts had been made and abandoned. The only weapon was a small pocket revolver, and with the products of this weapon, mostly red squirrels and a few fish, they lived until they reached the different caches. Many a meal was made of one red squirrel divided between them, and upon such food they were compelled to make the best time possible. On the way up the river the shoes of one of the party had given wholly out, and he was obliged to make a rude pair of slippers from the back of a leather pack. With torn clothes and hungry bodies they presented a hard sight indeed when they joined their friends at Rigolet on the 1st of September. The party composed of Messrs. Bryant and Kenaston was passed by Cary and Cole while on the way down, but was not seen. Probably this occurred on Lake Waminikapon, the width of the lake preventing one party from seeing the other. It seemed a waste of time and energy that two expeditions in the same summer should be sent upon the same object, but neither party knew of the intention of the other until it was too late to turn back.

Grand River has long been a highway for the dependents of the Hudson Bay Company. The company formerly had a post on Lake Waminikapon, and another, called Height of Land, on the plateau. Provisions were carried to these posts, and furs brought from them by way of Grand River, the parties proceeding as far as the lake, and then, leaving Grand River some distance below the canon, no longer being able to follow it on account of the swiftness of the water, they carried their canoes across the land to a chain of lakes connecting with the post. This station has been given up many years, and the river is used now chiefly be Indians and hunters in the winter.

It has long been known that Hamilton Inlet was of glacial origin, the immense basin hollowed out by this erosive agent being 150 miles in length. How much further this immense valley extended has never been known. Mr. Cary says that the same basin which forms Hamilton Inlet and enters Lake Melville, the two being connected by twelve miles of narrows, extends up the Grand River Valley as far as Gull Island Lake, the whole forming one grand glacial record. From Lake Melville to Gull Island the bed was being gradually filled in by the deposits of the river, but the contour of the basin is the same here as below. The bed of the country here is Archaean rock, and many beautiful specimens of labradorite dot the shores. In the distance the grim peaks of the Mealy Mountains stand out in bold relief against the sky.

The country about this interior basin is heavily wooded, and spars of 75 feet can be obtained in generous numbers. Were it not for the native inhabitants, mosquitoes, and flies, the interior would present conditions charming enough to tempt any lover of nature. It is the abundance of these invincible foes which make interior life a burden and almost an impossibility. To these inhabitants alone Grand Falls has ceased to chant its melodious tune. Hereafter its melodious ripple will be heard by Bowdoin College, which, in the name of its explorers, Cary and Cole, claims the honor of its discovery.—New York Times.

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ANTS.

By RUTH WARD KAHN.

Astronomy has made us all familiar with the conception of the world over our heads. We no longer speculate with Epicurus and Anaxagoras whether the sun may be as large as a quoit, or even as large as Peloponnesus. We are satisfied that the greater and the lesser lights are worlds, some of them greatly exceeding our own in magnitude.

In a little poem of Dante Rossetti's, he describes a mood of violent grief in which, sitting with his head bowed between his knees, he unconsciously eyes the wood spurge growing at his feet, till from those terrible moments he carries away the one trivial fact cut into his brain for all time, that "the wood spurge has a cup of three." In some such mood of troubled thought, flung perhaps full length on the turf, have we not as unconsciously and intently watched a little ant, trudging across our prostrate form, intent upon its glorious polity: a creature to which we, with our great spiritual world of thought and emotion and will, have no existence except as a sudden and inconvenient upheaval of parti-colored earth to be scaled, of unknown geological formation, but wholly worthless as having no bearing upon the one great end of their life—the care of larvae.

If we hold with Mr. Wallace that the chief difference between man and the lower animals is that of kind and not of degree—that man is possessed of an intelligent will that appoints its own ends, of a conscience that imposes upon him a "categorical imperative," of spiritual faculties that apprehend and worship the invisible—yet we must admit that his lower animal nature, which forms, as it, were, the platform of the spiritual, is built up of lower organisms.

