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Thus Mr. Davis's figures would, when in strict accordance with my statement, be as follows:

through the leaden pipes would dissolve a small quantity | with Gay-Lussac, it was equivalent to an admission of a of the lead. This, passing either into the cylinder or loss of from 5 to 10 per cent in chambers not connected boiler, would be reduced to the metallic state by the with Gay-Lussac columns. zinc with which the iron is "galvanised," and a voltaic action would be induced, the zinc acting as the positive and the lead as the negative metal. By this means a rapid and increasing action would be set up, which after dissolving the zinc would act upon the iron in precisely the same way as the bottom of iron railings, fixed into stone by means of lead, are corroded at their lower ends.

It is thus easy to see how the deposit, which was of a foxy-brown colour and friable, would soon be formed, and the small amount of lime and magnesia salts which are mixed with it prove that the action must have been rapid.

If, as seems probable, there was any metallic lead in the deposit when first removed, this had become oxidised by exposure to the air, to which it was exposed for some time previous to analysis. From a rough sketch of the boiler and fittings which I received, it seems probable that the lead pipes were in metallic communication with the galvanised iron, and if so a much more general action, as well as the local one before indicated, would take place, and destruction would occur at a proportionately greater

rate.

Analytical Laboratory,

19, Brunswick Street, Liverpool.

CORRESPONDENCE.

ENAMELLED IRON COOKING-VEssels.

To the Editor of the Chemical News. SIR, I had an cpportunity some weeks ago to examine several enamelled iron cooking-pans which were submitted to my approval. By heating the pans two hours on a water-bath, with diluted (7 to 8 per cent) acetic acid and some common salt, and by analysing the solution thus obtained, I found a considerable quantity of oxide of zinc; and as the combinations of zinc are considered to

be very injurious to health, and sauces, &c., very often contain mixtures of salt and vinegar, I think it useful to call the public attention to this examination. A family here of seven persons were poisoned by using these pans. The pans were of German and Belgium origin. I am, &c.,

P. F. VAN HAMEL-ROOS. Analytical Laboratory, City of Amsterdam,

May 19, 1879.

THE VITRIOL MANUFACTURE.

To the Editor of the Chemical News. SIR,-Permit me a few lines to point out an error which has crept into Mr. Davis's calculations (CHEMICAL NEWS, vol. xxxix., p. 216).

The error consists in Mr. Davis applying my 20 per cent allowance for chambers working with Gay-Lussac to a system having no such apparatus. When I assumed the loss at 20 per cent I did so fully alive to the fact that the introduction of the Gay-Lussac causes a difference not in the absolute quantity of nitre destroyed per 100 of sulphur, but in the relative quantity, as expressed on the nitre used. In works without Gay-Lussac tower the working nitre and the nitre used are the same quantity, and the loss expressed as percentage on either is identically the same. But in works with Gay-Lussac the working nitre is double and more of the nitre used; hence the same absolute loss will yield in this case two different ratios, depending upon the unit chosen being either the working nitre or the nitre used,-i.e., added to cover losses. When I used the latter quantity as unit for comparison, and admitted 20 per cent of loss in chambers working

Nitre used

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20 per cent decomposed in chambers, or 5'3 per cent on the 60 cwts.

10 per cent loss with exit gas
10 per cent loss with vitriol
5 per cent leakage

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Mr. Davis's own calculation would be more in accordance with Dr. Lunge's statement, since he puts the loss in systems connected with Gay-Lussac towers at 12 cwts. out of 16 cwts. used 75 per cent of the nitre used.-I am, &c., FERDINAND HURTER.

Laboratory, Gaskell, Deacon, and Co.

Widnes, May, 1879.

THE VITRIOL MANUFACTURE.

To the Editor of the Chemical News.

SIR, Against my wish I must again trouble you, but I hope for the last time on the present question, to afford me some space for replying to Dr. Hurter's and Mr. Davis's letters (CHEMICAL NEWS, vol. xxxix., pp. 215 and 216). So far as the question is concerned in which I took up my pen before, a reply would not be called for; for Dr. Hurter adduces no proof of an appreciable loss of nitre in the Glover tower, merely stating that "he has many reasons for thinking so." I am content to leave that question where it stands, and I refer again to my former letter and to our lengthy discussion in the pages of Dingler's Journal. I do not think that there is any inconsistency between my opinion as stated before and that expressed in my treatise, viz., "that certainly the Glover tower is in this respect no worse than any other denitrator," for hitherto, as far as I know, nobody has contended that in the steam columns, &c., any loss of nitrogen takes place by reduction to N20 or N. Since then, in a paper about to be published, I have proved that denitration by hot water or steam is insufficient when the nitrous vitriol, by faulty work, contains nitric acid.

