Scientific American Supplement, No. 620, November 19,1887
Author: Various
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[Footnote 1: Abstract from the presidential address delivered before the Association of Municipal and Sanitary Engineers and Surveyors, at the annual meeting in Leicester, July 18, 1887.]

By Mr. J. GORDON, C.E.

The average mortality for England and Wales was 22.4 in 1838, and in 1886 19.3, which shows a saving on last year's population of England and Wales of 86,400 lives annually, and a saving in suffering from an estimated number of about 1,728,000 cases of sickness. To accomplish all this, vast sums of money have been expended, probably not always wisely, inasmuch as there have been mistakes made in this direction, as in all new developments of science when applied in practice, and evils have arisen which, if foreseen at all at the outset, were underrated.

The great object of the public health act, 1848, was to enable local authorities by its adoption to properly sewer, drain, and cleanse their towns, and to provide efficient supplies of water, free from contamination and impurities dangerous to health. The raising of money by loans repayable in a series of years, which the act empowered, enabled all these objects to be accomplished, and, while the first duty of local authorities was undoubtedly the provision of a good supply of water and proper sewerage for the removal of liquid filth from the immediate vicinity of inhabited dwellings, the carrying out of proper works for the latter object has been of much slower growth than the former. Private companies led the way, in fact, in providing supplies of water, inasmuch as there was a prospect of the works becoming remunerative to shareholders investing their money in them; and in nearly every instance where local authorities have eventually found it to be in the interests of the inhabitants of their districts to purchase the work, they have had to pay high prices for the undertaking. This has generally led to a great deal of dissatisfaction with companies holding such works, but it must not be forgotten that the companies would, in most instances, never have had any existence if the local authorities had taken the initiative, and that but for the companies this great boon of a pure supply of water would most probably have been long delayed to many large as well as small communities.

The evils which have arisen from the sewering and draining of towns have been of a twofold character. First, in the increased pollution of rivers and streams into which the sewage, in the earlier stages of these works, was poured without any previous treatment; and secondly, in the production of sewer gas, which up to the present moment seems so difficult to deal with. These concomitant evils and difficulties attending the execution of sanitary works are in no way to be underrated, but it still remains the first duty of town authorities to remove, as quickly as possible, all liquid and other refuse from the midst and immediate vicinity of large populations, before putrefaction has had time to take place.

There are some minds whose course of reasoning seems to lead them to the conclusion that the evils attending the introduction of modern systems of sewerage are greater than those of the old methods of dealing with town sewage and refuse, but the facts are against them to such an extent that it would be difficult to point to a responsible medical officer in the kingdom who would be courageous enough to advocate a return to the old regime of cesspools, privy ashpits, open ditches, and flat bottomed culverts. The introduction of earth closets as one of the safeguards against sewer gas has made no headway for large populations, and is beset with practical difficulties.

In the Midland and Lancashire towns the system known as the pail or tub system has been much more largely introduced as a substitute for the water closet, and it has, from a landlord's point of view, many attractions. In the first place, the first cost, as compared with that of a water closet, is very small, and the landlord is relieved for ever afterward I believe, in most towns, of all future costs and maintenance; whereas, in the case of water closets, there is undoubtedly great difficulty in cottage property in keeping them in good working order, especially during the frosts of winter. There are, however, many objections to the pail system, which it is not proposed to touch upon in this address, beyond this, that it appears to be a costly appendage to the water carriage system, without the expected corresponding advantage of relieving the municipal authorities of any of the difficulties of river pollution, inasmuch as the remaining liquid refuse of the town has still to be dealt with by the modern systems of precipitation or irrigation, at practically the same cost as would have been the case if the water carriage system had been adopted in its entirety.

The rivers pollution act gave an impetus to works for the treatment of sewage, although much had been done prior to that, and Leicester was one of those towns which led the way so early as 1854 in precipitating the solids of the sewage before allowing it to enter the river. The innumerable methods which have since then been tried, and after large expenditures of money have proved to be failures, show the difficulties of the question.

On the whole, however, sewage farms, or a combination of the chemical system with irrigation or intermittent filtration, have been the most successful, so that the first evil to which the cleansing of towns by the increased pollution of rivers gave rise may now be said to be capable of satisfactory solution, notwithstanding that the old battle of the systems of precipitation versus application of sewage to land still wages whenever opportunity occurs.

