shows that the specific gravity and boiling-point of methylhexyl (methyl-caproyl) nearly coincide with those of ethylamyl; and although he had only sufficient of the former body to investigate its reactions, he believes that these also would be found to agree with those of ethyl-amyl, and he therefore concludes that the two bodies are identical. The next paper was "On Hydride of Heptyl from Azelaic Acid," by C. Schorlemmer and R. S. Dale. This body is obtained (with others) by heating a mixture of azelaic acid and caustic baryta to a dull red heat. This paper and that above give the results of the authors' examination of compounds having the formula C-H16, derived from several not, so far as at present known, be done economically. In most deep mines a considerable cooling of the air takes place by the expansion of the compressed gas (light carburetted hydrogen) as it escapes from the coal, where it has been long imprisoned under great pressure; and this has not always been allowed for by observers of temperature in such places. In newly-opened mines this pent-up gas forces off large pieces from the face of the coal, and it sometimes makes a noise like water rushing over a weir. In sinking a deep shaft at Wigan some years since the compressed gas in the coal forced up about four yards of strong bind, and made its way through it into the shaft. The rising of the roof of the coal as the shaft approaches it is well known to sinkers in deep and newly-opened coal-fields. Mr. EDWARD HULL, F.G.S., exhibited some etchings of caves, fissures, and isolated rocks on the coast of Cantyre, intended to illustrate three classes of phenomena belonging to the raised beach and coast known as "the 30-feet MANCHESTER LITERARY AND PHILOSOPHICAL beach," from the fact that its mean elevation is about SOCIETY. Ordinary Meeting, October 31st, 1865. 30 feet above the present tides. This raised beach has been described by several authors, from Mr. Smith, of Jordan Hill (1836), downwards, and is part of the same beach R. ANGUS SMITH, l'h.D., F.R.S., &c., President, in the which has been traced all along the western coast of Chair. The following communication from Sir J. F. W. Herschel, Bart., M.A., D.C.L., F.R.S., &c., Honorary Member of the Society, was read by Mr. Baxendell : "Collingwood, October 18, 1865. "In the printed proceedings of the ordinary meeting of the Society, on the 3rd inst., I observe a notice of a paper by Mr. Greaves, On the Internal Heat of the Earth as a Motive Power,' in which the high temperature of the carboniferous strata, at the depth of 4000 feet (120° Fahr.) is spoken of as likely to oppose an insuperable obstacle to the extraction of coal from that depth. On reading this it occurred to me that by employing condensed air, conveyed through conducting pipes, as a mode of working machinery at that depth-provided the air immediately on its condensation, and before its introduction into the pit, were drained of the heat developed in the act of condensation, by leading it, in pipes exposing a large external surface, through a sufficiently large supply of cold water (or in winter time of snow)-the workings below might be sufficiently reduced in temperature by the re-expansion of the air on its escape, when given out below in the act of working the machinery, to admit of workmen remaining there in comfort; at the same time that ventilation would be supplied. "If you think that this suggestion would be worthy the notice of the author of the paper referred to, or of those members of the Society who may have been present at its reading, or in any other way available, it is quite at your service for that purpose. "P.S.-Water at 120° Fahr., or even much higher, would, I fear, afford but an inefficient moving power, unless some means could be devised (without the expense of more power than the gain expected) of concentrating the heat of a large quantity of warm water into a smaller. This might, perhaps, be done through the intervention of air alternately rarefied and condensed." Mr. BINNEY, F.R.S., F.G.S., said that at the present time little is known as to the difficulties we should experience in working coal mines at a depth of 4000 feet from the surface. The exact increase of temperature in deep mines is not by any means well ascertained. All we can say is, that no great difficulties have been found in working at a depth of 2100 feet. It must always be borne in mind that the deeper a mine is the greater will be the natural ventilation; that is, the current caused by the air of the mine, at say a temperature of 80° Fahr., ascending the upcast shaft, while the air at the surface, of 40°, descends by the downcast shaft. No doubt a mine might be cooled by the expansion of compressed air, but it could Scotland, and the vestiges of which remain in a state of remarkable freshness to the present day. Mr. T. HEELIS, F.R.A.S., called attention to