As I do not wish to extend this letter to an undue length I refrain from going into some fresh matters raised in Dr. Hurter's letter, which are only slightly connected with this issue, much as I could say about them. But I cannot allow myself to be saddled, both by Dr. Hurter and Mr. Davis, with a statement which I entirely repudiate, viz., that the quantity of nitre lost in the chambers, or "in a manner not yet clearly understood " (as Dr. Hurter puts it), is 75 per cent of the total consumption, whatever that may amount to. In truth I am not guilty of such an assertion, which, as exemplified by Mr. Davis, involves a downright absurdity. At some factories only 2 parts, at others-not fitted with recovery apparatus-up to 13 or 14 parts of nitre are used for 100 sulphur; and I am made to say that in either case the loss in the chambers is three-fourths of the total loss! In my letter I had, for the sake of argument, adopted Dr. Hurter's caiculation, starting from a loss of 4 parts of nitre on 100 sulphur; and I had proved that, upon his own showing, coupled with evidence referring to the only point in which the two cases differ, the "chemical loss "at works denitrating by steam should be 75 per cent of the above, i.e., 3 parts of nitre to 100 sulphur. Mr. Davis applies that 75 per cent to works where the nitre was not recovered, and where 3 parts were consumed for 100 vitriol, or, say, 9 parts for 100 sulphur, so that my alleged 75 per cent would come to 6'75 parts instead of three parts. Dr. Hurter puts the

238

Explosions in Flour-Mills.

chemical loss of nitre at works having no recovery apparatus, which notoriously consume 10 to 12 parts of nitre to 100 sulphur, at 20 per cent,-i.e., 2 to 24 parts, which is not so very far from my 3 parts. Dr. Affleck, by increasing the absorbing space, has brought down the loss of nitre from 145 to 1'05 upon 100 pyrites, or, say, from 3.2 to 2.5 upon 100 sulphur, and he expects ultimately to come down to 075 nitre on 100 pyrites,-i.e., 167 on 100 sulphur. Even then there might be some loss of nitre in the exit gas as NO. But if we confine ourselves to the consumption of 25 parts of nitre, realised by Dr. Affleck as well as by some continental manufacturers (the instance quoted by Mr. Davis, 16 cwts. nitre to 100 tons of vitriol, comes to even less than that), and if we subtract from it the o'6 part allowed by Dr. Hurter (as 15 per cent of 4 parts) for "mechanical losses" in other ways, the maximum of possible "chemical loss" is reduced to 19 parts of nitre to too sulphur. But that is only a maximum figure; the real figure, if the exit gas was treated more thoroughly, according to Dr. Affleck might be 167, less o'6 for other mechanical losses, or merely I part of nitre to 100 sulphur-not 3 parts, as I had temporarily admitted entirely for argument's sake. In short, it is quite impossible to make even an approximately definite statement of the "chemical loss," and just for that reason I refrained from doing so in my treatise.

I hope that enough mere arguments have been exchanged now. Let us rather try to approach the solution of the difficulty in an experimental way. This I, for my part, have commenced to do in the investigation which I mentioned as being about to appear, and I am continuing my labours in this field.-I am, &c.,

[Technical Laboratory of the Federal Polytechnic Schools, Zürich.

THE CHEMICAL

GEORGE LUNGE.

REACTIONS OF THE
HOLLWAY PROCESS.

To the Editor of the Chemical News. SIR, The reactions which take place in the Hollway process of rapid oxidation must appear to chemists who have had the privilege of studying the matter to be very interesting (some of those reactions being entirely new), and to be well worth studying.

It is well known, of course, that if iron pyrites is heated in a neutral atmosphere, the result is ferrous sulphide and free sulphur (or something approaching it); but it is not so well known that when ferrous sulphide is heated at a higher temperature, it splits up into a lower sulphide and free sulphur (2FeS = Fe2S+S). At all events, on blowing through the molten sulphides in a Bessemer converter, sulphur was seen burning abundantly at the mouth, and condensed in the tubes for collecting the gases.

