by M. Le Roux on experiments relating to the employment of the electric light. M. Houzeau made known a method of estimating small quantities of peroxide of hydrogen. In the presence of an acid peroxide of hydrogen decomposes either in the cold, or when heated, a solution of neutral iodide of potassium; iodine is set at liberty, and potash formed, which combines with the acid according to the equation HO2+KI + acid = HO + KO, acid + I. As a consequence of this it is evident that by simply estimating the potash formed, the amount of peroxide of hydrogen is arrived at. The process is conducted as follows. Titrated acid is first added to the neutral oxygenated solution, and then a slight excess, usually a few drops, of neutral iodide of potassium. The mixture is heated to aid the reaction, and the iodine completely expelled by ebullition. Finally a titration is performed with an alkaline solution. Thus the amount of residual acid is estimated. The solution of iodide of potassium is made by dissolving three grammes of the salt in 100 grammes of water. When the sulphuric acid and neutral iodide of potassium are sufficiently diluted, they do not react upon each other, either in the cold or upon heating. Contrary to what has been observed with regard to ozone, oxygenated water does not seem to react with iodide of potassium when the solutions are neutral. But the vapour of peroxide of hydrogen blues, notwithstanding at the same time that ozone does the iodide and starchpaper. Neutral iodide of potassium can equally serve to detect oxygenated water when this has been previously acidulated. In most cases the yellow or pinkish colour given to the solution may be considered characteristic of peroxide of hydrogen; but the sensitiveness of the reaction is augmented by the employment of chloroform, which is rendered violet or rose-coloured by traces of iodine invisible in water. Nitrites, hypochlorites, and other analogous salts react on iodide of potassium in the same manner as oxygenated water. This source of error may be removed by operating as follows:-3 or 4 c.c. of liquor is rendered acid, if neutral or alkaline, by a sufficient quantity of very dilute sulphuric acid. The addition of a few drops of iodide of potassium is the next step. A yellow or red colouration produced indicates the presence of oxygenated water, or nitrites and analogous salts. The experiment is then repeated after previously boiling the acidulated solution for a few minutes to expel nitrous acid, etc. If upon the addition of the iodide it still produces a colouration, this indicates the presence of peroxide of hydrogen. If in the cold there is no colouration, the solution is heated; if the reaction takes place, oxygenated water is present. If no colouration is produced under this treatment, a drop of chloroform is added, and the mixture agitated for a few minutes about 40° C.; a rose tint indicates the presence of oxygenated water; if no tint is produced, it may be concluded that the solution does not contain oxygenated water, or that quantity is too minute to be detected. A solution may be concentrated either in vacuo or over quick-lime. Concentration may also be effected by heat. A very dilute solution of oxygenated water containing sulphuric acid may be boiled for some minutes without suffering an appreciable decomposition. A paper entitled "Researches on the action of chloride of cyanogen on zinc ethyl," by M. Gal, was presented by M. Fremy. M. Gal recounted the experiments he had made. He finds by acting upon zinc ethyl by gaseous chloride of cyanogen, a liquid is obtained, boiling at 98°, identical with hydrocyanic ether; the reaction is the followingC.H.C2N+ ZnCl. C2NCI+CH.Zn = The author undertook the research in order to throw light upon the constitution of hydrocyanic acid, and to determine which of the two isomeric ethers of this acid should be considered as its homologue: he has not been able to decide. One of the ethers boils at about 82°, the other at 98° C. On the 13th of January, M. Becquerel made known the results of further experiments upon electro-capillary actions; this is the fourth memoir upon the subject. In decomposing mixed metallic solutions, he has observed that the metals are deposited separately: from a solution containing nitrate of silver and nitrate of copper, the metallic silver is alone deposited. M. Thénard presented a paper, by M. Romier, on the blue colouring matter of certain dead woods. M. Romier thought of the matter being applicable to dyeing purposes, and specimens of silk owing their tints to it were examined by the Academy. At the meeting on the 20th of January, Father Secchi contributed a second note on stellar spectra. There was also a note on the colouration effects which are produced when the sparks from an induction coil pass between the surface of a liquid and a platinum pole, from M. Becquerel. M. Dupré