BaSO4

Rem.-Precipitant for SO3, BaCl2; for Ba, H2SO4. Precipitated in an extremely fine state of division (runs through filter paper) if formed in cold or dilute solutions, or such as contain ammonia salts. Forms slowly if small

in amount.

The tendency of the precipitate to creep up the side of a beaker may be checked by adding a drop of HCl. Cond.-Hot solution acidified with HCl. Hydro-fluosilicic acid or silica should be absent, also large proportions of calcium salts, or salts of the (NH4)2S group of bases.

Sol.-Soluble in concentrated H2SO4, in HCl when moderately strong and hot, and in HÑO, even when tolerably dilute. It is also soluble in hot Fe2Cl6, in alkaline and alkaline earth nitrates, citrates, and salts of some other organic acids.

Insoluble in water, in very dilute HCl, and in acetic

acid.

Contam.-The especial difficulty with BaSO4 is its tendency to carry with it other substances, as alkaline and alkaline earth nitrates, chlorates, sulphates, and chlorides. Potassium salts give more trouble in this respect than sodium salts. The precipitate may also contain silica, and basic ferric, aluminic, or chromic compounds.

Repeated boiling up with very dilute HCl assists in removing some of these to a considerable extent, though there is some danger of dissolving some of the precipitate by this treatment. Washing alternately with hot dilute HCl and with cold water is often advantageous. Stolba's method of purifying the precipitate consists in digesting (after washing) for ten to fifteen minutes at a boiling heat, with 40-50 c.c. of cold saturated solution of Cu(C2H3O2)2 and acetic acid, filtering, and washing free from Cu (vide Crookes's Select Methods," second edition, p. 492). Sloane recommends for purification from iron, to decant the supernatant liquid closely, then add 5 or 10 c.c. of concentrated HCl, and boil for one minute, dilute, and after nearly neutralising with ammonia, filter and wash thoroughly (Four. Amer. Chem. Soc., iii., 37). Archbutt advises to precipitate warm (not boiling), allow to stand until thoroughly cold and the precipitate has settled well, then to filter and wash with cold water (Four. Soc. Chem. Ind., ix., 25). Jannasch and Richards assert than no correct determination of SO3 can be made in the presence of Fe, because the precipitate always contains more or less of a double barium iron sulphate, from which SO3 is expelled on ignition. To avoid errors they therefore recommend the previous removal of the iron by ammonia (Fourn. Prac. Chem., [2], xxxix., 321), (vide also Lunge, Zeit. Angew. Chemie, 1880, 473). Zeigler (Pharm. Central., 1881, p. 555) recommends the addition of some AgNO3 to the solution (containing chloride), that the AgCl may enclose and carry with it the particles of BaSO4. After washing with water the AgCl may be dissolved off with ammonia.

Ign.-With C some BaS invariably forms. The difficulty may be remedied by adding a few drops of fuming HNO3 to re-oxidise the S, and igniting again, or better by re-igniting after the addition of a drop or two of concentrated H2SO4.

SIMPLEX GAS GENERATOR.

By C. G. MOOR.

THIS new pattern gas generator possesses several advantages over those now in use. It may be used equally well to prepare hydrogen, carbonic acid gas, chlorine (using the compressed chloride of lime), or sulphuretted hydrogen.

The last-mentioned can best be prepared by using commercial hydrochloric acid mixed with an equal bulk of water. The apparatus is easy to clean and charge, delivers a drier gas than most other forms of generator, and the liquid cannot travel up the gas tube. The parts may be had separate.

To GENERAL A. DE COURCY SCOTT, R.A., Water Examiner, Metropolis Water Act, 1871. London, October 8th, 1891. SIR,-We submit herewith the results of our analyses of the 181 samples of water collected by us during the past month, at the several places and on the several days indi. cated, from the mains of the seven London Water Com. panies taking their supply from the Thames and Lea.

