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In the morning the water was drawn off from the tubes by a pipette having a long fine point, and each transferred to a small test-glass. A drop of each solution was then taken out by a clean glass stirring rod and spread across pieces of blue litmus paper in a series of lines side by side with each other, the intensity of redness thus produced by the acids dissolved by the water compared, and the results noted.

Fifth.-Five grains of a moderately strong solution of ferrocyanide of potassium were then added to each water solution above mentioned, the mixture stirred, and left for four hours, when the amounts of the precipitates of ferrocyanide of copper were observed comparatively and the results noted. The results of these observations I have arranged in tabular form.

(To be continued.)


By MAJOR ROSS, late R.A. (Continued from vol. xxxiii.. p. 3.)

(11.) THE fact may have been noticed, with regard to the Scientific Loan Exhibition at South Kensington, that three-fourths of the apparatus, &c., there displayed are foreign, and that a great part of the remaining fourth, although the property of English" Manufacturers," has in reality been produced in Paris, Berlin, or some other French or German town, while Sir W. Thomson, Sir. J. Hawkshaw, and others less celebrated, who have lately arrived from America, are unanimous in the opinion that, unless we are careful, the Americans will shortly pass us in those manufactures of which we have hitherto been most proud. In short, look on the matter as we may, deny the fact as we will, it seems doubtful if nationally England occupies more than the third place in scientific Europe.

(12.) The reason of this appears that, like everything else, scientific knowledge is made a mere matter of barter in England. Only rich men can here afford to do anything original in the way of physical or chemical experimentation.

(13.) Here then, briefly, is what the blowpipe will do for a student who takes it up with due appreciation :(a) The necessary apparatus is, or ought to be, cheapest of the cheap, even the balance required for quantitative analysis being the smallest and cheapest kind made. (b) Accurate observations can be made so rapidly that even the public teacher in chemistry and physics can thus most beneficially employ his little leisure. (c) The field of observation is almost entirely unoccupied, so that the disciple, unencumbered by the terrific terminology of chemistry, may after a short time bring contributions to physical science really worthy of her acceptance; while geology and mineralogy will after a time acquire a new zest from such examinations. (d) If our manufacturers were only equal to the Germans or French, a traveller's apparatus might be made for a few shillings, in a leather case, which would roll up and go into the breast pocket of a coat, enabling the investigator to start at a moment's notice for the country or abroad. I shall try to induce Messrs. Griffin to make up such a case of blowpipe necessaries, and to sell it as cheaply as possible.

(14.) All sciences are so linked together that a correlation can be shown to exist even between two of the most apparently widely separated. Few, for instance, would suspect that the political economist could derive any benefit from the study of blowpipe analysis, and yet the case of the tumble-down barracks and public buildings all over Northern Indian, publicly stated, without denial, to have cost the Government £40,000,000, between the years 1861-75, is one in point; but the account of this must be reserved for the next paper.


By DR. FREDERICK versmann.


IN a paper "On Anthracen and Alizarin,” read before the Society of Arts in March, 1874, I ventured to express my opinion that the quinon test was not trustworthy, because it did not represent true anthracen convertible into alizarin, and also because the stipulated correction, equal to 1 per cent, made the whole process illusory.

At that time I stood alone in my opinion, but it is now perfectly well known among manufacturers and buyers of anthracen that the quinon test does not always indicate the exact and true value of the merchandise; and even Messrs. Meister, Lucius, and Brüning, who first proposed the test, now acknowledge its inaccuracy by issuing in last week's CHEMICAL NEWS (vol. xxxiv., p. 167) a new and improved method.

This new test differs from the previous one merely by an increase of the oxidising agent-chromic acid and its solvent acetic acid and water-and by the treatment of the quinon with fuming sulphuric acid instead of with potassium permanganate, and subsequent volatilisation of the remaining quinon.

The publication of this "new and improved method" induces me to collect the results of prolonged investigations on the subject, which, although not yet brought to a final conclusion, may tend to throw some light on the nature of the products obtained, and I am the more inclined now to publish my experience, because more than six months ago I tried tbe sulphuric acid myself, but found it neither satisfactory nor practical. In fact it was exactly the failure with sulphuric acid which induced me to follow up the subject in a different direction, and, as I believe, with more satisfactory results.

