two metals together in the desired proportions. The alloys were made and used by the Romans. They were mentioned in the first century of our era by Pliny in his Historia naturalis (34. 17, 48); and in the second century, G. Galen, in his De antiodotis epitomis (1. 175), drew attention to the danger attending the use of tin adulterated with lead. The early alloys were discussed by R. Weber.4 The tinlead alloys were examined by J. L. Proust, L. N. Vauquelin, A. Gummi, C. H. Pfaff, J. W. Richards, D. Mazzotto, G. Nannes, J. Pohl, F. Rudberg, A. Matthiessen, K. Honda, S. Konno, L. Peetz, R. C. Besley, D. Silow, R. H. Thurston, P. Bolley, J. H. Croockewit, W. Richter, A. P. Laurie, C. R. A. Wright, C. Pack, M. L. Lissberger, H. Stegmann, etc. C. H. Proctor, and W. Blum and H. E. Haring made the alloy by electrodeposition from fluoborate soln.; and W. Spring, by strongly compressing an intimate mixture of the powdered elements; the two solids form an alloy in a few hours at 150°-200°. The alloying of a mixture of the powdered metals by press. was discussed by W. Hallock, and W. Rosenhain and P. A. Tucker. When lead stannate is reduced by carbon (R. C. Besley), or when tin is heated with lead oxide, with stannous chloride, or with an alkali plumbate (L. Peetz), the alloy is formed. S. Bodforss and P. Frölich, and M. Kutscheroff prepared a colloidal solution of the tin-lead alloy. The f.p. curves have been studied by E. Wiedemann, H. Gautier, R. Gnehm, C. T. Heycock and F. H. Neville, F. Rudberg, E. S. Shepherd, F. C. Weld, B. Wiesengrund, P. N. Degens, K. L. Meissner, W. Guertler, A. Stoffel, W. C. Roberts-Austen, A. W. Kapp, L. Guillet, D. Mazzotto, C. R. A. Wright and co-workers, W. Spring and L. Romanoff, A. P. Laurie, A. von Vegesack, F. Guthrie, M. Plüss, M. Wählert, C. P. Steinmetz, E. Heyn and O. Bauer, K. Bornemann, L. Losana, J. Göbel, N. S. Kurnakoff, N. Parravano and co-workers, P. Ludwik, M. Dullo, P. Müller, K. Heine, A. Pleischl, K. Honda and T. Ishigaki, H. Stegmann, L. Sterner-Rainer, H. von Jüptner, D. Silow, J. Alexander, W. Rosenhain and P. A. Tucker, etc. The results are summarized in Fig. 55. There is no evidence of the formation of a definite compound, but P. N. Degens observed a transformation at 146° with all alloys containing between 0 and 88 at. per cent. of lead; the transformation is attended by the appearance of a constituent distributed through the lead, and it is suggested that a compound is formed at this temp. from the tin and lead in the solid state. W. Rosenhain and P. A. Tucker place the temp. at which heat is evolved with alloys containing 18-63 per cent. of tin at 149°, and rather less with FIG. 55. Freezing point Curves alloys containing 8-18 per cent. of tin. The of Lead-Tin Alloys. transformation is attributed to the passage of the solid soln. from what is called the B-form to the a-form, and it is attended by the rejection of part of the tin. The alloy with 8 per cent. of tin can remain in the B-form down to the temp. of liquid air. G. H. Gulliver calculated the difference in the relative proportions of solid (primary crystals) and liquid between the eutectic and the liquidus curves for very slow and very rapid rates of cooling. The transformation at 161° is due to the contained tin. The f.p. curve is of the V-type with the eutectic at 181° and 76 at. per cent. of tin; according to W. Rosenhain and P. A. Tucker, the eutectic is at 180° with 62-93 per cent. of tin. P. N. Degens said that at 181° tin retains only 0-21 at. per cent. of lead in solid soln., and lead, 12 at. per cent. or more of tin. N. Parravano and A. Scortecci found for the percentage solubility of tin in lead:

The subject was studied by D. H. Andrews and J. Johnston. The facility with

which the plumber can "wipe a joint" with solder, containing about 66 per cent. of lead, depends on the two f.p., A, B, Fig. 55, of these alloys. The pasty" condition occurs when the freezing alloy has granules of solid lead in a liquid matrix.