The second evil to which I have made reference, viz., that of sewer ventilation, seems still unsolved, and I would earnestly entreat members, all of whom have more or less opportunities of experimenting and making observations of the behavior of sewer gas under certain conditions, to direct their attention to this subject. It is admitted on all hands that the sewers must be ventilated—that is, that there must be a means of escape for the polluted air of the sewers; for it is well known that the conditions prevailing within the sewers during the twenty-four hours of the day are very varying, and on this subject the early observations of the late medical officer for the City of London (Dr. Letheby), and the present engineer for the City of London (Lieutenant-Colonel Heywood), and the still more recent investigations of Professor Pettenkofer, of Munich, Professor Soyka, of Prague, and our own members, Mr. McKie, of Carlisle, Mr. Read, of Gloucester, and others, are worthy of attention. It does not, however, seem to be so readily or universally conceded that a plentiful supply of fresh air is of equal importance, and that the great aim and object of sewer ventilation should be the introduction of atmospheric air for the purpose of diluting and oxidizing the air of the sewers, and the creation of a current to some exit, which shall, if possible, either be above the roofs of the houses, or, still better, to some point where the sewer gas can be cremated. The most recent contribution to this subject, in direct opposition to these views, is to be found in the address of Professor Attfield to the Hertfordshire Natural History Society and Field Club, in which it is laid down that all that is necessary is a vent at an elevation above the ground, and that, therefore, the surface ventilators, or other openings for the introduction of fresh air, are not only not necessary, but are, on the contrary, injurious, even when acting as downcast shafts.

These aims and objects are beset with difficulties, and the most scientific minds of the country have failed so far to devise a method of ventilation which shall at the same time be within the range of practical application as regards cost and universally satisfactory.

The report of last year of a committee of the metropolitan board of works is worth attention, as showing the opinion of metropolitan surveyors. Out of forty districts, the opinions of whose surveyors were taken, thirty-five were in favor of open ventilation, two were doubtful, two against, and one had no experience in this matter. The average distances of the ventilators were from 30 to 200 yards, and the committee came to the conclusion that "pipe ventilators of large section can be used with great advantage in addition to, and not in substitution for, surface ventilators." To supplement the street openings as much as possible with vertical cast iron or other shafts up the house sides would seem to be the first thing to do, for there can be no doubt that the more this is done, the more perfect will be the ventilation of the sewers. It must also not be forgotten that the anxiety, of late years, of English sanitarians to protect each house from the possible dangers of sewer gas from the street sewer has led to a system of so-called disconnection of the house drains by a water seal or siphon trap, and that, consequently, the soil pipes of the houses, which, when carried through the roofs, acted as ventilators to the public sewers, have been lost for this purpose, and thus the difficulty of sewer ventilation has been greatly increased.

In Leicester we have been fortunate enough to secure the co-operation of factory owners, who have allowed us to connect no fewer than fifty-two chimneys; while we have already carried out, at a cost of about L1,250, 146 special shafts up the house sides, with a locked opening upon a large number of them, by means of which we can test the velocity of the current as well as the temperature of the outflowing air. The connections with the high factory chimneys are all of too small a caliber to be of great use, being generally only six inches, with a few exceptionally of nine inches in diameter.

The radius of effect of specially erected chimneys, as shown by the experiments of Sir Joseph Bazalgette, and as experienced with the special ventilating towers erected at Frankfurt, is disappointing and discouraging when the cost is taken into consideration. It can not be expected, however, that manufacturers will admit larger connections to be made with their chimney; otherwise, of course, much more satisfactory results would be obtained. To fall back upon special shafts up the house sides means, in my opinion, that there should be probably as many in number as are represented by the soil pipes of the houses, for in this we have a tested example at Frankfurt, which, so far as I know, has up to the present moment proved eminently satisfactory.

The distance apart of such shafts would largely depend on the size of them, but as a rule it will be found that house owners object to large pipes, in which case the number must be increased, and if we take a distance of about 30 yards, we should require about 5,000 such shafts in Leicester. Whether some artificial means of inducing currents in sewers by drawing down fresh air from shafts above the eaves of the houses, and sending forth the diluted sewer gas to still higher levels, or burning it in an outcast shaft, will take the place of natural ventilation, and prove to be less costly and more certain in its action, remains to be seen. But it is quite certain that notwithstanding the patents which have already been taken out and failed, and those now before the public, there is still a wide field of research before this question is satisfactorily solved, so that no cause whatever shall remain of complaint on the part of the most fastidious.

