Digitized by the Internet Archive in 2011 with funding from The Library of Congress http://www.archive.org/details/metallicalloysprOObran THE METALLIC ALLOYS THE METALLIC ALLOYS. A PRACTICAL GUIDE MANUFACTURE OF ALL KINDS OF ALLOYS, AMALGAMS, AND SOLDERS, USED BY METAL-WORKERS; TOGETHER WITH THEIR CHEMICAL AND PHYSICAL PROPERTIES AND THEIR APPLICATION IN THE ARTS AND THE INDUSTRIES ; WITH AN' APPENDIX ON THE COLORING OF ALLOYS AND THE RECOVERY OF WASTE METALS. EDITED BY WILLIAM T. BRANNT, EDITOR OF THE "TECHNO-CHEMICAL RECEIPT BOOK," AND "THE METAL WORKER'S HANDY BOOK." ILLUSTRATED BY FORTY-FIVE ENGRAVINGS. THIRD EDITION, THOROUGHLY REVISED AND ENLARGED. PHILADELPHIA : HENRY CAREY BAIRD & CO., INDUSTRIAL PUBLISHERS, BOOKSELLERS AND IMPORTERS, 810 Walnut Street. 1908. * ,1 ! LIBRARY of CONGRESS One Cow Received M& 20 i^oa euwrMiin fentry ^~ /<* O "ra x « ** U H < fa U fa u fa U W u 100-00 Cu 8.89 — 8.791 _ 98.10 1. go SnCu 9 6 — — — — 8.564 — -- — 97-So 2.50 — — — — — 8.5II — — — 96.27 3-73 SnCu 4 s — — — — 8.649 8712 0.063 — 92.80 7.20 SnCu 34 — — — — 8.694 — — — 92-59 7-50 — — — — — 8.684 — — — 90.00 10.00 — — — — — 8.669 8.614 — 0.055 89.00 11.00 SnCuie 8.84 8.69 — 0.15 — — — 87.50 12.50 — — — — — 8.648 — — — 86.S7 13-43 SnCllia — — — — 8.681 8.534 — 0.147 84.33 IS.67 SnCu 10 8.87 8.60 — 0.27 — 82.50 17-50 — — — — — 8.792 — — — 81.15 18.85 SnCu 8 8.84 8.54 — 0.30 — — — — 80.00 20.00 8.740 8.444 — 0.296 79.02 20.98 SnCu T 8.72 8.50 — 0.22 — — — 77-50 22.50 — — — — — 8.917 — — — 76-32 23-68 SnCu 6 8.72 8.46 — 0.26 8.s65(?) — — — 72.91 27.09 SnCu 5 8,62 8.40 — 0.22 — — — 72.50 27-50 — — — — — 8.925 8.318 — 0.607 70.00 30.00 — — — — 8.932 — — 68.25 31-75 SnCiu 8.75 8.32 — 0.43 8.938 8.2S0 — 0.688 67.50 32.50 — — — — — 8.907 — — — 65.00 35-00 — — — — 8.947 — — — 62.50 37.50 — — — — — 8.956 — — — 61.71 38.29 SnCuj 8.91 8.21 — 0.70 8.970 8.i5o — 0-820 57.50 42.59 — — — — — 8.781 — — — 56.32 43-68 Sn 6 Cui2 — — — — 8682 — — — S2.50 47.50 — — — — — 8.643 — — — SI. 80 48.20 SnCu 2 8.15 8.04 — o.ii 8.560 7-999 — 0-561 47-95 52.05 SnjCuis — — — — 8.442 — — \ — 47-50 52.50 — — — — — 8.446 — — — 44.63 55-37 Sn 2 Cu 3 8-06 7-93 — o.i3 8.312 7-893 — °-4i9 42.50 57-50 — — — — — 8.437 — — — 41.74 58.26 Sn 3 Ciu — — — — 8.302 — — — 39-20 60.86 Sn 5 Cu 6 — — — — 8.182 — — — 37.50 62.50 — — — — — 8.101 — — — 34-95 65.05 SnCu 7.90 7-79 — 0.1 1 8.013 7-755 — 0-258 28.72 71.28 Sn 4 Cu 3 — — — — 7.948 — — 27.50 72.50 _ ~ 1 — — — — 7-915 — — — 24.38 75.62 Sn s Cu 3 I — — — — 7.835 — — — 22.50 77.50 — i — — — — 7-774 — — — 21.18 78.82 Sn 2 Cu 7-59 7.58 — 0.01 7 770 7-566 — °-2I4 17-50 82.50 — — — — — 7.690 — — — 15.19 84.81 Sn 3 Cu 7-44 7-50 0.06 — 7.657 7.487 — °-i70 12.50 87.50 — — — — — 7-543 — — — 11.84 88.16 Sn 4 Cu 7-31 7.46 0.15 — 7-552 7-443 — 0-109 g.70 90.30 Sn 6 Cu 7.28 7-43 0.15 — 7.487 7-415 — 0-072 7-50 92.50 — — — — — 7-417 — — — 4.29 95.71 Sni 2 Cu — — — — 7-36o 7-346 — °-0I 4 2.50 97-50 — — — — — 7-342 — — — 1. 11 98.89 Sn 4 sCu — — — — 7-30S — — — 0.55 99-43 Sn 96 Cu — — — — 7.299 — — — 1 100.00 Sn 7-31 ' 1 ~ 7- 293 ~ ~ 1 — By heating to a red heat copper-tin alloys with a certain content of tin and tempering in water, and vice versa by 74 THE METALLIC ALLOYS. reheating and subsequent slow cooling, the specific gravity is changed in a remarkable manner. From a series of ex- periments made in this direction, Riche obtained the fol- lowing results : Alloys with 20.80 per cent. tin. Specific gravities. I. II. III. IV. V. VI. VII. VIII. IX. X. Cast 8.787 8.858 8.825 8.862 8.863 8.780 8.715 8.822 8.842 — Tempered 8.8238.9158.8638.8968.906 — — — — 8.747 Annealed 8.817 8.907 8.847 8.886 8.894 8.808 8.739 8.844 3-863 — Tempered 8.8498.9278.8748.9078.922 — — — — 8.871 Alloys with 18 per cent. tin. Specific gravities. 1. 11 Cast 8.737 8.873 Annealed 8.733 8.863 Tempered 8.763 8.91 1 Annealed 8.753 8.889 Tempered 8.775 8.926 Tempered 8.786 8.927 Alloys with 20 per cent. tin. From a cast block weighing 4 lbs. four bars each weigh- ing about 4 jounces were cut and used for the experi- ments. Specific gravities. 1. 11. Tempered 8.704 8.719 Annealed 8.712 8.728 Tempered 8.730 8.747 Annealed , 8.724 8.744 Tempered 8.756 8.763 Annealed 8.741 8.759 Again annealed 8.751 8.769 Tempered 8.775 8.792 Specific" gravities. III. IV. Annealed 8.752 8.686 Tempered 8.780 8.713 Annealed 8.777 8.714 Tempered 8.804 8.736 Annealed 8.815 8.750 Tempered 8.841 8.774 Again tempered 8.850 8.787 Annealed 8.807 8.760 These experiments show that the specific gravity of cop- per-tin alloys with 18 to 21 per cent, tin is progressively increased by repeated tempering, while annealing has a GENERAL PROPERTIES OF ALLOYS. 75 contrary, but less powerful effect, i. e. the decrease in the specific gravity produced by annealing is unable to equalize the increase by tempering, so that by alternate tempering and annealing a constant average increase in the density remains perceptible. The limit above which a repetition of annealing produces no effect has not been determined. The increase in the specific gravities of the above-men- tioned alloys by tempering may probably be closely related to liquation decreased by rapid cooling, and the decrease by annealing to liquation promoted by slow cooling. Alloys poorer in tin, in which liquation, as a rule, is less perceptible, show, however, a different behavior. By re- peated tempering and annealing, Riche found the following specific gravities : Alloys with 12 per cent. tin. Specific gravities. Tempered 8.625 Annealed 8.632 Tempered 8.624 Annealed , 8.635 • Tempered 8.632 Alloys with 10 per cent. tin. Specific gravities. I. II. III. IV. Cast 8.564 8.677 8.684 8.491 Tempered 8.516 8.635 8.657 8.428 Annealed ....8.528 8.643 8.670 8.431 Tempered 8. 532 8.645 8.671 8.437 Annealed 8.536 8.648 8.674 8.434 Tempered 8.529 8.648 8.673 8.436 Annealed 8.526 8.643 8.676 8.436 Tempered 8.526 8.626 8.664 8.436 Further the same alloy : Specific gravities, v. VI. Cast 8.541 8.705 Annealed 8.491 8.689 Tempered 8.495 8.684 Annealed 8.504 8.692 Tempered 8.505 8.693 Annealed 8.479 8.651 Tempered — 8.661 7 6 THE METALLIC ALLOYS. Alloys with 6 per cent, tin Specific gravities. I I. Cast 8.S37 Tempered 8.491 Annealed 8.501 Tempered 8.502 Annealed 8.507 Tempered 8.505 Specific gravities. 11. in. Cast 8.519 — Annealed 8.492 8.807 Tempered 8.491 8.806 Annealed 8.496 8.802 Tempered 8.495 8.804 Annealed 8.496 8.809 A glance at the above tables shows that, as in alloys richer in tin, an increase in the specific gravity cannot be obtained by repeated tempering and annealing, but that rather a decrease takes place, and that in some cases the effect of one tempering results in a decrease of density, and of anneal- ing in an increase ; further, that the poorer the alloy is in tin the sooner the limit is reached at which further treat- ment of the alloy produces no change in the specific gravity. By mechanical working — hammering, pressing, rolling — the specific gravity of copper-tin alloys is increased. Copper-zinc alloys. By experiments executed in the same manner as with copper-tin alloys, Riche obtained the following results : Composition of th examined. e alloys Specific gravity. Difference. Zinc. Atomic Found. Calcu- Copper. formula. lated. Expan- sion. Contrac- tion. 100.00 _ 8.890 _ 90.65 9-35 ZnCu 10 8.834 8,707 — 0.127 85-34 14.66 ZnCu 6 8.584 8.602 0.018 — 79-51 20.49 ZnCu 4 8.367 8.489 0.122 — 65.98 34-02 ZnCu 2 8.390 8.345 — 0.045 59-26 40.74 Zn 2 Cu 3 8.329 8.119 — 0.210 49 23 50.76 ZnCu 8.304 7-947 — 0-357 39.27 60.73 Zn 3 Cu 3 8.171 7783 — 0.388 32.66 67.14 Zn,Cu 8.048 7.679 — 0.369 19-52 80.48 Zn 4 Cu 7.863 7.478 — 0.385 10.82 89.18 Zn 8 Cu 7-315 7-351 0.036 — 100.00 Zn 7.200 — — — GENERAL PROPERTIES OF ALLOYS. 77 Similar figures were obtained by Calvert and Johnson. While with an increasing content of zinc a steady reduction in the specific gravity seems to take place, alloys with 40 to 80 per cent, zinc show quite considerable contraction. A series of experiments similar to the above mentioned with copper-tin alloys made by Riche show 1, that the specific gravity of copper-zinc alloys richer in zinc (35 per cent.) is increased by mechanical working as well as by tempering, such increase, however, being largely and, occa- sionally almost entirely, equalized by annealing ; and 2, that the specific gravities of alloys poor in zinc (9 per cent.) are not effected by such treatment. Copper-zinc alloys. Karmarsch has determined the specific gravities of copper-silver alloys in a coined state (coins) to remove the influence of porosity, and found the values given in the subjoined table. Composition of the alloys examined. Specific : gravities. Difference. Silver. Copper. Found. Calculated. Expansion. Contraction. 100 10.547 94-4 5-6 10.358 10.399 0.041 — 89.3 10.7 10.304 10.351 0.047 — 81.0 19.0 10.164 10.203 0.039 — 75-0 25.0 10.065 10.098 0.033 — 66.3 33-7 9.927 9-951 0.024 — 62.5 37-5 9.870 9.890 0.020 — 56.25 43-75 9.76i 9.786 0.025 — 51.21 48.79 9.679 9.706 0.027 — 49.65 50.35 9-650 9.681 0.031 — 42.43 57-57 9-532 9.568 0.036 — 36.7 63.3 9-439 9.482 0.043 — 33-3 66.7 9.383 9-430 0.047 — 30.4 69.6 9-333 9.386 0.053 — 29-5 70.5 9-317 9-371 0.054 — 22.4 77.6 9-203 9.269 0.066 — 22.0 78.0 9.190 9.264 0.074 — — 100 8.956 ~ ~ 78 THE METALLIC ALLOYS. The series throughout shows expansion, it being most pronounced in alloys richest in copper, then decreases reg- ularly to the alloy with 37.5 per cent, copper and from there on increases again with the increasing content of silver. Nevertheless the greatest expansion does not at- tain the same extent as that in copper-tin and copper-zinc alloys. Copper-gold alloys. Roberts has determined the specific gravities of some alloys richer in gold in the form of blanks, and obtained the following values : Composition of the alloys examined. Specifi c gravities. Difference. Gold. Copper. Found. Calculated. Expansion. Contraction. 100 19.3203 _ 98.01 1.99 18.8335 I8-.8355 — 0.0030 96.88 3.12 18.5805 18.5804 — 0.0001 95-83 4.17 18.3562 18.3605 0.0043 — 94.84 5.16 18.1173 18.1378 0.0205 — 93.85 6.15 17.9340 17.9301 — 0.0039 93.20 6.80 17.7911 17.7956 0.0045 — 92.28 1-12 17.5680 17.6087 0.0407 — 90.05 9-95 17.1653 17.1750 0.0097 — 88.05 11-95 16.6082 16.8047 — 0.0015 86.14 13.86 16.4832 16.4630 — 0.0202 100.00 8.725 According to the above table neither regularly progress- ing expansion nor contraction takes place. In most cases the difference between the found and calculated specific gravities is extremely small, and hence it may be supposed that a change in volume is not caused, at least not in the alloys examined. For practical purposes this is of import- ance in so far as it allows of calculating the content of gold in a gold coin from its specific gravity. GENERAL PROPERTIES OF ALLOYS. 79 Silver-gold alloys. Determinations by A. Matthiessen gave the following results : Composition of the alloys examined. Specific gravities. Difference. Atomic Calcu- Silver. Gold. Found. formula. lated. Expan- sion. Contrac- tion. IOO. Ag 10.468 _ _ 76.5 23-5 Ag 6 Au 11.760 11-715 — 0.045 68.7 31-3 Ag 4 Au 12.257 12.215 — 0.042 52.3 47-7 Ag 2 Au 13.432 13.383 — 0.049 35-4 64.6 AgAu 14.870 14.847 — 0.023 21.5 78.5 AgAu 2 16.354 16.315 — 0.039 12.0 88.0 AgAu 4 17-540 17-493 — 0.047 8-3 91.7 AgAu 6 18.041 17.998 — 0.043 100. Au 19-265 ~ — Hence in alloying the two metals contraction, though to an inconsiderable extent, takes place throughout. Lead-gold alloys, according to Matthiessen : Composition of the alloys examined. Specific gravities. Difference. Atomic Calcu- Lead. Gold. Found. formula. lated. Expan- sion. Contrac- tion. 100 Pb 11.376 9i-3 8.7 Pb 10 Au 11.841 11.794 — 0.047 84.0 16.0 Pb 5 Au 12.274 12. 171 — 0.103 80.8 19.2 Pb 4 Au 12.445 12.346 — 0.099 76.1 23.9 Pb 3 Au 12.737 12.618 — 0.119 67.7 32.3 Pb 2 Au 13.306 13-103 — 0.203 51.2 48.8 PbAu 14.466 14.210 — 0.256 34.6 65.4 PbAu 2 15.603 I5-546 — 0.057 20.8 79.2 PbAu 4 17.013 16.832 — 0.181 — 100 Au 19.265 —_ 8o THE METALLIC ALLOYS. Hence contraction takes place in all proportions and is considerably greater than in silver- gold alloys. Silver-lead alloys, according to Matthiessen : Composition of the alloys examined. Atomic Silver. Lead. formula. 100. Ag 67.6 32.4 Ag 4 Pb 51-0 49.0 Ag 2 Pb 34-2 65.8 AgPb 20.6 79-4 AgPb 2 II-5 88.5 AgPb 4 4-5 95-5 AgPb 10 2.0 98.0 AgPb 25 — 100 Pb Found. 10.468 10.800 10.925 11.054 11. 144 1 1. 196 11.285 H-334 11.376 Specific gravities. Calcu- lated. 10.746 10.894 11.048 11. 175 11.263 11.327 H-355 Difference. Expan- sion. 0.031 0.067 0.042 0.021 Contrac- tion. 0.054 0.031 0.006 The above table shows a quite regular course. The alloys richest in lead possess a less specific gravity than calculated, the difference rising with the content of silver until the latter amounts to 11.5 per cent. From here on the differ- ence decreases with a further increase in the content of silver, and with 34 per cent, silver contraction instead of expansion takes place, the extent of contraction growing also with the content of silver. Antimony-tin alloys, according to Long: GENERAL PROPERTIES OF ALLOYS. 8l Compo sition of th examined. e alloys Specific gravities. Difference. Anti- Tin. Atomic Found. Calcu- mony. formula. lated. Expan- sion. Contrac- tion. IOO. Sb 6.713 _ ^^ m 92.6 7-4 Sb 12 Sn 6-739 6.752 0.013 — 89.2 10.8 Sb 8 Sn . 6.747 6.770 0.023 — 88.1 11.9 Sb 4 Sn 6.781 6.817 0.036 — 67.7 32.3 Sb 2 Sn 6.844 6.889 0.045 — 5i.4 48.6 SbSn 6.929 6.984 0.055 — 34-5 65.5 SbSn 2 7.023 7.082 0.059 — 26.0 74.0 SbSn 3 ! 7.100 7- 133 0.033 — 17.4 82.6 SbSn 5 , 7.140 7.186 0.046 — 9-5 90.5 SbSn 10 7.208 7-234 0.026 — 5-o 95-0 SbSn 20 : 7.276 7.262 — 0.014 2.1 97-9 SbSn 50 j 7.279 7.281 0.002 — 1.0 99.0 SbSn 100 i 7.284 7.287 0.003 — — 100. Sn 7.294 ~ ~ ~ Hence expansion takes place almost throughout, increas- ing from both ends of the series and reaching the highest extent in alloys containing from 50 to 65 per cent. tin. Deviations from the regular course of the series may prob- ably be due to fortuitous circumstances in the preparation of the alloys. Antimony -bismuth alloys, according to Holzmann : 6 82 THE METALLIC ALLOYS. Composition of th examined. e alloys Specific j gravities. Difference. Anti- Atomic Calcu- Bismuth. Found. mony. formula. lated. Expan- Contrac- Sb sion. tion. 100 6.713 _ 54-o 46.0 Sb 2 Bi 7.864 7.856 — 0.008 37-1 62.9 SbBi 8.392 8.385 — 0.007 22.7 77-3 SbBi 2 8.886 8.888 0.002 — 12.8 87.2 SbBi, 9.277 9.272 — 0.005 8.9 91. 