After boiling a sample of anthracen with chromic acid solution, and allowing the mixture to stand for hours, long, well-defined crystals separate, and on adding/water a further separation takes place, not in the form of crystals, but of an amorphous powder. The product collected on the filter is always a mixture of crystals and powder, part of the last of which is again removed by potassium permanganate and potassium hydrate.

This observation induced me to collect the crystals and powder separately, and to ascertain their nature by practical tests applicable for commercial analyses. As such I adopted, above all, the melting- and solidifying-points, and then the action of potassium permanganate and potassium hydrate.

The determination of the melting and solidifying. point I look upon as most important and valuable, and I can only express my surprise that it has not been introduced long ago, especially as it formed so important a part in the alcohol and bisulphide test.

I have collected in the following table some results from a great many, which fairly represent commercial anthracen from the lowest to the highest percentage. The first column gives the percentage of quinon actually obtained, i.e., without correction; the second and third columns give the crystals and powder separately; and the last column the number of drops of 5 per cent potassium permanganate solution required to leave a distinct colouration after prolonged boiling of each of the three products.

As to the operation itself, the first result was obtained by the usual test with appendix. In the separation of crystals and powder the solution was allowed to stand over night; the crystals were then collected on a small filter, and the solution allowed to run off to the last drop, before the crystals were washed with water, until the filter and filtrate were perfectly colourless. The filtrate was then diluted to 600 c.c., and after two hours' standing the powdery precipitate was also collected on a filter; both crystals and powder were then treated with potassium permanganate and potassium hydrate.

I have long adopted an increased addition of water, but for a different reason than the one now stated by Messrs.


Anthraquinon Test.

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Anthracen Testing.

Drops of 5 p.c.


Oct. 27, 1876.

Meister, Lucius, and Brüning. I have always doubted the accuracy of adding I per cent of quinon, supposed to be retained in solution, and I have satisfied myself on that point by actual experiment. I have frequently evaporated the green solution to perfect dryness, and exhausted the dry powder with benzol and alcohol, but I have never succeeded in separating real quinon. The larger quantity of water merely separates the powder more completely, 48 not at 300 15 3 20 which no doubt accounts for the increased quantity of potassium permanganate used with the powder.

9. 17.8 266-268 9.8 273-275 77 not at 300 27 4 27



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The conclusions drawn from this table, I may state as follows, viz. :—

1. The total of crystals and powder in all cases very nearly agrees with that of the mixture; no loss is incurred by the separation.

2. The melting- and solidifying-point of the mixture,
i.e., of the usual test, is mostly suspicious, in many
cases a direct indication of undoubted impurity of
the quinon.

3. The melting- and solidifying-points of the crystals
alone are much more uniform; the product is pure
4. The powder in almost all cases is no quinon at all;
in eleven cases out of thirty it does not melt at
300° C., but blackens and remains solid; in eleven
other cases the mean of the two points is below
270° C., and in several of the other cases the
melting- and solidifying-points were only partial or
indistinct at the points indicated.

5. The effect of potassium permanganate is uniformly
very trifling upon the crystals, very considerable
upon the powder, and exactly the same is the case
with potassium hydrate; while the mixture often
imparts distinct colouration to the solution and
becomes itself lighter in colour-from orange to
pale straw-yellow-the crystals alone scarcely show
any change, but the powder invariably gives a
strong colour to the solution.
6. While the crystals may safely be taken as pure quinon,
the question arises whether the powder always
consists of nothing but impurities, or whether it
still retains some quinon, as in a few cases the
melting-point tends to indicate.

Although I have not completed my experiments in that direction, I shall shortly be able to definitely settle this point by practical tests.

But I think it advisable not to delay the publication of my results hitherto obtained, as I am satisfied of the correctness of separating crystals and powder and of its undoubted advantage over the other known test.

I have meanwhile brought my test into practical working by taking the crystals as pure quinon, and by considering the powder as valueless impurity in all cases where the melting- and solidifying-point is below 270° or above 280°, and by adding the powder to the crystals as quinon whenever these two points range between 12 5 16 270° and 280'.

