50

Chemical Notices from Foreign Sources.

uanidin; and the action of bisulphide of carbon upon arbo-diphenylimid.

Various Communications.-V. Meyer.-These conist of researches on the aromatic sulph-acids, by E. Möling; a paper on the esters of the mercaptans, by W. Michler; and on dibrom-ethan, by V. Meyer.

Communications from the Laboratory of the University of Göttingen.-H. Hübner. This paper includes a memoir on benzanilid and nitric acid, by C. Stöver; one on isomeric mono-nitro-benzo-naphthylamids, and their various behaviour with hydrogen, by P. Ebell; on benzoyl-amido-phenols, by H. Morse; on nitrosalicylic acids, by L. B. Hall; and on amido-benzonitriles, by A. Fricke.

Preliminary Communications.-J. Post.-The author is engaged with the study of the chemical and physical properties of all known nitro derivatives of phenol for the purpose of solving the "questions which at present impel chemical research, namely, the respective position of atoms and groups of atoms in the molecule."

Contribution to the History of the Phenomena of Fermentation.-H. Struve.-A comment on Traube's

paper

"On the Behaviour of Alcoholic Yeast in Media

free from Oxygen Gas" (Berichte, No. 11). He complains that the researches undertaken by Döpping and himself the result of which was put forward by Liebig in his "Chemical Letters" (1865, p. 18)-have been completely overlooked. These experiments on fermentation have never been repeated by Pasteur. He avoided it, as they could not be brought to harmonise with his theory.

The Law of Multiple Deviations.-E. Mulder. The power of molecular rotation, which certain compounds of carbon possess in solution, can be modified by different agencies. In general, we have to distinguish a stable and an unstable modification of molecular rotation. As an instance of the former we may take tartaric acid. Dextrotartaric acid can be transformed into uvic acid (a compound of dextro- and lævo-tartaric acid); therefore, dextrotartaric acid is capable of interversion into the lævotartaric. Since uvic acid, as is generally admitted, remains optically indifferent under various agencies which affect the rotation of dextro-tartaric acid, the inference may be drawn that the molecular rotations of dextro- and lævotartaric acid, under similar circumstances, are respectively equal and opposite. If we assume with Landolt for the molecular rotation of dextro-tartaric acid,

(M)n = +2108,10,

then the molecular rotation of lævo-tartaric acid, under similar circumstances, is (M)n = 21:08. The inversion in question takes place only in accordance with the law of multiple rotations. As to the unstable modification of molecular rotation, there are carbon compounds whose molecular rotation is temporarily modified by certain agencies, and which return to their original rotatory power as soon as these agencies are withdrawn. Thus the molecular rotation of dextro-tartaric acid is temporarily modified by bases. (See Landolt, Berichte, vi., p. 1075.) A continued study of these modifications of molecular rotation may be of exceedingly great value in its scientific applications. The author names merely the study of the influence of salts upon salts, of acids upon salts when an optically active base or acid is present, by means of which we are enabled to trace the chemical decomposition quantitatively by means of polarised light.

Anhydrous Phloroglucin.-H. Hlasiwetz.-In the July number of this journal, p. 891, Piccard makes a communication on this body, C12H10O5, and remarks that, to the best of his knowledge, it has not been previously described the author has described it nine years ago. See Transactions of the Vienna Academy, I., II., 2 abth., p. 84.)

Detection of Alkaloids in Dead Bodies.-W. Schwanert.-Already noticed in the CHEMICAL NEWS.

Rauite a New Mineral from Brewig in Norway, -S. R. Paykull.-The mineral in question occurs in the Island Lamo, near Brewig. It is a blackish grey zeolite of finely granular texture, and must be a metamorphosis of Elaeolite, as it manifestly undergoes transition into the latter mineral. Its composition is

Silica
Alumina..
Ferric oxide
Lime
Soda
Water

39.21

3179

0'57

5'07

It approximates closely to Thomsonite. It is perfectly devoid of lustre, and contains traces of foreign bodies, as horn-blende, &c. Its sp. gr. 2:48, hardness =5. It is not met with crystalline.

Bulletin de la Societe Chimique de Paris,
No. 11, December 11, 1874.

At the monthly meeting of the Society, November 6, M. Fordos described his experiments on the action of alimentary and medicinal substances upon vessels of plumbiferous tin in presence of air. Wine and vinegar rapidly take up lead in however small proportion it may be present.