presented a memoir on molecular attractions and chemical operations. M. Miergnes addressed a communication describing a new pile composed of zinc and carbon. Having already covered the space accorded to him in these columns, your correspondent must content himself at present with simply announcing these interesting papers. CHEMICAL SOCIETY. Thursday, January 16. DR. WARREN DE LA RUE, F.R.S., &c., President, in the Chair. THE minutes of the previous meeting were read and confirmed., Messrs. G. W. Child, Edward Chapman, W. G. Mason, P. Griess, and Captain Alexander Walker were duly elected. Mr. Martin Murphy, of the College of Chemistry, Liverpool, was proposed for election, and the certificate read for the first time. The names of the candidates read for the second time were-Herbert M'Leod, Thomas Charlesworth, Robert Schenk, and John Wallace Hozier. A paper on the "Isomeric Forms of Valeric Acid," by Mr. ALEXANDER PEDLER, was read by the Secretary. The author separated the two varieties of amylic alcohol known as active and inactive, by conversion into baric sulphamylates, and fractionally crystallising. The amylic alcohol was then separated from these salts. By oxidation, valeric acid was obtained from the two varieties. The valeric acid yielded by the inactive variety (ie., that resulting from the further treatment of the less soluble sulphamylate) boiled at 175° C., and had no action on a polarised ray. The valeric acid yielded by the rotating alcohol (separated from the soluIt rotated the ray ble sulphamylate) boiled at about 170° C. 43° to the right. DR. DEBUS advanced some hypothetical views concerning thioformic acid-the acid which is obtained in combination with lead, when formiate of lead is treated with sulphuretted hydrogen. It contains the elements carbon, hydrogen, sulphur, and oxygen. Dr. Debus referred to the inability of Professor Limpricht and Mr. Herst, who have analysed this substance, to obtain concordant results. He showed that a relation might be traced in the analytical results between the carbon and the hydrogen, while in the case of the sulphur and oxygen there was an utter absence of this. But if the numbers of the sulphur and oxygen were added together they then gave figures bearing constant relation to the carbon and hydrogen. Dr. Debus gave the following formulæ as the expression of the analytical results obtained for two specimens: (1.) CH2O+2(CH2S). (2.) CH2O+3(CH2S). Dr. Frankland's lecture "On Water Analysis" followed. Dr. FRANKLAND said-"Having for some time past been engaged, in conjunction with my late pupil, Mr. Armstrong, in endeavours to place some of the determinations of water analysis upon a sounder basis, I proposed to give the results of our experiments to the Society in the usual form of a . (d.) Estimation of the nitrous and nitric acids. In this determination, Pew's process has been much used. It turns upon the conversion of stannous chloride into stannic chloride in the presence of nitric acid. Messrs. Chapman and Schenk have pointed out that this change is effected by many organic substances. paper, when our indefatigable senior Secretary suggested that unreliable. In experiments made upon nine kinds of organic the paper should be elevated to the rank of a lecture. To matter, only one, oxalic acid, was completely oxidised in six this suggestion I was at first much opposed, considering that hours. In the case of urea, hippuric acid, and creatin, the the Society had already, and even quite recently, received oxygen, abstracted from the permanganate, only represented several important communications on this branch of chemicalth of that required by theory. analysis. At last, however, I yielded to Dr. Odling's persuasion, but, in doing so, distinctly cast upon his shoulders the responsibility of summoning the Fellows to hear, under the title of a lecture on water analysis, what I fear will merely prove a dry communication on a few points only connected with this large subject; for, in the first place, I have no intention of discussing the whole subject, but only that portion of it which deals with those determinations comprehended under the term 'partial analysis of a water;' and secondly, even in reference to this corner of the subject, I have, except in one department of it, little that is novel to bring forward. So many difficulties surrounded the subject at the time this investigation was undertaken, that it was perhaps considered the least satisfactory of analytical processes. The difficulty chiefly experienced by water analysts was the determination (e.) Estimation of the ammonia. This is usually effected of the organic matters and the mineral products derived from by distilling with baryta water or sodic carbonate, and dethese, viz., nitrous and nitric acids and ammonia." The termining the ammonia either by neutralisation or by Nessler's lecturer mentioned the names of