1 SbBi 6 9-435 9-433 — 0.002 - ~~ 100 Bi 9.823 " ~ ~ The difference between calculated and found specific gravities is so small that, at least with alloys poorer in anti- mony, it may be supposed that the volume remains un- changed. A slight contraction seems to take place only with a higher content of antimony. Antimony-lead alloys, according to Matthiessen : Composition of the alloys examined. Specific gravities. Difference. Anti- Atomic Calcu- Lead. Found. mony. formula. lated. Expan- sion. Contrac- tion. 100. Sb 6.713 54-i 45-9 Sb 2 Pb 8.201 8.268 0.067 — 37-i 62.9 SbPb 8.989 9-045 0.056 — 22.7 77-3 SbPb 2 9.811 9.822 O.OII — 16.4 83.6 SbPb 3 10.144 10. 211 0.067 — 10.5 89.5 SbPb 5 10.586 10.599 0.013 — 5-5 94-5 SbPb 10 10.930 10.952 0.022 — 2.3 97-7 SbPb 25 11. 194 1 1. 196 0.002 — 100 Pb 11.376 — — — GENERAL PROPERTIES OF ALLOYS. 83 Hence, as far as this series extends, expansion takes place throughout in alloying. In alloys with more than 22 per cent, antimony, Riche also found expansion, but con- traction in alloys poorer in antimony and richer in lead, the maximum of 0.023 being reached in an alloy with about 90 per cent, lead (SbPb 5 ). Calvert and Johnson found expansion in all antimony- lead alloys. Tin-cadmium alloys, according to Matthiessen : Composition of th examined. e alloys Specific gravities. Difference. Cad- Atomic Calcu- Tin. Found. mium. formula. ! lated. Expan- sion. Contrac- tion. 100. Sn 7.294 _ 86.1 13-9 Sn 6 Cd 7-434 7-456 0.022 — 80.5 19-5 Sn 4 Cd 1 7-489 7.524 0.035 — 73-2 26.8 Sn 2 Cd 7.690 7.687 — 0.003 50.8 49.2 SnCd 7.904 7-905 — 0.001 34-i 65-9 SnCd 2 8.139 8.137 — 0.002 20.5 79-5 SnCd 4 8.336 8.335 — 0.001 14.7 85.3 SnCd 6 8.432 8.424 — 0.008 — 100. Cd 8.655 — — — The alloys richer in tin plainly show expansion, which, however, disappears when the content of tin amounts to less than about 75 per cent. Tin-bismuth alloys, according to Carty: 8 4 THE METALLIC ALLOYS. Composition of th examined. e alloys Specific gravities. Difference. Tin. Atomic Calcu- Bismuth. Found. formula. lated. Expan- sion. Contrac- tion. 100. ,_ Sn 7.294 92.4 7-6 Sn 22 Bi 7.438 7-438 — — 69.0 31.0 Sn 4 Bi 7-943 7-925 — 0.018 62.5 37-5 Sn 3 Bi 8.112 8.071 — 0.041 52.7 47-3 Sn 2 Bi 8.339 8-305 — 0.034 35.8 64.2 SnBi 8.772 8-738 — 0.034 21.8 78.2 SnBi 2 9.178 9.132 — 0.046 12.2 87.8 SnBi 4 9-435 9-423 — 0.012 3-3 96.7 SnBi 8 | 9-614 9.606 — 0.008 2.3 97-7 SnBi 12 9-675 9.674 — 0.001 1-3 98.7 SnBi 20 9-737 9-731 — 0.006 0-5 99-5 SnBi 60 9-774 9.792 0.018 — 100. Bi 9.823 ~ These alloys show contraction almost throughout, it reaching its greatest extent in the alloy with 78 per cent, bismuth, and from there on decreases with an increasing content of bismuth and decreasing content of tin. Riche obtained very similar results, he finding the maximum con- traction in the alloy Sn 2 Bi 5 . Tin-silver alloys, according to Holzmann : GENERAL PROPERTIES OF ALLOYS. 85 Composition of the alloys examined. Specific gravities. Difference. Atomic Calcu- Tin. Silver. Found. formula. lated. Expan- sion. Contrac- tion. 100. Sn 7.294 95-1 4.9 Sn 18 Ag 7.421 7.404 — 0.017 90.6 9.4 Sn 9 Ag 7-551 7-507 — 0.044 86.5 13.5 Sn 6 Ag 7.666 7.603 — 0.063 76.3 23-7 Sn 3 Ag 7-963 7-858 — 0.105 68.2 31.8 Sn 2 Ag 8.223 8.071 — 0.152 52.2 47-8 SnAg 8.828 8-543 — 0.205 34-9 65.1 SnAg 2 9-507 9.086 — 0.421 21. 1 78.9 SnAg 4 9-953 9.585 — 0.368 ~ 100. Ag 10.468 All these alloys show considerable contraction, which gen- erally increases with the content of silver and reaches its maximum with 65 per cent, silver. Tin-lead alloys, according to Long : Composition of the alloys examined. Specific gravities. Difference. Atomic Calcu- Tin. Lead. Found. formula. lated. Expan- sion. Contrac- tion. 100. _ Sn 7.924 77-0 23.0 Sn 6 Pb 7.927 7.948 0.021 — 69.0 31-0 Sn 4 Pb 8.188 8.203 0.015 — 52-7 47-3 Sn 2 Pb 8.779 8.781 0.002 — 35-8 64.2 SnPb 9.460 9-474 0.014 — 21.8 78.2 SnPb, 10.080 10.136 0.056 — 12.2 87.8 SnPb< 10.590 10.645 0.055 — 8-5 9i-5 SnPb 6 10.815 10.857 0.042 — 100. Pb 11.376 — — — All the tin-lead alloys examined show expansion, the 86 THE METALLIC ALLOYS. maximum being reached with a content of lead of about 80 per cent. Pillichody obtained similar results, only he found considerably greater expansion (minimum 0.29 in the alloy SnPb 4 ; maximum in the alloy SnPb); Kupffer, Thompson, as well as Calvert and Johnson, found expan- sion throughout. Tin-gold alloys, according to Holzmann : Composition of the alloys examined. Specific gravities. Difference. Atomic Calcu- Tin. Gold. Found. formula. lated. Expan- sion. Contrac- tion. 100. Sn 7.294 96.6 3-4 Sn 50 Au 7.441 7.446 0.005 — 90.7 9-3 Sn 15 Au 7.801 7.786 — 0.015 84.2 15.8 Sn 9 Au 8.118 8.092 — 0.026 77-9 22.1 Sn 6 Au 8.470 8.452 — 0.018 70.3 29.7 Sn 4 Au 8.931 8.951 0.020 — 63.8 36.2 Sn 3 Au 9-405 9.407 0.002 — 59-5 40.5 Sn 5 Au 2 9-715 9-743 0.028 — 54-0 46.0 Sn 2 Au 10.168 10.206 0.038 — 47-0 53-0 Sn 3 Au 2 10.794 10.885 0.091 — 37-0 63.0 SnAu n.833 1 1 .978 0.145 — 22.7 77-3 SnAu, 14-243 14.028 — 0.216 12.8 87.2 SnAt^ 16.367 15-913 — 0-454 100. Au 19.265 ~ This series exhibits a peculiar course : The alloys richest in gold show strong contraction, those with a medium content of gold, expansion, and those lowest in gold, again slight contraction. It must, however, be remarked that with the great difference in the specific gravities of the separate materials constituting the alloys, every small varia- tion in the actual specific gravity, and that upon which the calculation is based, is more perceptible than with approxi- mately equal specific gravities, and hence a small error — especially in the last mentioned contraction — may perhaps be supposed. GENERAL PROPERTIES OF ALLOYS. 87 Cadmium-bismuth alloys, according to Matthiessen : Composition of the alloys examined. Specific gravities. Difference. Cad- Bismuth. Atomic Found. Calcu- mium. formula. lated. Expan- sion. Contrac- tion. 100. Cd 8.655 _ _ 61.7 38.3 Cd 3 Bi 9.079 9.067 — 0.012 51.8 48.2 Cd 2 Bi 9-195 9.181 — 0.014 35-0 65.0 CdBi 9.388 9-38o — 0.008 21.2 78.8 CdBi 2 9-554 9-550 — 0.004 11.8 88.2 CdBi, 9.669 9.668 — 0.001 6.3 93-7 CdBi 8 9-737 9.740 0.003 -!- 4-3 95-7 CdBi 13 9.766 9.766 — — — 100. Bi 9.823 These alloys show slight contraction, increasing toward the middle of the series until the quantity of both metals is approximately the same. Cadmium-lead alloys, according to Holzmann : Composition of the alloys examined. Specific gravities. Difference. Cad- Atomic Calcu- Lead. Found. mium. formula. lated. Expan- sion. Contrac- tion. 100. Cd 8.655 _ _ 77.2 22.8 Cd 6 Pb 9.160 9.173 0.013 — 68.2 31-8 Cd 4 Pb 9-353 9.364 O.OII 51-8 48.2 Cd 2 Pb 9-755 9.780 0.025 35-0 65.0 CdPb 10.246 10.246 — — 21.2 78.8 CdPb 2 | 10.656 10.663 0.007 — 11.8 88.2 CdPb< 10.950 10.966 0.016 — 8.3 91.7 CdPb 6 i 1 1 .044 11.088 0.044 — ~ 100. Pb 11.376 "■ ~ ~~ 88 THE METALLIC ALLOYS. This series is not distinct, but expansion, which gener- ally increases with the content of lead, may be inferred from it. Bismuth-silver alloys, according to Holzmann : Compo sition of the alloys examined. Specific gravities. Difference. Atomic Calcu- Bismuth. Silver. Found. formula. lated. Expan- Contrac- Bi sion. tion. 100. _ 9.823 99.0 1.0 Bi 50 Ag 9.813 9.829 0.016 — 97-8 2.2 Bi 24 Ag 9.820 9.836 0.016 — 96.0 4.0 Bi 12 Ag 9-836 9.848 0.012 — 92.0 8.0 Bi 6 Ag 9-859 9.871 0.012 — 88.5 ".5 Bi 4 Ag 9.899 9.893 — 0.006 79-4 20.6 Bi 2 Ag 9.966 9.949 — 0.017 65.8 34-2 BiAg 10.068 10.034 — 0.034 49.0 51.0 BiAg 2 10.197 10.141 — 0.056 32.5 67-5 BiAg, 10.323 10.249 — 0.074 100. Ag 10.468 ~ The alloys richest in bismuth exhibit slight expansion, but contraction with an increasing content of silver. Bismuth-lead alloys, according to Carty : GENERAL PROPERTIES OF ALLOYS. 8 9 Composition of th examined. e alloys Specific gravities. Difference. Atomic Calcu- Bismuth. Lead. Found. formula. lated. Expan- sion. Contrac- tion. 100. Bi 9.823 95-2 4.8 Bi 20 Pb 9.893 9.887 — 0.006 93-5 6.5 Bi 16 Pb 9-934 9.902 — 0.032 88.8 11. 2 Bi 8 Pb 10.048 9-974 — 0.074 80.0 20.0 Bi 4 Pb 10.235 10.048 — 0.137 66.6 33.4 Bi 2 Pb 10.538 10.290 — 0.248 50.0 50.0 BiPb 10.956 10.541 — 0.415 33-4 66.6 BiBb 2 11. 141 10.805 — 0.336 25.0 75-0 BiPb 3 11. 161 10.942 — 0.219 20.0 80.0 BiPb, 1 1. 188 11.026 — 0.162 16.7 83.3 BiPb 5 11. 196 11.083 — 0.113 7-7 92.3 BiPb 12 1 1 .280 11.238 — 0.042 ~~~ 100. Bi 11.376 These alloys show contraction increasing regularly from both ends of the series, and reaching the maximum in the alloy with 50 parts bismuth and 50 parts lead. Similar results were obtained by Riche. The contraction is con- siderable and exceeds that of nearly all other alloys. Bismuth-gold alloys, according to Holzmann : 90 THE METALLIC ALLOYS. Compo I sition of the alloys examined. Specific gravities. Difference. Atomic Calcu- Bismuth. Gold. Found. formula. lated. Expan- Contrac- sion. tion. 100. Bi 9.823 _ 97-6 2.4 Bi 40 Au 9.942 9-935 — 0.007 95-4 4.6 Bi M Au 10.076 10.046 — 0.030 89.4 10.6 Bi 8 Au 10.452 10.360 — 0.092 80.8 19.2 Bi^B 356' 302° i I TIN 10 20 30 40 50 60 \ 70 80 90 100% LEAD 100 90 80 70 60 50 40 30 20 10 0% 686% It has previously been stated that the melting tempera- ture (618.8 F.), is lowered by the absorption of small quantities of silver (melting temperature 1760 F.), the lowest melting temperature — about 572 F. — being that of an alloy with about 4 per cent, silver. With a larger, as well as with a smaller, content of silver the melting temper- ature is higher. But few determinations of the melting temperatures of the more refractory metals have been made. Copper melts at 1983. 2° F.; silver at 1760 F. The eutectic alloy of both metals contains, as previously stated, y2 parts silver and 28 parts copper, and congeals at 1418 F., see Fig. 7. The melting temperature (2732 F.) of pure iron is con- siderably lowered by the addition of various bodies, es- pecially so by carbon which by itself is infusible in our ordinary fires. The melting temperature of iron is reduced about 212 F. by the absorption of 1 per cent, carbon. Iron with 4 per cent, carbon melts already at 1985 F. On the other hand there are alloys whose actual melting temperatures agree quite well with those obtained by cal- culation, or are even somewhat higher. If, in the first case, all the alloys of the same group behave in the same man- GENERAL PROPERTIES OF ALLOYS. 109 tier, the line in which the melting temperatures of the alloys converge and which connects the melting tempera- tures of the pure metals, is a straight one ; to this belong, for instance, the alloys of gold (melting temperature 1913 F.) and of silver (melting temperature 1760 F.) In the Fig. 7- ixrr iw 1760' ~I74~Z° «!»• 156?' W - • Wl° SILVER 100 COPPER 30 10 80 20 70 30 72% 60 40 SO 50 1983.2' 40 60 30 70 10 80 10 90 0% 100% second case the line of view of the melting temperatures lies above the straight line drawn between the melting temperatures of the separate metals. Copper-zinc alloys may be mentioned as an example. Zinc melts at 779 F., and copper at 1983. 2° F. Maurice Lucas found the follow- ing melting temperatures of alloys to which for the sake of comparison are added those found by calculation. - Melting Melting Copper Zinc temperature temperature per cent. per cent. found calculated °F. °F. 90.5 9-5 1868 1868 80.3 19.7 1832 1745.6 69-5 30.5 1733 1614.2 60.2 39-8 1616 1502.6 51.0 49.0 1533.6 1391 39-7 60.3 1493.6 1256 31-0 69.0 1457 1171.6 25-1 74-9 1292 1083.2 20.4 79-6 1097.6 1023.8 no THE METALLIC ALLOYS. Fig. 8 shows the line of melting temperatures. There being no eutectic temperature from the sharp curve of the line at about 30 per cent, copper, the presence of a more in- timate chemical combination may be inferred, the composi- Fig. 8. I922°F V 1852' 1742 9 \ V *s\ 1652' l\ 156? \ \*0 147? \ 1362° 9, 1250° '% 1 1202° \ 1112° \;< M 1022° \ * \ 932" \ 842' 752" COPPER 100 SO 30 70 60 50 40 30 20 10 ZINC 10 20 30 40 50 60 70 80 90 100 tion of which would correspond to the formula Zn 2 Cu ("with 32.8 per cent, copper and 67.2 per cent, zinc), and which during solidification separates from the alloys richer in zinc. This alloy, as confirmed by various investigators, GENERAL PROPERTIES OF ALLOYS. Ill is distinguished from the other alloys of this group by its great brittleness, color, and chemical behavior. Finally there are alloys of which single ones stand out prominently from the entire series with a higher melting temperature than the adjoining ones. As an example of this may serve the alloys of copper and antimony, the melting temperatures of which are represented in the line of view Fig. 9. Z0\Z°F 19832' 10 ZO 30 40 50 60 70 80 90 100 ANTIMONY 100 90 80 70 60 50 40 30 20 10 Fig. 9. The alloy with about 51.5 per cent, copper and 48.5 per cent, antimony has a higher melting temperature than the nearest ones richer in copper and richer in anti- mony. It is considered a chemical combination of the formula SbCu 2 . The series has two eutectic points. A eutectic alloy consisting of copper and the compound SbCu 2 solidifies at A, and one consisting of antimony and the compound SbCu 2 , at B. By the addition of a third or fourth metal to an alloy, a 112 THE METALLIC ALLOYS. further reduction in the melting temperature can be effected. Therefore, generally speaking, the greater the number of constitue?its of which the alloys consist, the farther the actual melting temperatures of the alloys lie below those found by calculation. This rule is frequently made use of in the manufacture of very fusible alloys, it being possible by combining several metals in suitable pro- portions by weight, to make alloys which melt in boiling water. An alloy of 8 parts lead, 3 parts tin, 8 parts bis- muth (Rose's metal) melts at 203 F., and another of 8 parts lead, 4 parts tin, 15 parts bismuth, 3 parts cadmium (Wood's metal), already at 154.4 F. b. Fluidity. In addition to the melting temperature the degree of fluidity of a melted metal also exerts an influence upon its casting capacity. The more thinly-fluid it is, the more readily and the more completely it fills the thinnest cross-sections of the mould. To be sure