CHEMICAL NEWS April 11, 1863. Royal Institution of Great Britain. and heavy; thallium certainly belongs to the heavy metals, not only on account of its specific gravity, which is 119, a trifle higher than that of lead, but also for other reasons which I shall come to presently. It is very malleable, and may readily be rolled into leaves as thin as tissue-paper, as shown by the specimen of foil before you. It is not very ductile, and can only be drawn into wire with great difficulty. By employing pressure, however, thallium wire can be made with the utmost facility. I have here a small hollow steel cylinder, with a piston fitting tight into it; at one end is a very fine hole, and upon filling the cylinder with thallium, and forcing in the piston by means of the vice, the thallium issues out through the fine hole in the form of wire. I have arranged an apparatus here by which the wire as it issues from the cylinder is conducted along a glass tube into a specimen bottle, a current of dry carbonic acid passing through the apparatus all the time. By means of the electric light I project the image of the specimen bottle on to the screen, and upon giving one or two turns to the screw of the vice you perceive the wire issuing forth and curling up in folds like a thick rope. The bottle is now filled with the coil of wire, and if I cement the stopper in, the specimen will preserve its metallic lustre and brilliant surface unchanged. Thallium is very soft, in fact it is the softest known heavy metal, being only exceeded in this respect by the alkali metals. A piece of lead scratches it, as you perceive, with the utmost facility, without itself receiving an appreciable impression. It also possesses the property of welding together in the cold by pressure. I can illustrate this by taking another steel cylinder and filling it with several pieces of metallic thallium. [Fourteen pieces were put in. A turn of the vice forces it out, as you see, into one solid rod, which, upon examination, will be found just as continuous and coherent as that made from one lump. Thallium marks paper like plumbago, forming a streak having a yellow reflection. The mark almost entirely fades out in a short time from oxidation. A week ago I wrote a word upon this sheet of paper; upon close examination I can just read it, but I do not think it is visible to any one else. I have, however merely to pass over it a sponge which has been dipped into sulphide of ammonium, when the word THALLIUM appears black, and visible to all. The electrical conductibility of thallium has been recently examined by Dr. Matthiesson, to whose instruction I am indebted for the wire-making process just shown. He finds it near lead in this respect. His researches were communicated to the Royal Society a few weeks ago. The magnetic relations of thallium are very interesting. Professor Faraday has been good enough to arrange an experiment by which its behaviour under the magnetic force can be rendered clearly visible to all in the room. A small sphere of thallium is fastened to the short end of a light wooden lever, a square index of white paper being at the other extremity. The lever is suspended horizontally by some long threads of cocoon silk in such a way that the sphere all but touches one of the conical poles of the large electro-magnet belonging to this Institution. I now pass the current of forty Grove's batteries round the electro-magnet, when you see, from the large arc travelled over by the paper index, how violently the thallium sphere is repelled from the pole of the magnet. It is, in fact, next to bismuth, the most diamagnetic metal known. Thallium is easily fusible, melting at a temperature of 550° Fah.; at a full red heat it may be distilled, but it begins to evolve vapours at a lower point. If I heat a piece on charcoal before the blowpipe, you perceive the metallic vapours flying off copiously, colouring the flame a rich green. The colour which it communicates to flame is better shown by holding, in a colourless gas flame, two or three platinum wires having an alloy of thallium and platinum fused on to their ends. I will place by the 175 side of this, other two flames coloured respectively with barium and copper, when you can judge of the extreme richness and purity of the thallium green by the manner in which it appears to kill the others. Thallium burns brilliantly in oxygen, and small fragments of the metal also take fire when thrown into a gas flame, giving rise to an intense green light. Exposed to the air it tarnishes very quickly; indeed, with almost the rapidity of an alkali metal, becoming coated with a film of oxide, yellow at first, and gradually darkening. This oxide is tolerably soluble in water, forming a highly alkaline solution. It, however, differs radically from potash and soda, and closely approaches oxides of silver and lead (which are likewise soluble and alkaline) in having scarcely any affinity for water; it being rendered anhydrous