In Table 1. we have recorded the analyses in detail of samples, one taken daily, from September 1st to September 30th inclusive. The purity of the water, in respect to organic matter, has been determined by the Oxygen and Combustion processes; and the results of our analyses by these methods are stated in Columns XIV. to XVIII.

We have recorded in Table II. the tint of the several samples of water, as determined by the colour-meter described in a previous report.

In Table III. we have recorded the oxygen required to oxidise the organic matter in all the samples submitted to analysis.

Of the 181 samples examined, the whole were found to be clear, bright, and efficiently filtered, excepting one, which was recorded as "very slightly turbid."

The satisfactory condition of the water supply to the Metropolis, recorded now for several consecutive months,

Comstock's formula, 3RO2+2RO3, for the Branchville uraninite was of course hereby invalidated. Of North American occurrences of this mineral it only remained to examine that from North Carolina. From the Black Hills, Dakota, where it has been reported to occur, I have been unable to procure specimens, and the same can be said of the-at that time unknown-Llano County, Texas, locality, whence a closely allied mineral, nivenite, has recently been described by Hidden and Mackintosh (Am. Four. Sci., 1889, [3], xxxviii., 482). Owing to its evident alteration it was not expected that light would be thrown on the question of original composition by an examination of the North Carolina material, but the presence or ab. sence of thoria could be ascertained, as it was affirmatively by finding that and other earths.

General Introductory Remarks. WHEN the work which is described in the following pages was commenced in 1888 it was simply as an analysis of a fragment of a large crystal of uraninite from Glastonbury, Connecticut, without thought of further extension. Thoria had been found in it, and quantitative analysis was made in order to learn if possible whether this belonged to the uraninite or was due to an accidental admixture of thorium silicate as found by Penfield (Am. Four. Sci., [3], 1882, xxiv., 250) to be the case, at least in part, for the thoria in monazite from Portland, Connecticut, and Amelia County, Virginia. It was hereby established that the 10 per cent of thoria found was a constituent of the uraninite, and the unexpected discovery was made that no formula in the slightest degree corresponding to that found by Comstock (Am. Four. Sci, [3], 1880, xix., 220) for the Branchville, Connecticut, uraninite, and by Blomstrand ("Geol. För. Förh.," 1884, vii., 59, and Jour. Prakt. Chem., 1884, xxix., 191) for the Norwegian and Bohemian varieties, could be assigned to this from Glastonbury. The hitherto unanalysed uraninite formerly found at Black Hawk, Colorado, was then examined, and was likewise not referable to the orthouranate formula of Blomstrand. No thoria was found in it, but instead about 7 per cent of zirconia. In both cases about 60 per cent of UO2 had been found, whereas the highest percentage given by any other analyst was in the neighbourhood of 54 per cent for the Branchville variety. My own experiments had shown such extraordiuary variations in the percentages of UO2 found by the ordinary method of decomposing with sulphuric acid in sealed tubes filled with carbonic acid, and titrating with potassium permanganate, that a examination of the Branchville mineral seemed desirable. Profs. Brush and Dana, of New Haven, very kindly placed at my disposal the remainder of their material from that locality, it being the same lot from which Comstock had selected his sample for analysis. While different samples showed different amounts of UO2, the results were from 10 to 18 per cent higher than Comstock's, and, moreover, about 7 per cent of thoria was found which had been entirely overlooked by him. This latter, as in the Glastonbury mineral, was not referable to any thorium

re

From Bulletin No. 78, U.S. Geological Survey, 1889-90." An abstract of this paper was published in the Am. Jour. Sci., vol. xl., p. 384.

