Transactions. Presents, February 8, 1894. Berlin :-Gesellschaft für Erdkunde. Zeitschrift. Bd. XXVIII. No. 4. 8vo. Berlin 1893. Birmingham:-Philosophical Society. The Society. Part 2. 8vo. Birmingham [1893]; [Annual Report.] 1893. 8vo. Birmingham [1893]. Boston:-Society of Natural History. Proceedings. Vol. VIII. The Society. Vol. IV. No. 11. 4to. Boston 1893; Proceedings. Vol. XXVI. Part 1. 8vo. No. 4. 8vo. Boston 1893. Memoirs. Bulletin. Cambridge, Mass.:-Museum of Comparative Zoology. pologie Préhistoriques. 11ème Session, Moscou, 1892. Tome Société Impériale des Amis des Sciences Naturelles, Moscow. Kew:-Royal Gardens. Bulletin of Miscellaneous Information. 1893. No. 84 and Appendix 3. 1894. No. 85. 8vo. London 1893-94. The Director. Klausenburg :-Erdélyi Museum-Egylet. Értesitő. Évfolyam XVIII. Szak 1. Füzet 1. Szak 2. London:-British Astronomical Association. No. 2. 8vo. London 1894. Füzet 1-3. 8vo. The Society. Journal. Vol. IV. The Association. East India Association. Journal. Vol. XXVI. No. 2. 8vo. London 1894. The Association. Geological Society. Quarterly Journal. Vol. L. Part 1. 8vo. The Society. The Society. Louvain; [Pub Proceedings. Vol. XV. Part 8. Vol. XVI. Part 3. 8vo. London 1893-94; Transactions. Vol. IX. Part 2. 8vo. London 1893. Louvain-Université. Annuaire. 1894. 8vo. lications Académiques. 1892-93.] 8vo. Paris-École Normale Supérieure. Annales. ment. 4to. Paris 1893. The University. Tome X. Supple The School. Société Philomathique. Bulletin. Tome V. No. 4. 8vo. Paris 1893. The Society. Transactions (continued). Siena R. Accademia dei Fisiocritici. Atti. Vol. V. Fasc. 7-8. Hefte 4-5. Bd. XVII. Heft 3. 4to. Wien 1893; Jahrbuch. The Institute. Bd. XLIII. Heft 2. 8vo. Wien 1893. K.K. Naturhistorisches Hofmuseum. Annalen. Bd. VIII. Nos. 2-4. 8vo. Wien 1893. The Museum. Observations and Reports. Portugal:-Direction des Travaux Géologiques du Portugal. Description de la Faune Jurassique du Portugal. Classe des Céphalopodes. 1re Série. 4to. Lisbonne 1893. The Director. Zurich-Schweizerische Meteorologische Central-Anstalt. nalen. Jahrg. XXVIII. 4to. Zürich [1893]. An The Institute. Journals. Agricultural Gazette of New South Wales. Vol. IV. Part 2. 1894. Institut Impérial de Médecine Expérimentale, Horological Journal. Vol. XXXVI. No. 426. 8vo. London The Editor. The Editor. Burnham (S. W.) The System of y Cancri. 8vo. [1894.] The Author. Newton (H. A.), For. Mem. R.S. [On the Small Bodies sent off from Comets which form our Shooting Stars.] 8vo. [Philadelphia 1893.] The Author. February 15, 1894. Sir JOHN EVANS, K.C.B., D.C.L., LL.D., Vice-President and Treasurer, in the Chair. A List of the Presents received was laid on the table, and thanks ordered for them. The following Papers were read: Alloys con I. "On Certain Ternary Alloys. Part VIII. taining Aluminium, Cadmium, and Tin; Aluminium, Antimony, and Lead; or Aluminium, Antimony, and Bismuth." By C. R. ALDER WRIGHT, D.Sc., F.R.S., Lecturer on Chemistry and Physics in St. Mary's Hospital Medical School. Received January 8, 1894. In Part VII* it has been shown that whilst cadmium can act as "solvent" metal towards either of the immiscible pairs-lead and zinc, bismuth and zinc-this is not the case when aluminium is substituted for zinc, because cadmium and aluminium (contrary to the usual statements in the text-books) are not miscible in all proportions, unlike cadmium and zinc. Accordingly, it becomes of interest to examine the behaviour of ternary metallic mixtures where cadmium and aluminium are the two immiscible metals, more especially when a "solvent" metal is employed also capable of use in similar fashion with the immiscible pairs, aluminium and lead, aluminium and bismuth, so as to trace out the effect of substituting cadmium for lead or bismuth. Such a solvent metal is tin; the volatility of cadmium, however, precludes the possibility of employing elevated temperatures above the boiling point of that metal (about 770° C.); but, thanks to the physical