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152
Determination of Gold in Pyrites.

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OA. 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 par.

ASSAYER. ticular attention of veterinary surgeons and others are these

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

CHEMICAL NOTICES FROM FOREIGN 2. That this salt is contained in the corn; and here arises the question whether corn is not for the horse as

SOURCES artificial a food as meat is for the human race.

3. The ease with which these calculi can be decom- Note.-All degrees of temperature are Centigrade, unless otherwise posed, broken up, dispersed, or dissolved by means of expressed. weak hydrochloric acid.

I am of opinion that repeated doses of very dilute Comptes Rendus Hebdomadaires des Scances, de l'Acadenie hydrochloric acid, say 2 to 5 per cent, in water or spirit,

des Sciences. No. 10, September 4, 1876. if it can be made to reach them, would destroy the largest

Pesearches on the Disappearance of the Ammonia of these calculi in a comparatively short space of time. Contained in Waters.-M. A. Houzeau.—Spring- and This treatment, with appropriate diet, would, I feel con- river water contains little ammonia, whilst rain, dew, and vinced, prove effectual even in very bad cases.

fog often contains it in abundance. Well-waters rapidly The disease no doubt originates from the cæcum lose their ammonia, even when contained in vessels herbecoming alkaline instead of remaining slightly acid as itmetically sealed. This loss is promoted by light. should be in a normal state of health; the calculus itself is alkaline, and contains minute quantities of carbonate of

Results obtained on the Extraction of the Juice ammonia and tribasic phosphate of magnesia, as well as of the Sugar-Cane by means of New Apparatus.the phosphate of ammonia

and magnesia which constitutes --MM. Mignon and Rouart.—The cane is cut up by the greater part of it. It is a very rapid disease; when once for reducing straw to a pulp for the paper manufađure.

means of a machine like that contrived by MM. Labrouse To cite one instance that has come under my own obser: The pulp thus obtained is subjected to hydraulic pressure vation, a fine cart-horse was born in Hereford, where it at 80 atmospheres. The canes thus yield 77 per cent of remained four years, and then went to Staffordshire, where rich juice. it lived five years longer. It died of calculus at nine years

Detection of Magenta used in the Sophistication of age, and the calculus was 20 inches in circumference- of Wines.-M. V. Didelot.-The author has forwarded the size of an ordinary gas-lamp globe—and weighed to the Academy a sample of gun-cotton dyed with a wine 8 lbs., so that it must have increased at least about i lb. containing magenta. a year, perhaps much more.

Dissociation of Bicarbonate of Soda at rooo.-M. The lime in the water drunk by horses, to which some | V. Urbain.—The author maintains, in opposition to M. have attributed the disease, has nothing to do with it. Gautier, that if dried plasma is submitted to a tempera. It originates in the food-in the corn—as I have stated ture of 100° the bicarbonate of soda which it contains is above, and is due no doubt, in great measure, to a want of not decomposed. salt in the food. When horses are highly fed for labour in the industrial districts, it is essential that they should

No. II, September 11, 1876. 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 Coloured.-M. L. Lamattina.—To detect wines artifi

Process for the Detection of Wines Artificially drainage of the stable is another important consideration cially coloured, the simplest method is to mix 100 grms. How many valuable beasts after a hard day's work pass of the wine with 15 grms. of wine in coarse powder, stir the night in an atmosphere loaded with fumes of am

the mixture for twelve to fifteen minutes, and filter through monia I-I am, &c.,

a double filter. If the wine is pure it passes through T. L. PHIPSON, Ph.D., F.C.S., &c.

colourless, but if it preserves its colour it has been artifi. Laboratory of Analytical Chemistry,

cially coloured. If pure peroxide of manganese has been Putney, London, S.W., September 24, 1876.