the proceedings of a scientific commission recently issued by his Highness the Viceroy of Egypt, who had succeeded in finding a tertiary coal basin in the valleys between Mount Olympus and the Bay of Oraniska, in the Gulf of Salonica, and also on the mainland of Asia Minor, near the Island of Samos; and mentioned some particulars of the coal there found, such as its specific gravity, in which it slightly exceeds the ordinary coal of the coal measures, and the results of experiments upon its combustion, which gives 20 per cent. of ash. ACADEMY OF SCIENCES. M. EUG. PELIGOT presented a memoir entitled "Chemical and Physiological Studies of Silkworms." In the present and in previous communications the author has sought to give the results of an application of the balance to the study of the phenomena manifested in the life and metamorphoses of the silkworm. The extent of his studies is indicated in the following passage:--"A certain quantity of eggs of the worm being given, determine their chemical composition, as well as that of the larvæ produced by the hatching of an equal weight of eggs; feed these larvæ under the usual conditions with mulberry leaves; determine the composition of the leaves given, the leaves left, the worms, and their excrements; make the same researches with the chrysalides and the butterflies; in a word, establish the statical chemistry of a silkworm from its exit from the egg to its death." The reader will see that the author set himself no simple task, notwithstanding that his researches were only directed to ascertain the elementary composition of the various matters. We need not, at all events at present, detain our readers with the various analyses, but give now only the author's conclusions:-1. The development of the larvæ is accomplished by the transport and assimilation of part of the nitrogenised matter of the mulberry leaves. As the chemical composition and anatomical structure are probably the same throughout this stage of the rearing, in the worm just born and in the worm arrived at maturity, the phenomena of nutrition are equally the same during the various phases of the growth of the larvæ. 2. The results of the analyses prove a considerable loss of carbor, which is found as carbonic acid in the air expired by the insect. The amount of carbonic shows that in order to fix 100 parts of carbon from the leaves the worm consumes NEWS from 40 to 50 other parts, which is transformed by respiration into carbonic acid. Regnault and Reiset have already remarked that the respiration of the silkworm is more active than that of most of the animals upon which they experimented. 3. There does not appear to be any exhalation or fixation of nitrogen during the development of the silkworm. 4. The analyses prove a loss of hydrogen that seems to correspond to a loss of oxygen, which points to the conclusion that some of the alimentary substance disappears in the form of water. M. Pouchet continued from last week the account of his "Experiments on the Congelation of Animals." The experiments show that an animal whose body is reduced to the freezing point throughout is killed beyond all chance of revivification. The experiments have a physiological rather than a chemical interest, but some of our readers will no doubt be glad to learn the author's conclusions. These are: 1. That the first phenomenon produced by cold is a contraction of the capillary vessels to such an extent that a globule of blood cannot enter; these vessels, therefore, remain completely empty. 2. The second phenomenon is an alteration of the blood globules which amounts to their complete disorganisation. 3. Every animal completely frozen is absolutely dead, and no power can reanimate it. 4. When only a part is frozen that part is destroyed by gangrene. 5. If the part frozen is not extensive, and only a few disorganised blood globules pass into the circulation, the animal may recover. 6. But if, on the contrary, the frozen part is of considerable extent, then the mass of altered globules brought into the circulation when the part is thawed, rapidly kills the animal. 7. For this reason a half-frozen animal may live a long time if maintained in the condition, since the altered globules do not get into the circulation; but it expires rapidly as soon as the frozen part is thawed. 8. In all cases of congelation, death is due to the alteration of the blood globules, and not to any effect on the nervous system. 