Moreover, as I pointed out at the adjourned meeting of the Society of Arts, the regulus of at least two of the experiments contain sulphur in the proportion to form Cu2S and Fe2S.

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{CHEMICAL NEWS

May 30, 1879.

gists, but in the Hollway process we find both the sub sulphides of iron and copper existing together. It contains no metallic copper, and I have failed to find metallic iron in a similar regulus produced by the same process. Moreover, I consider it extremely improbable, in taking into consideration Mr. Schweder's experiments, that there should be metallic iron and no metallic copper, or so long as subsulphide of copper is present.

It is evident, of course, that the high temperature of the Hollway experiments might be the means of producing the subsulphide of iron, but one would naturally expect that, in cooling, metallic copper and ferrous sulphide would be formed.-I am, &c., WM. GALBRAITH.

Sheffield, May 19, 1879.

EXPLOSIONS IN FLOUR-MILLS.

To the Editor of the Chemical News. SIR,-I noticed with interest the communication of Mr. Watson Smith in the CHEMICAL NEWS (vol. xxxix., p. 222), on the subject of explosions in flour-mills, and as few chemists have had practical experience (as I have had during the last fourteen years) in flour-mills, my observations might not be without interest. I have no doubt from all I have seen that Mr. Smith's explanation of the cause of the explosions is the true one, but I was not aware that he was the first to give it, being under the impression that Dr. Stevenson Macadam had made a very complete investigation immediately after the Glasgow explosion, and arrived at the same conclusions as those now given by Mr. Smith. The remedies Mr. Smith suggests are very difficult to carry into practical operation, as millers require a number of small lights disposed over the mill, and at present the electric light does not conveniently give these. The best plan is to dispense with the stive-room altogether, and to filter the air through flannel cloth as it leaves the stone case. This can be done to great advantage by the use of Messrs. Seck's automatic apparatus, which has proved here a perfect success, as not a particle of flour leaves the stone case as dust, mixed with the exhaust air, and the exhaust is greater than without its use could be allowed. There is another source of danger besides that from the stone exhaust, and which it is supposed caused the immense explosion in four mills at St. Louis, U.S.; that is, the exhaust from the middlings purifiers, in which the dust carried forward by the air is much drier than that from the stones, and therefore much more easily ignited. In this case also I recommend the filtration of the air immediately it leaves the purifiers. By these means the chance of an explosion is very much less, and should it occur will be much less powerful, as the volume of dust-laden air will be but a small fraction of what it would otherwise be without the filtration process. I am, &c.,

ARTHUR MCDOUGALL, B.Sc. City Corn Mills Manchester, May 26, 1879.

PS. Mr. Smith suggests the use of an electric lamp in the stive-room. No light is required in that room, which, if of sufficient volume, need only be entered once per week to be cleared out, and that can be done during the day.

I believe it to be the accepted explanation of the produc-
tion of moss copper in blue and white metal (at least it is
the one given by Percy as the most reasonable) that the CHEMICAL
subsulphide of iron might be formed, which in presence
of subsulphide of copper would form ferrous sulphide and
metallic copper (Fe2S+Cu2S=2(FeS) +2Cu); and in con-
nection with this Mr. Schweder finds that by melting sub-
sulphide of copper and metallic iron together the result is
ferrous sulphide and metallic copper,—

(Cu2S+Fe=FeS+2Cu).

He also failed to produce subsulphide of iron, and declares that it does not exist.

Of course these results of Mr. Schweder's confirm, to a large extent, what was known or believed by metallur

NOTICES FROM FOREIGN
SOURCES.

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

Comptes Rendus Hebdomadaires des Séances, l'Académie de des Sciences. No. 16, April 21, 1879. Complementary Researches on the Products of the Distillation of the Alcohols.-I. Pierre and E. Puchot.-The title of this paper is misleading; the

NEWS

1879. authors treat of the distillation of various commercial forms of ethylic alcohol, and not of the alcohols as a generic group of compounds.

Artificial Preparation of Manganic Peroxide.-A. Gorgeu. The author produces this compound by heating nitrate of manganese in a glass phial, placed in an oil or paraffin bath, to 155° to 162°. He supposes that in the natural formation of polianite and pyrolute iron suspended in the very fluid mass of nitrate of manganese has been first drawn off, the decomposition of the manganous nitrate taking place subsequently.