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Boil 1 grm. of the sample for four hours with 15 grms. 93 10 of chromic acid dissolved in 10 c.c. of glacial acetic acid and 10 c.c. of water; allow it to stand for twelve hours, collect the crystals on a small filter, and let the solution run off to the last drop; then wash the crystals with boiling water till the filter and filtrate are quite colourless, dilute the filtrate with water to 600 c.c., let stand for two hours, and collect the powdery precipitate on a filter and wash well. Then treat both crystals and powderseparately, of course-with potassium permanganate and potassium hydrate as hitherto, collect each on a double filter, dry and weigh, but do not add the correction; then take the melting- and solidifying-point of both. The

28. 563 275-277 53'9 274-277

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26 not at 300

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Oct. 27, 1876.

Practical Chemistry in the University of Virginia.

crystals to be taken as pure quinon, the powder also to be
taken as quinon if melting- and solidifying-points range
between 270° and 280°, but as valueless impurities if these
two points are below 270° or above 280°.

This test is more reliable, and more just to buyer and
seller, than either the usual quinon test or the one now
proposed by Messrs. Meister, Lucius, and Brüning.
My experience as to the action of sulphuric acid upon
crude quinon is as follows.

(To be continued.)

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(3.) On the Chemical Character of the Pigment of the
Negro Skin. By Dr. F. P. FLOYD, of Tazewell Co.,

It is natural to suppose that the substance which gives
the characteristic black colour to the skin of the negro is
probably modified blood pigment, as is pretty generally
assumed to be the case in reference to the "melanin" of
the choroid coat of the eye; but this point does not seem
to have been made until now the subject of experiment.
I suggested to Dr. Floyd to examine qualitatively the
character of the pigment in question, and to get, if pos-
sible, some approach to a determination of the amount of
iron in the ash as the means of testing the probability of
a connection with hæmatin.


This ash was dissolved in a very small = 2'0 per cent. quantity of sulphuric acid, the solution diluted, and the iron (easily diluted in previous quantitative experiments) reduced to a ferrous salt by a minimum of pure zinc, determined by a much diluted solution of potassium permanganate. The result was o'00859 grm. of Fe per cent of the ash.



No. 2-Skin from the outside of the thigh of a Negro woman, aged about 40 years, born in Virginia.-The cuticle was rather more completely separated from the true skin than in the last instance. The same trea ment was applied. 2 grms. of material dried at 100° C. left 2.8 per cent, and in this there was 0'056 grm. of ash e cent of ash. = € 2'54 present o'00142 grm. of Fe These specimen of negro skin were obtained from the Anatomical department of the University of Virginia; for those from white subjects, which at the time were not available here, we were indebted to my friend Dr. Souchon, of New Orleans.

No. 3.-Skin from the anterior surface of the thigh of a white man, 40 years of age, born in Maine.—The epidermis was taken off pretty clearly, with very little of the true skin remaining attached to it. Same chemical treatment as above. 18 grms. of the dry cuticle gave o‘207 grm. of 115 per cent, in which was found Fe = 0.00235 grm. 1'13 per cent of the ash.


No. 4.-Skin from anterior surface of upper portion of thigh of a white man, aged 45, born in France.-Cuticle taken off as clearly as possible and treated as before. I'14 **29 per cent of 15'354 grms. of dry skin gave o 175 grm. of ash : per cent, yielding o'00226 grm. of Fe the ash.

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It appears from the mean of these results that the negro cuticle leaves on being burned double as much ash as that of the white man (2.40 per cent against 1*15), and that the difference is nearly as great in the percentage of iron in the ash (2.28 against 1'21), thus rendering the presence of a considerable amount of iron in the black pigment highly probable, and increasing the likelihood of this being a product of the alteration of the colouring matter of the blood.

As regards the local distribution of the pigment granules In the older books they are said to occur in there seems to have been hitherto a little confusion of statement. the "rete mucosum" between the epidermis and cutis, and, although the existence of such a distinct middle layer of the skin is no longer admitted and the name for it has therefore disappeared, the same general idea seems to remain that the colouring matter belongs to the subcuticular portion of the skin, and hence impliedly that it does not extend outwards into the cuticle itself. I have found too in the Southern States many physicians under the impression that a blister produced upon the negro skin is white, or at any rate much lighter in colour than the surrounding surface. From the chemical inalterability of the pigment, as above ascertained, this would seem very unlikely; a few observations were therefore made upon the subject.