MM. Friedel and Guérin announce that they have obtained an oxychloride of titanium. The compound was previously observed by Ebelmen, who took it to be the protochloride. It is produced by passing a current of hydrogen and of tetrachloride of titanium through a tube heated to bright redness, and containing titanic acid. Sesquichloride, Ti2Cl6, is formed simultaneously. The oxychloride: it appears in brown rectangular lamellæ, which are red by transmitted light, and under the polarising microscope present the characters of orthorhombic bodies. Its composition is Ti2O2Cl2. If treated with ammonia it yields titanic acid, with disengagement of hydrogen, resulting from the oxidation of the sesquioxide of titanium. The titanic acid in the tube is transformed into a crystalline mass of a fine coppery metallic lustre. It is the sesquioxide, Ti2O3, and presents exactly the crystalline form of oligistic iron ore from Elba. identity of form confirms the explanation which M. Friedel has already given of the varying composition of titaniferous irons. They are merely mixtures of isomorphous compounds.

This

M. Thiercelein explained his process for extracting the iodine contained in phosphate of lime.

M. Schützenberger communicated the first results of a He has series of experiments on albumenoid bodies. studied especially the prolonged action of a boiling solution of baryta upon these compounds, as well as that of in the first case a notable evolution of ammonia at the dilute boiling sulphuric acid for a limited period. He finds outset, but which by degrees ceases entirely. The ammonia evolved represents about one-ninth of the total nitrogen of the albumen in question. There are formed at the same time oxalate and sulphate of baryta. The filtrate, when freed from excess of baryta by a current of carbonic acid, still contains a little baryta in the form of a soluble salt of complex composition. Almost the totality of the albumenoid body is converted into crystalline amidic compounds, such as tyrosin, leucin, and inferior homologues. The disengagement of ammonia during the action of baryta tends to show that one part of the nitrogen, oneninth at most, is found in the albumen in the form of urea. albumen, heated for some time with sulphuric acid diluted The following experiment supports this view:-Coagulated one, insoluble in water, but soluble in alkalies (containing to the tenth, is split up into two parts almost equal-the C, 533, H, 72, N, 14°2), the other, soluble in water, and precipitable by mercuric nitrate, is very similar to Mulder's teroxide of protein. The mercurial precipitate, decom

posed by sulphuretted hydrogen, gives, on evaporation, | Observations made with the visible tint should be as usual an amorphous product containing C, 5001; H, 65; represented by the symbol [a]j. N, 14'5. This product, on ebullition with baryta, yields a little ammonia and carbonate of baryta. The ammo nia and carbonic acid formed are in a ratio corresponding

to that which urea demands.

Amongst the soluble products obtained by the action of sulphuric acid, there is formed a substance presenting the characters of glucose.

M. Gautier added the following observations:-When caustic potash is heated with a little water, and dry albu. men is gradually thrown into it, a small quantity of ammonia is evolved if the heat does not exceed 250°. The product, dissolved in water and saturated with sulphuric acid, gives off an insupportable odour of excrements. Alcohol extracts from this product leucin, 12 to 15 per cent in amount; a substance resembling butalanin; and a crystalline matter, which appears to be the same as what Schützenberger has obtained by the action of baryta upon albumen, and which is analogous to leucin, but contains less hydrogen. By heating albumenoid bodies to 100° with pure water he obtained, e g., with gluten, syntonin, albumen, a variety of crystalline bodies, but neither fatty bodies nor urea. He announced, also, that his assistant, M. Danlos, was engaged with the products of the oxidation of albumen.

M. Gautier is resuming the study of the various proteic matters of the white of egg. He finds that albumen coagulable chiefly at 63° contains 17 to 18 per cent of sulphur; whilst that coagulating at 73° differs, not merely by its rotatory power, but also by its proportion of sulphur, which does not exceed 1'54 per cent.

M. Bourgoin gave an account of the perbromide of acetylen and its homologues.

M. Petit describes certain experiments on fermentation which completely confirm the existence, in the leaves of fruit trees, of a mixture of reducing and non-reducing sugars. In the leaves of the vine the proportion of nonreducing sugar sometimes reaches two-thirds of the whole quantity. Determinations by Fehling's liquor, confirmed by fermentation-experiments and polarimetric observations before and after inversion, show that this non-reducing sugar is, chiefly at least, cane-sugar.

