Obrazy na stronie


Determination of Gold in Pyrites.

CHEMICAL NEWS, Oct. 6, 1876.

found what I consider, at present, to be lithofellic acid, | by scorification or by reduction of litharge, concentration and a few other substances, but practically of no great of two or three lead-buttons so obtained, and cupellation. importance. -I am, &c.,

The points to which I wish to-day to call the particular attention of veterinary surgeons and others are these

1. That the calculi are owed almost entirely to phosphate of ammonia and magnesia.

2. That this salt is contained in the corn; and here arises the question whether corn is not for the horse as artificial a food as meat is for the human race.

3. The ease with which these calculi can be decomposed, broken up, dispersed, or dissolved by means of weak hydrochloric acid.

I am of opinion that repeated doses of very dilute hydrochloric acid, say 2 to 5 per cent, in water or spirit, if it can be made to reach them, would destroy the largest of these calculi in a comparatively short space of time. This treatment, with appropriate diet, would, I feel convinced, prove effectual even in very bad cases.

The disease no doubt originates from the cæcum becoming alkaline instead of remaining slightly acid as it should be in a normal state of health; the calculus itself is alkaline, and contains minute quantities of carbonate of ammonia and tribasic phosphate of magnesia, as well as the phosphate of ammonia and magnesia which constitutes the greater part of it. It is a very rapid disease; when once started a few years will find it increased very considerably. To cite one instance that has come under my own observation, a fine cart-horse was born in Hereford, where it remained four years, and then went to Staffordshire, where it lived five years longer. It died of calculus at nine years of age, and the calculus was 20 inches in circumferencethe size of an ordinary gas-lamp globe-and weighed 8 lbs., so that it must have increased at least about I lb. a year, perhaps much more.

The lime in the water drunk by horses, to which some have attributed the disease, has nothing to do with it. It originates in the food-in the corn-as I have stated above, and is due no doubt, in great measure, to a want of salt in the food. When horses are highly fed for labour in the industrial districts, it is essential that they should have access to lumps of salt to lick, or have salt in their food and a liberal supply of water to drink. The ventilation and drainage of the stable is another important consideration. How many valuable beasts after a hard day's work pass the night in an atmosphere loaded with fumes of ammonia I—I am, &c.,

T. L. PHIPSON, Ph.D., F.C.S., &c.
Laboratory of Analytical Chemistry,
Putney, London, S.W.,
September 24, 1876.

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To the Editor of the Chemical News. SIR,-Why do M. H. Schwarz and the gentleman signing himself "Latent" in the CHEMICAL NEWS, vol. xxxiv., p. 132, propose to fuse the pyrites with iron turnings at all? There is nothing whatever to be gained by so doing, and they would get the gold into a quantity of regulus very much larger than necessary and very inconvenient for further treatment. If they simply fuse the pyrites alone at a strong heat, with such flux as the gangue, if any is present, may require, a very much smaller regulus will result, equally sure to contain all the gold, and equally suitable for treatment with acid.



NOTE.-All degrees of temperature are Centigrade, unless otherwise expressed.

Comptes Rendus Hebdomadaires des Seances, de l'Acadenie des Sciences. No. 10, September 4, 1876. Researches on the Disappearance of the Ammonia Contained in Waters.-M. A. Houzeau.-Spring- and river water contains little ammonia, whilst rain, dew, and fog often contains it in abundance. Well-waters rapidly lose their ammonia, even when contained in vessels hermetically sealed. This loss is promoted by light.

Results Obtained on the Extraction of the Juice of the Sugar-Cane by means of New Apparatus.— MM. Mignon and Rouart.-The cane is cut up by means of a machine like that contrived by MM. Labrouse The pulp thus obtained is subjected to hydraulic pressure for reducing straw to a pulp for the paper manufacture. at 80 atmospheres. The canes thus yield 77 per cent of rich juice.

Detection of Magenta used in the Sophistication of Wines.-M. V. Didelot.-The author has forwarded to the Academy a sample of gun-cotton dyed with a wine containing magenta.

Dissociation of Bicarbonate of Soda at 100o.-M. V. Urbain.-The author maintains, in opposition to M. Gautier, that if dried plasma is submitted to a tempera. ture of 100° the bicarbonate of soda which it contains is not decomposed.

No. 11, September 11, 1876.