Hofinann and Blythe, Welt- test. It is liable to give inaccurate results in the case of zien, Dr. Miller, and Dr. Angus Smith, and the ways in which waters recently contaminated with sewage, owing to the they had severally contributed to the improvements of the gradual decomposition of urea. Dr. Frankland, in describing analytical processes regarding water. The determinations the processes and modifications he proposed to substitute, usually made in the partial analysis of a water are: a. The divided the water analysis into four, viz., the following detotal solid constituents. b. The organic and other volatile terminations: matters. c. The oxygen required to oxidise organic matter. d. The nitrous and nitric acids. e. The ammonia. These processes were considered seriatim. (a.) In the method usually adopted for the determination of the total solid constituents-the evaporation of the water with addition of sodic carbonate and drying at 120° to 130° C.-there are two prominent sources of error; firstly, the salts of ammonia are converted into carbonate, which volatilises during the operation; secondly, urea when present is decomposed, and some of the products are volatilised. In an experiment made to test this point 44 per cent. of urea was lost. These defects are lessened by not adding the alkaline carbonate, and by drying at 100° instead of at 120°-130°. A residue dried at 100° sometimes retains the elements of water, but these are chemically combined, and the amount obtained can therefore be fairly considered as representing only the solid constituents. With the exception of water containing much calcic and magnesic chlorides and sulphates, the difference made by drying at the one temperature or the other is not great. A water analysed (Thames water) gave as the total amount of solid matter in 100,000 parts, 27'02 parts when dried at 100°C.; and 26'54 parts at 120°-130°C. The lecturer recorded experiments upon this subject, which showed that the indications obtained in treating starch and sugar by this process were incorrect. I grm. starch digested for 20 minutes in a sealed tube with 3 c.c. of a solution of tannous chloride produced an oxidation equivalent to 00375 grm. nitric anhydride; I grm. sugar at 150° C. produced an oxidation equivalent to 007 grm. nitric anhydride. 1. The total solid constituents. 2. The organic carbon and nitrogen. 3. The nitrogen in the form of nitrates and nitrites. (1) Estimation of the total solid constituents.-For this purpose litre of water is evaporated as rapidly as possible, and the residue dried at 100° C. (2.) Estimation of the organic carbon and nitrogen.— The lecturer had no process to offer for the direct determination of the organic matter, but he was able to estimate the carbon and nitrogen, which were its most important elements, with accuracy. It is necessary in the first place to expel the carbonic anhydride. Sulphuric acid has been found to effect this easily, and for many reasons it has been found the most convenient acid. The solution is boiled for a couple of minutes with a small quantity of sulphuric acid and then evaporated; for this purpose hemispherical glass dishes have been found far more convenient than platinum. The evaporation is conducted in vacuo, and the residue dried at a steam heat. The heat is applied at the top of the bell, by means of a current of hot air; applied in this way the water never boils. Five samples of water could be evaporated at the same time in the apparatus shown to the Society. Dr. Frankland did not, however, consider the information afforded by this determination as great. In estimating the loss upon ignition, suffered by this residue, it must be pre-ferred to a combustion tube, the dish being rinsed with the viously heated to the higher temperature. (b.) In the determination of the volatile matter by the loss upon ignition, the magnesic and calcic carbonates are causticised, and have then to be recarbonated. In this operation all the organic matter cannot be expelled,-notably the case with water containing urea. Experiments were made with water containing known weights of urea and sodic carbonate. In three experiments only 146, 28°2, and 42 1 per cent. respectively became expelled; 854, 718, and 579 per cent. remaining in the residue in these cases. Dr. Frankland suggested the possibility of some of the elements of the urea being fixed in the condition of cyanate and cyanurate. A remarkable error is introduced in the case of some waters in recarbonating the alkaline earths, even with a pure solution of carbonic anhydride, the apparent amount of earthy carbonates being greatly in excess of the real amount. In such a case of course the process cannot be used. (c.) Estimating the amount of oxygen required to oxidise organic matter. Potassic permanganate has been commonly used in making this determination. A close examination of the