9. It results from these facts that the less rapidly a frozen part is thawed the more slowly the altered globules find their way into the circulation, and the greater are the chances of the recovery of the animal. M. V. Jodin presented a note "On the Asphyxia of Leaves." The author states that mercurial vapours only effect leaves during the nocturnal respiration, when they absorb oxygen and produce carbonic acid. In the diurnal respiration when they decompose CO, and evolve oxygen, the leaf appears to be unaffected by mercury. M. Persoz submitted another "Note on Solubility." In our last note, said the author, we studied the condensations produced by the solution of salts which fix salinic water, and showed that when, in a chemical reaction, this water is set free, there is always expansion. The author now deals with saturated solutions and the hydration of salts. On the latter subject he formulates the two following propositions : Salts, the base of which is an oxide of a metal the highest in a natural group, always crystallise in the anhydrous state. On the contrary, salts of a metal holding a lower place in the same group absorb a certain amount of water. In double decompositions the author states that he has verified the following law: When two saline solutions are in contact, their double decomposition, whether there is precipitation or not, always gives rise to the formation of two new salts having lower volumes than those of salts placed in contact. This law applies equally to the haloid salts. In the last place, M. Persoz states generally, that when four saline elements find themselves in contact under cir cumstances (wet or dry) in which double decomposition can take place, it is always the salt which can exist under the conditions of the experiment in the smallest volume that determines the arrangement of the elements. No illustrations of these laws are given, and we must wait for a more extended publication of the author's views. NOTICES OF BOOKS. Inorganic Chemistry for Science Classes. By FEARNSIDE HUDSON, F.C.S., F.A.G.L., &c. London: Whitaker and Co. 1865. seen. WE are disposed to look with much favour on this little book. It is the first attempt to introduce the new notation and nomenclature into an elementary work we have We might have said the newest nomenclature, for the author gives with all compounds, besides the Gerliamson's principle. We are not prepared to say that this hardtian name, another name framed on Professor Wiltions; but, at all events, the way in which it is used is double nomenclature always gives clearness to the descripcalculated to impress the names strongly on the memory of the student. Thus we read, under Carbonate of Calcium, Calcie Carbonate, the following account of the mode of preparation: bonate, is added to a solution of chloride of calcium, calcic "When a solution of carbonate of sodium, sodic carchloride, carbonate of calcium, calcic carbonate, is precipitated, and chloride of sodium, sodic chloride, remains in solution." for making a variety of calculations often required to be The Appendix, containing various tables and rules made, is not the least valuable part of the book, which, we may add, is well adapted for use in science classes. 2370. H. A. Bonneville, Rue du Mont Thabor, Paris, "Improvements in safety lamps for use in mines and other localities." A communication from A. J. Olanier, Rue du Sentier, Paris.-Petition recorded September 16, 1865. 2574. W. Clark, Chancery Lane, "Improvements in apparatus for steeping or treating paper pulp, and other matters subjected to the action of alkalies." A communication from Messrs. Neyret, Orioli, and Fredet, Boulevart St. Martin, Paris.-October 6, 1865. 46 2842. E. J. Northwood, Felix Place, Islington, Middlesex, Improvements in plating or combining gold, platinum, and other metals or their alloys."-November 3, 1865. 2882. G. A. Ermen, Eccles, Lancashire, "Improvements in treating vegetable fibres used in the manufacture of paper and other similar substances made from pulp." A communication from L. Horst, Cologne, Prussia.November 8, 1865. 2894. E. T. Hughes, Chancery Lane, "Improvements in the means of producing from rosaniline blue and violet colouring matters.' A communication from P. Mounet, Lyons, France.-November 10, 1865. 2903. W. E. Newton, Chancery Lane, "Improvements in making amalgams or alloys of metals." A communication from H. Wurtz, New York, U.S.A.-Nov. 11, 1865. 2919. W. Fox, M.D., Henrietta Street, Cavendish Square, "Improvements in preserving meat and other articles of food." 2922. W. R. Lake, Southampton Buildings, Chancery Lane, "An improved method or process for producing paper-makers' pulp from cane, bamboo, and other analogous substances."-A communication from C. Heaton, New York, U.S.A.-Nov. 13, 1865. 2929. J. Dickson, Abchurch Yard, London, "Improvements in purifying or refining iron."-Nov. 14, 1865. 2945. W. Clark, Chancery Lane, "Improvements in the manufacture or purification of hydrocarburets, and especially of petroleum oils, used for lighting purposes.' A communication from Dr. P. G. Barry and the Chevalier B. Degola, Boulevart St. Martin, Paris.Nov. 15, 1865. NOTICES TO PROCEED. 1797. J. Peel, Bowling, Bradford, and W. Hargreaves, Little Horton, Bradford, "Improvements in manufacturing grease from soap-suds." 1807. G. Fentiman, Upper East Smithfield, Middlesex, "Improvements in the preparation of paints."