Horsford gave a communication on the reduction of carbonic acid to carbonic oxide by phosphate of iron. An ethereal solution of chlorophyll is resolved by hydrochloric acid into a blue and a green stratum. The first mentioned contains iron, lime, and phosphoric acid-the constituents of Vivianite. Zinc and sulphurous acid destroy the colour. Carbonic acid, enclosed with ferrous phosphate in a tube, is gradually decomposed, while the salt of iron turns blue. About one-sixth of the carbonic acid is, in a few days, converted into carbonic oxide. Graebe and Caro communicated an interesting paper on the constitution of rosanilin. They ascribe to rosolic acid the formula C20H1603. Oppenheim gave an account of his researches on the product of the reaction of oxide of mercury upon benzamid. Lossen read a paper on amidic derivatives of hydroxylamin. Scheibler exhibited two specimens of arabinose, C6H12O6, a gum-sugar which he had recently described. V. Meyer gave the results of his experiments on the action of formiate of soda upon sulpho-benzoic acid and benzoic acid. Wislicenus added a notice that the observations of Richter have no connection with Meyer's reaction. He also made a communication on ethylenlactic acid. In the second session, September 20, Meyer read a paper on the action of sulphuric acid upon nitro-ethan. Wurston gave a short communication upon fulminic acid, for which he proposed the formula, H(NO2)C2NH. Boettger called attention to some new interesting lecture experiments on active hydrogen and active oxygen. Weith treated of desulphurising diphenyl-sulph-urea by oxide of mercury. Petersen gave his opinion as to the chemical location of the benzol derivatives. Fittig read a paper on chinons. In the third session Himyl gave an account of Schorer's water air-pump. P. Rasenach described a hydrocarbon obtained from the portion of coal-tar which boils at the highest temperature. Michaelis exhibited his derivatives of phosphenylchloride. Staedel described the reduction of benzophenon. Blockmann reported on two analyses of coal-gas, before and after passing through porcelain tubes at 1000°. The hydrogen had increased, and all heavy hydrocarbons had disappeared. Walter treated on the "changing valence" of nitrogen, phosphorus, &c. Bauman gave a paper on the addition of cyanamid. Gscheidlen exhibited an apparatus for mixing two solutions without access of air. Thudicum contended against the accuracy of Strecker's formula for bilirubin, on the ground that hexatomic acids were unknown in organic chemistry. He diction to Seegar and Nowak, he found the soda-lime process trustworthy, even in case of albuminates. pointed out that the soda-lime of commerce is often contaminated with nitrates and nitrites. Fleischer gave results on the respiration of sheep. Wildt gave an account of experiments on the secretion of hippuric acid. He considers that the cuticular substance of the vegetables consumed furnished the hippuric acid. Rabbits fed on pure grass yielded a trace of hippuric acid; if fed on clover, but little; but if allowed to eat dandelion a considerable quantity. Neubauer and Canstein discoursed on the movement of sap in the vine, and on the qualitative composition of this liquid. Mayer gave statistics on the results of manures. Wolff spoke on water cultivation, and on the influence of different doses of phosphoric acid upon the development of the oat plant. In the Mineralogical Section Flight described his experiments on the colours of the diamond. A rose-coloured diamond of 29 carats, exhibited at Paris in 1867 by Coster, of Amsterdam, was bleached in four minutes on exposure to diffused light, but resumed its colour when heated in asbestos, and retained it if preserved from daylight. Two dull yellow diamonds from the Vaal river were selected, one of which was preserved for comparison, while the other was subjected to modifying experiments. On being heated to redness in a current of hydrogen, it was found colourless when cold, but gradually assumed its colour on exposure to daylight. If heated in a current of chlorine the result was the same. Flight gave an account of the "distillation method" for the determination of silicic acid as developed by himself and N. Story-Maskelyne. The description of the apparatus requires a diagram. Flight gave last an account of the experiments of Douglas, Hermann, and Story-Maskelyne on the crystallisation of phosphorus. PATENTS. Grain. Straw. Kils. Kils. 962 2400 1324 4100 1600 3300 The ABRIDGMENTS OF PROVISIONAL AND COMPLETE SPECIFICATIONS. Heumann pointed out certain uniformities in the melting-points of chlorinised azo compounds of benzol. In the Section of Agricultural Chemistry, Wolff gave an account of the