In view of what had thus been learned regarding the uraninites of this country it seemed advisable to reexamine the European varieties. Specimens from Przibram, Joachimsthal, and Johanngeorgenstadt contained no rare earths whatever, but they were so contaminated with carbonates and sulphides, and some combination of vanadium, that it seemed for the present useless to attempt an estimation of UO2 in them. Through Prof. F. W. Clarke, of the U.S. Geological Survey, there were obtained from Prof. A. E. Nordenskiöld specimens marked cleveite from four localities near Moss, Norway, and to Prof. W. C. Brögger are due my thanks for specimens of Blomstrand's original bröggerite, and of the supposed thorium-free uraninite analyssd by Lorenzen ("Geol. För. Förh.," vi., 744), and quoted by Blomstrand (Fourn. Prakt. Chem., 1884, xxix., 223 ff.) as a striking proof of the correctness of his view that all varieties of unaninite may be referred to the orthɔuranate type. These six sampies contained, without exception, thoria and other earths, in no case less than 8 per cent, and the four from Prof. Nordenskiöld, with one exception, proved not to be cleveite. Notwithstanding certain variations in composition they were evidently one and the same mineral, just as were those from Branchville and Glastonbury; and the Norwegian and Connecticut varieties, though differing greatly in their relative proportions of UO2 and UO3 and in their resistance to the solvent action of acids, were manifestly specifically identical.

These analyses had been practically completed, and a portion of the results very briefly communicated to the public from time to time (Am. Jour. Sci., 1888, [3], xxxvi., 295; Bull. U.S. Geol. Survey, No. 60, 1887-1888, p. 131), when, in consequence of a certain observation and its results, an entirely new direction was given to the work and its scope wonderfully broadened. This was the discovery of a hitherto unsuspected element in uraninite, existing in a form of combination not before observed in the mineral world. As already published (Am. Four. Sci., 1889, [3], xxxviii., 329, where, by a typographical error, UO2 is made to read NO2) all tests unite in showing that this element is nitrogen, which is given off in a gaseous form on heating the mineral with a non-oxidising acid, or, as ascertained later, by fusing it with an alkaline carbonate.

It is very unfortunate that this discovery of an escape of gas when treated with an acid, or rather the recognition of its important bearing, for the observation was made at an early date, did not occur sooner; for then more satisfactory results could have been obtained with the-in more than one respect-most valuable material from Branchville, and nearly all the analyses would have been carried out with the most painstaking care, in order to secure the utmost possible accuracy in summation, the importance of which will appear in the sequel. Inasmuch as the analyses were made solely with a view to ascertain the percentages of rare earths and the relative proportions of UO2 and UO3, where a variation of half a per cent, or even more, from the true summation was of very little consequence, that extreme care in the preparation and use of reagents and in analytical manipulation which

subsequently acquired knowledge showed to be so necessary was not exercised. Partly in consequence of this, and partly because of the length of time required for these investigations, caused by a want of abundant material, which necessitated oftentimes awaiting the result of one experiment or analysis before venturing upon another, it has been impossible to bring this investigation as far forward as was expected. So much time has elapsed since it was begun, and results of so much im. portance have been achieved, that it seems advisable to make them public now in detailed form, incomplete as they are in some respects and difficult of interpretation in certain directions.

Before proceeding to discuss the analyses themselves it is necessary to give in some detail the methods of analysis pursued, in order that the degree of credence to be accorded the results may be fairly weighed, and to present the evidence upon which the gas obtained from uraninite has been pronounced nitrogen.

Preparation of Samples for Analysis.

As a prelude to the description of analytical processes employed, the manner of freeing the sample as far as possible from adhering gangue may be briefly described. The specimens consisted, except in the case of the amorphous Colorado, Bohemian, and Saxon varieties, of crystals and crystal fragments more or less coated and invaded by a felspar or mica, or both, sometimes by columbite or a little quartz, and the surfaces opened up by fractures were often more or less coated with a reddish infiltration product which was little, if at all, soluble in the weak nitric acid employed for dissolving the uraninite on commencing an analysis. The sample was reduced to two or three grades of fineness by crushing and passing through several small sieves superposed one upon the other, care being taken to form as little fine dust as possible. When all had passed the coarsest sieve the different fractions were washed by decantation to free from dust, and then carefully panned in watch glasses of suitable sizes. By this means all the mica and the greater part of the other lighter impurities were removed, and a very fair degree of purification was reached. The columbite, if present, remained mostly with the uraninite, but caused little subsequent trouble. When no more gangue could be panned out without too great loss of material the different portions were united, the specific gravity of the combined sample dried at 100° C. was taken, and it was then finely ground. The fine dust formed in the preliminary crushing was not used, unless for qualitative work, being generally too much contaminated with gangue. The panned material was always examined under the lens when dry, and aside from an occasional adhering reddish fragment appeared clean and free from foreign bodies. (To be continued).