On the Tri-tungstates.-J. Lefort.-The author treats of the salts which result from the decomposition of the best known earthy and metallic acetates by sodic tungstate. Equivalent proportions of the two salts are dissolved in a minimum of water. The tri-tungstates are generally instable, and if dried in the water-bath and treated with water they are more or less completely resolved into insoluble bitungstates and soluble quadritungstates.

as the chromates of potash, soda, or ammonia-is essentially inert as regards the mixtures of chlorates at the temperature at which the operation is conducted. Here M. Witz considers is the capital error of his opponent, whilst a trace of vanadium acts upon the chlorates in an indefinite manner. The chromates, when in contact with salts of aniline and in a suitable state of concentration, are reduced as soon as the reaction commences, and in proportion as they act they pass into that state of chromic sesquioxide, which remains insoluble and inactive in spite of the presence of the chromates. It is therefore necessary to use quantities of the chromates relatively considerable, because their action takes place only in equivalent quantities. Thickened mixtures containing chromates tri-coagulate rapidly, and to obviate in part this inconvenience M. Grawitz adds ammonia, a device introduced by M. Witz to get rid of any excess of free acid retained has been well-known and generally used for three years. among the crystals of aniline hydrochlorate, and which With this addition, though the development of the colour is slightly retarded, the doctors are completely preserved from corrosion and the design remains clear. When, however, ammonia is used along with the chromates the black is developed suddenly but too much on the surface of the cloth; a certain part of the thickening remains coagulated upon the fibre, and the shade produced has not the intense clear black tone produced with copper or vanadium; it is brownish, imperfect, and much more readily attacked by chlorine. Thus the addition of the chromates to an ordinary colour is distinctly injurious. Even if ammonium vanadiate costs I franc per gramme it is twelve times less expensive than copper sulphide paste, and certainly much less than the chromates, which act only in equivalent quantities.

Letter to M. Dumas Concerning the Apparatus of Lavoisier.-P. Truchot.-Lavoisier's chemical laboratory and physical cabinet have been reverently preserved by his family, and are now in the possession of M. E. de Chazelles, at Canière, near Aigueperse, Puy de Dome, where the author has seen them. The smallest of the three balances is sensitive to, grain. The weights belonging to these balances are wanting, but the kilogramme and its subdivisions as established by Fortin are present, recalling the fact that Lavoisier made all the determinations needful for fixing the weight of the kilogramme. There is a small model of an apparatus for the distillation of sea-water. There are a considerable number of precious stones, some of which have undergone the action of fire. Lavoisier is known to have made an experimental comparison of the heat produced by converging lenses with that of the blowpipe fed with oxygen.

Chemical Function of Anhydrous Acetic Acid.M. Loir.-Anhydrous acetic acid yields alcohol when treated with a hydrogenising agent. When combined with sodic bisulphite it produces a crystalline compound. With ammonia it forms a crystalline compound insoluble in ether. Finally, acetic anhydride is greedy of oxygen.

On Nitroso-guanidin.-L. Jousselin.-The author prepares this compound by stirring up dry nitrate of guanidin in fuming nitric acid and passing a current of nitrous acid through the mixture. He examines its behaviour with acids, alkalies, and reducing agents.

Value of Certain Chemical Agents Employed in Printing Aniline-blacks.-G. Witz.-The vanadic compounds have been employed for several years in printing textiles. On adding them in extremely minute quantities to thickened mixtures of aniline salts and of chlorates the generation of aniline-black is produced with a rapidity proportional to the doses of vanadium employed. In a letter, published in the Comptes Rendus for the session November 25, 1878, M. S. Grawitz has held up chromic compounds as possessing a greater energy than those of vanadium. He founds this opinion upon an experiment in which milligrm. bichromate of potassa to a litre of a mixed solution of aniline hypochlorate and of chlorates is said to have produced a colour intense enough to form a kind of ink upon paper. M. Witz has shown that a result such as described, and with such a proportion of chromate was inaccurate (Comptes Rendus, December 30, Ixxxvii.), and subsequently, M. Grawitz, in a further communication, by his silence on this point, seems not to contest the refutation of his original experiment. The modifications introduced by M. Grawitz at the same time, both in the proportions announced and in the nature of the chromates which he now selects in a neutral state (session of February 24, 1879), have given no better results in the check experiments undertaken. It cannot be otherwise, since chrome in its various conditions—and especially

Moniteur Scientifique, Quesneville.
May, 1879.