The microstructure of the alloys was investigated by W. Campbell, W. Guertler, G. Charpy, A. M. Portevin, H. Behrens, K. Bux, W. Rosenhain and P. A. Tucker, J. E. Stead, J. A. Ewing and W. Rosenhain, C. H. Green, and H. von Jüptner. Figs. 56, 57, and 58 represent some results by W. Rosenhain and P. A. Tucker with

alloys containing 10, 20, and 55 per cent. of lead respectively. By means of the X-radiograms, W. C Phebus and F. C. Blake found that lead and tin form solid soln. at room temp.; with from 0 to 3.6 per cent. of tin the lead spacelattice decreases from a=4-942 to 4-931; and with 10-93 per cent. of tin, both tin and lead lattices are present without the tin lattice being appreciably distorted. The sp. gr. was examined by F. C. Calvert and R. Johnson, G. Pillichody, S. Grimaldi, C. Long, T. Thomson, O. Kleinstück, G. Vicentini and D. Omodei, K. Gilbert, A. T. Kupffer, P. Bolley, J. Pohl, H. Kopp, A. Riche, J. H. Croockewit, H. V. Regnault, A. Matthiessen, and B. Wiesengrund; and C. Long gave:

Pb

0

7.924

23.0 31.0
7.927 8.188

47.3
8.779

64.2 78.2 87-8 91.5 100 per cent. 9.460 10-080 10-590 10.815 11.376

Sp. gr. According to E. von Maey, for alloys containing p per cent. of tin, the sp. vol. is 0-08811+0-0004900p. The shrinkage vol. on freezing was measured by C. M. Marx, E. Wiedemann, and B. Wiesengrund; the vol. changes during the formation of the alloy, by K. Karmarsch, D. Mazzotto, F. Wüst, K. Gilbert, J. Pohl, F. Hoffmann, H. Kopp, and B. Kosmann; the hardness, by A. Saposhnikoff, D. Stenquist, F. L. Brady, K. Gilbert, I. P. Göbel, P. Ludwik, L. Sterner-Rainer, E. Heyn and O. Bauer, and F. C. Calvert and R. Johnson; L. Guillet, M. Dubosc, and R. S. Dean and co-workers, the hardening of the alloys by quenching; the diffusion of tin in lead, by W. C. Roberts-Austen; the difficulty of thoroughly mixing the molten metals, by H. Kopp; the viscosity and sp. gr. of the liquid alloy, by M. Plüss, and R. Arpi; the elastic constants, by G. Wertheim, L. Sterner-Rainer, E. S. Sperry, E. Heyn and O. Bauer, I. P. Göbel, E. N. da C. Andrade, A. E. Dunstan, Z. Carrière, and J. Dewar; the coeff. of thermal

expansion, by A. Matthiessen, and G. Vicentini and D. Omodei; H. Moissan and A. J. P. O'Farrelly found lead can be almost completely distilled from alloys in the electric furnace; J. Joly and J. H. J. Poole separated the constituents to a small extent by centrifuging. A. Magnus and M. Mannheimer observed that a rise of temp. occurs when molten lead and tin are mixed. The thermal conductivity was measured by F. C. Calvert and R. Johnson, W. B. Brown, and A. W. Smith; the sp. ht., by E. van Aubel, U. Behn, H. Kopp, H. V. Regnault, A. Saposhnikoff, W. Spring, and F. Rudberg; the phenomenon of surfusion, by D. Mazzotto, B. Wiesengrund and W. C. Roberts-Austen; the heat of fusion, by W. Spring, and D. Mazzotto; the heat of formation, by J. Tayler; and the electrical conductivity, by E. Elsässer, W. H. Preece, W. Harris, S. Konno, P. W. Bridgman, W. Guertler, A. Matthiessen and co-workers, W. C. Roberts-Austen, E. J. Cuy, N. Parravano and A. Scortecci, C. L. Weber, P. Müller, K. Bornemann and G. von Rauschenplat, H. Rainy and R. D. Clackson, E. F. A. Obach, and G. Vicentini and B. Omodei. The results by W. C. Roberts-Austen are plotted in Fig. 59. The straight line is in agreement with the fact that the alloys are heterogeneous mixtures of the components. A. Matthiessen and C. Vogt examined the effect of temp., and of foreign metals on the conductivity; and H. Rainy and R. D. Clackson, the change of conductivity at the m.p. J. Trowbridge and E. Stevens, S. D. Muzaffar, N. A. Puschin, H. le Chatelier, A. P. Laurie, and O. Sackur measured the electrode potential of the alloys in different soln. W. Rollmann, J. L. Haughton, P. H. Dowling, H. Pélabon, and A. Battelli measured the thermoelectric properties, and the results by E. Rudolfi are plotted in Fig. 60. P. H. Dowling found no change