If we hold with Professor Allman that thought, will, and conscience, though only manifesting themselves through the medium of cerebral protoplasm, are not its properties any more than the invisible earth elements which lie beyond the violet are the property of the medium which, by altering their refrangibility, makes them its own—then the study of the exact nature and properties of the transmitting medium is equally necessary. Indeed, the whole position can only be finally established of defining experimentally the necessary limitation of the medium, and proving the inefficiency of the lower data to account with the higher.

It is these considerations of the wider issues that give such a peculiar interest to the patient observations which have recently been brought to bear upon the habits of the social insects, especially of ants, which, living in communities, present so many of the conditions of human life, and the development of the "tribal self" from these conditions, to which Professor Clifford attributed the genesis of moral sense.

In order to pass in review these interesting observations and bring out their significance, I must go over ground which is doubtless familiar to most of my readers.

The winged ants, which often excite surprise, are simply the virgin queens and the males. They are entirely dependent upon the workers, and are reared in the same nest. September is the month usually selected as the marriage season, and in the early twilight of a warm day the air will be dark with the winged lovers. After the wedding trip the female tears off her wings—partly by pulling, but mostly by contortions of her body—for her life under ground would render wings not only unnecessary, but cumbersome; while the male is not exposed to the danger of being eaten by his cannibal spouse, as among spiders, nor to be set upon and assassinated by infuriated spinsters, as among bees, but drags out a precarious existence for a few days, and then either dies or is devoured by insectivorous insects. There is reason to believe that some females are fertilized before leaving the nest. I have observed flights of the common Formica rufa, in which the females flew away solitary and to great distances before they descended. In such cases it is certain that they were fertilized before their flight.

When a fertilized queen starts a colony it proceeds much in this way: When a shaft has been sunk deep enough to insure safety, or a sheltered position secured underneath the trunk of a tree or a stone, the queen in due time deposits her first eggs, which are carefully reared and nourished. The first brood consists wholly of workers, and numbers between twenty-five and forty in some species, but is smaller in others. The mother ant seeks food for herself and her young till the initial brood are matured, when they take up the burden of life, supply the rapidly increasing family with food, as well as the mother ant, enlarge the quarters, share in the necessary duties, and, in short, become the real workers of the nest before they are scarcely out of the shell. The mother ant is seldom allowed to peer beyond her dark quarters, and then only in company with her body guard. She is fed and cared for by the workers, and she in turn assists them in the rearing of the young, and has even been known to give her strength for the extension of the formicary grounds. Several queens often exist in one nest, and I have seen workers drag newly fertilized queens into a formicary to enlarge their resources. As needs be, the quantity of eggs laid is very great, for the loss of life in the ranks of the workers is very large; few survive the season of their hatching, although queens have been known to live eight years. (Lubbock.)

The ant life has four well marked periods: First, the egg; second, the grub or larva; third, the chrysalis or pupa; fourth, the imago, or perfect insect. The eggs are small, ovate, yellowish white objects, which hatch in about fifteen to thirty days. The larvae are small legless grubs, quite large at the apex of the abdomen and tapering toward the head. Both eggs and pupa are incessantly watched and tended, licked and fed, and carried to a place of safety in time of danger. The larvae are ingeniously sorted as regards age and size, and are never mixed. The larvae period generally extends through a month, although often much longer, and in most species when the larvae pass into pupae they spin a cocoon of white or straw color, looking much like a shining pebble. Other larvae do not spin a cocoon, but spend the pupal state naked. When they mature they are carefully assisted from their shells by the workers, which also assist in unfolding and smoothing out the legs. The whole life of the formicary centers upon the young, which proves they have reached a degree of civilization unknown even in some forms of higher life.

It is curious that, notwithstanding the labor of so many excellent observers, and though ants swarm in every field and wood, we should find so much difficulty in the history of these insects, and that so much obscurity should rest upon some of their habits. Forel and Ebrard, after repeated observations, maintain that in no single instance has an isolated female been known to bring her young to maturity. This is in direct contradiction to Lubbock's theory, who repeatedly tried introducing a new fertile queen into another nest of Lasius flavus, and always with the result that the workers became very excited and killed her, even though in one case the nest was without a queen. Of the other kinds, he isolated two pairs of Myrmica ruginodis, and, though the males died, the queens lived and brought their offspring to perfection; and nearly a year after their captivity, Sir John Lubbock watched the first young workers carrying the larvae about, thereby proving the accuracy of Huber's statement, with some species at least. In spite of this convincing testimony, Lepeletier St. Fargeau is of the opinion that the nests originate with a solitary queen, as was first given.