-July 7, 1865. 1816. H. A. Dufrené, Rue de la Fidelité, “An improved self-acting apparatus for obtaining a circulation of volatile liquids."-A communication from F. Massot and A. Juquin, Rue Rivoli, Paris.-July 8, 1865. 2293. F. Tolhausen, Boulevart Magenta, Paris, "A new fire firework, producing instantaneously the forms of serpents and other forms of a like nature."-A communication from F. Barnet and C. A. Rouseille, Rue de Rivoli, Paris.-Sept. 7, 1865. 2350. T. Bell and T. L. G. Bell, Plaistow, Essex, "Improvements in apparatus used for calcining and roasting copper and other ores, and substances containing sulphur." -Sept. 14, 1865. 2436. T. V. Lee, Macclesfield, Cheshire, "Improvements in preparing peat or turf for firelights and fuel, and for machinery to be employed therein.”—Sept. 23, 1865. . 1841. H. Blair, Kearsley, Lancashire, "Improvements in the production of gases from aqueous vapour, and in the application thereof to heating purposes."-Petition recorded July 12, 1865. 1855. A. E. Molin, Fahlen, Sweden, "Improvements in separating gold from ores containing copper and gold.”— July 14, 1865. 1939. E. Spicer, New Bridge Street, Blackfriars, London, "Improvements in compositions similar to gunpowder, for blasting, for use in ordnance and fire-arms, and for other purposes."-A communication from P. Nisser, Melbourne, Australia.-July 26, 1865. 1980. A. V. Newton, Chancery Lane, "An improvement in refining petroleum and other hydrocarbon oils.”A communication from R. A. Cheeseborough, New Rochelle, New York, U.S.A.-July 13, 1865. 2677. A. H. Hassall, M.D., Wimpole Street, Middlesex, "Improvements in the preparation of meat for food." -Oct. 17, 1865. 2803. R. Cassells, Glasgow, N.B., and T. Morton, Motherwell Iron Works, in the county of Lanark, N.B., "Improvements in furnaces."-Oct. 31, 1865. 2872. G. A. Jasper, Middlesex, Mass., U.S.A., "Having reference to the cleansing or bleaching of sugar, which invention may also be applicable to other purposes of like character."-Nov. 7, 1865. CORRESPONDENCE. Pills of Extract of Cod-Liver. To the Editor of the CHEMICAL NEWS. SIR, Having observed your question in last week's journal with regard to the pills you have seen in our window, we beg to say that Guffroy's Dragées of Cod Liver Extract sold by us are not "cod-liver oil pills," but are composed of a concentration of the watery exudations which exist in the livers along with the oil, and which are NEWS held to be equal, if not superior, to the oil in the chemical constituents to which that substance owes its medicinal value. You will find the process for the preparation of the extract in our two patents dated respectively July 20, 1860, and July 29, 1861. We write this as we have suffered much annoyance through our preparation being called "Cod-Liver Oil Pills," with which medicine we have no connexion. We may also mention that our extract is exempt from the medicine stamp duty, as it is not a secret nostrum, but simply a modification in the "preparing medicinal substances and compounds from the livers of cod," and it is, therefore, not sold under stamp. to disabuse the minds of your readers of the fact that we Trusting you will give our explanation publicity, so as sell"a quack medicine," We are, &c. BARR AND Co. "It will be observed on referring to this analysis, that two somewhat novel organic substances-namely, propylamine and ichthyoglycine, occupy prominent places in the table. The former, as well as several of the inorganic constituents, exists in cod-liver oil, but in such minute quantities as generally to escape detection. It has, nevertheless, been more than suspected by Winkler and other German chemists, that the remedial properties of codliver oil are to be attributed to the existence in that body of the conditions necessary for the formation of propylamine." (See Pharmaceutical Journal for 1851, vol. xii., p. 450.) We need only add that the pills are unquestionably a genuine preparation of the extract, and not an imposture, like the "cod-liver-oil powder " examined by Dr. Attñeld.-ED. C. N.] The Utilisation of Soda Waste and Chlorine Residues. To the Editor of the CHEMICAL NEWS. SIR, It has been very gratifying to me to see in Mr. Walker's highly interesting letter the corroboration of some of my remarks; and I regret sincerely to have had no occasion of perusing their specification, which would have prevented me making unwittingly erroneous objections against a process never proposed by Messrs. Walker and Townsend. May I now be permitted to correct some ideas of Mr. Walker about the stumbling-block he has discovered in my own propositions? If in my process (or more precisely NEWS remainder of the waste is so thoroughly oxidised that it can be used as a tolerable manure, and in every case constitutes a nuisance no longer. in my proposed arrangement of