process, however, has led to its indications being found The residue is mixed with plumbic chromate and transchromate; a layer of pure cubric oxide is also added. The tube is sealed at one end and drawn out at the other to about the same size as the tube of the Sprengel's pump which it has to join. The anterior portion of the tube (the position of the layer of pure cupric oxide) is heated, and the tube then exhausted for 5 or 10 minutes. The combustion is now made, and the tube again exhausted, and the resulting gases collected over mercury. A gaseous mixture is obtained, containing free oxygen. After absorbing the oxygen by pyrogallic acid, the volume of the gaseous mixture is accurately measured. The whole of the carbon is obtained in the form of carbonic acid, the nitrogen partly as such, with nitric acid and nitric oxide. The amount of nitrogen found is made up of the nitrogen of the ammonia and the organic nitrogen; the former must therefore be subtracted. NEWS Carbon Found. *01 306 *00440 *00530 Calculated. *01460 *00480 '00510 Mr. WANKLYN wished to know whether the comparative experiments with the process devised by himself and colleagues were made with natural or artificial waters. He maintained that their process gave constant results with from A solution of a known weight of sugar and chloride of 1 to 6 parts of albumen in 100,000 of water. ammonium gave The permanganate method in several cases gave nitrogen where the combustion process showed none. (3) Estimating the nitrogen in the form of nitrates and nitrites, Dr. Frankland has found a process, devised many years ago by Mr. Walter Crum, to give very good results. Professor ABEL had thought the process alluded to by the last speaker might have been serviceable to him, and had instituted experiments to check their results. He had been totally unable to obtain concordant results. similar to Professor Abel's. Mr. CHAPMAN attributed the different results obtained by Dr. Frankland by the combustion process and their process, to sources of error in the former. Mr. THORPE, calculating the nitrogen as albumen, obtained results agreeing with other determinations, and found the process valuable as a method of controlling his results. Dr. VELCKER remarked that M. Nessler had told him of a simple method of separating the ammonia when present in moderately large quantity. The Nessler test, shaken in a bottle with the water, gave a precipitate which contained all the ammonia. By separating this by deposition, and treating it with sulphide of potassium, and distilling, all the ammonia will be separated, and may be collected in a solution of standard acid. Mr. SMEE and Mr. HAWKSLEY, the engineer, also took part in the discussion. The lecturer replied to the many remarks that had been made. The question put by the President was one of great interest, but he was unable to say definitely whether the point suggested by Dr. Volcker. reduction was carried to nitrogen. He should act upon the At a late hour the Society adjourned. Mr. Wanklyn wished to continue the discussion, and he therefore possesses the right to speak at the commencement of the next meeting. SOCIETY. Ordinary Meeting, December 24th, 1867. E. W. BINNEY, F.R.S., F.G.S., Vice-President, in the Chair. "On the Examination of Water for Organic Matters," by Dr. R. ANGUS SMITH, F.R.S. A concentrated solution of the nitrate or nitrite is mixed with rather more than an equal volume of sulphuric acid and agitated with mercury in as finely divided a state as possible. It is convenient in this operation to use the residue obtained in the determination of the total solid constituents. Chlo- MANCHESTER LITERARY AND PHILOSOPHICAL rides must not be present. To remove chlorine, argentic sulphate is added to the residue dissolved in 15 or 20 c.c. of water, the solution filtered, and evaporated to a small bulk. It is then transferred to a vessel standing over mercury. The vessel may be described as a narrow eprouvette drawn out at the top into a narrow tube with a stopcock, carrying above a cup-shaped piece. The last portions of the fluid are washed in with the acid itself. The tube has been filled up to the tap completely with mercury, and care is necessary in allow ing the descent of the fluid from the cup to the lower vessel to allow no air to enter the latter. The tap being carefully closed, the thumb is slipped under the end of the tube, which is then withdrawn and shaken. In this operation a short column of mercury must always remain between the thumb and the solutions. A strong pressure is produced, and the tube is occasionally returned to the trough, and the egress of some of the mercury permitted. The pressure is due to the formation of gaseous oxides of nitrogen. The nitrogen is determined in the resulting gas. The reduction of the nitrates and nitrites by this means was shown to the Society, the process described being performed