The ants indigenous to Leadville, besides feeding on small flies, insects, and caterpillars—the carcasses of which they may be seen dragging to their nests—show the greatest avidity for sweet liquids. They are capable of absorbing large quantities, which they disgorge into the mouths of their companions. In winter time, when the ants are nearly torpid and do not require much nourishment, two or three ants told off as foragers are sufficient to provide for the whole nest. We all know how ants keep their herds in the shape of aphides, or ant cows, which supply them with the sweet liquid they exude. I have often observed an ant gently stroking the back of an aphide with its antennae to coax it to give down its sweet fluid, much in the same way as a dairy maid would induce a cow to give down its milk by a gentle manipulation of its udders. Some species, principally the masons and miners, remove their aphides to plants in the immediate vicinity of their nest, or even introduce them into the ant home. In the interior of most nests is also found the small blind beetle (Claviger) glistening, and of a uniform red, its mouth of so singular a conformation that it is incapable of feeding itself. The ants carefully feed these poor dependent creatures, and in turn lick the sweet liquid which they secrete and exude. These little Coleoptera are only found in the nests of some species; when introduced into the nests of others they excite great bewilderment, and, after having been carefully turned over and examined, are killed in a short time as a useless commodity. Another active species of Coleoptera, of the family Staphylini, is also found in ant nests. I have discovered one in the nest of Formica rufa in the Jewish cemetery in Leadville. Furnished with wings, it does not remain in the nest, but is forced to return thither by the strange incapacity to feed itself. Like the Claviger, it repays its kind nurses by the sweet liquid it exudes, and which is retained by a tuft of hair on either side of the abdomen beneath the wings, which the creature lifts in order that the ant may get at its honeyed recompense. Such mutual services between creatures in no way allied is a most curious fact in the animal world.—Popular Science News.

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A GEM-BEARING GRANITE VEIN IN WESTERN CONNECTICUT.

By L.P. GRATACAP.

In the county of Litchfield, Conn., in the midst of some of the most attractive hill country of that region, a very striking mineral fissure has been opened by Mr. S.L. Wilson, which, in both its scientific and commercial aspects, is equally important and interesting. It is a broad crevice, widened at the point of excavation into something like a pocket and filled, between its inclosing walls of gneiss, with a granitic mass whose elements have crystallized separately, so that an almost complete mineralogical separation has been effected of quartz, mica, and feldspar, while associated aggregates, as beryl and garnet, have formed under conditions that make them valuable gem fabrics.

The vein has a strike south of west and north of east and a distinct dip northwest, by which it is brought below the gneiss rock, which forms an overhanging wall, on the northerly side of the granitic mass, while on the southerly edge the same gneiss rock makes an almost vertical foot wall, and exhibits a sharp surface of demarkation and contact. The rock has been worked as an open cut through short lateral "plunges," or tunnels have been used for purposes of exploration in the upper part of its extent. Its greatest width appears to be fifty-one feet, and the present exposure of its length three hundred. It undergoes compression at its upper end, and its complete extinction upon the surface of the country at that point seems probable. At its lower end at the foot of the slope wherein the whole mass appears, it reveals considerable development, and affords further opportunities for examination, and, possibly, profitable investment. It has been formed by a powerful thrust coincident with the crumpling of the entire region, whereby deeply seated beds have become liquefied, and the magma either forced outward through a longitudinal vent or brought to the surface by a process of progressive fusion as the heated complex rose through superincumbent strata dissipated by its entrance and contributing their substance to its contents. The present exposure of the vein has been produced by denudation, as the coarsely crystalline and dismembered condition of the granite, with its large individuals of garnet and beryl, and the dense, glassy texture of the latter, indicate a process of slow cooling and complete separation, and for this result the congealing magma must necessarily have been sealed in by strata through which its heat was disseminated slowly.