even at the ordinary temperature in a vacuum. I can illustrate the alkaline character of its oxide by taking this ingot of thallium, and rubbing it across a piece of moistened turmeric paper on a white plate. Wherever the thallium has touched a brown mark is produced. If I apply the tarnished surface of the metal to the tongue it tastes very caustic and biting, and somewhat metallic. When I place a piece of tarnished thallium in water, the superficial film of oxide dissolves, and exposes a bright surface of metal. Hot water cleans it at once, and renders the surface crystalline, like tinplate washed with acids. If the thallium be quite pure, and the water free from air, no sensible action appears to be exerted on the metal, but when exposed to the joint action of air and water it is gradually oxidised. Curiously enough alcohol acts upon it more than water does. The soluble oxide (the protoxide) is also formed very rapidly when thallium is melted in the air; it then fuses like litharge, and is absorbed in the same manner into a bone-ash cupel. When thallium burns in oxygen a peroxide is formed. Thallium dissolves in acids, its proper solvent being nitric acid; it forms two if not three basic oxides and an acid oxide. The salts of the protoxide are the only ones which have been much studied. They are a well-defined series, most of them being beautifully crystalline. Many of these compounds have been very skilfully investigated by MM. Lamy and Kuhlmann, jun. Some of the proto-, sesqui-, and per-salts are on the table, as also one or two thallates. Let me especially draw your attention to the beauty of the crystallised sulphate, nitrate, and chlorate of the protoxide, the yellow sesquichloride in glistening spangles, and this large bottle full of the protochloride, upwards of a pound in weight. On the table before me I have arranged three series of test glasses, the upper row containing protosulphate of thallium, the middle row nitrate of silver, and the bottom acetate of lead. To these I will apply the ordinary tests used in chemical analysis, and I think there is no doubt that my chemical friends who are present will admit with me that the true position of thallium is by the side of these two metals, and not, as M. Dumas and other French chemists affirm, in the potassium and sodium group. Gas light not being very well adapted for showing shades of colour, I have arranged to illuminate the table with electric light during these tests. I first add hydrochloric acid to the solutions, a white precipitate falls in each case: the protochloride of thallium being scarcely distinguishable from chloride of silver: it is, however, slightly soluble in water. Iodide of potassium gives a yellow precipitate with each metal. Bichromate of potash a yellow precipitate with thallium and lead, and a red one with silver. Sulphocyanide of potassium gives white, and sulphide of ammonium black precipitates in all three metals. Bichloride of platinum produces an insoluble double salt with thallium, and precipitates the silver and lead as chlorides. Ammonia produces no change in the thallium solution: gives a precipitate with silver which redissolves in excess, and permanently precipitates the lead salt. Sulphuretted hydrogen has likewise no action on the thallium salt, 176 Pharmaceutical Society. but precipitates the other two. When, however, I add ammonia to the thallium after addition of the sulphuretted hydrogen, a black precipitate is produced, and finally sulphuric acid produces (of course) no change in sulphate of thallium, a slight crystalline precipitate in nitrate of silver, and a dense white one in acetate of lead. From these tests you therefore perceive that whilst the similarities between the three metals are very great, there are, nevertheless, characteristic differences, though not greater than between most nearly allied metals. I have only time to show two reactions with solution of sesquichloride of thallium: the first is the precipitation of the slightly soluble protochloride upon addition of sulphite of soda, and the second the formation of a brown peroxide and precipitation of protochloride in crystals upon addition of ammonia. This latter reaction is a very curious one. Let me, in conclusion, say a few words respecting the position of thallium amongst elementary bodies. In classification observers generally err in regarding natural bodies as so many links in a perfect chain, and facts are frequently strained in order to make them agree with this preconceived opinion. In such a group as chlorine, bromine, and iodine, we have, doubtless, three consecutive links; but most frequently Nature should be looked upon more as a perfect net than a perfect chain. In seeking for the chemical relationships of thallium, it is found that this metal occupies a somewhat anomalous position, being well described by an eminent French chemist as the At first sight it might appear ornythorynchus of metals. to belong to the group of alkali