in the e.m.f. of contact of a solid and molten lead-tin alloy with 25 per cent. lead. R. Kremann and P. G. von Rehenburg found that on electrolyzing these alloys the tin accumulates about the cathode, the lead at the anode. P. H. Dowling studied the change in the contact e.m.f. of a lead-tin alloy, and Wood's metal with a nickel surface when the alloy is solid and when fused. The magnetic susceptibility curve, Fig. 61, by K. Honda is nearly a straight line, but with alloys containing 0-10 per cent. of lead there is a slight curvature corresponding with the presence of solid soln. E. L. Dupuy also investigated this property. M. Loutchinsky found the magnetic susceptibility of the hammered alloy less than where it is crystallized.

0.04

0.02

0

× -0.02

Mag.sus. x 106

-0.04

-0.06

-0.08

-0.10

-0.12

20 40 60 80
Per cent. tin
ercent.

of the Tin-Lead Alloys.

100

J. Fordos, L. Bessnou, H. Reckleben and J. Scheiber, A. Scala, F. Knapp, and L. Peetz examined the influence of oxygen, air, and other gases on the alloys. H. E. Armstrong, G. Charpy, FIG. 61.-Magnetic Susceptibility J. Pohl, A. Bauer and P. von Mertens, and L. Pitkin investigated the action of acids on the lead-tin alloys; O. Bauer, the action of sulphuric acid; F. P. Hall, C. H. Pfaff, J. Pohl, Z. Roussin, A. Pleischl, A. Gummi, J. L. Proust, O. Sackur, F. Knapp, and R. Weber, the action of acetic, citric, tartaric, and lactic acids; A. Scala, the

action of distilled water; and F. Knapp, and C. Reichelt, the action of soln. of sodium chloride-vide the action of natural waters on lead.

The technical uses of the tin-lead alloys were discussed by A. Guettier, N. Braunschweiger, M. von Schwarz, L. Hartmann, O. and A. Neumann, W. Kaiser, etc. E. Seel and K. Hils observed that 1.27-4-44 per cent. of lead was found in some tins used for canned foods. Solders usually consist of tin and lead in various proportions, and when a still more fusible solder is needed, bismuth is added. According to Pliny's Historia naturalis (34. 17, 48), the so-called tertiarium of the Romans contained twice as much lead as tin, and was used as a solder. It contained very nearly the eutectic proportion. W. Gowland found that a sample dating from 300 A.D., unearthed at Silchester, contained 61.93 per cent. of lead, and 28.01 per cent. of tin. An alloy containing equal parts of tin and lead was the argentarium of Romans, and it is a common solder of to-day. The standard tinman's solder has 1 part tin and 2 parts lead, and its fusibility is indicated by the line AB, Fig. 55. The solders were discussed by G. Strahl, M. von Schwarz, F. M. Feldhaus, M. Wählert, M. L. Lissberger, J. Rothe, J. Novel, F. Singer and H. Barthel, W. Kaiser, E. Johanson, P. Yanushewsky, and A. H. Munday and co-workers. The effect of a small proportion of bismuth, antimony, arsenic, copper, silver, zinc, cadmium, aluminium, or mercury was examined by C. O. Bannister, and H. J. Tabor and H. D. Smith. Pewter or latten ware-from the French laiton, brass or tinplate is an alloy of tin and lead, 4: 1, which came into use near the middle of the seventeenth century, and was used in making measures for wine and ale; by a Royal decree, the pewter vessels were stamped. The Pewterers' Company, incorporated in 1474, attempted to regulate the quality of pewter by permitting enough lead to bring the sp. gr. to that of tin; persons who departed from the regulations were liable to expulsion from the guild, but the rule was disregarded so much that it had little effect in keeping up the standard. Unalloyed tin is largely used in place of pewter being not only whiter, but also safer for domestic purposes on account of the poisonous nature of lead (q.v.). The pewter with 18 per cent. of lead is said to be harmless when used for vessels for wine and vinegar. Other pewters contain small proportions of other metals-e.g. zinc, copper, antimony, etc. Alloys of tin and lead are used for toys-e.g. toy soldiers-and an alloy of lead and tin in the proportions 3:5 is used for tinning certain articles of copper. The so-called Fahlum brilliants, used for stage jewellery, contain lead and tin nearly in the proportions 2:3; the molten alloy is cast in mould facetted like cut diamonds. Thin sheets of steel coated with an alloy of tin and lead (1 : 3) are used in packing dry goods and for roofing, and called terne plates. C. Baskerville described a cheaper substitute made by coating iron with antimony, and depositing lead thereupon. The uses of these alloys in making domestic utensils was discussed by F. Knapp.