Strips of cuticle with a little of the outer layer of true skin attached were taken from a negro cadaver, and having been well washed with water and alhohol, and with ether to remove fatty matter, were cautiously scraped with the blunt edge of a scalpel, in order, if possible, to loosen up the pigment granules and permit of their separation and purification by mechanical washing. A very little examination with the microscope, however, showed that this could not be done without breaking up the whole substance of the cuticular tissue, and mixing its débris with the granules, which therefore could not be obtained in a state of purity. By selecting only those parts in which there was most pigment, and cautiously treating these as above, enough of it was procured with but little admixture to establish the following points. The colouring matter is insoluble in water, alcohol, and ether. It is also undissolved by treatment with dilute acid or alkaline solutions. It is but slowly attacked by the strong acids, even by concentrated nitric acid. Chlorine, especially in the presence of alkalies, completely destroys it. Heated for some time with a strong solution of sodium hydrate it is gradually dissolved. and the solution when diluted yields a partial precipitate on neutralisation with an acid. In all these respects the behaviour of this substance agrees perfectly with the melanin of the eye.

In order to get an approximation to the quantity of iron present, as the pure pigment could not be had, comparative experiments were made with the cuticle of black and white subjects with the following results:

No. 1.-Skin from the outside of the upper arm of a Negro man, aged about 50 years, born in United States.The cuticle and a little of the outer portion of the cutis were taken, washed with water and alcohol, macerated in ether for twenty-four hours to remove fat, and then dried at 100° C. 21°249 grms. of the dry material on being carefully and completely burned left o424 grm. of ash

Thin vertical sections of negro skin from the cadaver were made, and these under the microscope showed brown and black granules to the very edge of the cuticular surface, which, however, seemed to have been partially removed, probably by post mortem softening and the washing which the subject had received.

A few extremely thin horizontal shavings were therefore taken off with a razor-like scalpel from the arms of two living negroes, man and woman respectively, drawing no blood and cutting with the blade so slanted as to thin off one side of the shaving to nothing. These sections showed under the microscope the pigment granules through the whole of the cuticle, though less easily observed among the epidermic scales than in the less dense structure beneath in which the flattening of the cells had not yet gone so far. Finally, one or two small blisters were produced by very small drops of a solution of can tharidine, and the raised cuticle from these gave quite th


Development of the Chemical Arts.

same result under the microscope. The blisters themselves before being punctured were distinctly brown to the naked eye, while no doubt the side light which comes in through the projecting mass of transparent colourless fluid has a tendency to produce the impression of lighter colour upon the observer.

There can be no doubt, I think, that the brown or black pigment originates in the outer layer of true skin, its production being probably connected with the loss of vitality of the cells, and that it accompanies these cells all the way to the surface, where it is mechanically removed by disquamation. The chemical modification of the red colouring matter of the blood corpuscles may possibly be in some way dependent on feebleness of circulation in the superficial capillaries, to which would seem to point a number of facts as to the diseases to which negroes are specially liable, as well as their extreme sensitiveness to low atmospheric temperature, a severe frost which would be little more than bracing to a white man often fairly benumbing all their faculties, bodily and mental.

(4) Analysis of Cinnabar from Oregon. By C. W.

DABNEY, Jun., of Hampden Sidney College, Virginia. A specimen of cinnabar in calcite from the land of Dr. F. C. Horsley, near Canyon City, Oregon, when pulverised and treated with dilute hydrochloric acid, gave off sulphuretted hydrogen. This fact seemed to make it worth while to analyse the specimen carefully, and it was placed in Mr. Dabney's hands for the purpose. It was found that after being thus treated with acid it gave, on heating in a closed tube, a small sublimate of sulphur, and the residue on being again treated with hydrochloric acid gave an additional amount of sulphuretted hydrogen,

whilst iron was found in solution.

A specimen freed from the calcite gangue by very weak acetic acid was dried, weighed, and acted on with hydrochloric acid of 6 per cent real acid. The sulphuretted hydrogen given off was collected as sulphide of silver, and its amount determined. The residue was then analysed by ordinary methods, adding in the small quan

tity of iron which the hydrochloric acid had taken up.

The results were :Mercury.. Sulphur

given off as H2S in residue..

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From the behaviour of the mineral with hydrochloric acid and on heating it may fairly be concluded that part of the iron exists as ordinary iron pyrites and part as magnetic pyrites. If now the sulphur be distributed, first, to mercury to form HgS; second, to the extent of that evolved as H2S, to iron to form magnetic pyrites (assuming this to be Fe-S8); and, third, the residue, to iron enough to form iron pyrites, the rest of the iron being assumed present (as some visibly was) as ferric oxide; the above analysis will stand thus:

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Oct. 27, 1876.