metals, on account of its forming a readily soluble, highly alkaline oxide; it likewise forms an insoluble platino-chloride, which also renders it analogous to some of the alkali metals, although not to others; but, on the other hand, its physical characters, its chemical reactions, and its high atomic weight (about 203), prove incontestably that the true position of thallium in the scale of elements is close to lead and silver. In these utilitarian days a discoverer must be prepared to give some kind of answer to the question,-"What is the use of it?" Now, the possible uses of a body depend chiefly on its abundance, and as soon as thallium is procured by the ton at no greater cost than it is now by the ounce, it will certainly be utilised in many directions. In the pure metallic state it probably tarnishes too readily, and is too quickly acted upon by atmospheric agencies for it to possess much practical value in this form. In the form of alloy, however, its uses are likely to be very great, as it readily mixes with many metals, and communicates to them valuable properties. The magnificent green which it communicates to a flame at once suggests a valuable application of thallium for pyrotechnic purposes. At the ordinary temperature of Hame, the thallium light is absolutely homogeneous, and even at the high temperature of the electric arc, the other lines, which Dr. Miller has shown are produced, and which I have attempted to copy on this diagram, fade before the brilliancy of the characteristic green line. Perhaps the best way for me to show the magnificent green light evolved by incandescent thallium vapour is by projecting on the screen the highly magnified image of the thallium electric arc. I have scooped out the lower carbon of the electric lamp into the form of a small cup, and, upon placing ten or a dozen grains of thallium in it, and making contact, the upper pole can be separated for a space of an inch or more, voltaic connection being maintained by the bridge of thallium vapour rising from the cup. The image of this on the screen fills up a space of twelve inches or more with absolutely monochromatic green light, and if I introduce into this green space variously-coloured bodies, a bouquet of bright flowers, or even my own face, you will see the strange changes it produces in the apparent colours of bodies, everything being either green or black, like as in the sodium flame every object is yellow or black. The reason why the homogeneous light given by sodium and thallium is so intense is owing to all the luminiferous energy of the element being concentrated into one ray, instead of being diffused over different portions of the spectrum. These experiments show that thallium is pre-eminently the pyrotechnic element; but regarded for the present merely from a scientific point of view, its early history will always be looked upon with interest, as proving the beauty and accuracy of spectrum analysis, and the striking manner in which the deductions therefrom have been confirmed. PHARMACEUTICAL SOCIETY. Mr. P. SQUIRE, President, in the Chair. Professor BENTLEY then said that as there was no paper Mr. D. HANBURY, jun., said there was no doubt that the salivary glands of the common swallow and martin were excited at the period of nidification, and secreted a matter similar to that of which these nests were made. It was difficult to conceive how the materials of which the martin made its nest could adhere together without some such matter to glue them. It would be interesting to examine some nests to see if it was present. Mr. P. SIMMONDS said he had not much to add to the statement of Professor Bentley. These nests had rather a fanciful value in the estimation of the Chinese. It had been settled beyond a doubt that they were constructed of animal matter, but the assertion that they were composed of vegetable matter was an error continued in some recent CHEMICAL N April 11, 1863. Pharmaceutical Society-Notices of Books. 177 very unmanageable substance. By itself it was too hard, and a very little oil made it perfectly fluid. The CHAIRMAN said he had found some proportions of oil and cacoa butter produce a compound of a good consistence, which kept perfectly free from rancidity for works. The nests by themselves were very insipid, and unknown. There was an enormous commerce in alga in Mr. HILLS said he bought the nests on the table of Messrs. Matthesons. They were rather expensive; he paid 140s. per lb. for them. Professor BENTLEY observed that Mr. Hills had bought them very well; 8. per lb. was very commonly paid for them. The Professor then called attention to a number of specimens of drugs from Manilla, 150 of which had been presented to the museum. He also exhibited a fine specimen of Scammony root, which was in Mr. Ransome's case in the International Exhibition, and had been given to the Society by that gentleman. Professor Bentley remarked that in this specimen the resin of the root could be seen