its fluidity is part- ially dependent on the degree of overheating above the melting temperature in melting, and the lower the latter is the more readily a thinly-fluid state will be obtained. How- ever, independent of this there is no conformity in the be- havior of the metals. Just as oil is more thickly-fluid than water even when both are to the same extent heated above their boiling points, one metal is more thickly-fluid than another. Such as gradually soften (copper, wrought iron, etc.) as a rule are also more thickly-fluid in a melted state than those which melt suddenly (bronze, cast iron). How- ever, as a rule, alloyed metals pass less gradually into the fluid state than pure metals, and this is without doubt closely connected with the fact observed in foundry practice that alloys — at least generally speaking — are more thinly-fluid than non-alloyed metals. On the other hand some metal- loids, especially oxygen and sulphur, render many metals by which they have been absorbed thickly-fluid. Copper and bronze containing oxygen are more thickly fluid than when free from it, and iron containing sulphur is more thickly-fluid than when free from it. GENERAL PROPERTIES OF ALLOYS. II3 c. Development of gases. The casting capacity of a metal is materially impaired if it possesses the property of developing gases while in a fluid state. If this development of gas takes place shortly before solidification the gases can no longer escape, and the resulting casting is full of gas- bubbles. On the other hand, if the metal previous to com- plete solidification passes through a dough-like condition, it swells up under the pressure of the developing gases, scatters when solidifying with a free surface, and becomes unfit to sharply fill any mould. Since the volume of gases increases materially with the temperature, this process is more plainly perceptible with refractory metals than with those more readily fusible. This feature frequently observed in casting metals may be ascribed to various causes. It may sometimes be due to gases in solution which shortly before the metal passes into the solid state reassume their gaseous form. Various metals (iron, copper) dissolve hydrogen and in melting find abundant opportunity for absorbing it. Nitrogen may also in certain quantities be dissolved by liquid metals, and some metals, for instance, silver, dissolve oxygen without entering into a more intimate combination with it. Whether or not and in what direction the capacity of metals to dissolve gases is changed by alloying has thus far not been definitely determined. Observations made in casting lead, however, lead to the conclusion that, as a rule, alloyed metals are less capable of dissolving gases than pure metals. The development of dissolved gases may, however, be sometimes prevented by adding to the metal a body which enters with the dissolved gas into a non-volatile combination which does not again disintegrate. Thus, for instance, the oxygen dissolved by fluid silver escapes with violence shortly before solidification, and frequently produces vigorous scatter- ing, and in every case renders the casting of pure silver a difficult process. If, however, copper be alloyed with the silver, an adequate portion of it combines with the absorbed 114 THE METALLIC ALLOYS. oxygen to cuprous oxide which, though it remains dis- solved in the metal, does not disintegrate; the development of gas is thus avoided if not caused by other conditions. The greater the proportion of copper to silver the more complete the result will be. Zinc, possessing a stronger tendency towards combining with oxygen, acts still more vigorously than copper. The gases, however, originate not less frequently from a chemical process in the interior of the liquid metal itself, their formation being first caused thereby. If, for instance, in addition to dissolved oxides — or under circumstances in addition to oxygen which was simply in solution — the metal contains other substances which enter into new gaseous combinations with the oxygen present, a development of gas must by this process be brought about. This develop- ment takes place very rapidly if the body combining with the oxygen has a strong affinity for the latter and is present in great excess. It progresses, however, more gradually, and for this very reason is more detrimental to the casting capacity, when the affinity for oxygen of the second body is only slightly greater than that of the metal whose oxide was dissolved, and when it is present in the metal-bath in a greatly diluted state. Thus, for instance, commercial cop- per contains in addition to certain quantities of cuprous oxide, certain quantities of cuprous sulphide; both of these bodies act one upon the other, gaseous sulphurous acid being thereby formed. The cuprous sulphide is, however, present in the liquid metal in a greatly diluted state and the action does not take place suddenly but progresses very gradually, so that gas is uninterruptedly evolved from the melted copper rendering the latter unfit for the manufac- ture of castings. By calculating the volume which definite quantities of sulphurous acid occupy in the solidifying temperature, it will be readily understood that even an ap- parently very small content of sulphur is capable of pro- ducing perceptible effects. Iron, as well as nickel, always GENERAL PROPERTIES OF ALLOYS. II5 contains carbon ; if now, in addition to carbon, oxygen is present in the metal, the formation of carbonic oxide is caused by their reciprocal action which, like sulphurous acid in the above-mentioned case, may make the metal unfit for casting purposes. The development of gas must stop if, in such cases, the metal is alloyed with a body which by reason of its stronger affinity for oxygen attracts the latter and the oxide of which is either separated in an insoluble state in the metal- bath, or at least is no longer disintegrated in the manner previously described. With copper, for instance, this re- sult is attained by the addition of zinc ; aluminium, phos- phorus or silicon acting still more vigorously. With nickel an addition of zinc also answers the purpose, though mag- nesium is still more effective. With iron, manganese is as a rule used for the disintegration of the dissolved ferrous oxide, but as the resulting manganous oxide is itself again affected by the carbon present, though somewhat more slowly than the ferrous oxide previously present, an entirely complete result is not attained. The object is however accomplished with greater certainty by aluminium and in fact large quantities of this metal are now used for this purpose ; but an excess of the added aluminium remaining in the iron makes the latter thickly-fluid and also impairs its mechanical behavior, and must therefore be avoided. From what has been said it is evident that by suitably alloying a metal its capacity for developing gases while in a liquid state can be decreased or entirely overcome. d. Shrinkage. When a liquid metal congeals it at first expands like freezing water and consequently the congealed portion floats upon the liquid metal like ice upon water. This, however, as cooling progresses, is followed by a con- traction which is nearly always greater than the previous expansion. Hence the articles produced by casting are, when cold, smaller in dimension than the moulds which served for the reception of the liquid metal. This process is called shrinkage. Il6 THE METALLIC ALLOYS. In many respects the shrinkage of metals renders the production of serviceable castings more difficult, and the greater the degree of shrinkage the more this fact becomes apparent. If a casting has in different portions cross-sec- tions of varying thickness which do not simultaneously congeal and shrink, a strain or even a crack may be formed in the casting, but where the metal remains liquid the longest, hence usually in the center of the casting, a hollow space is formed which may render the article entirely use- less. In casting liquating alloys accumulations of more readily fusible alloys may easily form in this hollow space. A law according to which the degree of shrinkage of alloys could be deduced from that of the separate metals cannot be laid down. Alloys frequently shrink to a greater extent than each of their constituents. Pure copper, for instance, shrinks but little* ; pure tin tjt, pure zinc gV. On the other hand a copper-tin alloy with 10 per cent, tin shrinks yso \ with 20 per cent, tin F V ; and a copper-zinc alloy with 30 per cent, zinc eV- The degree of shrinkage of tin-lead alloys is quite small and increases with the con- tent of lead. (Degree of shrinkage of pure lead 9V). 8. Conductivity for heat and electricity . Good conduc- tors for heat are, as a rule, also good conductors for elec- tricity, and vice versa. Amongst the metals silver is con- sidered the best conductor for heat and. electricity ; next comes pure copper, then gold, etc. Experiments, as well as observations in using metals, have shown that the purest metals are throughout the best conductors and by alloying their conductivity is almost always impaired. According to Matthiessen's investiga- tions, lead, tin, cadmium and zinc are the only metals whose conducting power for electricity is not materially impaired when alloyed with one another, but corresponds to that *Pure copper is generally not used for casting and an accurate determin- ation of its degree of shrinking is connected with difficulties by reason of its tendency to develop gases in casting and swelling up thereby. GENERAL PROPERTIES OF ALLOYS. \\J found by calculation. The conducting power of these metals, however, decreases also when they are alloyed with other metals. It becomes here also evident that, similar to the effect of alloying upon other properties, the conductivity of a less good conductor may be still further decreased by alloying even with a good conductor. Taking for instance the conductivity of silver for heat, as well as, for electricity as ioo, Wiedmann found the con- ductivity of : Copper for heat = 73.6; for electricity = 79.3 Zinc for heat = 28.1 ; for electricity = 27.3 and that of an alloy of 2.1 parts copper and 1 part zinc, for heat = 25.8, for electricity =25.4. Very small quantities of a foreign body are frequently sufficient to effect a considerable decrease in conductivity. According to Matthiessen and Holtzmann, the electrical con- ductivity of pure copper is diminished 27 per cent, by the absorption of only 0.13 per cent, of lead; 40 per cent, by 3.2 per cent, of zinc ; 14 per cent, by 2.45 per cent, of silver; 80 per cent, by 4.90 per cent, tin; 86 per cent, by 2.80 per cent, arsenic; and 92 per cent, by 2.50 per cent, phosphorous. Hampe found that the conductivity of copper may be diminished 50 per cent, by 0.35 per cent, arsenic, and about 25 per cent, by 0.5 per cent, silicon. In such cases, previously referred to, where a metal con- contains its own oxide in solution, the latter may, like another alloyed body impair the conductivity. Matthiessen and Holtzmann found that copper which had become oxidized by melting in the air conducted electricity only in the proportion of 63.37 to 93-00 as compared with copper whose content of oxygen had been destroyed by the action of hydrogen gas. The conductivity might possibly be in- creased by removing the content of oxygen from such a Il8 THE METALLIC ALLOYS. metal in the manner previously referred to, i. e. by the addition of a body which by reason of its greater affinity for oxygen combines with the latter, and the oxide of which is insoluble in the metal-bath. However, without an excess of such an addition, a complete separation of the oxygen is scarcely possible and there is then danger of this excess exerting just as an injurious, or still more injurious, effect than the oxygen originally present. An addition of phosphorus to copper for the purpose of increasing the conductivity by destroying the cuprous oxide present would, for instance, be scarcely a success, since, as shown by the figures given above, a very small quantity of phos- phorus in excess greatly diminishes the conductivity. As shown by Hampe's investigations, an addition of silicon, which has recently been frequently used in the manufacture of conducting wires, also impairs to a considerable extent the conductivity, and the actual object of such an addition is very likely that of increasing the strength of the wire. The problem of finding a suitable addition which will not impair the conductivity has thus far not been solved. 9. Color. Regarding the color of alloys, it may also be said that the intensity of the effect produced by the addi- tion of determined quantities of one metal to another is not equally strong throughout, but shows considerable varia- tions; the color of an alloy does not always form the com- pound color from the colors of the alloyed metals, but frequently exhibits independent tones. While, for instance, in copper-silver alloys the color of the one metal passes quite regularly into that of the other, and hence forms an actual compound color, in some copper-tin alloys, and still more so, in some copper-zinc alloys with a comparatively high content of copper, the red color disappears almost completely, being replaced by a yellow shade which cannot be produced by simply mixing red and white or red and gray. The diversity in color of the metals used for technical GENERAL PROPERTIES OF ALLOYS. I IQ. purposes is not very great, one metal, copper, being red and another, gold, yellow ; the rest are either white or pale gray, in the various shades of the pure white of silver and tin to the pale gray of lead, platinum, etc. Two or more white metals alloyed with one another always give white alloys. White metals alloyed with the red copper give reddish white, reddish yellow, pure yellow, gray or white alloys. White metals alloyed with gold give pale yellow, greenish or white alloys. As previously mentioned, the intensity of coloration pro- duced in an alloy by the addition of one or another metal, varies considerably. For the metals more frequently used for colored alloys, the following scale may be adopted : Tin, nickel, aluminium, Manganese, Iron, Copper, Zinc, Lead, Platinum, Silver, Gold. Each metal in this series standing before another exerts a stronger influence upon the color than the succeeding one, so that the color of the latter frequently disappears by the addition of comparatively small quantities of the former. However, the different shades of color do not appear gradually and uniformly with the increase or decrease in the content of the one metal, transitions by leaps or bounds being frequently observed, and it may even happen that an alloy with a larger quantity of a white coloring metal may show a darker tone of color than the same alloy with a smaller quantity of the same metal. The varying intensity of coloration produced by copper, 120 THE METALLIC ALLOYS. tin and zinc, may be very plainly recognized by a compari- son of the scale of color of copper-tin and copper-zinc alloys. Copper-tin alloys. Copper-zinc alloys. Copper -tin-zinc alloys. V a o o _fi .B • .5 _B w <+« Color. m-i Color. •^ •^ Color. o O O +j b S3 B s B u u V V V •M B B B B B O O O O O u u O U u 9S 5 Red yellow, gold-like. 5 Red, almost copper color — — — go 10 Reddish, gray-yellow. 