For 200 parts Hg

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Chlorine, Bromine, Iodine, and Fluorine. By Dr. E. MYLIUS, of Ludwigshafen. We may here also mention the bromiferous artificial saline mixtures prepared in imitation of the salts obtained from mineral springs. At Vienna the mother-liquors and their salts of Kreuznach, Kosen, Wittekind, &c., were exhibited by Frank, and by the United Manufactures of Leopoldshall. Finally, we must mention the arrangements adopted for preserving the workmen from the injurious action of bromine. It appears, in fact, that when these are applied no danger to health is to be appreIn the selection of workmen it is primarily essential to see that they have well-developed respiratory organs, and are free from any predisposition to asthma and catarrhal affections. The use of spirituous liquids must be strictly interdicted, as the irritability of the dangerous. On the other hand, a generous diet is recommucous membranes which they produce is exceedingly mended, and especially the abundant use of fatty and mucilaginous articles, butter, bacon, &c.


As it appears that the workmen do not make use of the respirators with which they are furnished, and at most merely tie a cloth over the mouth and nose when decanting large quantities of bromine, the most important point is to secure an efficient ventilation in all parts of the works. By attention in this respect, combined with the above-mentioned dietetic regulations, it has been found practicable to maintain the health of the workmen at Stassfurt, during the eight years of the existence of the of spirituous liquors (Frank). bromine manufacture, so long as they refrain from the use

recent excursion to Stassfurt to visit Frank's bromine (The editor of this Report has had opportunity during a works, and, it may be, permitted him to add certain results from his own observation in order to complete what has above been given in bold outline.)

The distillation of bromiferous mother-liquors with manganese and sulphuric acid is conducted in large cubic stone vessels made in one piece, and belted with iron bands in case of a fracture. Their average capacity is 3 cubic metres. At some distance from the bottom is a perforated plate of the same kind of stone, upon which the manganese is placed in fragments of the size of a nut. stone trough is covered with a heavy plate of the same material, which is raised and lowered by means of a rope with a counterpoise playing over a pulley. In this cover there is introduced a thick stoneware pipe for the introduction of steam; and it is also provided with a man-hole,


"Berichte über die Entwickelung der Chemischen Industrie Während des Letzten Jahrzehends."

In Germany such saline mixtures are used under the name of "bath salts" (bade-salxe).

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an aperture for pouring in the bromiferous liquid and the dilute sulphuric acid, and an opening for the escape of the bromine vapours.

Few stones are suitable for the construction of these vessels, and when the bromine manufacture was introduced at Stassfurt there was great difficulty in finding a suitable quality. Almost all the stones tried experimentally after a time allowed the chloride of manganese to ooze through, and required to be coated with tar to overcome this defect. This, however, gave rise to a new inconvenience, considerable quantities of bromine being lost by the conversion of the hydrocarbons of the tar into bromine compounds, and the bromine itself becoming contaminated. Dr. Frank estimates the loss for every new coating of tar at about 50 kilos. of bromine. Latterly a kind of stone has been found in the neighbourhood of Porta Westphalica which does not require this costly preparation and can be used at once. Still the high price of these stone troughs has given rise to attempts to manufacture bromine stills with large plates of slate, cramped together with iron bands and screws. A final decision has not yet been obtained.

(To be continued).


How to Avoid Typhoid Fever and Allied Diseases. By ARTHUR H. DOWNES, M.B., M.D. London: Baillière, Tindall, and Co.

THIS pamphlet gives plain and useful directions how to prevent the introduction of sewage-gases into dwellings. The dangers of allowing water-closets to be supplied from the same cistern which furnishes water for the culinary purposes of a household is clearly shown; so also are the shortcomings of the ordinary drain-traps, and of sinks which lead direct into the sewer. The author urges that water-closets should always be built projecting from the house, and be provided with a kind of ante-chamber fitted with a window on each side, so that the closet itself may not be ventilated into the house. Such arrangements are certainly very desirable, but unfortunately they are beyond the reach of the many. In some towns the closets are placed in the interior of the houses, without any window or any other direct communication with the open air. But even this is not the worst. We once observed clouds of steam issuing from the closet in a certain hotel where our evil star had led us to take up our quarters, and we fear that there must have been some connection with the hot-water cistern in the kitchen.