PROCEEDINGS OF SOCIETIES.

SOCIETY OF CHEMICAL INDUSTRY. (LONDON SECTION).

|

Probable Arrangements.

Nov. 2nd, 1891 (Monday): - Mr. W. C. Young, "On Volatile Organic Matter in Potable Water and a Simple Method of Estimating Volatile and Non-Volatile Matter in Water." Dr. S. Rideal, "Some Experiments on Solidifying Petroleum."

Dec. 7th:-Mr. Watson Smith, "A Contribution to our Knowledge of the Soluble and Resinoid Constituents of Bituminous Coals." Dr. Murray Thompson, The Salt Industry of India."

Jan. 4th, 1892 :-Mr. Boverton Redwood, "The Gallician Petroleum Industry."

NOTICES OF BOOKS.

An Elementary Handbook on Potable Water. By FLOYD DAVIS, M.Sc., Ph.D. New York, Boston, Chicago: Silver, Burdett, and Co. London Gay and Bird. Small 8vo., pp. 118.

THIS book does not by any means cover the same ground as the well-known treatise of Messrs. Wanklyn and Chapman. There are no instructions for the quantitative analysis of water or for its microscopical or bacteriological examination. The nine chapters treat successively of pure water, inorganic constituents, vegetable constituents, animal constituents, micro-organisms, water supplies, natural purification, artificial purification, and systems for central filtration. An appendix enlarges on the " Origin and Home of Cholera," and gives a few rough tests for the recognition of impure waters, such as the permanganate, the silver nitrate, Heisch's sugar test, and Pasteur's microzyme test.

There is here very little to which exception can be taken. Scarcely sufficient justice seens to be done to the action of green chlorophyllaceous vegetation in purifying water by means of the oxygen which it liberates. Nor can it be safely inferred that sewage fungus (Beggiatoa alba) is an indication of organic pollution. It is found flourishing luxuriantly in the water of sulphur springs and in the drainage of certain chemical works. The pollution of English streams is painted in a very exaggerated style. Says the author:-"The waters of many where city sewage enters them are actually offensive, and during the summer months, owing to the stench, the passenger traffic is forced to the railways." Polluted waters are not uncommon in England, but we never have met with a place where passenger traffic is "forced to the railways as above stated.

The purification of polluted rivers as they flow is something more than apparent, as it is proved both by chemical analysis and by observation of the organisms found in the water. The conclusion of the Royal Commissioners given here in a foot-note (or at least of the one Commissioner entitled to form a conclusion) is only in part justifiable. If the English rivers do not purify themselves, it is not a question of their length, but of the volume of sewage in proportion to the river water, and of the constant supplies of pollution which enter every few miles.

What is here said, and very truly said, concerning the inability of the soil to hold back pathogenic bacteria,

with water. Such are the ground-water system, or the filtering gallery. It is not often that a well of 40 feet in depth in or near a city is secured by an impervious stratum against the entrance of sewage. The national system" depends on the use first of precipitants, then, if needed, of filtration, and lastly, of aëration with compressed air under high pressure.

Cholera is traced to the armies of pilgrims frequently traversing India under the most anti-sanitary conditions.