Industrial Society of Mulhouse: Sessions of the Chemical Committee (February 12).-M. Prud'homme described a new colouring matter recently introduced into commerce by A. Bayer under the name of anthracen violet. The author considers that it has no connection with anthracen, but is a substitution-product of gallein, with which it agrees in its reactions, its spectrum, and in the shades produced with different mordants. March 12.

M. Kallab in a note addressed to the Committee admits that his new process for bleaching animal fibres does not yield a white equal in beauty to that produced by the old method, but thinks that the new white, being more permanent, should be preferred where a greenish shade is not objected to. MM. Schmidt and Baldensperger communicated a description of their new processes for the manufacture of magenta by means of vanadium chloride and of certain nitro derivatives, such as nitro-naphthalin. Both yield magenta of excellent quality. Vanadium chloride is allowed to act at 200° upon a mixture of nitrobenzol and commercial aniline, or of pure aniline and

nitro-toluol.

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240

Chemical Notices from Foreign Sources.

available quantity of the Craie grise is calculated at 14 millions cubic metres. Many attempts have been made to render this mineral soluble by steeping in water containing carbonic acid, in solutions of alkaline and ammoniacal nitrates, sulphates, &c., and in the drainage of dung-hills, but the results have been negative. In case of dung-hill liquor the phosphates already existing in solution have been precipitated. The Craie grise has also been applied to soils in the raw state, but without any appreciable effect upon the crops.

Action of Gypsum upon the Quality and Quantity of Clover Crops.-Prof. A. Pasqualini.-In the experiments described the yield of clover was increased, but its nutritive value underwent no improvement.

Excretion of Phosphoric Acid in the Herbivora. Dr. J. Bertram.-In the carnivora the phosphoric acid introduced into the system is almost exclusively excreted in the urine, whilst in herbivorous animals, under normal circumstances, it appears in the solid excrements, and is not to be detected in the urine unless the lime present in the food is not sufficient for its neutralisation.

Influence of Food on the Quality and Quantity of the Fat of Milk.-Both the percentage and the absolute quantity of fat in milk may vary considerably, even when the diet is unchanged. An addition of protein to the food increases the proportion of fat, but not so much as an addition of oil or stearic acid. The fat of cream melts about 2° lower than the fat remaining in skimmed milk.

Researches on the Ripening of Grapes and other Fruits.-C. Portele.-The ripening of stone fruit after being gathered consists in a decided decrease in acids and in cellulose, whilst the total proportion of sugars is lessened slightly, and in the dextrose is converted into levulose, which is sweeter. There is also under the same circumstances an increase of levulose in grapes, though to a less extent.

Purification of Saccharine Juices with Hydrate of Alumina.-Dr. O. Kohlrausch.-This process, introduced by Prof. Löwig, dispenses with animal charcoal and with the production of treacle. The author finds, however, that a certain quantity of alumina dissolves in the juices, so that the mineral acids present and also the colour are not entirely removed. Hence it is very doubtful whether the filtration over animal charcoal could be omitted. The production of treacle is also not obviated in Löwig's proThe elutriation of the hydrate of alumina requires

cess.

CHEMICAL NEWS,
May 30, 1879.

such quantities of liquid that the boilers and presses would require to be enlarged, and the consumption of fuel would be increased.

Foreign Colouring Matters in Red Wines.-Prof. J. Nessler. The author considers that we are not yet able to distinguish the red colouring matters of mallows and bilberries from that of grapes. It is very probable that they do not essentially differ.

On Casein.-Prof. O. Hemmarsten.-The author prepares casein by precipitation with acetic acid, avoiding excess, re-solution of the washed precipitate in a minimum of alkali, so that the liquid retains a faint acid reaction, filtration to remove fat, re-precipitation with acetic acid, and after several repetitions of the above-described process washing with alcohol and ether. Pure casein possesses the characters of an acid; if dissolved in a minimum of caustic alkali it has an acid reaction; it dissolves the carbonates of lime and baryta with liberation of carbonic acid, and even phosphate of lime.

Heft 3, March, 1879.

Temperature of the Soil in a Compact and a Loose Condition.-Prof. E. Wollny. In summer and in warm weather compact soils are on the average warmer than loose ones, but in winter, and on a fall of temperature in summer, they are colder. In warm weather compact soils are warmer by day and colder by night than loose ones, and are subject to greater fluctuations of tempera

ture.