use of cockchafers as food for pigs. The chitin was (as might be expected) found quite indigestible.provements being applicable to other oil and spirit lamps. John Robert A. Mayer gave an account of some important experiments undertaken to decide as to the power of absorbing ammonia-gaseous or in aqueous solution-possessed by the parts of plants above the surface of the ground. A variety of plants examined were found to possess this power, but, at least under the circumstances observed, a normal growth of plants seems impossible if the introduction of nitrogen through the roots be excluded. The leguminosa have, in these experiments, shown especial power of absorbing ammonia by their leaves and stalks, or of assimilating the trace of combined ammonia present in the atmosphere. no Improvements in gas-lamp blow-pipe apparatus, part of such im. Harper, Clerkenwell, Middlesex. April 4, 1873.-No. 1251. The first part of these improvements has for its object the combination of a current of air with the jet of ignited gas or vapour as it issues from the oil or spirit vessel and jet-pipe of such apparatus. The jet-pipe is surrounded by, or enclosed within, another pipe, open at each end, so that, when the jet of gas or vapour is ignited, a strong current of air is caused to enter the pipe behind the jet of ignited gas, with which it combines, thereby increasing the intensity of the flame so produced. By reason of this improved arrangement, the flame of an auxiliary lamp can be dispensed with. According to another part of these improvements, an additional jet-pipe (or pipes) is employed to evaporate and maintain the pressure in the oil or spirit vessel, in place of the auxiliary lamp heretofore employed for this purpose. According to another part of these improvements, the oil or spirit vessel is surrounded with a water- or steam-jacket, to which heat is applied for transmitting heat to the oil or spirit vessel for producing the gas which supplies the Kreusler reported on the accuracy of Will and Varrentrap's method of determining nitrogen in albuminates. jet or jets of the blowpipe apparatus. Another part of these improve In accordance with Maecker and Petersen, but in contra ments relates to the arrangement and construction of the safety-valves of such apparatus. The safety-valve is surrounded with a case to receive the gas when it escapes through the safety-valve and conduct it to the jet-tube, where it is consumed with the gas from the jet. In accordance with another part of these improvements, the oil or spirit vessel is formed with a chamber or passage through which the gas-jet and safety-valve tubes are conducted in order to afford ready access to the gas-cocks and apparatus. According to another part of these improvements, gas blowpipe apparatus when out of use is enclosed in a central chamber formed within an annular-chambered oil or spirit can or vessel containing a supply of benzoline, paraffin, or other cheap oil or spirit, thereby rendering the apparatus more convenient and portable. When auxiliary lamps are employed, a benzoline, paraffin, or other similar lamp is used in place of spirits of wine, as heretofore. A new colouring matter or "dye." Alexander Melville Clark, patent agent, 53, Chancery Lane, Middlesex. (A communication from Emile Digeon and George Goldsmith, both of Paris, France). April 10, 1873. No. 1331. This invention relates to the preparation of a yellow colouring matter from the roots of the asphodel (a plant of the order Liliaceae). The colour is obtained by decoction, or preferably by extracting the juice by any known means. By dipping fabrics dyed with this yellow in an alkaline bath, shades of maroon may be obtained. Improvements in the preservation of alimentary substances, and in apparatus for the same. Alexander Melville Clark, patent agent, 53, Chancery Lane, Middlesex. (A communication from Bernard Delrieu and Jean Marie Pernoud and Co., of Lyons, France). April 16, 1873. No. 1370. This invention is based on the desiccation of alimentary substances in vacus, in the presence of hygrometric matters capable of absorbing the vapours of water as they form, preferably sulphuric acid at from 48° to 52° Baumé. The desiccating apparatus consist of a series of boxes, and of two series of air-pumps, one for producing a vacuum in each box, and the other for acting on the whole of the boxes. Each desiccating box is divided vertically into two equal parts, each half containing rows of leaden trays for the acid, and of frames for the matters under treatment, disposed alternately, to avoid congelation. A new or improved composition for treating, impregnating, and coating wood, so as to preserve and render it impervious to water and other fluids. William Hockley, 26, Bloomsbury Square, Middlesex. April 16, 1873.