This is perfectly correct; but it should also have been mentioned that pilgrimages from India to Mecca spread the evil westwards, especially as the devotees encounter at the shrine of the prophet other pilgrims from Egypt and the northern coast of Africa. These facts show the folly of expecting to arrest the spread of cholera to Europe by any system of quarantine at Suez. These destructive pilgrimages could be arrested only, if at all, at the cost of a war infinitely worse than the Sepoy mutiny.

Burdett's Hospital Annual and Year Book of Philanthropy; 1891-1892. Containing a Review of the Position and Requirements of the Voluntary Charities, and an Exhaustive Record of Hospital Work. Edited by HENRY C. BURDETT. London: The Hospital (Lim.), 140, Strand, W.C.

THERE is in this volume much which, of necessity, withdraws itselt from our view as being economical or political rather than scientific. Such subjects are the policy, and, indeed, the very existence, of the Asylum's Board, the management of different hospitals, and the extent to which such charities are abused by persons well able to pay for private medical attendance. We cannot, how ever, avoid being painfully struck by the facts that not a few of these institutions are unable to pay their way, and that in many cases beds, and even entire wards, remain unoccupied or closed from the lack of funds. Nor is the amount of disease evidently existing a subject to be passed over lightly. It might probably be a good investment of money and energy if we attended less to the cure of disease and more to its prevention, and if we included in the "preventible" class many affections which are certainly not contagious.

We doubt whether the author has acted advisedly in contrasting the respective conditions and efficiency of the hospitals of Oxford and of Derby, and of holding up the former to censure. We should be apt to think that Derbyshire is far wealthier than Oxfordshire. The proposal to exclude from any share in the proceeds of Hospital Sunday those "Surgical Appliance or" Aid Societies" which require applicants to canvass for tickets is timely and wholesome.

The canvassing system, indeed! Unless we are mis informed, a "pushing" contemporary has opened a department for the purchase, sale, or exchange of admission tickets.

It is well known that medical establishments which are to all intents and purposes private speculations sometimes figure under the guise of hospitals. Hence the work before us is perfectly justified in suggesting that this should be stopped by law.

The author tells us in his chapter on nurses and nursing that "every boy in his teens wants to be a sailor; every girl in her teens wants to be a nurse." Which of the branches of this dictum is the more exaggerated it would be hard to decide.

A remark is made that "massage has no business to be regarded as a branch of nursing, but unluckily it constantly is." It advertisements are to be believed, proficiency in massage is growing to be required from governesses and lady-helps!

Under the rubric institutions and associations we find mentioned not a few of the most pronounced “anti" type, and having certainly little visible connection with hospitals. Thus we find a "Brown Institute," for the study and treatment of domestic animals, with an income of £1000, a home for stray dogs and cats in receipt of £3000 (!), and two Anti-vivisection Societies, the collective incomes of which reach the total of £2300. On the contrary, the "Society for the Promotion of Medicine by Research" is ignored.

We are very glad to find that the electric quacks, now so thriving, do not here figure in the character of philanthropists.

CORRESPONDENCE.

THE CONSTITUTION OF BUTTER, &c.

To the Editor of the Chemical News.

SIR,-In his letter (CHEMICAL NEWS, vol. lxiii., p. 201) Mr. Wanklyn takes exception to my statement that "Messrs. Wanklyn and Fox have never published a single original experiment in support of their assertion of butter and other fats exhibits any grave departure from that the proportion of glycerin yielded by saponification the amount required by the accepted view of their con

stitution."

statement is, I believe, perfectly correct as it stands. If No withstanding Mr. Wanklyn's denial, the above I had stated that "neither Mr. Wanklyn nor Mr. Fox had ever published" I should have been in error. Mr. Fox has not published anything of the kind to my recollection, and it is only fair to say that he has taken no share in Mr. Wanklyn's recent resuscitation of the isoglyceride theory. But Mr. Wanklyn did describe, in a paper read by him before the Society of Chemical Industry in January last (Journal, x., 89), a single experiment which he had made in 1883, but had not previously published.