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 DETERMINATION

of the wine dissolve the iron; magenta, if present, forms OF GOLD IN PYRITES.

an insoluble compound, which remains on the filter. The To the Editor of the Chemical News.

filtrate then takes a faintly yellowish colour, resembling

that of sesqui-salts of iron. In this case the peroxide of Sir, -Why do M. H. Schwarz and the gentleman signing manganese left upon the filter is treated with alcohol, himself “'Latent" in the Chemical News, vol. xxxiv., which dissolves the magenta, whilst the natural colouring p. 132,

propose to fuse the pyrites with iron turnings at matter of the wine is insoluble. If the alcoholic filtrate all? There is nothing whatever to be gained by so doing, remains of a blue slightly yellowish the presence of and they would get the gold into a quantity of regulus | magenta may be suspected. If we add to this liquid convery much larger than necessary and very inconvenient centrated acetic acid, and then a few drops of ammonia, for further treatment. If they simply fuse the pyrites the colour of the magenta reappears after stirring for a alone at a strong heat, with such flux as the gangue, if

few moments. any is present, may require, a very much smaller regulus will result, equally sure to contain all the gold, and from a letter to The Count Th. du Moncel.)

Note on the Radiometer.-W. Crookes.-(Extract equally suitable for treatment with acid.

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,

Justus Liebig's Annalen der Chemie, cover with assay-lead, fuse, and scorify in a muffle, finally

Band 182, Heft 1 and 2. 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,

,} Chemical Notices from Foreign Sources. Oct. 6, 1876.

153 nor a candle-flame the summit of the wick; and that a action of hydrochloric acid upon potassium chlorate by flame never comes in close contact with a cold body is G. Schacherl. due to the fact that heat is conducted away by the solid On Phosphorus Pentafluoride.--T. E. Thorpe.body. The flame-gases are cooled for a certain distance This compound, PF5, is a colourless gas of a very pun. below their ignition-point, and the flame is consequently gent odour, and strongly attacks the throat and the extinguished within this region. The distance between a

mucous membranes. It fumes in the air, and is decomgas-filame and the burner is considerably increased if the posed by water into phosphoric and hydrofluoric acids. inflammable gas or vapour streams out under a high pres- | It is four and a half times heavier than air, and can be sure, or is mixed with a large amount of some non-inflam- poured from one vessel to another like carbonic acid. It mable gas. This phenomenon is due not merely to the is neither combustible nor a supporter of combustion. It cooling action of the gaseous stream and of the external ) is not modified by the passage of electric sparks, nor by air, but to the fact that the speed of the issuing gas stream the introduction of oxygen or hydrogen. close to the burner is greater than the speed of the propa

Oxidation Product of Glycogen with Bromine, gation of ignition. When other influences are not essen- Silver-Oxide, and Water.-R. #. Chittenden.—The tial, the flame begins in that section of the issuing gas product is an acid, for which the author proposes the current where its speed equals the speed of the propagation of ignition. Hence this speed of propagation for different name glycogenic. He describes a number of its salts. gases and vapours may be experimentally ascertained. Amidous Derivatives of Hydroxylamin.—This emIn case of solids and liquids of a combustible nature the braces a notice of the metallic derivatives of hydroxylsame speed may also be readily found by experiment, and urea, and the double salts of other hydroxamic acids, by the results may be regarded as relative numerical expres

N. D. C. Hodges; and one on the ester of hydroxamic sions of the dangerous character of the combustibles in acids, ethyl-hydroxylamin, and methyl-hydroxylamin, by question.

W. Lossen and Dr. J. Zanni. Communications from the Laborarory of the Poly: Dr. W. F. Läbisch. - In this case the occurrence of

Chemical Investigation of a Case of Cystinury.technic School of Delft.--These communications consist of a paper on a-Xylenolol prepared from Metaxylol, cystin was accompanied by the usual marked decrease of by S. Lako, and a long and important dissertation by A.

urea and uric acid. Ć. Oudemanns on the “Specific Rotatory Power of the more important Cinchona Alkaloids."

Reimann's Farber Zeitung. Composition of the Dialurates.-M. Menschutkin.

No. 36, 1876. An account of the dialurates of ammonium, potassium,

Dr. Reimann, in a paper read before the Berlin Dyers' sodium, and barium.