10 Rellowish, red brownish. — — — 84 16 Reddish yellow, 16 Red yellow. 5 ! 11 Orange red. 80 20 Reddish gray. 20 Reddish yellow. 4 ! 16 Orange yellow. 78 22 Yellow gray. 22 Reddish yellow. ' 4 | 18 Orange yellow. 75 25 Reddish white. 25 Pale yellow. — . — 73 27 Reddish white. 27 Yellow. 4 23 Pale orange. 70 30 White. 30 Yellow. 3 27 Pale yellow. 65 35 Bluish white. 35 Deep yellow. 3 32 Light yellow. 62 38 Bluish gray. 38 Deep yellow. — — — 59 41 Gray. 41 Reddish yellow. — — — 50 50 Pale gray. 50 Handsome gold yellow. — — — 40 60 Gray white. 60 Bismuth gray, with strong luster. — — — 30 70 Gray white. 70 Antimony gray. — — — 20 80 Whitish. 80 Zinc gray. — — 10 90 Whitish. 90 Zinc gray. — — — From the above table it will be seen that, while the color of copper, vivid by itself, is almost completely covered by a content of 30 per cent, tin, it is converted by the same quantity of zinc first into yellow, and about 60 per cent, zinc is required to make it entirely disappear. The fact that in copper-zinc alloys with 25 to about 35 per cent, zinc the color appears pure yellow fbrass-yellow) and with a still higher content (up to 50 per cent.) of zinc golden yellow, is also of interest and considerable practical import- ance. Still warmer tones of color are obtained, as shown in the third column of the table, by replacing in the alloys richer in copper (70 to 80 per cent, copper) a portion of the zinc by tin. The great coloring power of nickel is best shown in nickel coins, which contain 75 per cent, copper and 25 per GENERAL PROPERTIES OF ALLOYS. 121 cent, nickel. Notwithstanding the large content of copper, the color of the latter has entirely disappeared. Gold possesses but slight coloring power. Gold-silver alloys with 64 per cent, gold show a greenish-yellow color, and with 30 per cent, gold a perfectly white color like fine silver. When gold is alloyed with copper, the gold color disappears completely with about 75 per cent, copper, the alloys exhibiting the red color of rosette copper, while in a silver-copper alloy with the same quantity of copper, the content of silver can be plainly recognized. 10. Resistance to chemical influences. A knowl- edge of the resistance of alloys to chemical influences is of considerable practical importance. Nearly all articles of metal and alloys are exposed to the action of gases con- tained in the atmosphere (besides the quite indifferent nitrogen : oxygen, carbonic acid, aqueous vapor ; in in- habited localities nearly always sulphuretted hydrogen, am- monia, etc.), and many of them to that of rain and snow, while utensils for culinary and technical purposes are in ad- dition affected by acid, alkaline, saline, or fatty fluids. For the manufacture of such utensils it might be desirable, as regards other properties, to alloy the metal to be used for the purpose with another, but the question is whether such an alloy possesses the same power of resisting chemical in- fluences as the pure metal. Thus, for instance, tin contain- ing lead is preferable in many respects to pure tin, it being harder, stronger and filling the moulds better in casting ; but if the alloy is to be used for kitchen utensils, drinking vessels or similar purposes, the important question arises whether, in view of the poisonous properties of lead it is capable of resisting in the same degree as pure tin the chemical influences to which it may be exposed in use. But few experiments have been made to determine the behavior of alloys in this respect. It is generally found that the action of the atmosphere is less severe on alloys than on their component metals. An instance of this is the ancient 122 THE METALLIC ALLOYS. bronze statues and coins, some of the latter of which have their characters still legible, although they have been ex- posed to the effects of air. and moisture for upwards of twenty centuries. The action of the atmosphere on an alloy heated to a high temperature is sometimes quite energetic, as is shown in the alloy of 3 parts lead and i of tin, which, when heated to red- ness, burns briskly to a red oxide. When two metals, for instance copper and tin, which oxidize at different temper- atures, are combined, they may be separated by continued fusion with exposure to the air. Cupellation of the precious metals is a like phenomenon. By alloying a metal with another the chemical action of a body upon the alloy is frequently reduced to a less degree than would correspond to the simple dilution of the metal, and two metals, which in a pure state are very sensitive to chemical influences, may even show a comparatively great power of resisting these influences when alloyed in definite proportions with one another. However, two alloys com- posed of the same metals, but in different proportions, may, in this respect, exhibit considerable variations, and it may happen that an alloy with a larger content of a metal pos- sessing but slight power of resisting certain influences, may be less attacked by the same agents than another alloy with a smaller content of the same metal. Some investigators have considered this peculiarity of some alloys an indication of the presence of actual chemical combinations. However, a contrary behavior has also been frequently observed. Thus, St. Claire Deville found that a lead-platinum alloy, which he kept in a closet, was entirely decomposed by the action of the air, the lead being con- verted into lead carbonate (white lead), while a piece of pure lead lying alongside it remained unchanged. Among the silver-copper alloys, that containing 25 per cent, of copper tarnishes to a greater degree in air containing sul- phuretted hydrogen than pure silver, etc. GENERAL PROPERTIES OF ALLOYS. L2T, Calvert and Johnson have investigated the resistance of different copper-tin and copper-zinc alloys to acids and salts, and made the remarkable observation that nitric acid of 1. 14 specific gravity dissolves the two metals in an alloy of zinc and copper in the exact proportion in which they exist in the alloy employed, while an acid of 1.08 specific gravity dissolved nearly the whole of the zinc and only a small quantity of the copper. Hydrochloric acid of 1.05 specific gravity, which readily dissolves zinc, was found to be completely inactive on all alloys of copper and zinc con- taining an excess of copper, and especially on the alloy con- taining equivalent proportions of each metal. Zinc was found to have an extraordinary preventive influence on the action of strong sulphuric acid on copper. The alloy Cu 4 Zn 3 (with 56.5 per cent, copper) was but little attacked by concentrated hydrochloric or nitric acid, and not at all by sulphuric acid. Copper-tin alloys were found to resist the action of nitric acid more than pure copper, but the preventive influence of tm presents the peculiarity that the action of the acid in- creases as the proportion of tin increases ; thus the alloy CuSn 5 is attacked ten times more than the alloy CuSn. Among the copper-tin-zinc alloys the two alloys Cu I8 SnZn with 86 per cent, copper, 9 per cent, tin, 5 per cent. zinc. Cu 10 SnZn •' 77 " " 14.5 " " 8 " were found to be only slightly attacked by strong nitric or hydrochloric acid, and, hence, behaved similarly to the above- mentioned alloy Cu 4 Zn 3 . The resistance of these alloys against the action of nitric acid deserves special attention, since the acid readily attacks each of the separate metals. Regarding the influence of sea water upon copper-zinc and copper-zinc-tin alloys, Calvert and Johnson found that from pure copper-zinc alloys zinc is chiefly dissolved, the copper being therefore protected by an addition of zinc ; and that in the ternary alloys of the mentioned metals, the 124 THE METALLIC ALLOYS- solution of zinc is smaller and that of copper considerably- larger than in copper-zinc alloys. Hence by the^ addition of tin the zinc is protected and the copper more exposed, though with an equivalent proportion of copper a reduction in the total effect could not be recognized. On the other hand, the action of sea water is weakened by a small addi- tion of lead and iron to copper-zinc alloys (see Muntz metal) . Articles of copper-tin alloys richer in copper, when ex- posed for a long time to the action of the air, acquire a beautiful pale green or brownish crust called patina, con- sisting mostly of the hydroxides and carbonates of the component metals. This patina is highly esteemed, partly on account of the beautiful appearance it presents, and partly as. a characteristic of antique articles, and it is sought to promote its formation partly by a suitable choice of the alloy and partly by the use of chemical agents. Upon an alloy consisting of Cu 89.78, Sn 6.83, Pb 1.85, Co, Ni 0.90, Fe 0.28, J. Schuler found a patina of the following com- position : Sn0 2 49.13 CuO 22.46 PbO 3-53 Fe 2 3 Al 2 3 I.7S CO, 6.3s H,0 8.48 Organic substance 0.76 H 0.65 Insoluble matter 6. 16 or, omitting the accidental foreign substances (organic sub- stances, sand, etc.) : Sn0 3 H 2 60.92 CuC0 3 .Cu0 2 H 2 34-55 (PbC0 3 ) 2 Pb0 2 H 2 4.51 It is remarkable that in this patina the proportion of cop- per to the other metals is much smaller than in the bronze. GENERAL PROPERTIES OF ALLOYS. I25 In copper-silver alloys the copper may protect the silver from the attack of single agents, but the silver, even when present in excess, does not protect the copper. Thus cop- per is dissolved by acetic acid from alloys with 80 per cent, and upward of silver, a fact which deserves attention in using utensils of silver alloyed with copper for household purposes. By boiling copper-silver alloys with dilute sul- phuric acid, the greater portion of the copper is dissolved, while nearly all the silver remains behind. It has previ- ously been mentioned that the action of sulphuretted hydro- gen is more pronounced upon silver alloyed with copper than upon pure silver ; the article becoming covered first with a yellowish and then a brownish coat, which finally turns blue. In gold-silver alloys the gold, if present in excess, may weaken or entirely overcome the action of certain acids upon silver. While from alloys poor in gold all the silver may be extracted by sulphuric acid, an alloy containing more than 50 per cent, gold is not affected. The action of acids and salt solutions upon lead-tin alloys has been more thoroughly investigated on account of the poisonous properties of lead, vessels of tin containing lead being much used for household and commercial purposes. Pleischl, Roussin, Reichelt, and others have shown that acetic acid and common salt solution, or a mixture of both, dissolve lead from lead-tin alloys even if they contain but 2 per cent, of lead, the quantity of lead dissolved increasing, of course, with the content of lead in the alloy, and depend- ing on the time of action. It is a curious fact that some alloys richer in lead are said to be more resistant than alloys with a smaller content of lead, Pohl giving an alloy of 5 parts tin and 12 parts lead, and Phlo one of 4 parts tin and 9 parts lead, hence almost identical with Pohl's. Knapp has investigated lead-tin alloys with the following results : Three alloys of different composition were pre- pared : 126 THE METALLIC ALLOYS. A. 30.8 parts tin and 69.2 parts lead (the above-men- tioned alloy of Phlo). B. 21 parts tin and 79 parts lead (corresponding to the formula SnPb 2/ ). C. 80 parts tin and 20 parts lead. Toward distilled water with the access of air the alloy A showed the greatest resistance, while from A and B a com- paratively large quantity of oxide of lead (consisting of lead, carbonic acid and waterj was separated. Cold vinegar dissolved in the course of seven days per 15.5 square inches surface: Lead, Tin, Total, gramme. gramme. gramme. From alloy A 0.0677 0.0267 0.0944 From alloy B 0.0773 0.0159 0.0932 From alloy C 0.0027 0.0337 0.0364 Hence the alloy richest in tin showed the greatest resist- ance toward the action of cold vinegar, while the alloy of Phlo proved no more resistant than the alloy with 79 parts lead. While for the same quantity of tin the alloy A con- tains about 9 times as much lead as C, it yields to vinegar 26 times as much lead. Boiling vinegar dissolved in the course of one hour Lead, Tin, Total, gramme. gramme. gramme. From alloy A 0.0130 0.0032 0.0162 From alloy B 0.0118 0.0055 0.0173 From alloy C 0.0058 0.0100 0.0158 The difference in the resistant power of the alloy richer in tin as compared with the two others is, therefore, con- siderably diminished by boiling and, by taking into consid- eration the total quantity of metal dissolved, Phlo's alloy proves nearly as resistant as the alloy richer in tin, the amount of lead dissolved being, however, nearly double. By taking into consideration the short time of action, it will be seen that the effect of the acid is considerably in- creased by the higher temperature. GENERAL PROPERTIES OF ALLOYS. I27 Cold common salt solution with about 3.5 per cent, com- mon salt, dissolved in the course of seven days from all three alloys only lead, no tin being dissolved. The amount of lead per 15.5 square inches surface was: From