processes, nearly all more or less known and practised) pure MnS was produced, the objection would have been perfectly right. Yet this is not the case. It seems evident to me that Messrs. Walker and TownsAfter dechloration of the chlorine residue, after neutrali-end and I have been working, independently one of each sation with evolution of sulphuretted hydrogen, which other, in the same direction. I should be glad to have must be burnt, either for sulphurous acid or for sulphur, Mr. Walker's opinion about a paper, dated July 10, 1855, if we have not the utilisation of SO2 immediately at hand which he will find recorded in a "Repertory of Patent there remains in solution neutral chloride of manganese. Inventions," vol. xxvii., 1856, p. 406, treating on hypoWhen the neutralisation has been completely accomplished, sulphite of alumina. no iron is found in solution, the soluble salts of iron being precipitated much more easily by soda waste, in the state of FeS, than the manganese salts. The chloride of manganese is now decomposed, not by soda waste itself, but by the liquid which drains from the heap of soda waste, and which is collected purposely for this precipitation. This makes a very great difference. It is possible that as regards several ideas I may have the one. The Past and Present History of Alum. To the Editor of the CHEMICAL NEWS. SIR,--I must leave your readers to judge whether my remarks upon Dr. Muspratt's Dictionary are correct or not according to his account, his work is "second to none.' Dr. Muspratt forgets when he says that this is the first and only time that the information in the Dictionary has been called into question, for when the article first appeared, Mr. Spence himself wrote to Dr. Muspratt informing him of the false statement; but the Doctor did not even deign to answer the letter, but left it to one of his sul-assistants or clerks, who wrote, that it could not be expected that Dr. Muspratt could be well up in all the minutiae of manufacturing chemistry; and concluded, that if Mr. Spence would like a better description, it should be given another time. The liquid drainings from accumulated soda waste, especially when the latter has been properly disposed, consists principally of a weak solution of persulphuret of calcium. It produces with Cl,Mn, not MnS, but sulphuretted sulphuret of manganese. Experiment has shown that the yellowish precipitate, when dry, contains from 44-90 per cent. sulphur, of which quantity approximately 28-39 per cent. can be extracted by sulphide of carbon, and, therefore, exists in the precipitate in the state of free sulphur. 2800 gallons of chlorine residue treated in this manner produce nearly two tons of phuretted sulphuret of manganese (containing nearly one ton of sulphur), which are easily washed, dried, and burnt, evolving then from 14 to 16 cwt. of utilisable sulphur in the state of sulphurous acid. I shall give with great pleasure the figures resulting from trials made upon a very large scale to any manufacturer who should be interested in this question, and wishes to try the process, for which no patent has been taken out in England. For the production of an abundant and well-composed solution of persulphuret of calcium, I should recommend the following manner of building up a heap of soda waste (or mountain? l'amas de charrée), in order that it may, without any extraordinary expense, be aërated in all parts, and undergo quickly the desirable oxidising reactions. The plan is founded on the principle, admitted, I believe, by all manufacturers, that soda waste is not susceptible, without evident pecuniary loss, to any manipulation requiring hard labour or costly mechanical arrangements. In every chemical work there is produced, in exact proportion to soda waste, a quantity of coal slag, from the sulphate and black ash furnaces, the steam-boilers, and the evaporating pans. The same furnaces produce, unhappily, much too quickly for the manufacturer, a certain quantity of broken and rotten bricks (briques usées). These bricks and coal slags are deposited upon the heap of soda waste in rows about one yard high and broad, and at a distance one from the other of four to five yards. Soda waste is thrown between these rows, and after a layer of a certain thickness has been deposited-say of two or three yardsnew rows of coal slag are established in alternative order with the first, &c., &c. The coal slag and the bricks represent the channels through which atmospheric air can penetrate in the interior of the soda waste and oxidise the CaS2 to CaS, and CaO. The heap of soda waste becomes in this manner a real apparatus of an enormous size, in which sulphur is quickly rendered soluble and concentrated in the rain water filtering through the heap. All round the heap there are dug open gutters, to collect the drainings and conduct the solution of polysulphuret of calcium to very large (reservoirs) tanks. If there should be not enough rain to produce a sufficient quantity of drain liquid, water pipes must be established at the top of the soda waste heap, and a regular lixivation organised. In a comparatively short time soda waste treated in this manner loses a considerable quantity of sulphur, and the Dr. Muspratt puts forth the excuse that the paper on "Alum was written nearly fourteen years since, making out that it was not possible to have known of Spence's patent then. Mr. Spence took his patent out in the year 1845, which is exactly twenty years ago. Therefore, I contend that whoever wrote the paper and mentioned Spence's patent, ought certainly to have read it, and given a proper description of the process, for the works were then in full operation at Pendleton. that in 1850-51 Mr. Spence made about twenty tons per In the CHEMICAL NEWS of September 21, 1861, it is said week. The writer of Muspratt's article was certainly some years behind his time, for Dr. Muspratt says each paper as it came out contained the latest improvement; he might have added, except in the case of alum. I can only repeat my former assertion, that it was a most unfair description of such an important improvement. I think "the great chemical work of the age "ought to keep pace with the great chemical improvements, and not be lagging a quarter of a century behind; but we must not forget to bear in mind that the brighter the diamond the darker appears the speck; and no wonder such an error looks greater in a work that has been "eulogised by the first savans of the world." The book, indeed, must be great to have only one error. But, "let another man praise thee, and not thine own mouth." Why I found fault with the article is certainly best known to myself, but which I can easily make known to others. It was simply to show that Mr. Spence's was not a pirated process, as one might have come to that conclusion on reading the article. I am afraid Dr. Muspratt's information on alum has not advanced further than it did twenty years ago, for he concludes his letter-" If I should re-write' Alum,' a better description will be given, if requisite." It may be news: to Dr. Muspratt to say that more than two-thirds of the alum made in this country is by Spence's process, and I think your readers will come to the conclusion that a better description of alum is certainly requisite. I am, &c. J. CARTER BELL, F.C.S., Associate of the Royal School of Mines. "Associate of the Royal School of Mines." To the Editor of the CHEMICAL NEWS. SIR,-The title quoted above must have caught the eye of all diligent readers of your own and other scientific journals, raising, as in my own case, a somewhat languid curiosity as to the precise value and meaning to be attached to this resounding affix to the names of some few writers on scientific subjects. Judging from a "History of Alum," by an "Associate," recently published in the CHEMICAL NEWS, correctness in English composition is clearly not rigidly exacted as a qualification for this honour; but it is to be hoped that the Conferrers of this title insist upon accuracy in matters of science, if they fail to require it in matters pertaining merely to purity of style. Degrees and diplomas bestowed by the Universities and Chartered Corporations empowered to grant these honours deserve respect; but what does this "Associate of the Royal School of Mines" signify, and by what authority is this title conferred? The Royal School of Mines, as a national institution, either is authorised to grant degrees and dignities to qualified persons, or the governing body must have exceeded its powers and taken upon itself to give what it has no right to bestow. Will the Registrar of the Royal School of Mines state for general information by what authority this degree of "Associate" is granted? am, &c. J. DENHAM SMITH. The Chemical Society's Specimens. were more desirous than any others of using gun cotton. He considers that the most valuable quality it possesses for their use is its freedom from smoke. This vein is extremely irregular, and its workings of great extent. Good ventilation cannot be maintained everywhere, and smoke of the richest "labores" in the mines are now seriously delayed by the smoke of blasting powder. The perfect freedom from smoke of the gun cotton would warrant the using a limited quantity at considerably greater cost than powder. In Nevada city district and Calveras the opinions expressed are equally favourable, and we may predict that in the Pacific States the use of gun cotton for mining purposes will eventually be universal.-American Gaslight Journal. Apropos to a Thermo-Electric Battery.