The ternary Pb-Sn-As alloys were investigated by W. Zimmer, and H. J. Roast and C. F. Pascoe; the Pb-Sn Sb alloys by H. Behrens and H. Baucke, W. Hommel, A. H. Munday and co-workers, R. W. Irwin, G. Charpy, H. Kopp, O. W. Ellis, W. Campbell and F. C. Elder, J. d'Arcet, L. J. Chaudet, F. Rudberg, J. W. Döbereiner, Isaac Newton, G. A. Erman, R. Loebe, G. H. Gulliver, C. O. Thieme, A. M. Portevin, R. H. Thurston, G. Wertheim, J. Hoyle, J. Czochralsky, J. C. Work, E. Heyn and O. Bauer, C. Pack, M. Wählert, A. Halfmann, M. le Gris, J. E. Stead, M. Dreifuss, G. H. Clamer, G. von Hanffstengel, L. E. Eckelmann, R. Meyer and S. Schuster, S. Zinberg, R. W. Irwin, and R. Weber. The alloys for stereotype work have lead 72-82 per cent.; tin, 3-10; and antimony, 15-19. The applications of these alloys were discussed by W. Campbell, E. Heyn and O. Bauer, A. Hague, J. Czochralsky, A. Halfmann, W. Kaiser, T. Goldschmidt, L. Revillon, H. M. Waring, C. F. Beyer, P. Yanushewsky, R. J. Shoemaker, C. Fischer, J. J. Watts and S. Harton, M. von Schwarz, F. Varrentrapp, and S. K. Patteson. M. Dubosc, R. S. Dean and co-workers, and L. Guillet, studied the hardening of the alloys by quenching. The Pb-Sn-Bi alloys were investigated by E. van Aubel, G. Charpy, M. Dullo, C. M. Marx, J. Würschmidt, K. Bux, H. Kopp, K. Gilbert, D. Mazzotto, H. Rainy and R. D. Clackson, P. T. Bachmetjeff and J. Wsharoff, C. Cattaneo, J. W. Döbereiner, C. Drewitz, G. A. Erman, G. Gore, C. C. Person, H. V. Regnault, W. C. Roberts-Austen, L. Schüz, W. Spring, C. L. Weber, G. Wiedemann, E. Heyn and O. Bauer, R. H. Thurston, G. Wertheim, M. Merle, T. J. Seebeek, H. von Löbell, H. Stegmann, E. S. Shepherd, F. Guthrie, P. Goerens, C. P. Steinmetz,

F. Hauser, K. Bux, E. Wiedemann, H. Behrens, G. W. A. Kahlbaum and E. Sturm, J. Faé, J. Johnston and L. H. Adams, K. Heine, C. von Hauer, J. M. Belin, L. Brennan, F. Wüst, L. Grunmach, J. Würschmidt, J. Joly and J. H. J. Poole, C. Schaefer, F. Faktor, etc. G. Charpy found that no compounds are formed, but there is a sharply defined ternary eutectic at 96°, as shown in Fig. 62. F. Wüst found that the alloy with 49.88 per cent. bismuth; 32-47, lead; and 17.38, tin, expands on cooling. The applications of these alloys were discussed by C. Drewitz, M. von Schwarz, R. Clayton, R. R. Maddison, C. W. Harrison, E. Lenssen, G. Homberg, W. Kaiser, W. F. Siemens and E. F. A. Obach, E. von Bibra, O. Trossin, L. Brennan, R. Jobson and R. J. Ransome, C. von Hauer, D. Mazzotto, H. V. Regnault, C. C. Person, W. Spring, G. W. A. Kahlbaum and E. Sturm, E. Jannettaz and co-workers, H. Grissel and T. Redwood, C. Cattaneo, J. Würschmidt, and H. Behrens.