Coloured.-M. L. Lamattina.-To detect wines artifiProcess for the Detection of Wines Artificially cially coloured, the simplest method is to mix 100 grms. of the wine with 15 grms. of wine in coarse powder, stir the mixture for twelve to fifteen minutes, and filter through a double filter. If the wine is pure it passes through colourless, but if it preserves its colour it has been artificially coloured. If pure peroxide of manganese has been employed this process is applicable to all the colouring matters artificially introduced, including magenta. If the peroxide of manganese is ferruginous, the acids and salts of the wine dissolve the iron; magenta, if present, forms an insoluble compound, which remains on the filter, The filtrate then takes a faintly yellowish colour, resembling that of sesqui-salts of iron. In this case the peroxide of manganese left upon the filter is treated with alcohol, which dissolves the magenta, whilst the natural colouring matter of the wine is insoluble. If the alcoholic filtrate remains of a blue slightly yellowish the presence of magenta may be suspected. If we add to this liquid concentrated acetic acid, and then a few drops of ammonia, the colour of the magenta reappears after stirring for a few moments.

Note on the Radiometer.-W. Crookes.-(Extract from a letter to The Count Th. du Moncel.)

Justus Liebig's Annalen der Chemie, Band 182, Heft 1 and 2.

The simplest mode of treating the insoluble residue after acting upon the regulus with acid, would be to collect it on a small filter, dry it, lay it upon a scorifier, cover with assay-lead, fuse, and scorify in a muffle, finally cupelling the lead-button. This method of assay might Contributions to the Theory of Luminous Flames. be advisable in cases where very small amounts of gold-Dr. Karl Heumann.-(Second section; see band 181, are to be determined; but in most cases it could not com- page 129.) The author considers the circumstances that pare, for convenience, with the direct treatment of the ore a gas-flame does not actually touch the edge of the burner,


Oct. 6, 1876.

Chemical Notices from Foreign Sources.

nor a candle-flame the summit of the wick; and that a flame never comes in close contact with a cold body is due to the fact that heat is conducted away by the solid body. The flame-gases are cooled for a certain distance below their ignition-point, and the flame is consequently extinguished within this region. The distance between a gas-flame and the burner is considerably increased if the inflammable gas or vapour streams out under a high pressure, or is mixed with a large amount of some non-inflammable gas. This phenomenon is due not merely to the cooling action of the gaseous stream and of the external air, but to the fact that the speed of the issuing gas stream close to the burner is greater than the speed of the propagation of ignition. When other influences are not essential, the flame begins in that section of the issuing current where its speed equals the speed of the propagation of ignition. Hence this speed of propagation for different gases and vapours may be experimentally ascertained. In case of solids and liquids of a combustible nature the same speed may also be readily found by experiment, and the results may be regarded as relative numerical expressions of the dangerous character of the combustibles in question.


action of hydrochloric acid upon potassium chlorate by G. Schacherl.

On Phosphorus Pentafluoride.--T. E. Thorpe.This compound, PF5, is a colourless gas of a very pungent odour, and strongly attacks the throat and the mucous membranes. It fumes in the air, and is decomposed by water into phosphoric and hydrofluoric acids. It is four and a half times heavier than air, and can be poured from one vessel to another like carbonic acid. It is neither combustible nor a supporter of combustion. It is not modified by the passage of electric sparks, nor by the introduction of oxygen or hydrogen.

Oxidation-Product of Glycogen with Bromine, Silver-Oxide, and Water.-R. H. Chittenden.-The gas-product is an acid, for which the author proposes the name glycogenic. He describes a number of its salts.

Communications from the Laborarory of the Poly

technic School of Delft.-These communications con

sist of a paper on "a-Xylenolol prepared from Metaxylol, by S. Lako, and a long and important dissertation by A. C. Oudemanns on the "Specific Rotatory Power of the more important Cinchona Alkaloids."

Composition of the Dialurates.-M. Menschutkin.An account of the dialurates of ammonium, potassium, sodium, and barium.

On Tartronaminic Acid.-M. Menschutkin.-A product obtained on the decomposition of dialurate of sodium by means of water. Its composition is C3H5NO4.

On Ethyl- and Methyl-Succinimid.-M. Menschutkin.-A brief account of the preparation, composition, and properties of these two bodies.

Substitution in Benzol.-F. Beilstein and A. Kurbatow. Not suitable for abstraction.