M. Henninger described M. Van't Hoff's researches on the preparation and properties of cyan-acetic acid. Coagulation of Albumen.-M. V. Urbain. The author, on behalf of himself and M. Mathieu, comments on an experiment of M. Gautier, laid before the Society on June 19, which, in the opinion of the latter, militates against the author's theory of the coagulation of albumen by heat. To justify such a conclusion, M. Gautier should have shown that the albumen still coagulable by heatthe result of the treatment which he indicates, no longer contained carbonic acid; this he has not done. The method which he has pursued is, M. Urbain holds, insufficient to remove the carbonic acid.

Contributions to the History of Cyan-Acetic Acid. —M. J. Van't Hoff.-The author took as his point of commencement mono-chlor-acetic ether, and by observing certain conditions, obtained almost the theoretical yield of cyan-acetic acid. It forms crystals, slightly coloured. fusible at 80°, and yielded on analysis 15'9 per cent of nitrogen, whilst the formula CH2CNCO2H would require 164. It is decomposed at about 165°, giving off carbonic acid, and forming a liquid composed mainly of acetonitrile.

Observations on the Rotatory Powers of Camphor, and of certain other Bodies.-J. de Montgolfier. This important paper does not admit of useful abstraction.

Symbols Employed to Designate the Rotatory Powers.-M. J. Ribau.-The author proposes that determinations made with the monochromatic flame of soda should be designated by the symbols a to express the absolute deviations, and [a]d for the rotatory power, thus recalling their relation with the ray D of Fraunhofer.

Rectification.-M. E. Demole. The author, referring to his paper on the preparation of glycol (Berichte der Deutschen, 1874, p. 641), points out that the alcohol must be used, not at 80, but at 91 per cent.

MISCELLANEOUS.

Gramme's Magneto-Electric Company. This com pany has been formed to utilise for industrial purposes Gramme's Magneto-Electric Machine. Amongst the important objects which the promoters have in view are the application of the machine to the production of light, the electro-deposition of metals, and to metallurgy and chemical manufactures. Most successful experimental results have been obtained, and useful as the invention will prove for industrial purposes, it possesses still higher value from a scientific point of view, being based on new principles. The capital of the company is to be £250,000 in 25,000 shares of £10 each, 14,000 of which are now offered for subscription. The share lists will close on Thursday, February 4, for London, and Friday, February 5, for country applications.

Metropolis Gas Supply.-Dr. Letheby, the Chief Gas Examiner appointed by the Board of Trade, has recently reported to the Corporation of the City of London, and to the Metropolitan Board of Works, on the quality of the gas supplied by the Chartered, the Imperial, and the South Metropolitan gas companies during the quarter which expired on the 31st of December last. He states that the average illuminating power of the common gas of the Chartered Company at the four testing places was as follows:-At Beckton, North Woolwich, 17:46 standard sperm candles; at Cannon Street, City, 16.68 candles; at Friendly Place, Bow, 17:02 candles; and at Ladbroke Grove, Notting Hill, 1663 candles. The illuminating power of the gas supplied by the Imperial Company averaged 16-68 candles at Carlyle Square, Chelsea; 15.63 candles at Camden Street, Camden Town; 16:58 candles at Graham Road, Dalston; and 17.36 candles at Bruce Terrace, Bow; while that of the South Metropolitan Company at Hill Street, Peckham, was 16:42 candles. The lowest illuminating power during the quarter was 15'5 candles in the case of the Chartered gas; 143 in that of the Imperial; and 153 in that of South Metropolitan. The cannel gas of the Chartered Company ranged from 20 standard candles to 22'4, the average for the whole quarter being 20.8 candles. It thus appears that the illuminating power of the gas supplied to each of the testing places has been at all times equal to the requirements of the several Acts of Parliament, viz., 16 standard sperm candles for the gas of the Chartered Company, and 14 for that of the two others. As regards purity, Dr. Letheby reports that on six occasions the gas of the Chartered Company at Ladbroke Grove was charged with sulphuwith the gas of the Imperial Company at Bruce Terrace. retted hydrogen. The same was the case on five occasions The average amount of sulphur in the gas at the several places was as follows:-Beckton, 12:27 grains per 100 cubic feet; Cannon Street, 10:37; Friendly Place, 983; Ladbroke Grove, 17'49; Millbank, 17.68; Carlyle Square, 14'99; Camden Street, 17:34; Graham Road, 15.59; Bruce Terrace, 1083; and Hill Street, 1986. The proportion of this impurity was in excess of the prescribed quantity on one occasion at Camden Street, on three occasions at Bruce Terrace, and on four occasions at Hill Street, Peckham. All these have been the subjects of special enquiry; and Dr. Letheby states that the excess of impurity (sulphur and sulphuretted hydrogen) was due to accidental derange ments of valves in the case of the Chartered and Imperial gas, but he was unable to find a satisfactory cause for the excess of sulphur in the gas of the South Metropolitan Company. The proportion of ammonia in the gas of the