attraction of molten aluminium for cadmium (comparable with that of water for gaseous hydrochloric acid), it is possible to keep molten in long narrow crucibles metallic mixtures containing simultaneously aluminium and cadmium, without any material amount of volatilisation of the latter metal taking place from the surface of the lighter alloy that floats up (of which aluminium necessarily constitutes the majority), so long as the *Part I, 'Roy. Soc. Proc.,' vol. 45, p. 461; Part II, vol. 48, p. 25; Part III, vol. 49, p. 156; Part IV, vol. 49, p. 174; Part V, vol. 50, p. 372; Part VI, vol. 52, p. 11; Part VII, vol. 52, p. 530. temperature does not exceed 700° to 750°. At temperatures of 800° and upwards, however, so much cadmium vapour is given off from the heavier alloy (in which cadmium predominates) as seriously to interfere with the experiment, not only because of the alteration in composition thereby produced, but also because of the intermixing effect tending to prevent proper separation by gravitation of the lighter and heavier alloys from one another. Binary Alloys of Aluminium and Cadmium. A series of observations was first made to determine the composition of the binary alloys formed when aluminium and cadmium are melted together and well stirred, and then allowed to stand at a temperature of 700-750° (averaging about 725°) for several hours. The following figures resulted as the averages from twelve tolerably concordant experiments : Hence the solubility of cadmium in aluminium, like that of lead and of bismuth in the same metal, is but small; whilst the solubility of aluminium in cadmium, like that in lead or bismuth, is inconsiderable, thus Mixtures of Aluminium, Cadmium, and Tin. The alloys were prepared by melting the aluminium, then adding the tin, and finally the cadmium, well stirring as soon as the latter was fluid, pouring quickly into the red-hot clay test-tubes, and maintaining these at 700-750° (averaging about 725°) for from six to eight hours in the lead bath. The analysis was made by dissolving in hydrochloric acid solution containing nitric acid, diluting and precipitating with sulphuretted hydrogen, and separating the tin and cadmium sulphides by means of ammonium sulphide, the tin being finally weighed as SnO2, and the cadmium as CdO. The filtrate from the sulphides was precipitated by ammonia, the weight of the Al2O3 finally obtained being corrected for traces of iron and silica present. As in all previous experiments, the percentages were calculated on the sum of the weights of the three metals found as 100. The following average values were deduced from the examination of twelve compound ingots (twenty-four alloys). No. of tie-line. 0123456 Heavier alloy. Lighter alloy. Excess of Tin. Cadmium. Aluminium. Tin. Cadmium. Aluminium. tin percentage in lighter alloy over that in heavier. Fig. 1 represents these values plotted on the triangular system, the dotted line No. 1 representing the curve obtained at 800° with aluminium-lead-tin alloys (Part VI), and No. 2 that similarly obtained with aluminium-bismuth-tin alloys. The points marked A and B represent two alloys that did not separate, containing respectively, Obviously the effect of substituting cadmium for lead is to depress the critical curve; it cannot, however, be said with certainty that the same remark applies to the substitution of cadmium for bismuth, although this is probable; for the cadmium curve, being obtained at 725°, is not directly comparable with the bismuth curve obtained at 800°; were the former obtainable with accuracy at 800°, it would doubtless be considerably depressed as compared with the curve at 725°, and would consequently probably lie wholly inside the bismuth curve at 800°; even as it is, the right-hand branch lies inside. In confirmation of this, experiments now in progress with aluminiumcadmium-silver alloys indicate that the critical curve for these alloys lies well inside that with aluminium-bismuth-silver alloys. |