Solid Compounds of Carbon in Meteorites.-J. Lawrence Smith.-To regard the carbonaceous matter of black meteorites as a kind of humus is contrary to all that we know of humus. The meteoric body is almost insoluble

in alkaline lyes, gives off water only at a very high temperature after being previously dried at 110°, and burns readily upon platinum foil almost without odour, leaving much ash. According to the author's experiments it is neither humus nor true coal, but is probably an analogue of the so-called hydrate of carbon.

Examination of the Rotatory Power of the more important Cinchonic Alkaloids.-O. Hesse.-A valuable paper, but quite incapable of useful abstraction. Behaviour of Phenol with the Cinchonic Alkaloids. -O. Hesse.-Cinchonidin and quinine combine readily with phenol, but the dextro-gyratory crystalline alkaloids, conchinin, cinchonin, and chinamin, are, in their free state, not capable of forming a phenol compound.

Remarks on Cynanchol.-O. Hesse.-The properties of this body as described by Butleroff agree with those of a mixture of echicerin and echitin.

Pyrophosphate of Lithia, Lithia-Soda, aud LithiaPotassa.-M. Nahnsen and E. Cuno.-Not suited for


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Amidous Derivatives of Hydroxylamin.-This em braces a notice of the metallic derivatives of hydroxylurea, and the double salts of other hydroxamic acids, by N. D. C. Hodges; and one on the ester of hydroxamic acids, ethyl-hydroxylamin, and methyl-hydroxylamin, by W. Lossen and Dr. J. Zanni.

Dr. W. F. Læbisch. In this case the occurrence of Chemical Investigation of a Case of Cystinury.cystin was accompanied by the usual marked decrease of urea and uric acid.

Reimann's Farber Zeitung.
No. 36, 1876.

Dr. Reimann, in a paper read before the Berlin Dyers' Association, described "Pittakall," the method of preparing which has been recently re-discovered by Grätzel, of Hanover. Pittakall is insoluble in water, but dissolves in alcohol and in acids with an orange colour, and in alkalies with a magnificent violet. It dyes wool and silk direct, but cotton only when previously mordanted. This colouring-matter is of an acid character, and yields-with salts of lead, barium, aluminium, and tin-violet precipitates. Patterns of silk, wool, cotton, and mixed goods, dyed with the new colour, were exhibited. These shades resist air and light perfectly and soap moderately.

coloured with magenta, because the tannin present would A correspondent points out that red wines cannot be precipitate it as a tannate.

Les Mondes, Revue Hebdomadaire des Sciences,
No. 1, September 7, 1876.

Three Years of Experience in the Evaporation of Mother-Liquors; Treatise on the Production of Salt, showing the Advantages of Combined Evaporation from the Bottom and the Surface.-Otto Pohl.-The author, a Liverpool salt merchant, describes in this paper a series of very carefully conducted experiments on the preparation of salt, and appears to have effected very decided improvements.

No. 2, September 14, 1876.

Advancement of Science, held at Clermont-Ferrand, the At the recent meeting of the French Association for the inaugural discourse was delivered by M. Dumas. The following passage is significant :-"Except the soul, its origin, and its destiny, which pertain to the sphere of faith, the rest of the universe belongs to science. Let us leave the soul to God, morals to religion and to philosophy (metaphysics), and human passions to the poets, and let us march on resolutely to the scientific conquest of the universe; the field is vast enough for our free discussions."

Hoffmann's "Fringe” Polarimeter.-The construction of this instrument cannot be made intelligible without the accompanying illustration.


Chemical Notices from Foreign Sources.

A meteorological observatory has been established on the summit of the Puy de Dôme.

No. 3, September 21, 1876. Fuming Sulphuric Acid.-M. Winckler proposes to manufacture this acid by passing a proper mixture of sulphurous acid and oxygen over platinised asbestos.

Gazzetta Chimica Italiana.

Anno vi., 1876, Fasc. v. and vi.

Use of Hydrosulphite of Soda as a Reagent in the Analysis of Colours fixed upon Tissues.-G. ScuratiManzoni. The facility with which orchil is discoloured by the action of hydrosulphite suggested the idea of using it for estimating the value of orchil-paste and extract, but the attempt proved unsuccessful.