mixtures of tar-acids above mentioned to the sufficiently prolonged action of temperatures varying between 15° F. and 56 F.; (2) to separate by suitable means the more or less hydrated carbolic acid crystals thus formed from the mother-liquors containing the liquid tar-acids and a residue of carbolic acid dissolved in them; (3) to effect complete purification of the more or less hydrated carbolic acid solution in water with subsequent refrigeration; and (4) to prepare crystals thus obtained by re-crystallisation either by partial fusion or carbolic acid of high or complete degrees of purity by dehydrating the partially or wholly purified more or less h, drated carbolic acid Improvements in treating guano. William George Sharp Mockford, manufacturing chemist, Old Broad Street, London. April 25, 1874.No. 1450. This Provisional Specification describes reducing megillones or other guano to a fine state of division by grinding, and then adjusting the percentage of nitrogen by the addition of nitrate of soda, also in a state of powder, and mixing the nitrate with the guano. Or in some cases the nitrate of soda may be used in a state of solution before it has been boiled down, and crystallised, and mixed with the crude guano. The compound is then thoroughly dried in a stove, and is afterwards ground to a fine powder.

crystals above mentioned.

ATTRACTION AND REPULSION RESULTING
FROM RADIATION.*

By WILLIAM CROOKES, F.R.S., &c.
(Concluded from page 45.)

74. THROUGHOUT the course of these investigations I have endeavoured to keep in my mind the possible explanations which may be given of the actions observed, and I have tried, by selecting some circumstances and excluding others, to put each hypothesis to the test of experiment. The most obvious explanation is that the movements of the beam, or of the horizontal index (69, 70), are due to the currents formed in the residual gas, which, theoretically, must be present to some extent even in those vacua which are most nearly absolute.

In favour of this explanation it may be urged that a highly rarefied gas may be much more mobile than when it is denser, and therefore the more rapid impingement of its particles, when set in ascension by warmth, would increased their mechanical action. Increased momentum may counterbalance diminished number.

That the residual gas in an air-pump vacuum is capable of exerting considerable mechanical action, may be assumed by the phenomena attending the passage of meteorites through the upper regions of the atmosphere, their friction against the air at an average height of 65 miles above the earth's surface raising them to incandescence, although at that height the attenuation of the air probably surpasses that of most artificial vacua.

On the other hand, it is most difficult to believe that the residual air in a Sprengel vacuum, where the gauge and barometer are appreciably level, can exert, when gently warmed by the finger, an upward force capable of instantly overcoming the inertia of a mass of matter weighing several grains, and setting it in motion. It must be remembered that the upward current supposed to do this is simply due to the diminished weight of a portion of the gas, caused by its increase in volume by the heat applied.

75. Another argument in favour of the air-current explanation can be drawn from the fact that when a light beam, having equal weights of pith and platinum suspended at the ends, is sealed up in a Sprengel vacuum, the application of warmth below causes the pith to rise more readily than the platinum (62); the pith obviously offers a much more extended surface than the platinum does to the impact of air-particles.

This, moreover, is not an isolated instance. Throughout the whole of these experiments the law appears to be that the force exerted is in proportion to the extent of surface exposed (48, 62, 63, 64, 65, 67) rather than in proportion to the mass. Much surface and extreme lightness are the requisites in selecting materials for the beam, index, or gravitating mass; and when the masses have the same specific gravity and extent of surface, their position in respect to the source of heat determines the extent of movement. Thus a cylinder of pith is more sensitive when arranged for the heat to act on its side than on its end; and the film of mica in experiment 65 was more affected when the heat struck its flat surface than its edge, although the difference was not so great as might have been expected had air-currents been the cause of motion.

a repulsive action of radiation, it is reasonable to suppose that extended surface, weights being equal, would have an advantage. The repulsion by radiation only acts on the surface of bodies, and does not seem to act on the molecules which constitute thickness. When radiant heat gets below the surface of a body, it spends itself in doing mechanical work of another kind, viz., dilatation or expansion.