Association, described “ Pittakall,” the method of preOn Tartronaminic Acid.-M. Menschutkin.--A pro- paring which has been recently re-discovered by Grätzel, duct obtained on the decomposition of dialurate of sodium of Hanover. Pittakall is insoluble in water, but dissolves by means of water. Its composition is C3H5NO4. in alcohol and in acids with an orange colour, and in

On Ethyl- and Methyl-Succinimid.-M. Menschut- alkalies with a magnificent violet. It dyes wool and silk kin.—A brief account of the preparation, composition, and direct, but cotton only when previously mordanted. This properties of these two bodies.

colouring-matter is of an acid character, and yields—with Substitution in Benzol.-F. Beilstein and A. Kurba salts of lead, barium, aluminium, and tin-violet precipitow.-Not suitable for abstraction.

tates. Patterns of silk, wool, cotton, and mixed goods,

dyed with the new colour, were exhibited. These shades Solid Compounds of Carbon in Meteorites.-J. resist air and light perfectly and soap moderately. Lawrence Smith.—To regard the carbonaceous matter of black meteorites as a kind of humus is contrary to all that coloured with magenta, because the tannin present would

A correspondent points out that red wines cannot be we know of humus. The

meteoric body is almost insoluble precipitate it as a tannate. 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 Les Mondes, Revue Hebdomadaire des Sciences, neither humus nor true coal, but is probably an analogue

No. 1, September 7, 1876. of the so-called hydrate of carbon.

Three Years of Experience in the Evaporation of Examination of the Rotatory Power of the more Mother-Liquors; Treatise on the Production of Salt, important Cinchonic Alkaloids.-0. Hesse.- A showing the Advantages of Combined Evaporation valuable paper, but quite incapable of useful abstraction from the Bottom and the Surface.-Otto Pohl.-The

Behaviour of Phenol with the Cinchonic Alkaloids. author, a Liverpool salt merchant, describes in this paper -0. Hesse.-Cinchonidin and quinine combine readily a series of very carefully conducted experiments on the with phenol, but the dextro-gyratory crystalline alkaloids, preparation of salt, and appears to have effected very conchinin, cinchonin, and chinamin, are, in their free decided improvements. state, not capable of forming a phenol compound.

No. 2, September 14, 1876. Remarks on Cynanchol.-0. Hesse.— The properties of this body as described by Butleroff agree with those of Advancement of Science, held at Clermont-Ferrand, the

At the recent meeting of the French Association for the a mixture of echicerin and echitin.

inaugural discourse was delivered by M. Dumas. The Pyrophosphate of Lithia, Lithia-Soda, aud Lithia. following passage is significant :-" 'Except the soul, its Potassa.-M. Nahnsen and E. Cuno.-Not suited for origin, and its destiny, which pertain to the sphere of faith, abstraction.

the rest of the universe belongs to science. Let us leave Derivatives of Glycerin.-K. Kraut.-Among the deri- the soul to God, morals to religion and to philosophy vatives described are iodtriethylglycinammoniumethylester (metaphysics), and human passions to the poets, and let glycin, chlortriethylglycinammoniumplatin chloride, and us march on resolutely to the scientific conquest of the diethylglycinethylester.

universe ; the field is st enough for our free discus. Communications from the University Laboratory

sions." of Graz.-These consist of a paper on trichloro-butyric Hoffmann's " Fringe" Polarimeter.—The construcacid, by K. Garzarolli-Thurnlak; another by the same tion of this instrument cannot be made intelligible without author on certain salts of glyceric acid ; and one on the I the accompanying illustration.