-No. 1382. This invention has for its object the preparation of a composition for treating, impregnating, and coating wood so as to render it impervious to water and other fluids, being particularly applicable for treating and impregnating the interior of casks, vats, or other hollow vessels made of wood, to render them impervious to the action of the malt liquor or other fluids they are required to contain. For this purpose what is generally known as paraffin wax is employed, purified, and refined by boiling. To this gum anemie and gum galguminum are added, in the proportions of about 1 ounce each to 7 lbs. of paraffin. About the same proportion of gum copal may be combined with the above ingredients for some purposes, if desired. NEWS 27, 1874 translated and edited with the Author's sa:.ction by E. ATKINSON, Ph.D., F.C.S., Professor of Experimental Science, Staff College: Elementary Treatise on Physics, Experi mental and Applied, for Colleges and Schools. Taanslated from GANOT'S "Eléments de Physique." Sixth Edition, with 4 Plates and 746 Woodcuts. Post 8vo., price 155. "This treatise is too well known and appreciated to require any special notice beyond the fact that the present edition has received numerous additions, both in the way of letterpress and illustrations. Those parts referring to physiological electricity have been revised, and in a great measure re-written, by Dr, Martin, of Christ's College, Cambridge. Altogether the sixth edition of Ganot's "Physics' in every way an excellent book for students of physical science." Lancet. Natural Philosophy for General Readers and Young Persons. Translated and edited from GANOT'S "Cours de Physique; with 440 Woodcuts. Crown 8vo., price 7s. 6d. "This is a good text-book of physics for the middle and upper classes of boys' and girls' schools, embracing a familiar account of physical phenomena and laws for the general reader. The subjects are the properties of matter, hydrostatics, pneumatics, acoustics, heat, light, magnetism, and electricity; and the treatment is entirely free from mathematical formulæ. The engravings of the instruments and of the experiments detailed are good and suggestive, and calculated to be of assistance not only to the learner but to the teacher." -Nature. London: LONGMANS, GREEN, and CO., Paternoster Row. MR. WATTS'S DICTIONARY OF CHEMISTRY. A Dictionary of Chemistry, and the Allied Branches of other Sciences. By HENRY WATTS, F.R.S., assisted by eminent Scientific and Practical Chemists. Also, in One thick Volume, 8vo., price 31s. 6d., FIRST SUPPLEMENT TO WATTS'S DICTIONARY OF CHEMISTRY, bringing the Record of Chemical Discovery down to the end of the year 1869; including also several Additions to, and Corrections of, former results which have appeared in 1870 and 1871. In the press, in One thick Volume, 8vo., SECOND SUPPLEMENT TO WATTS'S DICTIONARY OF CHEMISTRY, bringing the Record of Chemical Discovery down to the end of 1872, including also the more important Additions to the Science, published in the early part of 1873. London: LONGMANS, GREEN, and CO., Paternoster Row. PROFESSOR ALLEN MILLER'S CHEMISTRY. Latest Edition, complete in 3 vols., 8vo., price 60s., lements of Chemistry, Theoretical and Practical. By WILLIAM ALLEN MILLER, M.D., F.R.S., &c., late Professor of Chemistry in King's College, London. Ele May be had separately: PART I-CHEMICAL PHYSICS, 5th Edition, revised, with Additions, by H. C. MACLEOD, F.C.S., with 274 Woodcuts, 158. PART II-INORGANIC CHEMISTRY, 5th Edition, revised, with Additions, by H. C. MACLEOD, F.C.S., with 376 Woodcuts, 215. "Mr. Macleod has done his work of revision well, and these goodly volumes retain their place as the standard text-book for all classes of students of chemistry."-English Mechanic. PART III.-ORGANIC CHEMISTRY, 4th Edition, 24s. London: LONGMANS, GREEN, and CO., Paternoster Row. NEW EDITION OF CULLEY'S TELEGRAPHY. Just published, in 1 vol. 8vo., with 144 Woodcuts and 5 Plates of Machinery and Apparatus, price 16s. cloth, A Handbook of Practical Telegraphy. By R. S. CULLEY, Member Inst. C.E., Engineer-in-Chief of Telegraphs to the Post Office. (Adopted by the Post Office and by the Department of Telegraphs for India.) A New Edition, being the Sixth, thoroughly revised and enlarged. London: LONGMANS, GREEN, and CO., Paternoster Row. is a further improvement. The nitric acid, in acting upon the metal in 4, evolves fumes, which mechani cally carry off traces of nitrate of thallium. In the vessel shown in Fig. 12, these fumes are washed in the nitric acid, offering, however, no great advantage; but, in the series of bulbs shown in Fig. 13, b