It is

Methods of Preparing the Iodides of Potassium and Sodium and the Bromide of Potassium.-P. Chiappe and O. Malesci.-To a solution of potassa at 30° B. the authors add iodine in fine powder till the mass remains coloured slightly red by iodine in excess. then mixed with iron filings, and heated in the sand-bath. Observation on a Process for obtaining Iodic Acid by causing Chlorine to Act upon Iodine Suspended in Water.-G. Sodini.-In order that all the iodine should be converted into iodic acid, I part should be used in 20 parts of water.

Oct. 6, 1876.

Assay of Commercial Oils.-A. Pinchon. - The author recommends, for ascertaining the purity of com'mercial samples of oils, a hydrometer inclosing a thermometer. A precisely similar instrument has been in use in Germany and in England for about twenty-five years, under the name of Fischer's oleometer.

Anti-fermentescible Action of Salicylic Acid.-M. Neubauer. An examination of the power of salicylic acid to arrest fermentation.

Chemical Indications relating to the Applications of Salicylic Acid.-H. Kolbe.

Use of Salicylic Acid to prevent the Fermentation of Syrups.-H. Lajoux.

from their title.
The nature of these two papers is sufficiently evident


Our Notes and Queries column was opened for the purpose of giving and obtaining information likely to be of use to our readers generally. We cannot undertake to let this column be the means of transmitting merely private information, or such trade notices as should legitimately come in the advertising columns.

Organic and Mineral Phosphates in Manure-Will any of your readers inform me of a method of distinguishing accurately between organic and mineral phosphates in a mixed manure.-E. C.


Elementary Physics and Geology.-Will any of your readers physics and on elementary geology.-W. T. PHILIPSON.

Magistery of Sulphur.-M. Sansoni and G. Capellini. Kindly give me the name of a good German book on elementary -The authors think it unnecessary to use pure hydrochloric acid, and employ the commercial quality, but free from arsenic.

Method of Detecting the Adulteration of Iodide of Lead.-L. Alessandri and C. Conti.-The usual adulterations are the chromate and carbonate of lead and the sulphate of baryta. Among the available tests they give the preference to potassa and ammonia, with which the detection of chrome is easy.

Now ready, New Edition, 8vo., 7s. 6d.,

Professor of Materia Medica and Therapeutics at Montreal.
J. and A. CHURCHILL, New Burlington Street.

A New Reagent for the Detection and Determina- WATER ANALYSIS: a Practical Treatise

tion of Glucose.-A. Soldiani.-416 grms. of bicarbonate of potassa; 15 grms. of basic carbonate of copper, dry; 1400 grms. of distilled water are placed to heat on the sand-bath in a porcelain capsule for about six hours, the liquid being kept always at the same level by adding water to make up for what is lost by evaporation, and stirring. The heat is withdrawn when the evolution of carbonic acid ceases; it is left to settle, and filtered, and concentrated to 800 c.c.

Preparation of Ferric and Cupric Oxides from their respective Sulphates without the Production of Basic Sulphates.-A. Oglialoro.--The author recommends to pour the sulphate of iron into a solution of an alkaline carbonate.

Moniteur Scientifique, du Dr. Quesneville,
September, 1876.

Relations of Chemistry with Physiology and
Pathology considered especially with regard to the
Brain.-C. T. Kingzett.

Chemistry of Diabetes Mellitus.-C. T. Kingzett. These two papers are translated from the English. Pepper and its Principal Adulterations.—E. Laudrin.-Amongst the ordinary sophistications of pepper, the author enumerates pepper-dust, the epidermic portion detached from the pepper; mineral matters, such as plaster, chalk, clay, ochre, &c.; grains of paradise; dregs from the manufacture of potato-starch; farina of leguminaceous seeds; olive kernels freed from oil and ground (these are regularly sold to the trade in France as "olive crusts-grignons-for pepper "); laurel leaves and oil


on the Examination of Potable Water.

FOURTH EDITION, thoroughly revised, crown 8vo., cloth, 5s.
London: TRÜBNER and CO., Ludgate Hill.

Early in October.



STUDENTS preparing for Matriculation (University of London),
College of Surgeons, Science and Art Department, and other Ex-
aminations. By THOMAS ELTOFT, F.C.S., Chemical Teacher to the
Matriculation Classes, St. Bartholomew's Hospital; Chemical
Lecturer, City of London College, St. Thomas, Charterhouse, Science
Schools, &c. Cloth, post 4to.

London: SIMPKIN, MARSHALL, and CO., Stationers' Hall Court
Manchester: JOHN HEYWOOD, Deansgate.