For upon the most cursory inspection of the vein, the eye is arrested at once by the large masses of crystalline orthoclase, the heavy beds of a gray, brecciated quartz and the zones and columns of large leaved mica. It was to secure the latter that Mr. Wilson first exploited this locality, and only latterly have the more precious contents of the vein imparted to it a new and more significant character. The mica, called by Mr. Atwood, the superintendent of the work, "book mica," occurs in thick crystals, ranged heterogeneously together in stringers and "chimneys," and brilliantly reflecting the sunlight from their diversely commingled laminae. This mica yields stove sheets of about two to three by four or five inches, and is of an excellent, transparent quality. It seems to be a true muscovite, and is seldom marred by magnetic markings or crystalline inclusions that would interfere with its industrial use. Seams of decomposition occur, and a yellowish scaly product, composed of hydrated mica flakes, fills them. The mica does not everywhere present this coarsely crystalline appearance, but in flexures and lines of union with the quartz and orthoclase is degraded to a mica schist upon whose surfaces appear uranates of lime and copper (autunite and torbernite), and in which are inclosed garnet crystals of considerable size and beauty. The enormous masses of clean feldspar made partially "graphic" by quartz inclosures are a conspicuous feature of the mine. In one part of the mine, wooden props support an overhanging ledge almost entirely composed of feldspar, which underneath passes into the gray brecciated quartz, which again grades into a white, more compact quartz rock. It is in this gray brecciated quartz that the beryls are found. These beautiful stones vary extremely in quality and color. Many of the large crystals are opaque, extensively fractured, and irregular in grain, but are found to inclose, especially at their centers, cores of gem-making material.

The colors of the beryls grade from an almost colorless mineral (goshenite) though faintly green, with blue reflections, yellowish green of a peculiar oily liquidity (davidsonite), to honey yellows which form the so-called "golden beryls" of the trade, and which have a considerable value. These stones have a hardness of 8, and when cut display much brilliancy. Many assume the true aquamarine tints, and others seem to be almost identical with the "Diamond of the Rhine," which as early as the end of the fifteenth century was used as a "fraudulent substitute for the true diamond" (King). Few, very few, belong to the blue grades, and the best of these cannot compare with those from Royalston, Mass. Those of amber and honey shades are beautiful objects, and under artificial light have a fascination far exceeding the olivine or chrysoberyl. These are not as frequent as the paler varieties, but when found excite the admiration of visitor and expert. It seems hardly probable that any true emeralds will be uncovered and the yellow beryls may not increase in number. Their use in the arts will be improved by combining them with other stones and by preparing the larger specimens for single stone rings.

Very effective combinations of the aquamarine and blue species with the yellow may be recommended. Tourmaline appears in some quantity, forming almost a schist at some points, but no specimens of any value have been extracted, the color being uniformly black. The garnets are large trapezohedral-faced crystals of an intense color, but penetrated with rifts and flaws. Many, no doubt, will afford serviceable gem material, but their resources have not yet been tested by the lapidary.

While granite considered as a building stone presents a complex of quartz, mica, and feldspar so confusedly intercrystallized as to make a homogeneous composite, in the present mass, like the larger and similar developments in North Carolina, these elements have excluded each other in their crystallization, and are found as three separate groups only sparingly intermingled. The proportions of the constituent minerals which form granite, according to Prof. Phillips, are twenty parts of potash feldspar (orthoclase), five parts of quartz, and two parts of potash mica (muscovite), and a survey of Mr. Wilson's quarry exhibits these approximate relations with surprising force.

There can be but little doubt that this vein is a capital example of hydrothermal fusion, whereby in original gneissic strata, at a moderate temperature and considerable depth, through the action of contained water, with the physical accompaniment of plication, a solution of the country rock has been accomplished. And the cooling and recrystallization has gone on so slowly that the elements of granite have preserved a physical isolation, while the associated silicates formed in the midst of this magma have attained a supremely close and compact texture, owing to the favorable conditions of slow growth giving them gem consistencies. The further development of the vein may reveal interesting facts, and especially the following downward of the rock mass, which we suspect will contract into a narrower vein. At present the order of crystallization and separation of the mineralogical units seems to have been feldspar, mica, garnet, beryl, quartz.