contains the nitric acid, which can, by means of the tap c, be admitted in the RESEARCHES ON THE ATOMIC WEIGHT OF required quantity to the metal. The fumes are washed THALLIUM." By WILLIAM CROOKES, F.R.S., &c. Continued from p. 97). SECTION IV. PROCESSES AND RESULTS. THE processes and manipulation necessary to the determination of an atomic weight are at all times difficult and delicate, but especially so in the case of a metal such as thallium, so readily oxidisable. This strong tendency to combine with oxygen renders the ordinarily exact processes of weighing out pure metals inapplicable to the present purpose. The chances of contact with the oxygen of the atmosphere must be reduced to a minimum, and to this end the following modes of operation were devised. The method found to be the most accurate, and that adopted in repeating the determinations, will receive a description more detailed than the first, and what may be termed approximate, methods. Process of the Conversion of Thallium into Nitrate of Thallium. Thallium being a metal of very high atomic weight, the change in weight in the interconversion of its compounds is comparatively too small to be estimated with any approximation to accuracy. For instance, the conversion of acetate of thallium into chloride of thallium is an operation hardly to be effected without such loss as would seriously interfere with the calculated result. The immediate conversion of the metal into one of its salts is therefore the method affording results less liable to be affected by errors in observation; and the conversion of thallium into its nitrate has been that ultimately adopted. Pure thallium, obtained as described, is cut into small bars with a very sharp steel knife, and dropped into a dish of pure water slightly warmed, and forming the sub-stratum to an atmosphere of carbonic acid in a vessel large enough to admit both hands easily. In this bath the original surface of the ingot is removed and rejected. The bars are then well rubbed with fine cambric to smooth down all sharp edges. Any pieces which contain pores are rejected.‡ A stoppered tube (Fig. 11) is half filled with water, and weighed. The bars of thallium are then quickly removed from the warm water of the carbonic acid bath, rapidly wiped dry with warm cambric while in the carbonic acid, and put into the weighed tube of water. It is found that no appreciable oxidation takes place during this transference, and that the whole of the moisture can be removed. The tube and its contents are then weighed again. Fig. 12 represents a vessel for the conversion of thallium into its nitrate, the pure metal as weighed in the manner described above in a tube of water being placed in the bulb a, and the pure nitric acid in b. The tubes are accurately ground, and fitted to each other at c. d is a permanent stopper to the upper bulb, well ground. eandf are platinum wires for the support of the flask in the balance. The process of converting the thallium into its nitrate coincides in detail with this apparatus with the process ultimately adopted, and particularly described in the succeeding pages. With an apparatus of this kind the determination A was performed, the metal being purified by the process already described under a (p. 96). in the water contained in g, the water being evaporated to obtain the nitrate of thallium held in solution. In this apparatus, and with metal purified by the process described under the letter a, the determination B was effected. The metallic thallium is weighed sealed up in hydrogen in the following manner : The lump or ingot of pure metallic thallium prepared by the process a, already described, is cut up into parallelograins, all the original surface being removed with a A Paper read before the Royal Society June 20, 1872. An error of 005 grain in the weighing accumulates to an error of c95 in the atomic weight. The upper surface of the fused lump is full of pores for a depth of one-sixteenth of an inch; one-quarter inch is therefore removed for greater certainty. very sharp steel knife. The parallelograms, immersed and boiled in very dilute sulphuric and hydrochloric acids, are subsequently washed, boiled repeatedly in water, and then transferred to the glass tube a, Fig. 14. Into this tube pass and are fused the platinum wires, bc, these wires being the reducing and oxidising electrodes respectively in connection with two Grove's elements. At d the tube is drawn out to a fine orifice, and at e is passed in a current of pure hydrogen prepared as before described, as shown in Fig. 15. The electric current being passed through the water, to preserve the pure metallic surface of the thallium, heat is applied until the water is