in situ. He then noticed some oil of worm seed also given to the museum by Mr. Ransome. This is obtained from the fruit of the Chenopodium anthelminticum, and has long been known as an excellent anthelmintic. It is largely used as a vermifuge in the United States, and the Professor hopes it will receive a trial here. The fruit itself is powdered, and sometimes administered to children, and the dose of the oil is from four to six drops taken on sugar, for three or four days, and then followed by a cathartic. So used it was a very successful evacuant of "round" worms. The CHAIRMAN observed that no remedy had been found so successful for tape worms as the etherial extract of the male fern. It was in general made from the young rhizome, but an etherial extract of the young fronds had been found to answer just as well. Mr. HILLS wished, as this was the last meeting of the year, to ask the Chairman whether glycerine was to be introduced into the new Pharmacopoeia? Some time ago he had a sore throat, and was prescribed a gargle of tannin, glycerine, and infusion of roses. They made a very nice gargle, and he had found it keep quite well for three months. He had also found that glycerine was a very good solvent for some alkaloids, such as morphia and atropia, and other matters, but he had had no time to work out the matter. Plasına or solid glycerine, too, was a useful compound, which kept well, and altogether he thought glycerine a very valuable substance, which deserved to be placed in the Pharmacopoeia. The CHAIRMAN doubted whether plasmata would keep well. In the pharmacopoeia of the Royal Ophthalmic Hospital, there were several such compounds as Mr. Hills had suggested, and some he had seen had kept well, but in general his experience was against plasmata. It was very desirable to find something which would supply the place of lard in pharmacy, the tendency to rancidity of lard being a great objection to its use. He had made many experiments to find a substitute, but the only things which seemed to succeed were the mixture wax and oil called Linimentum Simplex in the Edinburgh Pharmacopoeia, and a mixture of cacoa butter and oil, which was perhaps the best substitute. Mr. HASELDEN said the solvent powers of glycerine, as well as its antiseptic properties, had long been known. He had himself made many experiments on the subject, and had contributed the results of some to the Society, He did not believe any compound of glycerine would answer for ointments, and he had found cacoa butter a two years. Professor BENTLEY then noticed some specimens of the bread fruit, and made some observations thereon, which we defer; and Mr. Palmer exhibited a piece of flint from a gravel pit, which gave rise to some remarks on flint implements, and the means by which they were made. In announcing the adjournment of the meeting, the Chairman said that, as this would be the last in his year of office, he their attendance and courtesy during the period he had would take the opportunity of thanking the members for filled the chair. NOTICES OF BOOKS, First Outlines of a Dictionary of the Solubilities of Chemical ANY one wishing to gain some notion of the immensity, as "The term 'solubility' in the title of the present publication is to be taken in its most comprehensive sense. I have no intention, at this time, of attempting a strict definition of the word, or of discussing the forces upon which solution may depend. In the present state of science, the collection of experimental data, and the study and comparison of well-authenticated special observations, seem to be of far greater importance than the disputes of the earlier chemists whether the phenomena in question should be referred to the domain of chemical affinity, or be studied as a purely physical problem. It need only be remarked that I am accustomed to class among phenomena of solubility all those reactions of liquids upon solids or gases, and those combinations of liquids with liquids, excluding for the present molten metals, and other substances in a state of igneous fusion, in which the chemical force as understood by Berzelius, for instance, is not the principal, and as it were the overwhelming force in action. We may have, perhaps, 'solution' depending upon merely physical forces, like adhesion or cohesion, and also upon these forces plus a certain amount of chemical force. It can indeed hardly admit of a doubt that the chemical force is exerted in many cases of solution, while at the same time other forces unquestionably come into play, in which connexion the old adage, that 'like dissolves like,' should be borne in mind. Hence, while the manifestations of chemical affinity proper, as evinced by the combination of bodies in simple and definite proportions, constitute the main subject of chemical text-books, many of the less 178 Notices of Books-Correspondence. clearly-defined phenomena of chemical science may fairly come within the scope of a treatise on solubilities. Thus, though