154
Chemical Notices from Foreign Sources. {

CHEMICAL NEWS

Oct. 6, 1876. A meteorological observatory has been established on Assay of Commercial Oils. — A. Pinchon. – The the summit of the Puy de Dôme.

author recommends, for ascertaining the purity of com

mercial samples of oils, a hydrometer inclosing a thermoNo. 3, September 21, 1876.

meter. A precisely similar instrument has been in use in Fuming Sulphuric Acid.—M. Winckler proposes to Germany and in England for about twenty-five years, manufacture this acid by passing a proper mixture of under the name of Fischer's oleometer. sulphurous acid and oxygen over platinised asbestos. Anti-fermentescible Action of Salicylic Acid.-M.

Neubauer.-An examination of the power of salicylic acid to arrest fermentation.

Chemical Indications relating to the ApplicaGazzetta Chimica Italiana.

tions of Salicylic Acid.-H. Kolbe. Anno vi., 1876, Fasc. v. and vi.

Use of Salicylic Acid to prevent the Fermenta. Use of Hydrosulphite of Soda as a Reagent in the tion of Syrups.-H. Lajoux. Analysis of Colours fixed upon Tissues.-G. ScuratiManzoni.- The facility with which orchil is discoloured by from their title.

The nature of these two papers is sufficiently evident the action of hydrosulphite suggested the idea of using it for estimating the value of orchil-paste and extract, but the attempt proved unsuccessful. Methods of Preparing the lodides of Potassium

NOTES AND QUERIES, and Sodium and the Bromide of Potassium.-P. Chiappe and O. Malesci.—To a solution of potassa at

Our Notes and Queries column was opened for the purpose of 30° B. the authors add iodine in fine powder till the mass giving and obtaining information likely to be of use to our readers remains coloured slightly red by iodine in excess. It is generally. We cannot undertake to let this column be the then mixed with iron filings, and heated in the sand-bath. means of transmitting merely private information, or such trade

notices as should legitimately come in the advertising columns. Observation on a Process for obtaining lodic Acid by causing Chlorine to Act upon Iodine Suspended your readers inform me of a method of distinguishing accurately

Organic and Mineral Phosphates in Manure:-Will any of in Water.-G. Sodini.-In order that all the iodine should

between organic and mineral phosphates in a mixed manure.-E. C. be converted into iodic acid, I part should be used in Porler. 20 parts of water.

Elementary Physics and Geology.-Will any of your readers

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

Now ready, New ition, 8vo., 7s.6d., Method of Detecting the Adulteration of Iodide of CHEMIA COARTATA: Lead.-L. Alessandri and C. Conti.—The usual adultera

OR, THE KEY TO MODERN CHEMISTRY. tions are the chromate and carbonate of lead and the sul

By A. H. KOLLINYER, A.M., M.D., phate of baryta. Among the available tests they give the

Professor of Materia Medica and Therapeutics at Montreal. preference to potassa and ammonia, with which the detection of chrome is easy.

J. and A. CHURCHILL, New Berlington Street.

ATER ANALYSIS: a Practical Treatise tion of Glucose.-A. Soldiani.—416 grms. of bicarbonate

on the Examination of Potable Water. of potassa; 15 grms. of basic carbonate of copper, dry;

By J. A. WANKLYN, M.R.C.S. 1400 grms. of distilled water are placed to heat on the FOURTH Edition, thoroughly revised, crown 8vo., cloth, ss. sand-bath in a porcelain capsule for about six hours, the

London: TRÜBNER and Co., Ludgate Hill. liquid being kept always at the same level by adding water to make up for what is lost by evaporation, and stirring.

Early in October.

COMBINED NOTE-BOOK AND acid ceases; it is left to settle, and filtered, and concen. The heat is withdrawn when the evolution of carbonic LECTURE NOTES FOR THE USE OF CHEMICAL trated to 800 c.c.

STUDENTS preparing for Matriculation (University of London),

College of Surgeons, Science and Art Department, and other Ex. Preparation of Ferric and Cupric Oxides from their aminations. By Thomas Eltoft, F.C.s., Chemical Teacher to the respective Sulphates without the Production of Matriculation Classes, St. Bartholomew's Hospital; Chemical Basic Sulphates.-A. Oglialoro.--The author recom

Lecturer, City of London College, St. Thomas, Charierhouse, Science

Schools, &c. Cloth, post 4to. mends to pour the sulphate of iron into a solution of an

London : SIMPKIN, MARSHALL, and CO., Stationers' Hall Court alkaline carbonate.