I am sorry that Mr. Wanklyn did not remind me of this one solitary experiment when I made the statement, to which he he now takes exception, in his presence some months since. It was certainly with no intention of inadequately stating Mr. Wanklyn's case that I omitted to mention the matter in my paper printed on page 179. At the meeting of the Society of Chemical Industry at which Mr. Wanklyn read his paper the experiment was very strongly criticised, as being badly devised and inconclusive in several respects, and Mr. Wanklyn made no sufficient answer to the objections then raised. Wanklyn's detailed account of the experiment, as printed in the Journal of the Society of Chemical Industry, contains abundant internal evidence of the-to put it mildly

Mr.

inconclusive nature of the experiment, as I am quite prepared to show if required. I am therefore somewhat surprised that Mr. Wanklyn still lays stress on the experiment, and regards it as lending support to his theory. The result is absolutely inconsistent with the more recent experience of various independent observers, and Mr. Wanklyn would have been wise to allow the record of the experiment to remain in his note-book, where he had already let it rest for seven or eight years.

66

Since the appearance of Mr. Wanklyn's letter I have attempted to repeat his experiment of heating slaked lime with butter-fat, but have met with a practical difficulty in which I shall be glad of his advice. Mr. Wanklyn kept the mixture on the water-bath for a long period," stirring constantly. My experiment has now continued for nearly forty hours, and my stirring powers are exhausted; in fact, they long since degenerated from "constant "to" frequent," and from that to "occasional." Under these circumstances I started a fresh quantity in a closed flask in the water-oven. This flask has been frequently shaken during several days, but there is no apparent sign of saponification having taken place. It appears still to be simply melted butter, with slaked lime in suspension. How long did Mr. Wanklyn's constant stirring continue? Where am I wrong, and when am I to regard the saponification as complete ?

Dr. William Johnstone writes:-"Mr. Allen charges me with having stated that tallow required 23 per cent of caustic potash (KHO) for its saponification, against 193-19.8 per cent as the united experience of other observers. I never said or wrote anything of the kind; the statement is purely a misrepresentation." This is rather a strong denial, and somewhat more positive than the facts warrant. What I stated (page 182) was that Dr. Johnstone had "recently published experiments

expressed

his correction was unfair and unnecessary. Dr. John

stone's position is similar to that of a man who has stated that he was born in 1868, and then objects to others holding that his age is now twenty-three.

Dr. Johnstone's reference to Mangold's recent results, and his claim that they furnish "an unexpected confirma tion" of his own statements, have already been dealt with by Mr. Hehner. Whether or not butyric acid is oxidised to oxalic acid under exceptional conditions is beside the question. Mangold's results, like my own experiments, absolutely contradict Dr. Johnstone's statement that Benedikt and Zsigmondy's process for determining glycerin by oxidation to oxalic acid by alkaline permanganate is rendered inaccurate by the presence of butyric acid. Neither does Mangold in any way endorse the "eccentric equation " C4H8O2+06=2C2H2O4+H4, according to which Dr. Johnstone appears to hold that free hydrogen is evolved in presence of excess of alkaline permanganate.

The other remarks of Dr. Johnstone scarcely call for comment. As the estimation of glycerin by bichromate, which I quoted as having yielded 11-83 per cent on the butter, was made on an acidulated liquid which had already been distilled to a small bulk, the "volatile fatty acid which readily reduces acid bichromate " could scarcely have interfered. No one contends that the oxidation processes of estimating glycerin are reliable in all cases-in fact, I have stated exactly the opposite. Similarly, no one doubts that, under very extreme conditions chromic acid, and possibly alkaline permanganate, will oxidise butyric to carbonic acid; but that is not the point at issue. I am, &c.,

Sheffield, October 24, 1891.

BEHAVIOUR OF

ALKALINE

ALFRED H. Allen.

BUTYRIC ACID WITH

PERMANGANATE.