in the term solubility of a substance we ordinarily include only the comportment of the substance towards water, alcohol, wood-spirit, ether, oil of turpentine, benzine, and analogous hydrocarbons, and the other neutral solvents, it is obviously sometimes proper to add observation on the action of acids and alkalies; for example, any account of the solubility of nitrate of baryta would be manifestly incomplete without a statement of the fact that the salt is taken up but sparingly by nitric acid. Again, in the solution of chloride of silver in ammonia, and that of various salts, sulphate of lime, for example, in acids, there are probably at work other forces than the usual solvent power, but until the whole theory of solution is better understood, we must be content to treat of these allied phenomena under the same general head of 'solubilities.' Pains have also been taken to bring forward facts known respecting those cases in which two or more salts acting upon each other in the presence of water, or the like are to a certain extent mutually decomposed and dissolved, as in the familiar instance of nitrate of potash and chloride of sodium which promote each other's solubility; or that of the reciprocal decomposition which ensues when sulphate of baryta is treated with a solution of an alkaline carbonate." Our readers will see that a large ground is here laid out, and we can assure them that it is well filled up. We know of no other work on chemistry which exhibits so much industry in compilation as this, except the great work of Gmelin. The quotations our limited space allows us to make will give our readers but a poor idea of the extent of information they will find in these pages, but we may extract what relates to the chloro-platinates of cæsium, potassium, and rubidium, the different solubilities of these bodies affording the readiest means of separating them. CHLORO-PLATINATE OF CESIUM. C&Cl,PtCl2. By experiment 100 parts of water at Less soluble than chloro- 。°dissolve o'021 part of it II 40 0.072 68 100 0'234 : CHEMICAL NEWS, From these results the following table was obtained by 100 parts of water at 20 1'12 In conclusion, we may direct especial attention to the articles alcohol, arsenious acid, and chloride of sodium, as exhaustive on the subject of solubilities, and of the greatest practical value; and we may add that this is From these results the following table was obtained by emphatically a book which no chemist's library should be without. interpolation: 99 0'050 CORRESPONDENCE. Spectrum Analysis. To the Editor of the CHEMICAL NEWS. SIR, I find by repeated examination that the potassium line Ka a, coincident with the Fraunhofer line A of the solar spectrum, is a double line slightly thicker than the sodium lines, and quite as distinctly separate. As I believe that it has always been mapped down as a single line, I shall feel much indebted by the insertion of this note in the CHEMICAL NEWS.-I am, &c. WM. EDWD. KILBURN, Burleigh House, Bridge Road, St. John's Wood. Deaths from Nitric Acid. To the Editor of the CHEMICAL NEWS. SIR, It is not my desire to prolong the correspondence on this subject, but the letters in your last issue incite me to address you again. Mr. Spencer's caution, so far as regards myself, is alto CHEMICAL, NOWE} April 11, 1863. Correspondence-Chemical Notices. gether unnecessary, and I would remark that it is the caution I have always used that will prevent Mr. S. from hearing of myself being "the next victim to the deadly power of nitrous acid gas." Had a little caution been used in the case quoted by Mr. Spence, the life of the party named would have been saved, if, indeed, death did result from the causes set forth. I am no stranger to the action of the fumes of this and other acids when inhaled, and I agree with Mr. Tratchsel in saying "that the experience of men employed in the manufacture of nitric acid is quite contrary to the idea that the mere breathing of the fumes of this acid for a short time could produce death." I concur in the remarks of this gentleman as to the powerful effects of this acid upon the blood, and his letter tends to throw more light on the subject of "deaths from nitric acid." It would be interesting to know whether any wounds were found on the hands or any other part of Mr. Stewart and his assistant, and in what condition the blood was noticed to be. I presume a post-mortem examination was made. This would, I think, help to prove the action of this acid upon the circulation of the blood when admitted into the body by a cut received from glass, &c. It is far from my wish to throw any one off their guard with respect to this acid, and I sincerely hope that we shall not hear of another accident like that at Edinburgh. Still, such occurrences should be inquired into. It certainly adds to our knowledge of things. I am, &c. J. H. SWINDELLS. Meadows Bridge, Wigan. Action of Heat and Force upon Matter. To the Editor of the CHEMICAL NEWS. SIR,-I