Composition of the Milk of Cows of Different Breeds.-E. Marchand.-The author finds free lactic acid, a constituent hitherto invariably overlooked, present to the average amount of 2 grms. per litre. The relative proportions of albumen and casein fluctuate much, but their joint weight is little affected. If the cow has eaten cruciferous plants the milk is rendered poor in casein and rich in albumen, thus effecting the production of cheese.

Composition of Clover-hay Rapidly Dried or Exposed to Rain.-Dr. C. Briminer.-The quantity of protein is reduced o7 per cent, but the non-nitrogenous extractive matters are diminished by 7'1 per cent.

Artificial Horse-dung.-Prof. Mayer.-A manure is said to be exported from England to Holland which has the outward appearance of stable manure, but on examination proved to be a mixture of straw and decayed leaves.

COMPOSITION AND QUALITY OF THE METROPOLITAN WATER.
APRIL, 1879.

THE following are the returns of the Society of Medical Officers of Health :

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0'000 0'003 0315 0.005
28 10 10 860 0.841
0'000 0'003 0135 0.008 21.50 7'950 0'540
0'000 0'006 0165 0.028 21:40 8.230 0.684

2.830 2.970 17.6 5'10

1880 1130 143 3'30

Total Solids.

2 120 1970 14.8 2.80

The quantities of the several constituents are stated in grains per imperial gallon.

NOTE. The amount of oxygen required to oxidise the organic matter, nitrites, &c., is determined by a standard solution of permanganate of potash acting for three hours.

C. MEYMOTT TIDY, M.B.

Lime.

, Magnesia

Grs.

Grs.

Degs. Degs

Chlorine

Sulphuric

hydride.

Before

Boiling.

After

Boiling.

NOTES AND QUERIES.

Manufacture of Sulphuric Acid.-Has it ever been suggested that the pot containing nitre or nitrate of soda and sulphuric acid be replaced by one containing sulphur and nitric acid, so that the manufacture of a by-product, and the heat, time, and labour consequent thereon be avoided. Of course this plan would not be so suitable for stone acid manufacturers. The principal objection would seem to be the greater cost of the nitric acid, but when the densities of the former and sulphuric acid are taken into account, the cost is considerably lessened.-SULPHURIC ACID, Swansea.

Mineralising Flannel.-Can you or any of your readers inform me of a process by which flannel may be mineralised or preserved from the action of a continuous flow of water at a high pressure in which it is immersed, as I find that after a few months use the flannel loses its nature, the threads being partially decomposed? Would water have the same effect upon silk?-ANDREW BELL.

Blue Manifold Paper.-Will you kindly favour by answering, through the columns of your valuable paper, a recipe for making blue manifold paper.-B. M. P.

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"On

THURSDAY, 5th.-Royal Institution, 3. "Suggestions to Students and Readers of History," Prof. J. R. Seeley. Chemical, 8. "On Eardenine," Dr. Stenhouse and Mr. Groves. "Theory of Fractional Distillation," F. D. Brown. "Action of Organo-zinc Compounds on Quinons," F. R. Japp. Chlorstannic Acid," J. W. Mallet, F.R.S. "On Indigo-purpurin and Indirubin," Edward Schunck, F.R.S. "Third Report to the Chemical Society on some Points in Chemical Dynamics," Dr. Wright, Mr. Luff, and Mr. Rennie.

FRIDAY, 6th.-Royal Institution, 9. Prof. Dewar.

Geologists' Association, 8.

SATURDAY, 7th.-Royal Institution, 3. "On Swift," Prof. H. Morley.

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I. Colour and its Recognition.

II. Early Traces of Man. By G. De Mortillet.

III. Leaves and their Functions. By Rev. L. J. Templin,
Hutchinson, Kas.

IV. Molecular Physics in High Vacua. By William Crookes,
F.R.S. (Illustrated.)
Correspondence-Imperfections of Nature-Sound as a Nuisance.
Reviews of Scientific Works-Science Notes-Proceedings of
Scientific Societies.

London: 3, Horse-Shoe Court, Ludgate Hill.
UNIVERSITY OF LONDON.

With 94 Engravings, crown 8vo., 12s. 6d.

SANITARY EXAMINATIONS of WATER,

AIR, and FOOD. A Vade-Mecum for the Medical Officer of Health. By CORNELIUS B. Fox, M.D., Lond., Medical Officer of Health of East, Central, and South Essex.