Dr. Downes denounces the vile practice of placing the foundations of houses upon "made ground."-i. e., accumulations of putrescent rubbish. For this offence an appropriate legal enactment, with penalties heavy enough to penetrate to the conscience of the wealthiest contractor, is sorely needed. Not less do we require a stringent measure prohibiting the passage of drains beneath the flooring of houses, a mal-practice against which a large number of medical health-officers have formally protested.

Dr. Downes gives instances where the excreta of a patient suffering from typhoid fever having been thrown upon a dunghill, communicated the disease afterwards to men employed in carting the heap away. It is exceedingly probable, therefore, that fields irrigated with sewage containing fever "germs" will communicate the disease to persons employed in their cultivation. The author indeed remarks, in a foot-note,-"There is no evidence to show that even when a cow has been fed upon sewagemanured grass the milk acquires any infectious property per se." But there is evidence to show that the juices of sewage-grass differ in their properties and behaviour from those of natural grass, and that the milk of cows fed upon sewage grass enters into putrefaction much more rapidly than that of cows placed upon ordinary diet.


In speaking of epidemics of typhoid fever the author states "In the case of the Marylebone epidemic, in 1873, the cause was traced to the milk from a certain farm far away in the country. The farmer had died of typhoid, and his excreta had contaminated a certain well, with the water from which the milk-cans were washed." We really were of opinion that this alleged Marylebone epidemic had been consigned to the realms of mythology. There is scarcely a sound link in the chain of evidence which was produced on the occasion. The deaths from typhoid in the district, at the time given, were below the average. The farmer was certified as having died of a disease of the heart. The water of the accused well was used for domestic purposes by several people in the village, none of whom were attacked with enteric fever.

A regular inspection of dairies, as Dr. Downes recommends, would be an exceedingly difficult thing to carry out in practice, and would assuredly be avenged upon consumers in the shape of a fearful rise in the price of milk and butter.

Upon the whole we must say that this little work deserves a wide circulation, and is calculated to effect much good.

Vegetable Fibre, and its Preparation for Industrial Uses* By Dr. HUGO MÜLLER (of London). Brunswick: F. Vieweg.

THIS valuable work is a reprint from the official report of the Vienna Exhibition of 1873. The author sets out with an account of cellulose, the formation of wood and cork, textile vegetable tissue, the nature of the bleaching process, the distinctive characteristics of the different vegeand the hygroscopic nature of vegetable fibre. On the table fibres, the quantitative determination of cellulose, which we learn that Belgian flax in its air-dried condition latter very important subject the author gives a table, from Contains 5'70 per cent of water, cotton 6'66, and Manilla hemp as much as 12.5. In air saturated with aqueous vapour the amounts taken up are much greater. Thus cotton absorbs 20.99 per cent, and Manilla hemp 40. These figures have not merely a commercial importance for the purchaser of fibrous materials, but they are even more interesting as regards public health. Substances which when supposed to be dry may contain 6 per cent of water must certainly have a deleterious effect when worr next to the skin. An astonishing number of coughs and rheumatic attacks, and in tropical climates of more acute diseases, are due to the linen and cotton under-clothing still worn by so many.

On the recognition of the different vegetable fibres Dr. Müller very justly remarks that this end cannot, as a rule, be effected by chemical means, since the essential substance present, cellulose, must when pure give always the same reaction. Only in exceptional cases certain raw fibres give characteristic coloured reactions due to their less important constituents. Thus Phormium tenax, New Zealand hemp, gives a red coloration with nitric acid, and jute and its allies a yellow colour with the sulphate of aniline; but when the fibres have been bleached these distinguishing reactions no longer appear. The microscopic characteristics are more widely available. As has been shown by the researches of Wiesner, almost all vegetable fibres under the microscope display features by which they may be recognised. In addition to the generally constant length, breadth, and thickness of the membrane of the cells which constitute any given fibre, there are commonly detected other histological elements and crystalline mineral inter-deposits, which together form a basis for methodical examination. The application of certain micro-chemical reagents-such as ammoniuret of copper, sulphuric acid and iodine, sulphate of aniline, &c. -is of great value. Still the detection of a manufactured fibre remains a task which requires no little skill and experience.

"Die Pflangenfaser und ihre Aufbereitung für die Technik."

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