send you copies of a letter which I addressed to Mr. Dyer, and of his reply, which sufficiently explain themselves; will you be so good as to give them publicity. I am, &c. BARNARD S. PROCTOR. "11, Grey Street, Newcastle, March 28, 1863. "DEAR SIR, -I have just been reading in the CHEMICAL NEWS the report of your paper 'On the Action of Heat and Force upon Matter.' My first impulse was to send a note to the CHEMICAL NEWS, pointing out an error into which you appear to have fallen, but second thought dictated my writing to yourself. What I allude to is this :You say the heat required to convert one pound of ice into vapour would fall far short of melting five pounds of cast iron. In the first place Tyndall only says 'to its melting point.' So that the latent heat of melted iron is not required. "In the second, as (according to your quotations) he does not say from what temperature the iron would be raised up to its melting point, we must understand it to be not intended as an accurate, but as an approximative statement. "In the third, according to established data, Tyndall's statement is very near the truth; thus: "The heat required to melt 1 lb. of ice will raise 1 lb. of water "The heat required to evaporate 1 lb. of water at 32° will raise 1 lb. . I 142° . 1123° 1265° 179 CHEMICAL NEWS, either to correct or substantiate your statement, "I remain yours faithfully, "To J. C. Dyer, Esq." "BARNARD S. PROCTOR. Barnage, March 31, 1863. "DEAR SIR,-In reply to your letter of the 28th, I beg to thank you for pointing out the slight error in the published abstract of the paper read by me at the Literary and Philosophical Society. I stated the 'heat for melting the cast iron in place of saying for raising the cast iron literally quoted a few lines above, the reader could hardly to the melting point.' Now, as this latter expression is be misled by my words, especially as no reference is made to the heat that becomes latent or specific in the iron when it passes from the solid to the liquid state. It must therefore be seen that I took into view only the two ferred and entering the iron to raise its temperature to the sums of latent heat, as given by you about 1262°, so transmelting point. I should be extremely sorry to afford the slightest ground of complaint to Professor Tyndall, and I fully trust that the above explanation will be satisfactory to that gentleman and his friends. I am averse to public controversy, and would fain avoid giving occasion for any; and I leave with you to communicate my reply to your letter, or its substance, either to Professor Tyndall direct, or through the journal you mention, as you may think best. "With respect to the second point you adduce against my view of the action of heat in raising the temperature of the iron, as this involves unsettled questions relating to the line, if any, to be drawn between the heat latent or the heat specific in bodies. The subject is too wide for discussion on this form, yet I must respectfully dissent from the conclusion at which you arrive-in making the tenfold amount of sensible heat in the iron at the melting point. I therefore must leave this matter for future inquiry by those who can make it clear either way. "I am, Sir, yours faithfully, "To Barnard S. Proctor, Esq." "J. C. DYER. Chemical Notices from Foreign Sources. Antidote for Arsenic.-The hydrated peroxide of iron requiring to be freshly precipitated to be useful as antidote for arsenic, and the preparation in the ordinary way requiring some time when every moment is of importance, it has been proposed to keep a solution of the persulphate iron, and to add when the oxide is wanted calcined magnesia, the mixture being administered, which saves the trouble of washing the precipitated oxide, and at the same time gives a purgative to the patient. We may suggest that an excess of the calcined magnesia should always be used, and then the mixture would be unobjectionable and perhaps useful. Estimation of Glucose in Beer.-Vogel (Chem. Centralblatt, 1862, p. 1244), suggests the use of the dialyser for separating saccharine from gummy matter in the examination of beer. Preparation of Nitric Ether.-M. Persoz (Comptes Rendus) uses two parts of the strongest and purest nitric acid and one part of absolute alcohol, both cooled by the application of ice. The alcohol is slowly added to the acid, and the two are continually shaken. The ether is produced immediately. He operates on small quantities at a time, and when the reaction is finished adds a small piece of ice. The ether is purified in the ordinary way. Process for the Decortication of Seeds.-M. Lemoine suggests the use of moderately strong sulphuric acid, which he agitates with the barley, for instance, for fifteen or twenty minutes, and then washes away, using in the last washing a little carbonate of soda. In the case of barley he assists the operation by the application of a gentle heat. After the grain is dried the husk is easily separated. |