-Not unnaturally, this thermo-electric battery is exciting the imaginations of men of science, causing them to call up wonderful visions of a future when much of the work of the world shall be done by sunshine. Thus a contemporary suggests that, "like windmills, thermo-electric batteries might be erected all over the country, finally converting into mechanical force, and thus into money, gleams of sunshine, which would be to them as wind to the sails of a mill. What stores of fabulous wealth are, as far as our earth is concerned, constantly wasted by the non-retention of the solar rays poured on the Desert of Sahara. Nature here refuses to use her wonderful radiation-net, for we cannot cover the desert sands with trees, and man is left alone to try his skill in retaining solar energy. Hitherto helpless, we need not be so much longer, and the force of a Sahara sun may be carried through wires to Cairo, and thence irrigate the desert, or, possibly, if need be, it could pulsate under our streets, and be made to burn in Greenland." A fascinating dream enough, and one which may prove to be "not all a dream."-Scientific American. SIR,-There is one interest attaching to the specimens which the Council are about to distribute, which was not alluded to at the meeting, but which, I think, ought not to be overlooked in estimating their value, and deciding on the disposal of them. It is that they are all what I may Essence of Apples.-By essence of apples is meant call authentic historic specimens. I must confess that I an alcoholic solution of valerianate of oxide of amyle. have never been at the pains to inspect the contents of the This product is sometimes simply prepared by distilling case, but I have no doubt there will be found in it some crude potato oil in presence of sulphuric acid and bichrothings the discovery of which marks an era in the develop-mate of potash; but in this way a mixture is obtained ment of chemistry. Every attendant at the Royal Insti- of very little essence of apples and very much amylic tution will remember the value attached to the small alcohol. It is better first to prepare the valerianic acid specimen of benzole first isolated by Faraday, and which by the following method:-Mix gradually one part of is always produced when aniline and its compounds form potato oil with three parts of sulphuric acid and two of the subject of illustration. There may be nothing of equal water; mix separately two parts and a-half of bichromate value to that in the Society's case, but there may be many of potash and four parts and a-half of water; then mix things which, at some future time, may be looked at with the two liquids so as to keep up the boiling in the retort, great curiosity; and when the specimens are not returned saturate the distilled liquid by carbonate of soda, and to the donors, care should be taken to commit them to the crystallise the valerianate of soda. Then take one part by custody of some institution in which their value may be weight of potato oil, and carefully mix it with an equal duly estimated. The Jermyn Street people will, probably, weight of sulphuric acid, add one part and a-half of well look with contempt on the collection,- -as so many dirty dried valerianate of soda, and keep it gently heated in a bottles; but perhaps the College of Chemistry may some water bath. The addition of water causes the ether to day be lodged in a building in which space could be found separate, when it may be purified as above. This valerofor the display of specimens, which all chemists must look amylic ether mixed with five or six times its volume of on with much interest. I am, &c. F.C.S. alcohol constitutes the pleasantly scented essence of apples. Nov. 19, 1865. -Des Odeurs, des Parfums, et des Cosmetiques, by S. Piesse. MISCELLANEOUS. Gun Cotton in the American Mines.-The application of Messrs. Prentice's (Stowmarket) gun cotton is becoming very general in the mines of California and Nevada, the greatest satisfaction being expressed with regard to it in every instance in which it has been employed. At the New Almaden Quicksilver Mines it has been largely used, and Mr. C. E. Hawley, the chief engineer, reports that the gangue rock of the Almaden vein is very hard magnesian limestone, in many place worth $30 per foot-lineal-to work in ordinary drifts of 6 ft. by 5 ft. In other parts of the mine the rock is partially decomposed and easy to work. To his surprise, the miners in soft rock Chemical Society.-The next meeting of this Society will take place on Thursday evening next, at 8 o'clock, when a paper, by Dr. Gladstone, will be read "On Pyrophosphotriamic Acid.” ANSWERS TO CORRESPONDENTS. M.D.-Received. Ge. L.-Use oxide of gold as the colouring agent. Dr. F. J. Bond.-See the book reviewed this week. The last edition of Miller gives the new formula. Hamburgh and Rotterdam. We have seen a formula which directs the fermentation of a decoction of rye meal and honey, but cannot put our hands upon it at this moment. Formula.-German yeast is mostly obtained from the distilleries at Books Received." The Fairy Tales of Science," by John C. Brough. |