In the artificial preparation of crystals it is invariably found that perfect and symmetrical crystals, and crystals of large size, are produced by slow, undisturbed cooling of solutions; the quiet accretion permits complete molecular freedom and the crystal is built up with precision. Nor is this all. In mixtures of chemical compounds it is presumable that the separate factors will disengage themselves from each other more and more completely, and form in purer masses as the congelation is slowly carried on. A sort of concretionary affinity comes into play, and the different chemical units congregate together. At least such has been the case in the granitic magma of which Mr. Wilson now possesses the solidified results. The feldspar, the quartz, the mica, have approximately excluded each other, and appear side by side in unmixed purity. And does it not seem probable that this deliberate process of solidification has produced in the beryls, found in the center of the vein at the points of slowest radiation, the glassy gem texture which now makes them available for the purposes of art and decoration?

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THE STUDY OF MANKIND.

Professor Max Muller, who presided over the Anthropological Section of the British Association, said that if one tried to recall what anthropology was in 1847, and then considered what it was now, its progress seemed most marvelous. These last fifty years had been an age of discovery in Africa, Central Asia, America, Polynesia, and Australia, such as could hardly be matched in any previous century. But what seemed to him even more important than the mere increase of material was the new spirit in which anthropology had been studied during the last generation. He did not depreciate the labors of so-called dilettanti, who were after all lovers of knowledge, and in a study such as that of anthropology, the labors of these volunteers, or franc-tireurs, had often proved most valuable. But the study of man in every part of the world had ceased to be a subject for curiosity only. It had been raised to the dignity and also the responsibility of a real science, and was now guided by principles as strict and rigorous as any other science. Many theories which were very popular fifty years ago were now completely exploded; nay, some of the very principles by which the science was then guided had been discarded. Among all serious students, whether physiologists or philologists, it was by this time recognized that the divorce between ethnology and philology, granted if only for incompatibility of temper, had been productive of nothing but good.

CLASSIFICATION.

Instead of attempting to classify mankind as a whole, students were now engaged in classifying skulls, hair, teeth, and skin. Many solid results had been secured by these special researches; but as yet, no two classifications, based on these characteristics, had been made to run parallel. The most natural classification was, no doubt, that according to the color of the skin. This gave us a black, a brown, a yellow, a red, and a white race, with several subdivisions. This classification had often been despised as unscientific; but might still turn out far more valuable than at present supposed. The next classification was that by the color of the eyes, as black, brown, hazel, gray, and blue. This subject had also attracted much attention of late, and, within certain limits, the results have proved very valuable. The most favorite classification, however, had always been that according to the skulls. The skull, as the shell of the brain, had by many students been supposed to betray something of the spiritual essence of man; and who could doubt that the general features of the skull, if taken in large averages, did correspond to the general features of human character? We had only to look around to see men with heads like a cannon ball and others with heads like a hawk. This distinction had formed the foundation for a more scientific classification into brachycephalic, dolichocephalic, and mesocephalic skulls. If we examined any large collection of skulls we had not much difficulty in arranging them under these three classes; but if, after we had done this, we looked at the nationality of each skull, we found the most hopeless confusion. Pruner Vey, as Peschel told us in his "Volkerkunde," had observed brachycephalic and dolichocephalic skulls in children born of the same mother; and if we consider how many women had been carried away into captivity by Mongolians in their inroads into China, India, and Germany, we could not feel surprised if we found some long heads among the round heads of those Central Asiatic hordes.

DIFFERENCES IN SKULLS.