the alloy A 0.0023 gramme. From the alloy B trace. From the alloy C 0.0499 gramme. In this case the alloy poorest in lead loses the greatest quantity of it. At a boiling heat the same common salt solution in the course of one hour also dissolved tin, the amount per 15! square inches surface being : Lead, Tin, Total, gramme. gramme. gramme. From the alloy A 0.0078 0.0022 0.0100 From the alloy B o.oc8o 0.0012 0.0092 From the alloy C 0.0036 0.0020 0.0056 In this case the alloy richest in tin suffers the smallest total loss in metal, but in proportion to its content of lead, a comparatively large amount of the latter is dissolved. The results of these experiments show the extent to which the resisting power of one and the same alloy is de- pendent upon the nature of the influences to which it is ex- posed and the temperature at which they act. R. Weber has made quite a number of experiments with lead-tin alloys in regard to their behavior towards vinegar. His investigations show that generally speaking the alloys are the more strongly attacked the greater their content of lead, no exception from this rule for some alloys richer in lead, as supposed by Pohl and Phlo, having been found. Further, a content of antimony does not prevent the alloy from being attacked, and that when vinegar is mixed with % its volume of tartaric acid, the quantity of metal dis- solved is increased fourfold. In Germany, by law, vessels intended for measuring fluids must not contain more than 1 part lead to 5 parts tin. CHAPTER V. PREPARATION OF ALLOYS IN GENERAL. Alloys are generally prepared by directly melting to- gether the metals which are to take part in the mixture. At the first glance this would seem a very simple affair, requiring scarcely any explanation, but in fact great skill and judgment are necessary for the successful accomplish- ment of the object. Some alloys are in fact very difficult to prepare, and require special precautionary measures. For melting purposes various kinds of utensils are em- ployed. An iron kettle may be used for the manufacture of alloys with low melting temperatures, especially those of lead and tin, or alloys of these metals with antimony. For heating the kettle ordinary fuel or, when working on a small scale, illuminating gas may be used. For alloys with higher melting temperatures crucibles are used in place of a kettle. Crucibles are more expensive and require frequent renewal, but they are indispensable for melting alloys with higher melting temperatures, for instance, the alloys of copper, nickel, silver, gold. In most cases crucibles are made of fire-clay mixed with graphite. The latter improves the refractory quality, prevents the crucible from cracking in burning it, and impedes the pas- sage of oxidizing fire-gases through the red-hot walls of the crucible. The crucibles are generally heated in a furnace, coke being used as fuel. They are, as a rule, taken from the furnace by means of tongs and emptied by tilting. In doing this there is, however, danger of the crucible break- ing, this danger increasing with the weight of the crucible, and therefore the capacity of the latter is generally limited to about ioo lbs. Hence if larger quantities are to be (128) PREPARATION OF ALLOYS IN GENERAL. 1 29 melted, several crucibles have to be used and their contents combined after melting. This method has, however, several drawbacks. To overcome these, furnaces have been in- troduced in which the crucible is stationary and for the purpose of emptying it, the entire furnace is tilted over by means of a mechanical appliance. The crucible of such a furnace has a capacity of up to iooo lbs. When working on a large scale, the crucibles are some- times placed upon the flat hearth of a furnace where they are heated by the passing flame of the fuel. The crucibles are emptied, as previously mentioned by means of tongs. If, however, considerable quantities are at one time to be melted, and damage to the quality of the alloys from com- ing in contact with the gases of combustion need not be feared, a reverberatory furnace is used. The metal is placed upon the trough-shaped hearth of the furnace and directly melted by the passing flame. The melted metal is drawn off through the tap-hole. This process is generally employed in bronze foundries when bells and other large articles are to be cast. Wood is preferably used as fuel, since the content of sulphur in coal might pass from the gases into the metal and impair its quality. In many works gas is now used for heating the furnace. Special pre- cautions must be taken to keep up a deoxidizing flame within the furnace. A small portion of the heat, which otherwise could be used for melting the metals, is some- times lost thereby ; but the great advantage is gained that as long as the gases of combustion passing over the metals absorb oxygen, the melting metals will actually remain in a metallic state. This is especially of great importance with metals which readily oxidize when exposed in a fused state to the action of the air. It may here be remarked that the oxides formed by careless work from the metals seldom take part in the formation of the alloy, so that even if the quantities of metals have been accurately weighed, the resulting alloy will not show the desired composition, since 9 I3O THE METALLIC ALLOYS. the portion of the metals converted into oxide does not enter into the alloy. For preparing alloys on a smaller scale in a crucible, special precautionary measures must be taken against oxidation of the metals. For this purpose the surface of the metals is covered with bodies which prevent the access of air, without, however, exerting any influence whatever, or at least only to a very small extent, upon the metals. In many cases anhydrous borax is used ; but independently of the fact that borax is rather expensive and unnecessarily increases the cost of the alloys, its employment is accom- panied by many evils. It is well known that in borax a portion of the boric acid is not perfectly saturated, and that in melting borax with base metals a certain portion of the acid is always absorbed, which with the sodium borate forms double salts of a glassy nature. Hence by fusing metals under borax a certain portion of them will be lost by forming a combination with the borax. Glass consists of a mixture of silicates, and forms, when thrown upon fusing metal, a coating which completely ex- cludes the access of air to the surface of the metal. Though it has also the property of absorbing certain metals when brought in contact with them in a liquid state, the influ- ence it exerts upon alloys is, generally speaking, much less than that of an equal quantity of borax. If the metals to be fused together are such that a combination with carbon need not be feared, the fusing mass can also be protected from the influence of the oxygen of the atmosphere by covering it with a layer of pulverized charcoal. Many man- ufacturers are in the habit of throwing a certain quantity of fat upon the heated metal before fusion. The fat on being suddenly strongly heated decomposes and evolves a con- siderable quantity of gas, which exerts a protecting influ- ence upon the surface of the metals. After the evolution of gas has ceased, there remains a very finely divided carbon which protects the metals from oxidation. PREPARATION OF ALLOYS IN GENERAL. I3I For the preparation of alloys from noble or costly metals it is recommended to effect the fusion in crucibles of graphite or of graphite mixed with clay, as the metal read- ily and completely separates from such crucibles. In regard to graphite crucibles we would draw attention to a circum- stance, which, though unimportant in itself, may become very disagreeable in preparing alloys from costly metals. It sometimes happens that a graphite crucible a short time after being placed in the furnace bursts with a loud report, and the metals contained in it fall into the fire, from which they have to be rescued with considerable trouble. This phenomenon in most cases is due to faulty work in the making of the crucible. If for instance the mass of the crucible contains a small bubble filled with air or moisture, these bodies will expand strongly on heating, and this ex- pansion may go so far as to cause the bursting of the cruc- ible. But, as this defect cannot be recognized from the ap- pearance of the crucible, it is recommended to test every crucible before using it for melting metals. This is done by putting them in a place where they gradually become strongly heated. Bad crucibles crack in most cases, and the others are sufficiently dried out so that they can be used for melting the metals without fear of cracking. In preparing alloys the metal most difficult to fuse should be first melted, and the more fusible ones only introduced after the complete fusion of the first. The varying densities of the metals to be combined frequently render the formation of a homogeneous mass very difficult. Moreover, in many alloys certain chemical combinations are readily formed, while the rest of the metals form alloys, the preparation of which was not intended. If two metals with greatly varying densities are alloyed and the mass is allowed to be quiescent, it will be observed that, after cooling and taking from the crucible, it shows clearly perceptible layers varying in color and appearance. By chemically examining these layers it will be found that 132 THE METALLIC ALLOYS. each of them contains different quantities of the metals used in alloying. To obtain in such case as homogeneous an alloy as possible, the metals, while in a state of fusion, must not be allowed to remain quiescent, but an intimate mix- ture be effected by vigorous stirring, sticks of dry soft wood being in many cases used for this purpose. By stir- ring the fused mass with one of these sticks, the wood is more or less carbonized according to the temperature of the mass. In consequence of the destructive distillation of the wood taking place thereby, there is evolved an abund- ance of gases which, by ascending in the fused mass, con- tribute to its intimate mixture, The stirring should be continued for some time and the alloy then cooled as rapidly as possible. The production of proportionate solutions of the metals one in another in melting can sometimes be promoted by certain manipulations. To these belong, for instance, the process of allowing the alloy to cool and then remelting it. In casting articles scraps and waste generally result, which in order to be utilized have to be remelted. So-called old metal consisting of articles which have become useless by having been broken or otherwise damaged are also fre- quently remelted. The above-mentioned effect of remelt- ing accounts for the fact that a moderate addition of such scraps, provided they consist of the same alloy, may be beneficial as regards the properties of the alloy to be melted. However, the metals chiefly used for alloying are quite readily oxidizable in the melting temperature, and many of them possess the property of dissolving their own oxides whereby their usefulness may be impaired. Now the more frequently the alloy is remelted, the more ample the opportunity for the absorption of oxides will be. From this it will be seen that the melting of old metal without the addition of fresh metal is only possible without produc- ing an injurious effect when no oxides are absorbed during melting. No rule can be laid down regarding the propor- PREPARATION OF ALLOYS IN GENERAL. 133 tion of old to new metal most suitable for the production of serviceable alloys, since the old metal has, as a rule, been more or less often remelted. When larger quantities of one metal are to be alloyed with smaller quantities of another, it is advisable to first melt together approximately equal quantities by weight of the two metals, and by a second melting combine the re- sulting alloy with the remainder of the metal. This method is frequently employed when there is considerable difference between the melting temperatures of the metals. If, for instance, a small amount of copper is to be alloyed with a large quantity of tin, an alloy, the melting tempera- ture of which will be considerably lower than that of cop- per, is first made by melting the copper together with about the same quantity by weight of tin, and then adding to this the remaining tin. The same method is adopted when three or more metals of different melting points are to be alloyed in varying proportions by weight. To make, for instance, an alloy from 3 parts lead (melting point 6 18. 8° F.), 1 part tin (melting point 446 F.), and 1 part antimony, (melting point 1166 F.), the most suitable pro- cess is to first alloy one-third, i. e. 1 part, of the lead with the entire quantity of antimony by dissolving the latter in the lead after it has been melted, then adding the rest of the lead and finally combining with this lead-antimony alloy the tin which is most readily liquified, and being also the most expensive of the three metals, its oxidation should as much as possible be prevented. The same object might also be accomplished by alloying one part of the lead, as previously described, with the antimony, another part of the lead, or under circumstances the entire remainder of it, with the tin, and then combining the lead-antimony alloy with the lead-tin alloy. When a larger amount of copper (melting point 1983. 