Manchester : JOHN HEYWOOD, Deansgate.

KING'S COLLEGE.-EVENING CLASSES.
Moniteur Scientifique, du Dr. Quesneville,
September, 1876.

WINTER SESSION, 1876-77.
Relations of Chemistry with Physiology and
Pathology considered especially with regard to the | The Evening Lectures commence on Monday,
Brain.-C. T. Kingzett.

October 9th, and terminate in March.

CHEMISTRY–Mr. W. N. Hartley, at 7 o'clock. Mondays and Chemistry of Diabetes Mellitus.-C. T. Kingzett.

Thursdays. Fee, £i 118.6d. These two papers are translated from the English. ANALYTICAL CHEMISTRY- Tuesday from 7 to 9. Fee, £2 29. Pepper and its Principal Adulterations.-E. Laud

SALICYLIC ACID. rin.-Amongst the ordinary sophistications of pepper, the

HEREBY GIVEN author enumerates pepper-dust, the epidermic portion de

that tached from the pepper; mineral matters, such as plaster,

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

Coleman Street, London, E.C., are the Sole Consignees of Salicylic chalk, clay, ochre, &c.; grains of paradise ; dregs from Acid manufactured by Dr. F. Von Heyden, Chemical Manufacturer, the manufacture of potato-starch ; farina of legumina. Dresden, under Letters Patent, No. 595, 1874. Legal proceedings will ceous seeds; olive kernels freed from oil and ground be taken against all persons manufacturing, importing, or sending (these are regularly sold to the trade in France as olive Salicylic Acid produced according to the said Patent without the

License of the Patentee.--Dated the 18th day of September, 1876. crusts-grignons—for pepper''); laurel leaves and oil.

J. HENRY JOHNSON, 47, Lincoln's Inn Pields, W.C., cakes.

Solicitor for the Patentee, Professor Hermann Kolbe.

A New Reagent for the Detection and Determina: WATE

NOTICE IS

manure.

Oct. 13, 1876.
,} Effect of Temperature on the Growth of Potatoes.

155

of combination in which the sulphur occurs be determined. THE CHEMICAL NEWS. 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 VOL. XXXIV. No. 881.

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.
DYSODILE,
By Prof. A. H. CHURCH.

NOTE ON THE EFFECT OF TEMPERATURE The paper-coal from Melili, Sicily, has been long known. ON THE GROWTH OF POTATOES. Similar minerals have been described from several lignite

By J. B. HANNAY, F.R.S.E. 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 In a former paper published in this journal* I gave my

reasons for rejecting the theory that the proportions of the described in 1864 (Phil. Mag., IV., xxviii., 465). Both minerals burn with a most offensive odonr, fully accounted inorganic constituents have much to do with the health

of the plant; in short, that we could not by an analysis of for in the case of tasmanite by the presence of much un. oxidised sulphur in union with the carbon, hydrogen, and potato ash declare whether the tuber had been sound or

not. I there showed that sound or diseased potatoes from oxygen of the mineral. Analysis shows, however, that the resemblance of the two species is very slight, as the organic compounds, while potatoes from the same seed

the same field had virtually the same proportions of in. following results will demonstrate.

grown on different soil may have very different proporA characteristic specimen of dysodile from Rotl, near

tions of these compounds. These results have since been Bonn, was submitted to examination. To remove matters soluble in water, and notably gypsum, it was powdered, corroborated by other investigators, but I would wish to

place on record further evidence I have obtained by and then washed with much water. Subsequently it was treated with moderately strong hydrochloric acid, until analysis of the ash of potatoes grown near the sea-shore as neither iron nor sulphuric acid could be detected in the compared with that of tubers from the same seed grown

at some distance from it; both soils were gravelly. In acid liquid or washings. Thus it was expected that the high percentage of mineral matter in the original sample the subjoined analyses No. 1. is that from the shore, and

No. II. that from inland. They both received the same would be lowered, while all sulphates would at the same time be removed. The latter change was probably

The method of analysis was that used by

Bunsen. accomplished, not so the former. The following figures

No. I. No. II. comprise the chief analytical data from which the ultimate

Percentage of ash fromĮ 4:25 composition of dysodile may be deduced :

dried tuber A. Dysodile thoroughly washed with Water and Soluble portionHydrochloric Acid, and dried at 100° C.