The Evening Lectures commence on Monday,

October 9th, and terminate in March.
CHEMISTRY-Mr. W. N. Hartley, at 7 o'clock. Mondays and
Thursdays. Fee, £1 119. 6d.
ANALYTICAL CHEMISTRY-Tuesday from 7 to 9. Fee, £2 25.




GIVEN that Coleman Street, London, E.C., are the Sole Consignees of Salicylic

Messrs. Burgoyne, Burbidges, Cyriax, and Farries, of 16

Acid manufactured by Dr. F. Von Heyden, Chemical Manufacturer,
Dresden, under Letters Patent, No. 595, 1874. Legal proceedings will
be taken against all persons manufacturing, importing, or sending
Salicylic Acid produced according to the said Patent without the
License of the Patentee.-Dated the 18th day of September, 1876.

J. HENRY JOHNSON, 47, Lincoln's Inn Fields, W.C.,
Solicitor for the Patentee, Professor Hermann Kolbe.

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THE paper-coal from Melili, Sicily, has been long known. Similar minerals have been described from several lignite deposits in different parts of Europe. I have often desired to ascertain whether there might be any near relationship between this paper-coal (sometimes termed dysodile) and the tasmanite, which I analysed and described in 1864 (Phil. Mag., IV., xxviii., 465). Both minerals burn with a most offensive odonr, fully accounted for in the case of tasmanite by the presence of much unoxidised sulphur in union with the carbon, hydrogen, and oxygen of the mineral. Analysis shows, however, that the resemblance of the two species is very slight, as the following results will demonstrate.

A characteristic specimen of dysodile from Rotl, near Bonn, was submitted to examination. To remove matters

soluble in water, and notably gypsum, it was powdered, and then washed with much water. Subsequently it was treated with moderately strong hydrochloric acid, until neither iron nor sulphuric acid could be detected in the acid liquid or washings. Thus it was expected that the high percentage of mineral matter in the original sample would be lowered, while all sulphates would at the same time be removed. The latter change was probably accomplished, not so the former. The following figures comprise the chief analytical data from which the ultimate composition of dysodile may be deduced :

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of combination in which the sulphur occurs be determined. As tasmanite can be obtained (by the use of mechanical means, aided by the action of hydrochloric and hydrofluoric acids) contaminated with no more than 1 per cent of a white or grey ash, we can prove that the high percentage of sulphur in that species exists in organic union with carbon, hydrogen, and oxygen, and not in the form of iron pyrites.



IN a former paper published in this journal* I gave my reasons for rejecting the theory that the proportions of the inorganic constituents have much to do with the health of the plant; in short, that we could not by an analysis of potato ash declare whether the tuber had been sound or not. I there showed that sound or diseased potatoes from the same field had virtually the same proportions of inorganic compounds, while potatoes from the same seed grown on different soil may have very different proportions of these compounds. These results have since been place on record further evidence I have obtained by corroborated by other investigators, but I would wish to analysis of the ash of potatoes grown near the sea-shore as compared with that of tubers from the same seed grown at some distance from it; both soils were gravelly. In No. II. that from inland. They both received the same the subjoined analyses No. I. is that from the shore, and manure. The method of analysis was that used by Bunsen.

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Sulphur.. Nitrogen Oxygen ..

In 100 parts.


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It is thus evident that dysodile does not belong to the same group of minerals as tasmanite, for the latter species is 10 per cent richer in carbon than the former. Dysodile, indeed, is possibly, perhaps even probably, a mixture of two or more distinct substances. Nor can the percentages given above be regarded as necessarily representing the carbonaceous constituent of the mineral. The sulphur, for example, may really belong to some fixed sulphide, such as pyrites, in the ash. Not till dysodile can be secured tolerably free from ferruginous ash can the mode

* See Dana's "Mineralogy," 5th edition, pp. 746 and 747.

Both these samples of potatoes were pretty good, the last portions of the carbon were very difficult to burn away, and the starch granules were large, and on being boiled the skin of the potato burst owing to the swelling of the starch granules which the tuber contained, and yet we see that as in the case of some other plants a large proportion of one element may be replaced by another without injuring the root. It will be noticed that in diseased or weakly tubers the potassium and sodium are nearly always present in greater quantity than in those of a healthy nature. I do not think that that is so much owing to an actual excess of these elements in the diseased tubers as to the fact before mentioned that it is

"On the Inorganic Constituents of Sound and Diseased Potatoes," CHEMICAL NEWS, vol. xxvii., p. 147.