77. However strong may be the reasons in favour of the air-current explanation, they are, I think, answered irrefragably by the phenomena themselves. An air-current produced by heat can cause the beam of a balance to rise, can drive a suspended index sideways, and, by a liberal assumption of eddies and reflections, can perhaps be imagined to cause these movements to take place sometimes in the opposite directions; but as rarefaction proceeds these actions will certainly get less, and they will cease to be appreciable some time before a vacuum is attained; a point of no action or neutrality will be reached. But this neutral point should certainly be nearer a vacuum when a light body exposing much surface, such as pith, is under experiment than when the mass acted on is heavy like brass; whereas in practice the contrary obtains. Pith and thin glass balances, which should be sensitive to highly attenuated air-currents, cease to respond to heat at a rarefaction of 7 millims. (30) and 45 millims. (66), whilst brass only ceases to be affected when the gauge and the barometer are appreciably level (43).

76. But these facts can equally well be used on the opposite side; for assuming that the movement is due to From the Philosophical Transactions of the Royal Society of

London, vol. clxiv., part 2.

But even could the phenomena up to neutrality be explained by air-currents, these are manifestly powerless to act after this critical point is passed. If a current of air within 7 millims. of a vacuum cannot move a piece of pith, certainly the residual air in a Sprengel vacuum should not do so; and, a fortiori, the residual air in a chemical vacuum could not move a piece of platinum (55). It is, however, abundantly demonstrated that in all cases, after this critical point is reached, the repulsion by radiation is most apparent, and it increases in energy as the vacuum approaches perfection.

78. Again, the movements not only reappear on passing a particular point of atmospheric density, but they take place in the opposite direction (31, 32, 33, 44, 46, 66). Thus in all cases, when the atmospheric density is between the neutral point and a vacuum, the action of a body hotter than the moving beam or index is to repel it, whilst the action of a colder body is to attract. Now it is very probable that were it not for the interference of aircurrents the action in air of greater density would always be for the hot body to attract. This is actually the case in many experiments (27, 37, 38, 40, 41, 66, 70, 72); and observations more recently made, but only alluded to in par. 72, have proved that in air of ordinary density a cold body repels.

On the supposition that air-currents are the motive power, the effects noticed when the source of heat is internal to the tube, and applied above the moving beam (37. 39, 40, 41, 45), are inexplicable, whilst they are easily comprehended on the repulsion-by-radiation hypothesis. If an additional argument is necessary to show that aircurrents are not the cause of the repellent action of a hot body, I bring forward the fact that the movement attains its maximum when there is no air at all present (54, 55, 68).

79. Effects probably due to this repulsive action of radiation are constantly met with. I will instance the following: Cohesion and adhesion are diminished by heat. This naturally follows if increased temperature augments the force of repulsion between the molecules.

The phenomenon of the spheroidal state is probably due in some measure to a repulsive force exerted between closely approximated bodies, one of which is at a very high temperature. This action is generally supposed to take place only when one of the bodies is volatile, and the rapidly formed skin of vapour is held to be a sufficient cause of non-contact. I venture to anticipate that a condition similar to the spheroidal state will be found to

obtain between non-volatile bodies.

54

Attraction and Repulsion Resulting from Radiation.

CHEMICAL NEWS,
February 5, 1875-

By C. A. CAMERON, M.D.,
Professor of Hygiene, Royal College of Surgeons, Ireland.

Colour of Milk.

THE author states that the colour of milk is chiefly due to the reflection of light from the myriad of solid caseous capsules in which most of the fats of milk is contained. They are translucent, and (but to no great extent) refract light. In fresh milk there are globules of free fat, sometimes numerous, but rarely exceeding o'0015" in diameter. By continued ebullition of a mixture of milk (rendered slightly alkaline with KHO) and other liquids, all, save the merest trace of fats, may be removed, leaving a perfectly milk-like liquid. Attention was called to the fact that butter-milk containing 0.5 per cent of fats was whiter than skimmed milk containing 13 to 2 per cent of fats. In the former the caseous envelopes of the so-called fat globules were left; from the latter a large proportion was removed, in the form of cream. From these and other facts the author concluded that the opacity and whiteness of milk were due not to the liquid being an emulsion of fats, but to the reflection and refraction of light by solid caseous matter suspended in it.