entirely volatilised. At this point, and while the tube is very hot, the dry hydrogen still passing, the end of the tube at d is sealed up, and then the tube at h, previously much contracted, is closed before the blowpipe. The metal is thus enclosed hermetically in an atmosphere of pure hydrogen. The tube and its contents are then cooled for six hours, and, when cooled, weighed first in air and then in the vacuumbalance. The tube is now cut across the middle with a cutting-diamond, wrapped up in smooth platinum-foil to secure any splinters of glass which might be thrown off, and then broken with a sharp blow opposite the cut. The thallium is carefully removed from the pieces of tube, and introduced into the apparatus where the subsequent operations are to take place. The pieces of tube, with any splinters which may have broken off, are weighed, first in air and then in a highly rarefied atmosphere. The difference between the weighings of the full and empty tube, after correcting for the hydrogen contained at first, | employment of the Sprengel and Bunsen pump at different gives the weight of thallium taken. stages of the operations. These two forms of apparatus were found to answer the purpose tolerably well. Several improvements, however, suggested themselves whilst the determinations were in IG. 13. Although each determination with this improved apparatus still took many weeks for its successful performance, a great saving of time was effected when compared with FIG. 16. Some of the metallic thallium, prepared by one of the methods already described, is cut by means of a sharp steel knife into prisms about one-eighth inch square and half an inch long, no particular care being taken to avoid oxidation. The prisms are boiled in dilute hydrochloric acid to remove any trace of iron which the knife might have communicated. They are then washed in water, dried with blotting-paper, and introduced into the cylindrical portion a, Fig. 16, of the apparatus. The outer extremity of a is then drawn out and sealed before the blowpipe. The end c is also sealed up, and the horizontal tube e is connected to the Sprengel pump and a vacuum obtained, the apparatus and the thallium being kept warm to drive off any moisture which might have been introduced with the thallium. When the vacuum is perfect, the tube is sealed at f. The apparatus, sealed up and entirely free from air, is now laid on its side, and the cylinder a and the bulb b imbedded in a bath of magnesia held in a copper vessel heated by gas. The temperature is then raised to above the fusing-point of thallium (561° F.), when by careful manipulation the oxide may be separated from the liquid metal, and the greater part of the oxide collected at the closed end of the cylinder a. The magnesia is then removed from about the narrow part of the tube d (which should be somewhat long and very much contracted), and by a dexterous movement the magnesia-bath containing the apparatus is suddenly tilted up, and the liquid metal allowed to run through the contracted part into the bulb b. In some instances portions of oxide or of metal stick in the channel; then the operation is lost, and a fresh attempt has to be made with another apparatus; but, if the channel is entirely or in great part clear, it may be sealed up at the contraction, care being taken to apply the heat at such a place that no particles of metal or oxide are entangled in the fused glass. The apparatus has now the form shown in Fig. 17. It is hermetically sealed, entirely free from air, and contains a certain quantity of pure metallic thallium entirely free from oxide and as brilliant as mercury. The next operation is to ascertain the combined weight of the apparatus and metal. It is washed on the outside with dilute sulphuric acid to remove any particles of magnesia that might adhere to it, and, after rinsing with water, is dried and gently warmed. Its weight is then taken in the air-balance-not necessarily with extreme accuracy, but to enable a calculation to be made as to how much it will probably weigh in the vacuum-balance at a greatly reduced atmospheric pressure. As the substance weighed consists of thallium and glass in unknown proportions, the vacuum-weight cannot be calculated with any approach to accuracy; but it is generally easy to arrive at some approximation to the relative proportions of thallium and glass, and in this manner the probable vacuum-weight may be estimated. The apparatus is now transferred to the vacuum-balance, and weights put which it is judged will balance it at an atmospheric pressure a few barometric inches short of a vacuum. The balance-case is then sealed up, and the exhaustion proceeded with. As the rarefaction proceeds, the beam is occasionally liberated until it is found that the apparatus and weight are in equipoise. If the barometer-gauge shows a rarefaction not equal to 25 inches of mercury, the air had better be let in, the requisite additional weight added, and the exhaustion re-commenced; but if, when the balance is in equilibrium, the rarefaction is above 25 inches, the weighing may be continued. Two sources of error have now to be guarded against :— 1. The alteration of temperature inside the iron case, consequent on the rarefaction. 