2 F.) is to be alloyed with smaller quantities of nickel (melt- ing point 2732° F.) and zinc (melting point 779 F.), one 134 THE METALLIC ALLOYS. part of the copper may first be melted together with the nickel and another part with the zinc, finally combining the nickel-copper alloy with the zinc-copper alloy. The reason for this apparently more troublesome process may be found in the fact that, on the one hand, uniform combination is facilitated by the formation of intermediate alloys with melt- ing points less far apart than those of the constituent metals, and, furthermore, that readily oxidizable or volatile metals, for instance, zinc, are less subject to oxidization or volatilization when alloyed than when in a pure state. While formerly only a few alloys were known, a large number are at present used in the industries, and we find very rare metals sometimes employed for the preparation of alloys to impart special properties. One of the principal causes of this advance in the industry is the progress of mechanics. We need only to consider the bearings of shafts and axles in order to understand the varying demands made by the engineer as regards the properties of alloys. How different must be the nature of an alloy which serves for the construction of the bearing of an axle revolving with a light load perhaps once in a second, from that which has to bear a heavily-loaded shaft making many hundred revolutions per minute ! For many purposes alloys pos- sessing great ductility are required, for others the chief requisite is hardness, others again must have a high degree of elasticity, and still others as low a melting point as pos- sible. It will be readily understood that these different de- mands can only be satisfied by adding to the alloys suitable quantities of metals of varying properties. Though most heavy metals are at the present time used in the manufacture of alloys, copper, tin, zinc, lead, silver and gold are more frequently employed than others, the alloys of these metals being at the same time those which have been longest known and used. In modern times the alloys prepared with the assistance of nickel have also be- come of great importance, as well as those of which alumi- nium and vanadium form a constituent. PREPARATION OF ALLOYS IN GENERAL. 1 35 Everyone who pays close attention to the subject of alloys knows that the amount of information which has been gained upon this important branch of metallurgy is comparatively meagre, and that much is still to be expected from the progress of chemistry. The metallurgist, if left to himself, cannot be expected to arrive at certain results, because, probably, he may be wanting in chemical knowl- edge or in the methodical course of investigation which must be possessed by those who are qualified to success- fully prosecute such researches. These qualifications are so much the more indispensable when it is remembered that every new alloy, by the fact of its properties being dif- ferent' from those of its constituents, may be regarded as a new metal. Before proceeding with the description of the most important alloys, it may be convenient to say a few words about the best methods of making experiments in the preparation of new alloys. It is known that the elements always combine with one another in certain quantities by weight, which are termed atomic weights. (A table of the atomic weights of the principal metals is found upon page 22.) By mixing the metals according to equivalent quantities, alloys of deter- mined characteristic properties are, as a rule, obtained. If these properties do not answer the demands made of the alloy, the object is frequently attained by taking two, three, or. more equivalents of one metal. An exception to this rule is only made in certain cases, and especially where, according to experience, a very small quantity of a metal suffices considerably to change the properties of the alloy. It is then most suitable to prepare the mixtures serving for the experiment according to thousandths, and with every new experiment change the proportion between the separ- ate metals a certain number of thousandths. For combining metals with non-metallic elements, for in- stance with sulphur or with phosphorus, it is, however, not sufficient to choose the proportions according to thou- I36 THE METALLIC ALLOYS. sandths, it being necessary to add these bodies according" to ten thousandths. For these elements the form in which they are used is also of importance, which, however, will be referred to in speaking of them later on. It may here be remarked that the application of the term alloy to such metals which, so to say, are contaminated by phosphorus or sulphur, is entirely incorrect. It is used, however, for want of a better one, since it at least indicates that we are not dealing with a pure metal. CHAPTER VI. COPPER ALLOYS. Pure copper by reason of its great ductility and tenacity forms a very important and valuable material for various applications in the arts, but its employment for many pur- poses is connected with difficulties. It is, as previously mentioned, but seldom used in the foundry on account of its tendency to develop gases in casting whereby it swells up, and sound, strong castings can only be obtained with great difficulty, even if the work is done with the greatest care. However certain alloys of copper possess, in addition to the valuable properties of the latter, others which render them especially suitable for certain industrial purposes, and moreover, it is possible to impart to such alloys the most desirable properties, as they can be made soft or very hard ; brittle or elastic, malleable or non-malleable, etc. The production of copper alloys is attended with certain difficulties, since this metal has a very high melting point and the presence of very small qnantities of foreign bodies exerts a great influence upon its own properties as well as upon those of its alloys. Thus a content of —oVo to 10 3 oo of lead somewhat increases the ductility of copper to be rolled ; but the presence of one full thousandth of lead renders the metal unfit for the preparation of brass which is to be rolled into sheets or drawn out into wire. By adding to copper up to —oVo of lead, it acquires the property of being red-short or hot- short, and by increasing the content of lead to one per cent, it becomes entirely useless, it being both red-short and cold-short. A content of lead always exerts an injuri- ous influence upon the properties of copper, this influence (137) I38 THE METALLIC ALLOYS. being more strongly observed at a higher temperature than at an ordinary one. A content of iron exceeding yoVo has also an injurious effect upon the properties of copper, rendering it hard and brittle. Small quantities of nickel affect copper injuriously in making it less malleable, the evil being still further in- creased if besides this metal a small quantity of antimony be present. Antimony and arsenic by themselves mixed with copper considerably decrease its highly-valued prop- erty of ductility. Copper containing only -0V0 of antimony can no longer be worked for sheet brass. Bismuth acts in a manner similar to antimony. Zinc mixed with copper up to tooo makes it red-short. Certain alloys of copper and zinc can, however, be well worked, the most important of such alloys being brass. A content of tin and silver seems not to have an injurious effect upon the properties of cop- per, and these two metals, if added in certain proportions, yield alloys which are distinguished by special valuable properties. An admixture of cuprous oxide makes copper both red- short and cold-short, especially if present in larger quanti- ties, and further imparts to it the disagreeable property of considerably contracting in casting. Moreover, the cast- ings from such copper show an unequal density, so that plates of it cannot be used for copper-plate printing. It may here be remarked that most brands of copper found in commerce contain certain quantities of cuprous oxide, it being claimed that an admixture of one-half to two per cent, of it is even beneficial, as it counteracts the injurious influence of foreign metals upon the copper. Beside the above-mentioned metals, many brands of cop- per found in commerce frequently contain bodies belonging to the non-metals, such as sulphur, silicon, and phos- phorus. The influence of these bodies is, as a rule, very injurious. A content of sulphur makes the copper red-short and COPPER ALLOYS. 139 castings of it blown. By a content of silicon the copper loses its pure red color and acquires one shading into white, its ductility being at the same time considerably affected. Copper containing nearly two per cent, of silicon can only be rolled in the cold, as it cracks in the heat. With a still greater content of silicon the copper becomes a yellowish-white metal of extraordinary brittleness, so that it can no longer be worked to advantage. A content of phosphorus exerts a considerable influence upon the properties of copper, generally increasing its hardness and at the. same time making it more fusible. With an admixture of Woo of phosphorus the copper can only -be rolled in the cold, while with a still greater content it becomes brittle in the cold. Some alloys of copper with phosphorus, known as phosphor-bronze, are, however, used for certain industrial purposes on account of their special properties, they being distinguished by particular strength, ductility, and beautiful color. These combina- tions will be referred to later on. According to the more recent researches by Hampe, copper shows the following behavior towards admixtures : — With a content of between T oVo and T ffo of cuprous •oxide, the properties of the copper are not sensibly affected, it becoming red-short only in the presence of drW; and a content of this compound always acts in such a manner as to increase the brittleness of the metal more in the cold than in the heat. One-thousandth of arsenic exerts no in- fluence upon the copper, but tIthf of it render it cold-short and hard. It only becomes red-short with tttto of arsenic, but is not cold-short, which is contrary to the opinions formerly held in regard to the influence of arsenic upon copper. Antimony acts similarly to arsenic, except that a smaller quantity of it will make the copper red-short. A content of one and a half thousandths of lead exerts no influence upon the properties of copper ; a slight brittle- ness in the heat shows itself, however, with a content of nnnr I40 THE METALLIC ALLOYS. which becomes greater with one of ttrrt, and is clearly per- ceptible in the cold. According to these more recent researches a content of bismuth exerts an especially injurious influence upon the properties of copper, an indefinitely small quantity sufficing to decrease the ductility in the heat, while with a content of nnnr tne copper becomes exceedingly red-short and sensibly cold-short. A considerable portion of the copper occurring in com- merce is extracted from minerals containing a number of other metals, this holding especially good in regard to those brands obtained from gray copper ore or fahl ore.* Ex- perts can tell from the external properties of the metal, es- pecially by the color, fracture, and ductility, whether it is suitable for certain purposes or not. But it is, of course, impossible to recognize in this manner the quantities of foreign bodies. In buying a large lot of copper for alloys it is therefore recommended to subject it to an accurate chemical analysis, in order to be sure that it is free from lead and bismuth, which are especially injurious. As previously mentioned, the number of copper alloys is very large, the most important being those with tin, zinc, nickel, gold, silver, platinum, and mercury, and further, with aluminium ; the alloys of copper with lead, antimony, and iron are less frequently used. After giving a brief introductory sketch of the alloys of copper with the precious metals, which have been used from very remote times, we shall first speak of the alloys of copper with the base metals, they being of special interest for industrial purposes, and, besides, presenting more tech- nical difficulties in their preparation. Copper-gold alloys. — Gold, as previously mentioned hav- ing but a slight degree of hardness, must be alloyed with other metals in order to prevent its wearing too rapidly, * It contains copper, antimony, arsenic, and sulphur. COPPER ALLOYS. 141 copper and silver, either by themselves or together, being generally used for the purpose. Beside the fact that the gold alloys show a greater degree of hardness than the pure metal, the color of the latter is also changed by alloy- ing with silver or copper, there being gold with a color shading into white (alloyed with silver) and other varieties shading into red (alloyed with copper). There is also a green gold, which is an alloy of gold, silver, and copper. According to the purpose for which gold alloys are to be used, they are prepared either with copper or silver alone, or with the assistance of both metals. The gold coins of Europe consist always of an alloy of gold with copper, a content of silver, which must, however, be very small, being due to the use of argentiferous gold. The preparation of alloys of gold and of silver has become very extensive on account of their being used for coinage and articles of jewelry, and will be referred to later on. Copper-silver alloys, — The alloys of copper with silver are extensively used for coinage and silverware. As may be seen from the properties of both metals, these alloys possess a considerable degree of ductility, and if the pro- portions in which the metals are mixed are so chosen that the copper slightly predominates, their properties are almost exactly a mean between those of the two metals. They will be fully discussed later on, and we only mention here that most alloys of silver and copper contain more of the former than of the latter metal. The alloys of the other noble metals, especially those of the platinum group, find but a limited application in the in- dustries ; they will be referred to latter on. Alloys of copper with the base metals. — Although the number of alloys of copper with the base metals is very large, those known under the general terms of brass and bronze are so extensively used in the various industries as to make most of the others appear unimportant in compar- ison. Bronze has been known from very remote times, and 142 THE METALLIC ALLOYS. was used by the ancients in casting statues and other orna- ments. The bronze used by the prehistoric nations con- tained no lead, and came nearest to what is at the present time designated by the term bronze, i. e., an alloy of cop- per and tin. The bronze used by the Romans and post- Romans was rarely an alloy of pure copper and tin, but contained usually more or less lead. Brass, the other important alloy of copper mentioned above, was manufactured by cementing sheets of copper with calamine or carbonate of zinc long