The ternary Pb-Sn-K_alloys were examined by W. Stockmeyer and H. Hanemann; the Pb-Sn-Na alloys, by J. Göbel, and W. Stockmeyer and H. Hanemann; the Pb-Sn-Ca alloys, by C. G. Carroll and W. H. Adams; the Pb-Sn-Ba alloys, by Metallbank und Metallurgische Gesellschaft; and the Pb-Sn-Cu alloys, by R. E. Lee and F. B. Trace, and R. H. Thurston; A. French, G. Charpy, and E. J. Ball-these ternary alloys were found by F. Giolitti and M. Marantonio to contain either Cu,Sn or Cu,Sn. N. Parravano studied the Pb Sn-Ag alloys; A. von Vegesack, C. O. Thieme, and W. Stockmeyer and H. Hanemann, the Pb-Sn-Mg alloys; W. Hommel, A. and L. Svanberg, C. R. A. Wright and coworkers, F. Rudberg, J. Czochralsky, A. H. Munday and co-workers, A. Guettier, G. Wertheim, S. Fox and J. W. Slater, W. Sharman, F. Osmond and J. Werth, M. Levi-Malvano and O. Ceccarelli, C. F. Grimm, C. Pope, H. Grissell and T. Redwood, G. Wegner, W. E. Day, A. M. Ayala, J. R. Kinder, and A. Hanszel, the Pb-Sn-Zn alloys; M. Levi-Malvano and O. Ceccarelli obtained no compounds in the ternary system, and the ternary eutectic occurred at 177° with an alloy containing 71 per cent. of tin, 24 of lead, and 5 of zinc. A. K. Aster, W. J. Humphreys, A. Stoffel, E. S. Sperry, C. P. Steinmetz, M. Wählert, W. Hommel, B. Wood, C. W. Hill, C. von Hauer, K. Heine, L. J. Gurevich and R. W. Woodward, S. W. Stratton, F. Halla and A. Hoffmann, J. Scoffern, W. Kaiser, A. Lassieur, and P. Speier studied the Pb-Sn-Cd alloys. A. Stoffel observed that no compounds were formed, and that there is a ternary eutectic at 143°, as indicated in Fig. 63. F. Weld, and

W. J. Humphreys studied the Pb Sn-Hg alloys; C. R. A. Wright and co-workers, W. D. Bancroft, and J. Cayorca, the Pb-Sn-Al alloys; and C. G. Fink and C. H. Eldridge, the Pb-Sn-Tl alloys.

The so-called fusible alloys-discussed by K. Heine, N. F. Budgen, L. Losana, E. F. Davis, G. K. Burgess and P. D. Merica, A. Lassieur, and many others contain tin and lead with one or more metals—bismuth, cadmium, mercury—in addition. They are used for obtaining casts of delicate objects which would be damaged at a high temp.e.g. casts of portions of post-mortem specimens can be obtained by adding th of its weight of mercury to say bismuth 2, tin I, and lead 1. The fusible alloys are used for very soft solders. Fusible safety plugs, are used for boilers, etc. An alloy for fusible teaspoons is composed of bismuth 8, tin 3, lead 5, and mercury 1-2. The composition of some well-known fusible alloys is represented in Table VIII. The so-called G. C. Lichtenberg's alloy is really that given by Isaac Newton; and that often quoted as I. Newton's alloy (3:5: 8, m.p. 94.5°) was not given by him at all.

The quaternary Pb-Sn-Sb-P_alloys were studied by J. T. Dwyer; the Pb-Sn-Sb-As alloys, by J. E. Stead and L. J. Spencer; the Pb-Sn-Sb-Na alloys, by P. S. Braucher; the Pb-Sn-Sb-Al alloys, by the Dellinger Hüttenwerke, and the Allgemeine ElektrizitätsGesellschaft; the Pb-Sn-Bi-Sb alloys, by S. Singley, P. Bolley, R. Clayton, W. Kaiser, and E. Heyn and O. Bauer; the Pb-Sn-Bi-Na and Pb-Sn-Bi-K alloys, by G. Bredig and F. Haber; the Pb-Sn–Zn-P alloys, by S. R. Bailey, and J. F. Gross; the Pb-Sn–Zn-Sb alloys, by J. U. V. de Strubing, J. Segura, B. Kohlmann, K. Küppers, S. M. Meyer and W. James, and T. Lambert and H. C. Soper; and the Pb-Sn-Bi-Cd alloys, by A. Gouy, G. Gore, J. Faé, W. Campbell, D. Mazzotto, W. Spring, F. Guthrie, L. Losana; E. Wiede