experimentally, and a considerable quantity of gas was obtained. This process has been tried with known quantities of nitre, also with uric and hippuric acids, and found to give satisfactory results. (4.) Determination of the ammonia. Dr. Frankland considered it advisable to decolorise the water before using Nessler's colour test, using for this purpose calcic chloride, sodic carbonate, and a few drops of potassic hydrate. The distillate from this gave accurate indications. The PRESIDENT, in returning the customary vote of thanks, took occasion to inquire whether the reduction of the nitrates was carried to nitrogen. The subject being evidently a fertile one for discussion, the speakers were limited to a few minutes each. He THE author repeated his opinion that the mere expression M. R. Radau has just published a most interesting work on Acoustics (Paris, Hachette) with 114 wood-cuts; it contains the new experiments by M. Regnault on sound and kænigon vowels. CHEMICAL NOTICES FROM FOREIGN glass, exhales rearly as much carbonic anhydride as it would SOURCES. Cement.-Sorel describes a new cement which he prepares by mixing magnesic oxide with a more or less concentrated solution of magnesic chloride. The hardness of the cement increases with the strength of the solution; 20 to 30° Baumé is found most suitable. Its blinding power is greater than that of any other cement, it being capable of producing hard blocks with more than twenty times its weight of sand or other inactive material.(Comptes R. lxv. 102). Glycogen. The amyloidical matter found in mollusks is, according to Bizio, glycogen. If the latter, after precipitation with alcohol, is allowed to dry gradually, it coheres together in lumps. Rapid desiccation leaves it as a fine powder, in which condition glycogen has commonly been observed. In contact with white of egg or casein, lactic acid fermentation slowly sets in. Dried at 100° C., its composition is Є,H,,. -(Comptes R. lxv. 175). Monamines derived from Aldehydes.-H. Schiff. Prolonged action of alcoholic ammonia upon acetic aldehyde, at ordinary temperature, gives rise to the formation of two bases HN or H,N (Picolin), distilling at 60°-70° C., soluble in water, and N.(EH), remaining in the residue after distillation. The latter (which has not been obtained pure) is decomposed by water and acids with formation of another soluble base-,H,,NO. The derivation of this third, a tertiary monamine from aldehydeammonia, is explained by the following equation:NS N H, +2¤‚H‚0 = 2H,0 +N {& When aldehyde is treated with ammonia at 100°, two other bases are obtained--€10H, NO, and E,H,,NO, of which the latter has already been noticed by Heintz and by Wislicenus. Hydro-œnanthamide N (E,H,,), is decomposed by boiling water, and the compound N(E,H13)2(E,H14, OH) formed, which shows no basic properties. in the dark.-(Comptes R. lxv. 322.) Synthesis of Diethylated Toluol.-Lippmann and of the constitution of the radical amyl, and of finding a new Longuinine. With a view of arriving at a clearer conception method for the synthesis of aromatic hydrocarbons, the benzol (chloride of oil of bitter almonds). The reaction that authors investigated the action of zincic ethide upon chlorotakes place is the following HHCl, + Zn(€2H)2 = Соны €н(Є2H)2 + ZnCl2 6 The hydrocarbon H. must be considered as toluol in which 2 atoms of hydrogen of methyle are replaced by 2 of ethyl. Its density was found = 51107, calculated = 51245. Its boiling point when pure, is at about 180° C. or 15° lower than that of Fittig's amylbenzol, which has the same composition. It follows from this that the two are differently constituted, and that the formula of amyl is not correctly represented as(Є,Hs)2 (Comptes R. lxv. 349.) e { H Aldehyde and Cyanhydric Acid.-M. Simpson and A. Gautier. Equal mol. of acetic aldehyde, and dry cyanhydric acid unite by direct addition, when exposed for ten to twelve days to a temperature of 20° to 30° C. The body thus formed has the composition ЄNH,E,H,. It is a colourless, oily liquid, boiling at about 183°, but rapidly resolving itself into its constituents at that temperature. It is soluble in water and in alcohol, absorbs ammonia readily, and when heated with it to 100°, is converted into a syrupy mass of basic properties. The action of chlorhydric acid and water upon cyanhydric aldehyde gives rise to the formation of lactic acid according to the following equation:€NH,C,H,O + HCl + 2H,O NHẠC + CHO, (Comptes R. lxv. 414.) = Conversion of Gallic Acid into Tannin.-T. Löwe finds that gallic acid in aqueous solution is converted into tannic acid by the oxidising influence of argentic nitrate. The Related to these are valeral-ammonia and Erdmann's tri- oxidation is more complete if a salt of gallic acid is employed. oxyamylidene, to which the formulæ H2 This base resembles closely those derived from acetic aldehyde. Ammonic sulphhydrate converts acrolein and œnanthol into acrothialdin E,H,,NS, and oenanthothialdin €21H3NS2. From the reactions of these bodies the author concludes that the thialdines likewise are tertiary amines, in which three typical hydrogens are replaced by three radicals containing the sulphur, as sulphydril (SI), just as the bases above mentioned contain oxhydril (OH).