Only we must not adopt the easy expedient of certain anthropologists who, when they found dolichocephalic and brachycephalic skulls in the same tomb, at once jump to the conclusion that they must have belonged to two different races. When, for instance, two dolichocephalic and three brachycephalic skulls were discovered in the same tomb at Alexanderpol, we were told at once that this proved nothing as to the simultaneous occurrence of different skulls in the same family; nay, that it proved the very contrary of what it might seem to prove. It was clear, we were assured, that the two dolichocephalic skulls belonged to Aryan chiefs and the three brachycephalic skulls to their non-Aryan slaves, who were killed and buried with their masters, according to a custom well known to Herodotus. This sounded very learned, but was it really quite straightforward? Besides the general division of skulls into dolichocephalic, brachycephalic, and mesocephalic, other divisions had been undertaken, according to the height of the skull, and again according to the maxillary and the facial angles. This latter division gave us orthognatic, prognathic, and mesognathic skulls. Lastly, according to the peculiar character of the hair, we might distinguish two great divisions, the people with woolly hair (Ulotriches) and people with smooth hair (Lissotriches). The former were subdivided into Lophocomi, people with tufts of hair, and Eriocomi, or people with fleecy hair. The latter were divided into Euthycomi, straight haired, and Euplocomi, wavy haired. It had been shown that these peculiarities of the hair depended on the peculiar form of the hair tubes, which in cross sections were found to be either round or elongated in different ways. All these classifications, to which several more might be added, those according to the orbits of the eyes, the outlines of the nose, and the width of the pelvis, were by themselves extremely useful. But few of them only, if any, ran strictly parallel. Now let them consider whether there could be any organic connection between the shape of the skull, the facial angle, the conformation of the hair, or the color of the skin on one side, and what we called the great families of language on the other.

CONNECTION OF LANGUAGE AND PHYSICAL CONFORMATION.

That we spoke at all might rightly be called a work of nature, opera naturale, as Dante said long ago; but that we spoke thus or thus, cosi o cosi, that, as the same Dante said, depended on our pleasure—that was our work. To imagine, therefore, that as a matter of necessity, or as a matter of fact, dolichocephalic skulls had anything to do with Aryan, mesophalic with Semitic, or brachycephalic with Turanian speech, was nothing but the wildest random thought. It could convey no rational meaning whatever; we might as well say that all painters were dolichocephalic, and all musicians brachycephalic, or that all lophocomic tribes worked in gold, and all lisocomic tribes in silver. If anything must be ascribed to prehistoric times, surely the differentiation of the human skull, the human hair and the human skin would have to be ascribed to that distant period. No one, he believed, had ever maintained that a mesocephalic skull was split or differentiated into a dolichocephalic and a brachycephalic variety in the bright sunshine of history. Nevertheless, he had felt for years that knowledge of languages must be considered in future as a sine qua non for every anthropologist. How few of the books in which we trusted with regard to the characteristic peculiarities of savage races had been written by men who had lived among them for ten or twenty years, and who had learned their languages till they could speak them as well as the natives themselves. It was no excuse to say that any traveler who had eyes to see and ears to hear could form a correct estimate of the doings and sayings of savage tribes.

TRAVELERS' IMPRESSIONS.

It was not so, as anthropologists knew from sad experience. Suppose a traveler came to a camp where he saw thousands of men and women dancing round the image of a young bull. Suppose that the dancers were all stark naked, that after a time they began to fight, and that at the end of their orgies there were three thousand corpses lying about weltering in their blood. Would not a casual traveler have described such savages as worse than the negroes of Dahomey? Yet these savages were really the Jews, the chosen people of God. The image was the golden calf, the priest was Aaron, and the chief who ordered the massacre was Moses. We might read the 32d chapter of Exodus in a very different sense. A traveler who could have conversed with Aaron and Moses might have understood the causes of the revolt and the necessity of the massacre. But without this power of interrogation and mutual explanation, no travelers, however graphic and amusing their stories might be, could be trusted; no statements of theirs could be used by the anthropologist for truly scientific purposes. If anthropology was to maintain its high position as a real science, its alliance with linguistic studies could not be too close. Its weakest points had always been those where it trusted to the statements of authorities ignorant of language and of the science of language. Its greatest triumphs had been achieved by men such as Dr. Hahn, Bishops Callaway and Colenso, Dr. W. Gill and last, not least, Mr. Man, who had combined the minute accuracy of the scholar with the comprehensive grasp of the anthropologist, and were thus enabled to use the key of language to unlock the perplexities of savage customs, savage laws and legends, and, particularly, of savage religions and mythologies. If this alliance between anthropology and philology became real, then, and then only, might we hope to see Bunsen's prophecy fulfilled, that anthropology would become the highest branch of that science for which the British Association was instituted.

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