Potassium

32'55 38.81

Sodium 0*328 grm. gave oʻ1640 grm. ash, or 50'00 p.c. ash.

10:87

3'96 0'328

0.0980
Fe2O3, or 28.88
Magnesium

1'04
0.651
BaSO4, or 1917 »

Carbon dioxide..
0'0555
S.

14'29 14'97
CO2,

Phosphoric oxide 0'593 0'7515 or 34:56 ,

4'01 5.83 0'2685 "

H20, 0593

or 5'03 "
Sulphuric oxide

274 5'22
Chlorine

10:59

6:58
B. Dysodile treated with Water and stronger

Insoluble portion-
Hydrochloric Acid.

Silica..

1.85 1'94 0'0885 grm. gave 0'0298 grm. ash, or 33.67 p.c. ash.

Ferric oxide and alumina..

0'25 0.80 0'3415 0'0615 ,, PtAm,Cl6 or 1'13 N.

Calcium

3'09 4'17 Magnesium

I'15 0'73 It appears from the above figures that the composition

Carbon dioxide..

I'31 1.88 of the carbonaceous or combustible part of dysodile may be

Phosphoric oxide

3:40 4:17 represented by the following percentages, if the ash present

Unburnt carbon

0:50

0.62 be previously deducted :

Oxygen equivalent to

metals minus equivalent 11•63 10.68
Composition of Dysodile.

proportion of chlorine ..
In 100 parts.
Carbon ..
69'01

100'45 101'40
Hydrogen

10:04 Sulphur..

Both these samples of potatoes were pretty good, the

2'35 Nitrogen

1970

last portions of the carbon were very difficult to burn Oxygen ..

16.90

away, and the starch granules were large, and on being

boiled the skin of the potato burst owing to the swelling It is thus evident that dysodile does not belong to the of the starch granules which the tuber contained, and yet same group of minerals as tasmanite, for the latter species we see that as in the case of some other plants a large is 10 per cent richer in carbon than the former. Dysodile, proportion of one element may be replaced by another indeed, is possibly, perhaps even probably, a mixture of without injuring the root. It will be noticed that in two or more distinct substances. Nor can the percentages diseased or weakly tubers the potassium and sodium are given above be regarded as necessarily representing the nearly always present in greater quantity than in those of carbonaceous constituent of the mineral. The sulphur, a healthy nature. I do not think that that is so much for example, may really belong to some fixed sulphide, owing to an actual excess of these elements in the dis. such as pyrites, in the ash. Not till dysodile can be eased tubers as to the fact before mentioned that it is secured tolerably free from ferruginous ash can the mode

*"On the Inorganic Constituents of Sound and Diseased Potatoes," * Sec Dana's “ Mineralogy," 5th edition, pp. 746 and 747. | Chemical News, vol. xxvii., p. 147.

4'08

2'22

» Zn0z.

C.
H.

156

2'04

5'08

Blowpipe Analysis of Henwoodite.