(Comptes R., lxv. 320.) Influence of Coloured Light on the Decomposition of Carbonic Anhydride by Plants.-L. Cailletet. The red and yellow rays of light are the most favourable in promoting the decomposition of carbonic anhydride by plants. Light which passed through a solution of iodine in carbonic disulphide prevents decomposition altogether. Under the influence of green light, not only does no decomposition take place, but new quantities of carbonic anhydride are formed. A fresh leaf exposed to sunlight, under a bell-jar of green -Journ. Pr. Chem. cii. 111.) Acetylene.-R. Rieth. The imperfect combustion of coal gas which takes place when the flame of a Bunsen's burner has gone down, so as to burn within the tube, has been found to be a rich source of acetylene. The escaping gases are collected by means of a funnel placed over the burner, and connected with an aspirator. The quantity of the silver compound of acetylene obtained from one burner in twelve hours amounted to 100 grammes.-(Zeitschr. f. Chem. N. F. iii. 598). Oxidation of Potassium and Sodium.-The oxidation of potassium and sodium, when exposed with a clean surface to the air, is accompanied, according to H. Baumhauer, with evolution of light.-(Journ. Pr. Chem. cii. 123). Viridinic Acid.-O. Cech. This acid may be obtained direct from coffee by pulverising the beans, extracting them with ether alcohol, to remove fat, and exposing them in moist condition to the air. After a few days the mass, which has assumed a green colour, is exhausted with acetic acid and alcohol, which takes up the viridinic acid formed.-(Ann. Chem. Pharm. cxliii. 366.) Preparation of Iodhydric Acid.-C. Winkler. Instead of preparing this acid by passing a current of sulphuretted hydrogen through water, containing iodine in suspension, the author proposes the following plan of working. Iodine is dissolved in carbonic disulphide, water placed on the top of this, and the sulphurretted hydrogen passed to the bottom of the vessel into the iodine solution. The dark colour of the latter gradually becomes lighter, while the iodhy Derivatives of Xylol and Dimethylbenzol.-R. Fittig. A careful comparison of methyltoluol, or dimethylbenzol E.H.(EH,), (obtained by replacing in toluol one atom of hydrogen by one of methyl) with xylol from coal-tar, has shown that these hydrocarbons are not indentical. Both, however, are converted by oxidation with diluted nitric or chromic acid into the same derivatives, i. e., toluylic and terephtalic acid. Amongst the compounds prepared and examined were nitroamidoxylol, nitroamidomethyltoluol, diamidoxylol, dibromxylol, dibrommethyltoluol, parabromtoluylic acid, nitroparabromtoluylic acid, paradibromtoluylic acid, monobromnitroxylol, dixylyle.-(Zeitschr. Chem. N. F. iii. 523-) Derivatives of Sulphurous Chloride.-Fr. Grauhe. Sulphurous chloride is prepared by passing a current of sulphurous acid into phosphoric perchloride, and subjecting the products of the reaction to fractional distillation. The pure chloride boils between 78° and 79° C. Argentic cyanide converts it into sulphurous cyanide S2O2(CN)2, which is insoluble in water, soluble in alcohol and ether. From the latter it crystallises in long needles. Zinzic ethide decomposes sulphurous chloride with formation of ethylic sulphide according to the equation S2O2Cl2+3ZnC、H.=S, {C,H;+2ZnCl+ZnO+C,H,O An experiment in which sulphurous chloride and benzol were made to act upon each other with a view of obtaining phenylsulphurous acid, was unsuccessful. (Ann. Chem. Pharm. cxliii. 263.) Double-chlorides of Platinum.-K. Birnbaum. Plumbic chloride dissolves readily in a concentrated neutral solution of platinic chloride. On evaporation crystals of plumboplatinic chloride Pb Pt Cl.+4H2 separate. An ammoniacal solution of argentic chloride added to ammoniacal platinic chloride, causes the formation of a yellow crystalline precipitate, which after desiccation over sulphuric acid had the composition 2NH3+2AgCl + PtCl + H2→. NOTICES OF BOOKS. First Principles of Modern Chemistry. A Manual of Inorganic Chemistry for Students and for Use in Science Classes. By U. J. KAY SHUTTLEWORTH. London: John Churchill & Sons. 1867. (Pp. v. and 214.) THIS little book is mainly founded on Dr. Williamson's lectures at University College in the session 1864-5, and on those delivered by Dr. Frankland at the Royal College of Chemistry in the following winter. It was originally intended to supply the want of a strictly elementary manual for the use of science classes-a want, however, which, in