One other important question common to all towns is that of the collection and disposal of the ashes and refuse of the households. It is one which is becoming daily more difficult to deal with, especially in those large communities where the old privy and ashpit system has not been entirely abolished. The removal of such ashes is at all times a source of nuisance, and if they cannot be disposed of to the agriculturists of the district, they become a source of difficulty. In purely water-closeted towns the so-called dry ashpits cannot be kept in such a condition as to be entirely free from nuisance, especially in the summer months, inasmuch as the refuse of vegetable and animal matter finds its way into them, and they are, in close and inhabited districts, necessarily too close to the living apartments of the dwellings. The tendency therefore now is rather to discourage the establishment of ashpits by the substitution of ashbins, to be collected daily or weekly as the case may be, and I think there can be no doubt that from a sanitary point of view this is by far the best system, harmonizing as it does with the general principle applicable to town sanitation of removing all refuse, likely by decomposition to become dangerous to health, as quickly as possible from the precincts of human habitations.

The difficulty of disposing of the ashes, mixed as they must necessarily be with animal and vegetable matter, is one that is forcing itself upon the attention of all town authorities, and the days of the rich dust contractors of the metropolis are practically numbered. Destruction by fire seems to be the ultimate end to be aimed at, and in this respect several towns have led the way. But as this is a subject which will be fully dealt with by a paper to be read during the meeting, I will not anticipate the information which will be brought before you, further than to say that the great end to be aimed at in this method of disposing of the ashes and refuse of towns is greater economy in cost of construction of destructors, as well as in cost of working them.

The progress in sanitation on the Continent, America, and the colonies has not been coincident with the progress in England, but these countries have largely benefited by the experience of the United Kingdom, and in some respects their specialists take more extreme views than those of this country in matters of detail. This is, perhaps, more particularly the case with the Americans, who have devised all sorts of exceptional details in connection with private drainage, in order to protect the interior of the houses from sewer gas, and to perfect its ventilation. In plumbing matters they seem also to be very advanced, and to have established examinations for plumbers and far-reaching regulations for house drainage.

Time will not permit me to examine into the works of a sanitary character which have been undertaken in the several countries after the example of England, but they have been attended with similar beneficial results and saving in life and sickness as in this country, although the Continental towns which have led the way with such works cannot as yet point to the low rates of mortality for large towns which have been attained in England, with the exception of the German towns of Carlsruhe, Frankfurt, Wiesbaden, and Stuttgart, which show death rates of 20.55, 20.64, 22, and 21.4 respectively. The greatest reduction of the mortality by the execution of proper sewerage and water works took place in Danzig, on the Baltic, and Linz, on the Danube, where after the execution of the works the mortality was reduced by 7.85 and 10.17 per 1,000 respectively, and in the case of Danzig this reduction is almost exclusively in zymotic diseases. Berlin is also a remarkable example of the enterprise of German sanitarians, for there they are demonstrating to the world the practicability of dealing with the sewage from a population of over 11/4 million upon 16,000 acres of land, of which about 10,000 acres are already under irrigation.

In taking this chair, it has been usual, when meetings have been held out of London, for your president to give some account of the works of his own town. In the present instance I feel that I can dispense with this course, in so far as that I need not do more than generally indicate what has been the course of events since I read to a largely attended district meeting in May, 1884, a paper on "The Public Works of Leicester." At that time large flood prevention works were in course of construction, under an act obtained in 1881, for continuing the river improvement works executed under previous acts. The works then under contract extended from the North Mill Lock and the North Bridge on the north to the West Bridge and Bramstone Gate Bridge on the south, along the river and canal, and included bridges, weirs, retaining walls, and some heavy underpinning works in connection with the widening and deepening of the river and canal. These works were duly completed, as well as a further length of works on the River Soar up to what is known as the old grass weir, including the Braunstone Gate Bridge, added to one of the then running contracts, at a total cost, excluding land and compensation, of L77,000. At this point a halt was made in consequence of the incompleteness of the negotiations with the land owners on the upper reach of the river, and this, together with various other circumstances, has contributed to greater delay in again resuming the works. In the interval, a question of whether there should be only one channel for both river and canal instead of two, as authorized by the act, has necessarily added considerably to the delay. But as that has now been settled in favor of the original parliamentary scheme, the authority of the council has been given to proceed with the whole of the works.

One contract, now in progress, which members will have an opportunity of inspecting, was let to Mr. Evans, of Birmingham, in March last, for about L18,000. It consists of a stone and concrete weir, 500 feet in length, with a lock of 7 feet 6 inches lift and large flood basins, retaining and towing path walls, including a sunk weir parallel with the Midland Railway viaduct. This contract is to be completed by March next. The remainder of the works about to be entered upon include a new canal and flood channel about 1,447 yards long, and the deepening and widening of the River Soar for a length of about 920 yards, with two or three bridges.