2. The slow and almost unavoidable leakage of air into the balance through the iron, the numerous joints, and the stuffing-boxes. This leakage should not exceed o'r inch in an hour. Equilibrium having been obtained, two or three extra strokes are made with the air-pump, and the exhaustion raised to such a point that by about six hours' leakage the balance is again in equipoise. The weights will at first appear lighter than the apparatus. The balance is allowed to remain well protected from external thermal influences, until the time has nearly arrived when the leakage of air into its interior has reduced the rarefaction to the point at which the weights and apparatus will be exactly in equilibrium. The observer now enters the room, and, after liberating the beam and setting it in oscillation, watches the movements of the index through a telescope fixed 10 feet By reason of the gradual leakage of air, the inequality of the oscillations gradually diminishes, until at last the arcs are of the same value. At this moment the temperature inside and outside the balance-case, the height of the barometer-gauge, and the reading of the standard barometer are observed. Six hours are generally sufficient to restore the temperature reduced by the exhaustion; but, if the inner and external thermometers differ, I again rarefy by a few strokes of the pump, and repeat the observation after waiting for a few hours longer. Having obtained the accurate weight in a rarefied atmosphere, the next step is to weigh the apparatus in air of the ordinary density. Air is allowed slowly to enter the balance through the U-tubes at the side, and in a few hours, when the inner and outer temperatures are uniform, the weight is again taken. For the final adjustment of the weight, the rider may be used. I, however, prefer, as being more accurate, to place a weight slightly in excess in the pan opposite to the apparatus to be weighed, and then, having sealed up the balance, to exhaust a little beyond the point of equilibrium of weight, and continue the operation exactly as in weighing in a rare atmosphere. By taking care that the air contained in the balance shall only be half an inch or so rarer than the external atmosphere, the data afforded by the two weighings will be sufficient to enable the true vacuumweight of the apparatus to be calculated with accuracy. This method of ascertaining minute differences of weight, not by the addition to, or subtraction of, material weights from one arm of a balance, but by varying the density of the air in which the operation is performed, is, I believe, attended with a greater approach to accuracy than the method generally adopted. It can, however, only be adopted when the weights and the substance weighed differ in specific gravity. (To be continued). ON THE CONDITION IN WHICH SILICON EXISTS IN PIG-IRON. By E. HANDFIELD MORTON, F.C.S. THE author was induced to make a few experiments upon the subject of this paper, by noticing that silica was obtained in the insoluble residue when pig-iron containing a large quantity of silicon was dissolved by dilute sulphuric acid in vacuo instead of silicon, which might have been expected as the result of the decomposition of the pig-iron under these conditions. This fact appeared to clearly point out that the theory of the silicon being intimately mixed with the pig-iron was untenable, at least as regards this particular pig, which was a No. 1 Bessemer iron containing 4612 per cent of silicon, and was therefore not at all unlikely to contain silicon in admixture, if that element ever occurred in pigiron in such a condition. A considerable number of experiments were made with the view of aecertaining how far this conclusion was correct. Weighed quantities of the Bessemer pig-iron were placed in sealed tubes with Nordhausen sulphuric acid, in atmospheres of carbon dioxide and hydrogen, and also in vacuo: the tubes were then heated in an air-bath by two Bunsen burners for twenty-four hours, but in every case the silicon contained in the pig-iron had been converted into silica, and a small quantity of sulphur dioxide formed in the tube, which occasioned sufficient pressure to blow |