our opinion, has had no real existence since the appearance of Professor Roscoe's excellent Lessons in Elementary Chemistry." The great and rapidly-increasing popularity attained by Dr. Roscoe's book is no less an indication of the reality of the want of a manual of this character, than a measure of the success with which that want has been met. Already the book has been translated and favourably received in Germany, and we understand that Professor Beilstein is about to prepare a Russian edition for the use of his students at St. Petersburg. Without laying claim to any great degree of originality, the author of the book before us has attempted to indicate how the study of the non-metallic elements may be facilitated by the aid of modern theories, and thus the student's early steps rendered less tedious and more sugges tive than they commonly are. Dr. Frankland's system of notation is employed throughout the work, together with Dr. Crum Brown's method of graphic formula; the author considering that the advantages of the former ought to insure its universal adoption, whilst what is sometimes urged as a fundamental objection against the use of the latter, namely, that students are prone to regard graphic formulæ as physical arrangements of the atoms, he believes not to be warranted by the experience of those who have given the method an impartial trial. No detailed directions for manipulation are given, the author justly considering that such directions are seldom very intelligible, except when given orally in presence of the objects used. Practical study in a laboratory should invariably accompany a course of reading in chemistry, although the manifest advantages of such method of study have hitherto, in the system of cram so much in vogue, been too frequently lost sight of. In the few instances in which they have been No definite compound could be obtained with mercuric chlo- attempted, the detailed descriptions of apparatus are fairly ride. (Zeitschr. f. Chem. N. F. iii. 520). Cymol from. Camphor.-Longuinin and Lippmann. Equal molecules of camphor and phosphoric perchloride are intimately mixed, and the mixture very slowly distilled from a retort. The distillate is washed with water, dried, and rectified over sodium. It is then quite pure, having its boiling point between 175° and 178° C.-(Bull. Soc. Chim. vii. 374.) Isoxylol, Preliminary notice.-R. Fittig. Mesitylenic acid, the product of the reaction of diluted nitric acid upon mesitylene, is decomposed by being heated with caustic lime according to the equation The new hydrocarbon isoxylol resembles its isomer xylol very closely in many points, but widely differs from it in its behaviour towards oxidising agents. Chromic acid, for instance, converts xylol into terephtalic acid, while isoxylol is oxidised to isophtalic acid, isomeric with the former. This new acid is readily soluble in alcohol, almost insoluble in cold, sparingly soluble in hot water. From the latter it crystallises in long needles, which fuse above 300°C. A dibasic homologue of isophtalic of the composition H., has been obtained by slow oxidation of mesitylenic acid, besides tribasic trimesinic acid, described on a former occasion.-(Zeitschr. Chem. N. F. iii. 526.) given. The author, however, has erred with other compilers of chemical manuals, when describing the method of determining the composition of water by volume (p. 83) in ascribing the invention of the pear-shaped vessel with its elaborate system of screws, glass stoppers, brass and glass stopcocks, etc., to Cavendish. True the apparatus here referred to is the one selected by the Cavendish Society as their emblem, and appears on the title-pages of its publications, but withal Cavendish never employed such an instrument. The apparatus, as described by him in his memoir in the Philosophical Transactions, consisted simply of a glass globe provided with a stopcock, wires for the passage of the spark, and an arrangement for suspending it to the beam of the balance. The eudiometer figured in the pages of its publications (and in Mr. Shuttleworth's book) represents the instru ment as constructed at the period of the formation of the Society, and not as it was actually employed by Cavendish. Before entering on the more special part of the subject two chapters are devoted to a consideration of such of the principles of physics as may be deemed indispensably necessary to the student. The author believes these chapters to contain nearly all the knowledge of heat required by the University of London for its matriculation examination, and moreover the subject is treated very much in the order laid down in the University Calendar. In the description of the different thermometric scales in use, the commonly received opinion is that Fahrenheit fixed his zero-point at the temperature of a mixture of snow and salt or sal-ammoniac, on the supposition |