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Every chemist knows that cotton is chiefly composed of cellulose, C_{6}H_{10}O_{5}, with some other substances in smaller quantities. This, although the usual opinion, is only true in a partial sense, as the author found on investigating samples of cotton from various sources. Thus, while mere cellulose contains carbon 44.44 per cent. and hydrogen 6.173, he found in Surat cotton 7.6 per cent. of hydrogen, in American cotton 6.3 per cent., and in Egyptian cotton 7.2 per cent. The fact is that along with cellulose in ordinary cotton there are a number of celluloid bodies derived from the inspissated juices of the cotton plant.

In order to gain information on this subject, the author has grown cotton under glass, and analyzed it at various stages of its life history. In the early stage of unripeness he has found an astringent substance in the fiber. This substance disappears as the plant ripens, and seems to closely resemble some forms of tannin. Doubtless the presence of this body in cotton put upon the market in an unripe condition may account for certain dark stains sometimes appearing in the finished calicoes. The tannin matter forms dark stains with any compound or salt of iron, and is a great bugbear to the manufacturer. Some years ago there was quite a panic because of the prevalence of these stains, and people in Yorkshire began to think the spinners were using some new or inferior kind of oil. Dr. Bowman made inquiries, and found that in Egypt during that year the season had been very foggy and unfavorable to the ripening of the cotton, and it seemed probable that these tannin-like matters were present in the fiber, and led to the disastrous results.

Although the hydrogen and oxygen present in pure cellulose are in the same relative proportions as in water, they do not exist as water in the compound. There is, however, in cotton a certain amount of water present in a state of loose combination with the cellulose, and the celluloid bodies previously referred to appear to contain water similarly combined, but in greater proportion. Oxycellulose is another body present in the cotton fiber. It is a triple cellulose, in which four atoms of hydrogen are replaced by one atom of oxygen, and like cellulose forms nitro compounds analogous to nitro glycerine. It is probable that the presence of this oxycellulose has a marked influence upon the behavior of cotton, especially with dye matters. The earthy substances in cotton are also of importance. These are potassium carbonate, chloride, and sulphate, with similar sodium salts, and these vary in different samples of cotton, and possibly influence its properties to some extent. Then there are oily matters in the young fiber which, upon its ripening, become the waxy matter which Dr. Schunk has investigated. Resin also is present, and having a high melting point is not removed by the manipulative processes that cotton is subjected to. When this is in excessive amount, it comes to the surface of the goods after dyeing.

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MM. Vabet and Vienne, in a recent number of _Comptes Rendus_, state that by passing a current of acetylene through 200 grammes of benzene containing 50 grammes of aluminum chloride for 30 hours the oily liquid remaining after removal of the unaltered aluminum chloride by washing was found to yield, on fractional distillation, three distinct products. The first, which came over between 143 deg. and 145 deg., and which amounted to 80 per cent. of the whole, consisted of pure cinnamene or styrolene (C_{6}H_{5}.CH.CH_{2}), which is one of the principal constituents of liquid storax, and was synthetized by M. Berthelot by passing acetylene and benzene vapor through a tube heated to redness. The second fraction, coming over at 265 deg.-270 deg., consisted of diphenyl ethane ((C_{6}H_{5})_{2} CH.CH_{3}); and the third fraction, boiling at 280 deg.-286 deg., was found to consist entirely of dibenzyl (C_{6}H_{5}.CH_{2}.CH_{2}.C_{6}H_{5}), a solid substance isomeric with diphenyl ethane. These syntheses afford another instance of the singular action of aluminum chloride in attacking the benzene nucleus.

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Now that a supply of this reputed substitute for sugar has been placed upon the London market, it will doubtless have attracted the attention of many pharmacists, and as information having reference to its characters and properties is as yet somewhat scarce, the following notes may be of interest.

The sample to which these notes refer represents, I believe, a portion of the first supply that has been offered to us as a commercial article, and may therefore be taken to represent the same as it at present occurs in commerce. I think it desirable to call attention to this fact, because of the wide difference I have seen in other samples obtained, I think, by special request some weeks ago, and which do not favorably correspond with the sample under consideration, being much more highly colored, and in comparison having a very strong odor. Saccharin now occurs as a very pale yellow, nearly white, amorphous powder, free from grittiness, but giving a distinct sensation of roughness when rubbed between the fingers. It is not entirely free from odor, but this is very slight, and not at all objectionable, reminding one of a very slight flavor of essential oils of almonds. Its taste is intensely sweet and persistent, which in the raw state is followed by a slight harshness upon the tongue and palate. The sweetness is very distinct when diluted to 1 in 10,000. Under the microscope it presents no definite form of crystallization.