"His clear, practical, and common-sense manual."-Chem. Rev. "Eminently practical, yet scientific. One of the best contributions to the literature of hygiene which has been made within the last few years."-Dub. Med. Jour.

"In the execution of his task the author has wisely adopted a style as free from technicalities as possible, so that one who possesses only the average chemical knowledge of a qualified medical practitioner may, by the aid of the handbook, instruct himself in the methods of sanitary examination."-Med. Times and Gaz.

By the same Author, Second Edition, with 9 Engravings,
crown 8vo., Is. 6d.

'HE DISPOSAL of the SLOP-WATER of

THE

VILLAGES.

London: J. and A. CHURCHill.

Now ready, fcap. 8vo., 23. 6d.

SKELETON NOTES on ANALYTICAL

CHEMISTRY for STUDENTS in MEDICINE.

By ALBERT J. BERNAYS,

Professor of Chemistry at St. Thomas's Hospital Medical College; Examiner in Chemistry at the Royal College of Physicians.

By the same Author, Sixth Edition, fcap. 8vo., 3s. 6d.

NOTES for STUDENTS in CHEMISTRY:

A Syllabus.

London: J. and A. CHURCHILL.

NEW EDITION OF MUTER'S CHEMISTRY. Just published in two Vols. as follows:Vol. I.-AN INTRODUCTION TO CHEmistry (Theoretical and Descriptive). Second Edition. 400 pp., royal 8vo., price 10s. 6d.

Vol. II. AN INTRODUCTION TO ANALYTICAL CHEMISTRY. Second Edition. 216 pp., royal 8vo., with copious tables and concise instructions for the qualitative and quantitative analysis of metallic salts, alkaloids, water, &c., price 7s. 6d.

This well-known work, although specially designed for pharmaceu tical and medical students, will be found very useful to all commencing the study of general chemistry, the novel principle on which they are arranged ensuring a rapid and comprehensive grasp of the subject by the learner,

London: Published by W. BAXTER at the Office of the South London School of Pharmacy, Kennington Cross, and sold by Messrs. Simpkin and Marshall and Messrs. Baillière, Tindal, and Cox, and at all booksellers.

The

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he President has offered Two Prizes of £50 each for the two best original investigations involving Gas Analysis. These Prizes will be open to Associates, and to all persons (except Fellows of the Institute) who shall before the 31st December next have qualified for the Associateship in all respects short of passing the prescribed practical examination, and successful competition for these prizes will be accepted in lieu of such practical examination-Further information may be obtained on application to the Secretary, Mr. C. E. GROVES, Somerset House Terrace, W.C.

NOTICE IS HEREBY GIVEN, That the Advertiser (22), trained in the Science Schools,

next Half-yearly Examination for MATRICULATION i this University will commence on MONDAY, the 30th of June, 1879. In addition to the Metropolitan Examination, Provincial Examinations will be held at Owens College, Manchester; Queen's College, Liverpool; Queen's College, Birmingham; St. Cuthbert's College, Ushaw; Stonyhurst College; St. Patrick's College, Carlow; St. Stanislaus College, Tullamore; University College, Bristol; and (for Ladies only) at the Ladies' College, Cheltenham.

Every Candidate is required to transmit his Certificate of Age to the Registrar (University of London, Burlington Gardens, London, W.) at least Fourteen Days before the commencement of the Examination.

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South Kensington, seeks an Engagement in Chemical or other Scientific Laboratory. - Address, G.C., 59, Robert Street, Chelsea,S.W

Young Man (19), who has had two years

experience as Assistant in the Laboratory of a Chemical Works, seeks a similar position. Highest references.-Address. J. R. W., 914, Belmont Row, Birmingham.

A Chemist, trained at Royal School of Mines,

with Eight Years' practical experience, desires an Engagement. Excellent references.-Apply F.I. C., CHEMICAL NEWS Office Boy Court, Ludgate Hill, London, E.C.

Advertiser, with Six Years' Experience in

Analytical Chemistry, desires an Engagement as Assistant or as Chemist in Works. No objection to go abroad.-Apply, H.H., CHEMICAL NEWs Office, Boy Court, Ludgate Hill, London, E.C. anted an Intelligent Workman who thoroughly understands the manufacture of Acetic Acid and other Wood-products.-Apply to "Wood," CHEMICAL NEWS Office, Boy Court, Ludgate Hill, London, E.C.

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