Many finely divided chemical precipitates, when in- | SOME POINTS IN THE CHEMISTRY OF MILK.* candescent in a platinum crucible, assume a remarkable mobility and flow about like water. Precipitated silica is an instance which will occur to chemists. A space can readily be distinguished between the powder and a hot capsule containing it. Electricity may, however, play some part in this action; for precipitates, when heated, sometimes become sufficiently electrical by stirring with a glass rod to fly out of the basin containing them; oxalate of lime possesses this property in a remarkable degree." 80. It must, however, be remembered that my experiments show the action of hot bodies in air to be that of attraction, and that the repulsion by heat only becomes evident near upon a vacuum. It is seen, therefore, that radiant light or heat has an attractive or repulsive action, according to the medium in which it acts, corresponding results being furnished by cold. There appears to be an interfering action of air other than that of the currents caused in it by heat, which masks or overcomes the true action of heat; but in a vacuum this interfering cause is absent, and radiant heat is free to exert its full repellent action, whilst cold or negative heat acts in the opposite direction. Heat and cold, heat present and heat absent -molecular activity and molecular rest-are therefore antagonistic in their action on a body free to move in empty space. The molecules of matter whose mode of motion constitutes heat are drawn together and condensed as these vibrations diminish in amplitude, whilst heat drives them apart, expanding a solid, changing a solid into a liquid and a liquid into a gas.

The masses used in my experiments are likewise repelled by heat and drawn together by cold. And it is with no weak force or feeble action that I have been dealing. It is so decided that in some of my balances the approach of a finger will completely overturn them, whilst the radiant warmth of the body affects them 6 feet off; and at higher temperatures and with larger masses the action must be still more energetic.

81. It is not unlikely that in the experiments here recorded may be found the key of some as yet unsolved problems in celestial mechanics. In the sun's radiation passing through the quasi vacuum of space we have the radial repulsive force, possessing successive propagation, required to account for the changes of form in the lighter matter of comets and nebula; and we may learn by that action, which is rapid and apparently fitful, to find the cause in those rapid bursts which take place in the central body of our system; but until we measure the force more exactly we shall be unable to say how much influence it may have in keeping the heavenly bodies at their respective distances.

So far as repulsion is concerned, we may argue from small things to great, from pieces of pith up to heavenly bodies; and we find that repulsion shown between a cold and warm body will equally prevail, when for melting ice is substituted the cold surface of our atmospheric sea in space, for a lump of pith a celestial sphere, and for an artificial vacuum a stellar void.

Attraction being developed by radiant heat under influences connected with air, it is not easy to conceive how it will be produced for cosmical purposes by heat; the upper surface of our atmosphere must present a very cold front, and from this we might argue repulsion by the sun, unless we fill space with a body acting like air, when we should have attraction. We might readily find conditions for both, but how to harmonise them is a difficulty.

Although the force of which I have spoken is clearly not gravity solely as we know it, it is attraction developed from chemical activity, and connecting that greatest and most mysterious of all natural forces, action at a distance, with the more intelligible acts of matter. In the radiant molecular energy of solar masses may at last be found that "agent acting constantly according to certain laws" which Newton held to be the cause of gravity.

Cow's Milk.

The results of several thousand analyses of cow's milk made by the author, since 1865, led him to conclude that the mixed milk of town cows never contained less than 12, and that of country cows 115, per cent of solids; and he agreed with Prof. Wanklyn that the solids, minus fats, never sank below 11.3 per cent. Several hundreds of convictions for selling adulterated milk occurred in Dublin, and though in many cases the alleged amount of adulteration with water was only 12 per cent-and in each case a duplicate sample was produced in Court-the accused never elected to have it re-examined, though on other points barristers and solicitors constantly raised issues. Forty analyses of pure milk from Dublin dairy cows gave the following average results :

his "Lehrbuch der Physiologischen Chemie," states that Gorup-Besanez, in page 416 of the second edition of 6-872 per cent of fats. Clemm found it rich in solids, mare's milk contains 17.163 per cent of solids, including and to contain nearly 7 per cent of fats. Simon, in his

Physiological Chemistry," states it to be very rich in solids. It is probable that the milk analysed by these chemists could not have been that of the mare, which, being akin to the ass, would be likely to yield, like the latter, a milk poor in solids, and poorer still in fats. The the solids to vary from 8.5 to 11.5 per cent, the fats from author examined the milk of fourteen mares, and found 0.6 to 2:12, the casein from 1'46 to 24, the sugar from 5'67 to 6.87, and mineral matter from 0.33 to 0.44 per cent. The average of the fourteen specimens gave

Water ..
Fats
Albumenoids
Sugar..

Mineral matters..

90'310

1'055

I'953

6.285

O'397

100'000

Mare's milk is bluish-white; sp. gr. about 1'031; reaction neutral, or faintly alkaline.

* Abstract of a paper read before the Royal Dublin Society,

Faraday's "Experimental Researches in Electricity," vol. ii., p. 163. January 18, 1875.