before zinc in a metallic form was known. COPPER-ZINC ALLOYS. The compounds under this heading comprise brass, tombac, and allied alloys which contain copper and zinc as chief constituents. The first account of the alloy of copper and zinc transmitted to the present times was written by Aristotle, who states that a people who inhabited a country adjoining the Euxine Sea prepared their copper of a beau- tiful white color by mixing and cementing it with an earth found there, and not with tin, as was apparently the custom. Strabo also alludes to the preparation of the alloy of copper and zinc by the Phrygians from the. calcination of certain earths found in the neighborhood of Andera, and other au- thors, in the time of Augustus, speak distinctly of cadmia and its property of converting copper into au? r ichalcum, under which title the zinc alloy was subsequently known. Several writers of the Christian era who have referred to this compound are not more explicit than their predeces- sors ; still it is evident, from various recent analyses of old alloys, that zinc was contained in many of those prepared about the commencement of the present era. The influence of zinc upon copper has several times been previously referred to. It renders copper fit for casting, and the copper-zinc alloys do not show the strong tendency towards liquation peculiar to copper-tin alloys. According COPPER ALLOYS. I 43 to Charpy,* copper-zinc alloys with a content of up to 33 per cent, consist of an aggregation of dendritic (fir-tree- like) crystallites which form solidified solutions of the cop- per and zinc (mixed crystals of the two constituents) with- out liquation or disintegration, as is the case with eutectic alloys, having previously taken place. In alloys with 33 to 45 per cent, zinc, crystallites are noticed which are sur- rounded by a mass, probably of the combination CuZn 2 , consisting of fine crystals. In alloys richer in zinc two different constituents can also be recognized. The strength and hardness of copper are, to be sure, in- creased to a less extent by zinc than by tin, but its flexi- bility is far less decreased by it, so that, while copper-tin alloys with a content of about 6 per cent, tin can no longer be worked at the ordinary temperature, copper-zinc alloys with even 50 per cent, zinc can with care be worked at the ordinary temperature, provided they do not contain other bodies which impair their flexibility. If, however, the con- tent of zinc exceeds 50 per cent, the alloy becomes rapidly brittle. On the other hand, many copper-zinc alloys cannot be worked so well at a red heat as some copper-tin alloys ; only a few with a fixed content of zinc stand working in a heated state, and are malleable. Hence copper-zinc alloys are, as a rule, worked cold by hammering, pressing, rolling, drawing, etc., and this property of standing such manipulations without previous heating, is without doubt an advantage. However, like most metals worked cold, they become by these manipulations hard and brittle, and occasional annealing is, as a rule, required to restore to them their lost flexibility. BRASS, ITS PROPERTIES, MANUFACTURE, AND USES. The manufacture of brass was introduced, in 1550, in *G. Charpy. "Etudes microscopiques des alliages metalliques." Bul- letin de la Societe d' Encouragement. 1907. 144 THE METALLIC ALLOYS. Germany by Erasmus Ebener, an artist of Niirnberg, who prepared it by fusing copper with so-called tutia fornacem or furnace cadmia. In England the first brass by the direct admixture of copper and spelter, with or without the inclu- sion of calamine, was made in 1781, by James Emerson, who took out a patent for the process. Brass, generally speaking, should contain only copper and zinc, but most varieties found in commerce contain small quantities of iron, tin, arsenic, and lead. In many cases these admixtures are due to contaminations mixed with the ores from which the copper or zinc is extracted, while in others they have been intentionally added in order to change the ductility, fusibility, etc., of the alloy. Copper and zinc can be mixed together within very wide limits, the resulting alloys being always serviceable. Generally speaking, it may be said that with an increase in the con- tent of copper the color inclines more towards a golden, the malleability and softness of the alloy being increased at the same time. With an increase in the content of zinc the color becomes lighter and lighter, and finally shades into a grayish-white, while the alloys become more fusible, brittle, and at the same time harder. Just as different as the properties of the respective alloys is also the cost of pro- duction, the price of brass increasing with the greater con- tent of copper. Very extensive researches have been made in regard to the behavior of alloys of copper and zinc, which may be briefly expressed as follows: — An alloy con- taining from 1 to 7 per cent, of zinc still shows the color of copper, or at the utmost only a slight yellow tinge. With 7.4 to 13.8 per cent of zinc, the color of the alloy undergoes a considerable change, it being a pleasant red- yellow. With from 13.8 to 16.6 per cent, the color may be designated a pure yellow, while that of alloys containing up to 30 per cent, of zinc is also yellow, but not pure. It is a singular fact that with a content of over 30 per cent, of zinc a red color appears again, which is most pronounced COPPER ALLOYS. 145 with equal parts by weight of the metals, an alloy of 50 parts of copper and 50 of zinc having almost a golden color, but exhibiting also a high degree of brittleness. With a still higher content of zinc the gold color rapidly decreases, becoming reddish-white with 53 per cent., yel- lowish-white with 56 per cent., and bluish-white with 64 per cent.; with a still higher content of zinc the alloy ac- quires a lead color. The physical properties of alloys of copper and zinc differ very much according to the quantities of copper and zinc contained in them. Alloys containing up to 35 per cent, of zinc can be converted into wire or sheet, in the cold only, those with from 15 to 20 per cent, being the most ductile. Alloys with from 36 to 40 per cent, of zinc can be worked in the cold as well as in the heat. With a still higher con- tent the ductility decreases rapidly, and an alloy with, for instance, from 60 to 70 per cent, of zinc is so brittle that it cannot be worked. If, however, the content of zinc is increased up to a maximum (70 to 90 per cent.), the duc- tility increases again and the alloy can be worked quite well in the heat ; but not at red heat. Brass shows always a crystalline structure, which is the more pronounced the more brittle the alloy is, and hence that prepared from equal parts of copper and zinc shows the most distinct crystalline structure. In connection with this some researches in regard to metals becoming crystalline, made by S. Kalischer, may be of interest. By heating rolled zinc to from 302 to 338 F., it suffers a series of permanent changes without its ex- ternal appearance being directly altered. It loses its clear sound and becomes almost without sound, like lead. It can be more readily bent, but breaks more easily, and in bending emits a noise similar to the " cry of tin." All these alterations are due to a change in the molecular structure of the zinc, it becoming crystalline. This crys- 10 I46 THE METALLIC ALLOYS. tallization can be readily rendered perceptible by dipping a heated strip of zinc into a solution of sulphate of copper, the copper, which is immediately precipitated, showing clearly perceptible crystallization. The fracture of the rolled and heated zinc is also crystalline. To avoid this change it is recommended not to exceed a temperature of 266 F. in manufacturing sheet-zinc. Sheets of cadmium and of tin become crystalline at about 392 ° F. Sheet-iron and sheet-copper are also crystalline, but sheet-steel is not. Kalischer examined four varieties of sheet-brass constituted as follows: Parts. Copper Zinc . . I. II. III. IV. 66 62.5 60 56.8 34 37-5 40 43-2 Samples Nos. I. and II. were undoubtedly crystalline, and sample No. IIT. showed traces of crystallization, while No. IV. did not become crystalline even by heating. Sheets of tombac composed of — Parts. I. II. III. Copper 73.74 80.38 90.09 Zinc 25.96 1929 9.91 Tin 0.30 0.33 — were all crystalline. No crystallization could be observed in bronze-sheets composed of — Parts. I. II. Copper 90 88.23 Zinc 5 8.82 Tin 5 2.95 Rolled lead is crystalline, but rolled fine silver and gold are not. By reason of these observations and experiments. COPPER ALLOYS. I47 Kalischer is of the opinion that the crystalline state is natural to most metals, but they can be deprived of it by mechanical influences, and many can be reconverted into it under the influence of heat. If a very ductile brass is to be prepared, great care must be had to use metals of the utmost purity, since exceed- ingly small admixtures of foreign metals suffice to injure considerably the ductility, rendering the fabrication of very thin sheets or fine wire impossible. The strength of brass, as shown by many experiments, is also intimately connected with its composition, that con- taining about 28.5 per cent, of zinc showing the greatest absolute strength. The strength depends, however, to a considerable extent, also on the mechanical treatment the metal has received. A piece of brass of o.ooi square inch breaks with the following loads : — Cast brass breaks with 2777.5 pounds. Ordinary wire 7293 ' ' Hard-drawn thin wire 9080.5 Annealed thin wire 7100 to 8628 " The molecular structure of brass can be much changed by treatment, it becoming more brittle by continuous mani- pulation, so that in drawing wire it must be frequently an- nealed to prevent it from becoming brittle. If brass is strongly heated and rapidly cooled, its hardness decreases, its behavior in this respect being opposite to that of steel. Brass which, for instance, as a constituent of machines, is subjected to repeated shocks, becomes brittle and fragile. A very important factor in brass is its melting point, there being wide deviations in this respect, which are readily explained by the great difference in the melting points of the two constituent metals. Generally speaking, the fusing point of brass lies at about 1832 F. If brass in a fused state is kept for some time in contact with air, its composition undergoes an essential change by the com- I48 THE METALLIC ALLOYS. bustion of the greater portion of the zinc contained in it, which explains the change of color frequently observed in brass fused for some time in contact with air. Old copper derived from worn-out copper articles is fre- quently used in the manufacture of brass. Such copper contains, however, generally foreign metals in the shape of solder, etc., which may exert either a favorable or an in- jurious influence upon the properties of the brass. Lead, tin, and iron are the most frequently occuring contamina- tions. If the brass is to be used for castings, their injur- ious influence is not so great as in the manufacture of thin sheet or wire. To brass intended for castings up to two per cent, of lead is frequently added, such addition making the alloy somewhat harder, and depriving it at the same time of the disagreeable property of fouling the tools in working, which is of special importance in filing and turn- ing. In casting brass containing lead care must, however, be had to cool the castings very rapidly, as otherwise the lead readily separates in the lower portion of the casting and produces unsightly spots. By a slight addition of tin the brass becomes more fusible, somewhat denser, and takes a better polish ; it is also rendered somewhat less brittle. The presence of a small quantity of iron increases the hardness of brass con- siderably, such brass on exposure to the air being, how- ever, easily stained by rust. In the arts brass is commonly employed in the construc- tion of scientific apparatus, mathematical instruments, small parts of machinery, and for many other purposes. A dis- tinction is generally made between sheet brass used in the manufacture of wire and sheets, and cast-brass, which re- quires no further rnechanical manipulation than turning and riling. A number of alloys occur in commerce under var- ious names, but, as regards their composition, they must be included in the generic term, brass, though some of them are especially adapted for certain purposes. COPPER ALLOYS. 149 The table given below shows the manner in which the properties of the finished alloy are affected by its composi- tion. In the column " cohesion " is given the weight in tons required for breaking a bar of one square centimeter. The minimum of hardness and fusibility is denoted by 1. Composition of the alloys according to Equiva- Per lent's cent. Cu:Zn. Cu. 1:0 100 10:1 90.72 9:1 89.80 8:1 88.60 7:1 87.30 6:1 85.40 S:i 83.02 4:1 79.6s 3:1 74.58 2:1 66.18 1:1 49-47 1:2 32.85 8:17 31-52 8:18 30.36 8:19 29.17 8:20 28.12 8:21 27. TO 8:22 26.24 8:2^ 25-39 1:3 24-50 1:4 19.65 1:5 16.36 0:1 0. Properties of the alloys. ui 8667 8-505 8.607 8.633 8.^87 8.591 8.415 8.448 8.397 8.299 8.J30 8.263 7-721 7-836 7-019 7.603 7.058 7.882 7-443 7-449 7-371 6.605 6.895 Color. Fracture. red reddish-yellow yellowish-red pale yellow vivid yellow dark yellow silver-white pale gray ash gray pale gray ash gray dark gray pale gray coarse-grained fine-fibrous coarse-grained conchoidal vitreous conchoidal finegrained U 24.61 12. 1 11. sl 12.8I 13-2 14.1 13.7 14.7 I3-I 12.5! 9.2' 19.3! 2.11 2.2 0.7 3-2 0.9 0.8 S-9 3-1 1-9 1.8 IS-2 Ductility at 59° F. very brittle brittle very brittle slightly ductile very brittle brittle ffi|tt- 22|I5 21 14 20iI3 I9|I2 l8lll 17(10 16! 9 I5 ! 