{CH

Oct. 13, 1876. more difficult to completely oxidise the carbon in healthy

No. I. No. II. tubers than in the diseased ones, and that a portion of Percentage of ash

3.85 4'27 these volatile substances is lost during the protracted ignition. This fact that the inorganic constituents are Potassium

38:25 3973 less intimately combined with the carbon compounds in

Sodium

2:17 diseased tubers than in those which are healthy led Magnesium

2:42 2.87 me to the conjecture that a kind of constitutional decay Calcium

4'02

3'75 was the precursor of the real disease. The paper above Phosphoric oxide

10'94 10:51 referred io concluded as follows:-“On the whole I think Sulphur.c oxide

5*22 6.83 the potato disease is a problem for the naturalist or the Chlorine

6:15 physiologist rather than the chemist.” Now the researches of Mr. Worthington Smith have proved that the The principal result to which I wish to draw attention, conjecture was correct, but the fact still remains unex- however, is the manner in which the starch granules are plained that even during the worst periods of disease developed in the two sets of tubers. First as to quantity. some fields escape infection. And I found on careful The method of estimating the starch was as follows:inquiry that as a general rule those fields which escaped

! The best potatoes from both portions of the soil were cut were of a darker colour than those attacked, and this led up and dried, and a weighed portion treated with alcoholic me to the conjecture that the heat caused by the absorp. potash to remove sugar, sat, &c., and dried and weighed; tion of the solar rays must strengthen the constitution of then treated with diluted hydrochloric acid to remove the the plant. Besides, as I pointed out in my former paper, starch, and again dried and weighed. The difference soot is considered by practical men as a preventive of the between the last two weighings gives the starch in the disease, and it occurred to me to determine by experiment original quantity. In this way the potatoes grown under whether, besides the good which its contained ammoniacal soot gave 22'5 per cent of starch and those in the plain salts does, a part of its virtue may not lie in its imparting ground 17.5 per cent, a difference of 5 per cent. Then as a dark colour to the soil and so rendering it a better ab- to the size of the starch granules :- Micrometrical sorbent of solar heat. I therefore had the following ex. measurements of 20 average granules in the good potatoes periment tried to decide this question :

gave an average of 0:175 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 growih 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

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

HENWOODITE. actual average temperature of the earth, but they serve the purpose I intended to show-the higher temperature

By MAJOR ROSS, late R.A. of the dark coloured earth.

The first number of the Mineralogical Society's Fournal Earth Covered with Soot. Pure Earth.

contains the blowpipe analysis by Berzelian methods of Depth 2 ins. Depth 8 ins. Depth 2 ins. Depth 8 ins.

this interesting mineral, written by Dr. C. Le Neve

Foster, H. M. Inspector of Mines, who seems also to have 55'4 52:6 53'0 52'1

discovered it; and Mr. J. H. Collins, the Society's Secre56.9 5590

554

tary, having been so kind as to forward me by letter a few 67'2 63'9 65'1 бо:8

pin's-head fragments of the mineral for the purpose of 63'2 63.8

testing them by my methods, I have the pleasure now to
5867
58:8

58.0
63.0
60:6

send you an account of these, but, in the first place, 59'2

append Dr. Foster's analysis. 5801

56.9 572 56'3 6402 62'2

бr:8

Colour.-Turquoise blue.
65'4 63.8 63.9 62'0

Streak.-White, with bluish green tinge.
63'2
бr'4
боо
60'0

Matrass.-Turns brown, gives H20, slight decrepita.

tion. Average 61096 59.83 60:19 58.74

“ Pt forceps.-Colours flame green, does not fuse.

" C alone. ---Does not suse. These numbers show distinály that the potatoes grown Borax.-0.F. green hot, blue cold. in a dark soil have a warmer climate, so to speak, than · Borax.R.F. un C; Cu reduced. those in a light one. The tubers with no soot were weak “Carb. soda on C; obtained metallic Cu. and a great deal of disease among them, whereas those · Berzelius's test for P205:-Boric acid and Fe on C which had the covering were larger and nearly all healthy.

obtained round globule of phosphide of iron. Still, as the following numbers show, the principal in. Dissolved in H2SO4, added ammonia, blue solution, organic constituents were present in nearly the same

and white flocculent precipitate (Al2O3). proportions. No. I. is from the soot-covered tubers, " Filtered, added oxalate of potassium ; decided lur. No. 11. from the others.

bidity (CaO).

55'2

64:5 61°7

624

614

6385

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