Blowpipe Analysis of Henwoodite.

more difficult to completely oxidise the carbon in healthy tubers than in the diseased ones, and that a portion of these volatile substances is lost during the protracted ignition. This fact that the inorganic constituents are less intimately combined with the carbon compounds in diseased tubers than in those which are healthy led me to the conjecture that a kind of constitutional decay was the precursor of the real disease. The paper above referred to concluded as follows:-" On the whole I think the potato disease is a problem for the naturalist or the physiologist rather than the chemist." Now the researches of Mr. Worthington Smith have proved that the conjecture was correct, but the fact still remains unexplained that even during the worst periods of disease some fields escape infection. And I found on careful inquiry that as a general rule those fields which escaped were of a darker colour than those attacked, and this led me to the conjecture that the heat caused by the absorption of the solar rays must strengthen the constitution of the plant. Besides, as I pointed out in my former paper, soot is considered by practical men as a preventive of the disease, and it occurred to me to determine by experiment whether, besides the good which its contained ammoniacal salts does, a part of its virtue may not lie in its imparting a dark colour to the soil and so rendering it a better absorbent of solar heat. I therefore had the following experiment tried to decide this question:

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Percentage of ash

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Phosphoric oxide

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Sulphuric oxide

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The principal result to which I wish to draw attention, however, is the manner in which the starch granules are developed in the two sets of tubers. First as to quantity. The method of estimating the starch was as follows:The best potatoes from both portions of the soil were cut up and dried, and a weighed portion treated with alcoholic potash to remove sugar, fat, &c., and dried and weighed ; then treated with diluted hydrochloric acid to remove the starch, and again dried and weighed. The difference between the last two weighings gives the starch in the original quantity. In this way the potatoes grown under soot gave 22.5 per cent of starch and those in the plain ground 17'5 per cent, a difference of 5 per cent. Then as to the size of the starch granules :-Micrometrical measurements of 20 average granules in the good potatoes gave an average of o'175 m.m., whereas 20 of those from A piece of ground was chosen, little adapted for the the diseased tubers gave only o'155 m.m. We see from growth of potatoes, consisting of a kind of blue till. The this that not only were the granules smaller but their ground was divided into two parts, and both were planted substance was altogether of a more fibrous nature. It number was less. In the potatoes poor in starch the with potatoes in the ordinary way, using stable manure. The one half was left as planted, while the other was thus appears that the increase in temperature gives a covered with soot which had been carefully washed till great impetus to the growth of starch granules both in no soluble matter remained in it. Those with the soot size and number. I know that an investigation like this sprouted first and were all through much healthier than would require to be extended over several years to make the others. A series of temperatures were taken until the sure of a definite law, and such was my intention, but as foliage was too thick for much sunlight to penetrate, and I had to leave this country last spring the experiments I then resumed when the foliage was beginning to fail till intended to carrry on this year were not accomplished, the tubers were dug up. The temperature of the air was and I have no prospect of being able to resume the invesnot kept, as we have no idea from it what is the real tem-tigation soon; so I considered in these circumstances that perature of the leaf, as we do not know how much heat it the above results were sufficiently striking to warrant absorbs from the sun's rays. All the temperatures were publication. taken on sunny days as on otherwise there was no differ ence in temperature. The following table gives the two series of temperatures. They were taken at 2 and 8


inches below the surface and always simultaneously, but BLOWPIPE ANALYSIS OF THE NEW MINERAL not at regular intervals, and in reality do not represent the actual average temperature of the earth, but they serve the purpose I intended to show-the higher temperature of the dark coloured earth.

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By MAJOR ROSS, late R.A.

THE first number of the Mineralogical Society's Journal contains the blowpipe analysis by Berzelian methods of this interesting mineral, written by Dr. C. Le Neve Foster, H. M. Inspector of Mines, who seems also to have discovered it; and Mr. J. H. Collins, the Society's Secretary, having been so kind as to forward me by letter a few pin's-head fragments of the mineral for the purpose of testing them by my methods, I have the pleasure now to send you an account of these, but, in the first place, append Dr. Foster's analysis.

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Colour.-Turquoise blue.

Streak.-White, with bluish green tinge. "Matrass.-Turns brown, gives H2O, slight decrepita


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