A temperature of 100 deg. C, even if continued for some time, has no perceptible effect upon saccharin; it loses no weight, and undergoes no physical change. It fuses at a temperature of from 118 deg. to 120 deg. C., and at 150 deg. C. forms a clear light yellow liquid, which boils a few degrees higher. At the latter temperature dense white fumes appear, and a condensation of tufts of acicular crystals (some well defined) is found upon the cool surface of the apparatus. These crystals, except for a slight sweetness of taste, correspond in characters and tests to benzoic acid. The sweet flavor, I think, may be due to the presence of a very small quantity of undecomposed saccharin, carried mechanically with the fumes. The escaping vapors, which are very irritable, and give a more decided odor of hydride of benzole than the powder itself, also communicate a very distinct sensation of sweetness to the back part of the palate. Heated over the flame, with free access of air, saccharin carbonizes and burns with a dull yellow smoky flame, leaving a residue amounting to 0.65 per cent. of sodium salts. It does not reduce an alkaline copper solution, but, like glycerine, liberates boracic acid from borax, the latter salt dissolving saccharin readily in aqueous solution, due no doubt to a displacement of the boracic acid.

The strong acids, either hot or cold, show no characteristic color reaction; the compound enters solution at the boiling point of the acid, and in the case of hydrochloric shows a white granular separation on cooling. Sulphuric acid develops an uncharacteristic light brown color.

The compound, like most of the organic acids, shows a characteristic reaction with ferro and ferrid cyanide of potassium. In the former case no change is perceptible until boiled when a greenish white turbidity appears, with the liberation of small quantities of hydrocyanic acid. In the latter case a trace also of this acid is set free, with the formation of a very distinct green solution, the latter reaction being very perceptible with a few drops of a 1 in 1,000 solution of saccharin in water. Heated with lime, very distinct odors of benzoic aldehyde are developed.

Saccharin possesses very decided acid properties, and combines readily with alkalies or alkaline carbonates, forming anhydro-ortho sulphamine-benzoates of the same, in the latter case at the expense of the carbonic anhydride, causing strong effervescence. These combinations are very soluble in water, the alkaline carbonate thus forming a ready medium for the solution of this acid, which alone is so sparingly soluble. Another advantage of some importance is that, while the harshness of flavor perceptible in a simple solution of the acid is destroyed, the great sweetness appears to be distinctly intensified and refined.

The following shows the solubility of saccharin in the various liquids quoted, all, with the exception of the boiling water, being taken at 60 deg. F.:

Boiling water 0.60 parts per 100 by volume. Cold water 0.20 " " " Alcohol 0.800 4.25 " " " Rectified spirit 0.838 3.20 " " " Ether 0.717 1.00 " " " Chloroform 1.49 0.20 " " " Benzene 0.40 " " " Petroleum ether insoluble.

It is also sparingly soluble in glycerin and fixed oils, and to a greater or less extent in volatile oils. Benzoic aldehyde dissolves saccharin in large quantities.

I was somewhat disappointed at the slight solubility of saccharin in ether, as it has been repeatedly stated to be very soluble in that liquid.

The quantity of saccharin required to communicate an agreeable degree of sweetness, like sugar, differs with the material to be sweetened; but from half to one and half grains, according to taste, will be found sufficient for an ordinary breakfast cup full of tea or coffee infusion.—Pharm. Jour.

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In a paper entitled "The Oxidation of Ethyl Alcohol in the Presence of Turpentine," communicated to the Chemical Society by Mr. C.E. Steedman, Williamstown, Victoria, the author states that dilute ethyl alcohol in the presence of air and turpentine becomes oxidized to acetic acid. He placed in a clear glass 16 oz. bottle a mixture of 2 drachms of alcohol, 1 drachm of turpentine, and 1 oz. of water. The bottle was securely corked and left exposed to a varying temperature averaging about 80 deg. F. for three months. At the end of that time the liquid was strongly acid from the presence of acetic acid. One curious fact appears to have light thrown upon it by this observation.

Mr. McAlpine, Professor of Biology at Ormond College, Melbourne University, has a method of preserving biological specimens by abstracting their moisture with alcohol after hardening in chromic acid, and then placing the specimen in turpentine for some time; great discrepancies arise, however, according as the alcohol is allowed or not to evaporate from the specimen before dipping it into turpentine.

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