To the Editor of the Chemical News. SIR,-In reply to your correspondent, Mr. Otto Hehner (CHEMICAL NEWS, vol. lxiv., p. 212), I decline the compliment and the reproach as well as his literal translation, and beg to inform him that I quoted from an English translation of Mr. Mangold's paper, made by a German whose knowledge of the English language is infinitely superior to that of your correspondent's, and is as follows:- Mangold, speaking of his modification of Benedikt and Zsigmondy's method, says "The presence of butyric acid does not affect the result, since butyric acid does not become oxidised in the cold by an alkaline solution of permanganate; butyric acid yields oxalic only when boiled for a considerable time with an excess of alkalı and potassium permanganate.”

Mangold's experiments are made upon pure glycerin, and not upon the soluble products of a saponification; but why does Mangold use cold alkaline permanganate if oxalic acid is not produced? However, Mr. Hehner in his literal translation admits that "the amount of oxalic acid is either not increased at all in the presence of butyric acid, or only very slightly." Exactly, and by prolonged boiling one can obtain the theoretical quantity. If the fact "was not carefully suppressed to my disadvantage," it certainly at all events was not suppressed to my advantage, as time will tell.-I am, &c.,

Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences. Vol. cxiii., No. 15, October 12, 1891. Variation of the Composition of Jerusalem Artichokes at different Stages of their Vegetation. The part played by the Leaves.-G. Lechartier.-The author determines the composition of these plants in September when they have already reached their normal growth, and when the tubers exist only in small proportions. The leaves wither and die from the moment when they do not contain a sufficient quantity of phosphoric acid or of potassa. The minimum quantities per kilo. of dried vegetable matter are-Phosphoric acid 3:48 to 4'10 grms,, potassa 3.18 to 3:36.

Circulation of the Specific Heat of Liquids.-G. Hinrichs.-The molecular specific heat of liquids at any given temperature is determined by the minimal momentum of inertia of the molecule, i.e., the molecules revolve on the natural axis the momentum of inertia of which is the smallest.

Fusion-Point of Certain Binary Organic Systems. Leo Vignon. In all the cases examined the meltingpoints observed differ from the melting points calculate If we represent graphically the melting points observed with reference to the variations in weight of one of the bodies composing the mixture, we have two possible cases. (a) The melting-points observed differ greatly from those calculated and are lower. For certain proportions of the components the mixture melts below the melting. observed differ little from those calculated and are rather point of the most fusible body. (b) The melting-points higher. The chemical functions of the bodies in question

do not seem to affect these results.

Calorimetric Researches on the Condition of Silicon and Aluminium in Cast-Irons.-F. Osmond.— Silicon may combine with iron with disengagement of heat; but the compound formed is dissociated by an excess of iron, and subsists only if the presence of silicon in the compound is sufficient. Aluminium, in the conditions in which it is used in siderurgy, dissolves in melted iron with absorption of heat. If the reverse phenomenon is observed, as manufacturers maintain, the liberation of heat cannot be ascribed to an exothermic combination of aluminium with iron, but only to the reduction by alumi. nium of the dissolved iron oxide, and probably to an allotropic modification of the iron.

Formation-Heat of Platinic Bromide and of its Principal Compounds.-Léon Pigeon.-Not adapted for useful abstraction.

Zeitschrift fur Analytische Chemie.
Vol. xxx., Part 3.

Separation of Cobalt and Nickel by the Nitrite Method.-M. Baubigny (Aunal. de Chemie et de Phys.). This method, first proposed by N. W. Fischer, is known to be excellent. It is, however, as Künzel and Erdmann have shown, not available if barium, strontium, or calcium is present, since, in this case, along with the potassiumcobalt nitrite, there is thrown down a compound of this salt with barium, strontium, or calcium nitrite. Baubigny now calls attention to a further nitrite which contains lead, nickel (nickelous oxide), and potassium. As lead salts in many respects are approximate to the barium salts it seemed to the author probable that the former would behave similarly with potassium nickelous nitrite. This conjecture was confirmed by the following experi ment:-If to a solution of potassium nitrite mixed with