8 14' 7 13 6 T2] 6 io, 6 5: 5 6i S 7 5 3 5 9 S 8 5 1 5 4 3 Sheet brass (for the manufacture of sheet and wire). Especially pure metals, as free as possible from foreign bodies injurious to ductility (bismuth, antimony, arsenic, tin, lead, iron) have to be used for this purpose. Sheet to be stretched very thin under the hammer, for instance, the best quality of German sheet-brass for musical instruments contains, as a rule, 19 to 21 per cent, zinc, sheet still suita- ble for most purposes, 22 to 30 per cent., and sheet for toys and articles easily shaped 30 to 40 per cent. Brass for wire requires similar composition. For the purpose of investigating the influence of anti- mony upon the cold-shortness of brass, E. S. Sperry pre- pared brass plates of the best quality of Lake copper and 150 THE METALLIC ALLOYS. refined zinc with varying quantities of antimony and tested their behavior in rolling and by the condition of their frac- tures. The hardest alloy of 60 per cent, copper and 40 per cent, zinc was selected so that the influence of the addition of antimony should be more apparent. The additions of antimony amounted to 0.01, 0.02, 0.05, 0.1, and 0.65 per cent. While Kerl states that 0.001 per cent, of antimony in copper renders the brass unfit for wire and sheet, Sperry found that brass with 0.006 per cent. — hence from copper with 0.01 per cent. — antimony could be satisfactorily rolled; with softer alloys the influence of the same quantity of anti- mony is said to be still less injurious. A content of 0.02 per cent, antimony could be readily recognized by the con- dition of the fracture. Since some brands of electrolytic copper contain from 0.001 to 0.08 per cent, of antimony and are generally used for brass without being previously tested, the objections of some manufacturers to such copper are readily explained. Filings and turnings always contain small quantities of iron particles and hence are not suitable as an addition to the better qualities of brass. Silesian zinc, as a rule, con- tains not less than 0.75 per cent. lead. Missouri zinc is very pure, and also Spanish zinc, brand R. C. A. Refinado, the latter being free from arsenic, antimony and sulphur, and contains only 0.05 per cent, lead and a trace of iron ; it is used for the best quality of sheet-brass (cartridge shells). The more sheet-brass is to resist the action of acid and alkaline fluids, the richer in copper it should be, and ac- cordingly, the following proportions of copper to zinc may be recommended : 70 : 30, 66 : 34, and 60 : 40. Brass for cartridge shells contains 72 parts copper and 28 parts zinc, with at the utmost 0.25 per cent, lead, or still better en- tirely free from lead. The best evidence of the quality of a brand of copper is that it yields brass suitable for the preparation of thin sheet and wire, and the sharpest test for the quality of the cop- COPPER ALLOYS. 151 per consists in that when the brass is drawn out to tubes over a corebar, the tubes show no cracks. The following analyses show the composition of different varieties of brass for sheet and wire. Brass. Sheet Place of derivation. Wire Jemappes Stolberg Romany Rosthorn (Vienna) Iserlohn and Romilly Ludenscheid (brittle) Hegermtihl pker England [Augsburg Neustadt-Eberswalde (Good quality) (Brittle) (Good composition for sheet and wire) China, best quality brass China, ordinary qual- ity brass Copper. Zinc- 64.6 33-7 64.8 32.8 70.1 29.26 68.1 31-9 7i-5 28.5 71.36 28.15 71.10 27.6 70-1 29.9 72.73 27.27 63.66 33.02 70.16 27.45 69.98 29.54 70.29 29.26 71.89 27.63 70.16 27.45 71.36 28. 1 5 7i. 5 28.5 71.0 27.6 65.4 14-6 65.5 32.4 67 32 10 5 10 2.7 Lead. 1.4 2.0 0.28 trace 2.52 079 0.97 0.28 0.8s 0.20 Tin. 0.2 0.4 0.17 Silicon. Antimony. Iron. i Japanese brass (Schin-chiu) contains as a rule 30 parts zinc to 70 parts copper, though there are also alloys with 35 parts zinc. Alloys with 34 to 37 and 40 per cent, zinc are frequently used for the manufacture of sheet and wire, sheet with 37 per cent, zinc being distinguished by extraordinary tough- ness and ductility in a cold state. Cast-brass being used for the most diverse purposes, it is difficult to give a composition of general value, since the demands made on this metal vary much according to the article to be manufactured, it being used for very ordinary wares, such as locks, keys, shields, escutcheons, buttons, hinges, etc., as well as for the finest mechanical instruments and objects of art. As a rule cast-brass contains more zinc than that which is to be worked into sheet and wire. It is therefore more 152 THE METALLIC ALLOYS. fusible, but at the same time harder and more brittle than wire-brass. The materials not being chosen with such great care as for wire, a chemical analysis reveals frequently the presence of a considerable number of foreign metals. The turnings, chips, and other brass waste are generally utilized by melting them together by themselves, or as ad- dition in fusing cast-brass. As, besides brass, such waste frequently contains iron and bronze, the contamination of the cast-brass with iron, tin, and lead is readily accounted for ; sometimes a small quantity of arsenic is also found. Cast-brass is also much used in the manufacture of the so- called hard solder for soldering articles exposed to a high temperature. In the following table we give an analysis of different kinds of cast-brass, which shows the great varia- tions in its composition. Variety. Copper. Per cent. Cast brass from Oker 71. Cast brass from Oker 64.24 Black Forest clock wheels. 60.66 Black Forest clock wheels. 66.06 Cast brass from Iserlohn.. 63.7 Cast brass from Iserlohn.. 64.5 French yellow brass {Potin\ jaune) j 71.9 English sterling metal . . . . 66.2 English sterling metal. . . . 66.66 Zinc. Iron. Lead. Tin. Per cent. Per cent. Per cent. Per cent. 24.42 2.32 I.09 — i 37-27 0.12 0.59 — 36.88 O.74 — i-35 ; 31.46 1-43 0.88 1 33-5 — 0.3 2.5 32.4 — 2.9 0.2 24.9 — 2.0 1.2 33-11 0.66 2.0 — 26.66 0.66 — — Ordinary cast-brass {potin jaune, potin gris, sterling metal). — The mixture of metals known under these names is the poorest quality of brass, and its composition varies so much as to make it impossible to state it within narrow limits. This quality of brass is generally prepared by fus- ing together old brass-waste of all kinds and subjecting it to a casting test. If the fracture is not too coarse-grained and the metal not too brittle, it is used without further ad- dition for articles known under the collective term of brazier's ware (spigots, candlesticks, mortars, etc.). Brass COPPER ALLOYS. 153 of this quality is readily worked with the file, but difficult to turn. By adding to ordinary cast-brass a certain quantity of lead and tin, a metal of a somewhat whiter color is ob- tained, which is called potin gris by the French, and is more easily worked with the lathe and file. The so-called " ster- ling metal'" is somewhat harder in consequence of a con- tent of iron, and can therefore be much better worked than ordinary brass. By adding to sterling metal some tin, it acquires still greater hardness and takes a good polish. Fine cast-brass. — Brass to be suitable for the manufacture of fine articles must, besides being readily worked with file and chisel, possess other properties of great importance in the manufacture of such articles. It should allow of being readily cast and fill the moulds exactly. Further, articles of luxury manufactured from brass are frequently to be gilded, and experience has shown that brass of a beautiful color approaching that of gold requires less gold for the purpose than brass of an Unsightly pale-yellow color. In order to be enabled to save gold, it is therefore of import- ance to manufacture the alloy so as to show a color shad- ing into reddish. Generally speaking, such alloys contain from 20 to 50 parts of zinc to ioo parts of copper ; lead or tin, or both, in the proportion of 0.25 to 3 per cent, of each metal being added, according to the purpose for which the alloy is to be used. In the following we give the com- positions of several alloys which have stood a practical test in this respect. Tough brass for tubes. — In chemical factories tubes and other utensils of brass are frequently used, which must be cap- able of resisting chemical influences as well as pressure. In preparing alloys for this purpose very pure materials should be employed. The following compositions may be recom- mended : I. II. III. IV. Copper 80 70 66 60 Zinc 20 30 34 40 154 THE METALLIC ALLOYS. Alloy No. I. is used chiefly in England ; the other three are employed in German factories. Hamilton 's metal, mosaic gold, chrysorin. — The alloys known under the above names have a very beautiful color, closely resembling that of gold, and are distinguished by a very fine grain, which makes them especially suitable for the manufacture of castings to be subsequently gilded. The alloys are, as a rule, composed of copper, too parts ; zinc, 50 to 55. In order to obtain a thoroughly homogeneous mixture of the two metals it is recommended first to bring into the the crucible one-half of the zinc to be used ; place upon this the copper, and fuse the mixture under a cover of borax at as low a temperature as possible. When the contents of the crucible are liquid, heat the other half of the zinc, pre- viously cut in small pieces, until almost melted, and throw it into the crucible in portions ; stir constantly, to effect as intimate a mixture of the metals as possible. French cast-brass for fine castings. — As is well known, the bronze industry has reached a high degree of perfection in France, where clock-cases, statuettes, and other articles of luxury are manufactured on a large scale. The so-called bronze used for these articles is, however, in most cases not actual bronze, but fine cast-brass. In the following table we give the compositions of a few mixtures of metals generally used by the French manufacturers. They can be readily cast, worked with file or chisel, and easily gilded. Parts. I. 63.70 33-55 2.50 0.25 II. 64-45 32.44 0.25 2.86 III. 70.90 24.05 2.00 3-05 IV. Copper Zinc Tin Lead 72-43 22.75 1.87 2.95 COPPER ALLOYS. 155 Bristol brass {Prince s metal). — The alloy known by this name possesses properties similar to those of the above- mentioned French varieties of brass, and can be prepared according to the following proportions : I. II. III. Copper.'. 75-7 67.2 60.8 Zinc 24.3 32.8 39.2 Regarding the preparation of this and similar alloys, the same holds good as has been said under Hamilton's metal. Ronia metal consists of brass, with a small quantity of cobalt, manganese, and phosphorus. D'Arcet's gilding metals have the following composition : I. II. III. IV. Copper 63.70 64.45 70.90 72.43 Zinc 33.55 32.44 24.05 22.75 Tin 2.50 0.25 2.00 1.87 Lead 0.25 2.86 3.05 2.95 Specific gravity 8.395 8.542 8.492 8.275 Malleable brass. — For castings which are to be shaped by forging or rolling, copper alloys rich in zinc (Muntz metal) and copper-zinc-iron alloys (Aich metal, sterro-metal, delta metal) are especially suitable, as they possess great strength, and the valuable property of being ductile in the cold as well as at a red heat. A content of i to 3 per cent. of iron is claimed to increase the malleability at a red heat. It is not yet decided whether the small content of iron pro- duces these properties, or whether they are due to the ab- sorption of the oxygen of the copper by the iron. By a larger addition of iron the ductility of the alloys is im- paired. The observation that brass, which as ordinarily composed is brittle at a red heat, becomes ductile at that temperature when it contains not less than 35 per cent., and not more than, 45 per cent, of zinc, appears to have first been made by J. Keir of Westbromwich, near Birming- ham, who, in 1779, took out a patent for a metallic mixture I56 THE METALLIC ALLOYS. of copper 54, zinc 40.5, and iron 5, which could be forged cold as well as at a red heat. This alloy was to be used for ship-sheathing, in the manufacture of nails and rivets com- ing in contact with sea-water, etc. The matter fell into ob- livion, and in 1832 another Englishman, Muntz, took out a patent for an alloy of copper, 60 parts, and zinc, 40 parts, or copper 56, zinc 43 %, and lead 3^, intended for the same purposes. This alloy became known as Muntz metal or malleable brass. It is still employed, chiefly for ship- sheathing, bolts and rivets, instead of copper, because it is claimed that the sea-water attacks the zinc gradually and uniformly over the entire surface, and that it prevents the deposit of barnacles, etc. According to the most recent investigations, this brass, however, is corroded not uni- formly, but in holes. To the malleable varieties of brass belong : Malleable brass, Muntz metal, yellow metal, etc. — These alloys possess the valuable property of being ductile in the heat, and castings prepared from them can be worked warm like iron. Yellozv metal. — This metal possesses the property of being less attacked by sea-water than pure copper, and it was formerly much used for ship-sheathing and in the man- ufacture of nails and rivets coming in contact with sea- water. Since the introduction of iron as material for larger vessels it has, however, lost some of its former importance. Yellow metal or Muntz metal (so-called after its inventor) consists generally of copper 60 to 62 parts, zinc 40 to 38. The metal is prepared with the observance of certain precautionary measures in order to obtain it with as uni- form a grain as possible, experience having shown that only fine-grained alloys of uniform density can resist sea- water. To obtain as uniform a grain as possible, small samples taken from the fused mass are quickly cooled and examined as to fracture. If the latter does not show the desired uniform grain, some zinc is added to the fused COPPER ALLOYS. 157 mass. When this zinc has been intimately mixed with the mass a fresh sample is taken and tested, this being con- tinued until the desired object is attained. It need scarcely be mentioned that considerable experience is required to tell the correct composition of the alloy from the fracture. The mass is finally poured into moulds and rolled cold. Macht's yellow metal. — This alloy, consisting of copper 33 parts and zinc 25, has a dark golden-yellow color, great strength, and can be forged at a red heat, properties which make it especially suitable for fine castings. Bobierre's metal, consisting of copper 66 parts and zinc 34, is claimed to be especially suitable for ship-sheathing. From experiments made it has been learned that all alloys containing up to 58.33 per cent, of copper and up to 41.67 per cent, of zinc are malleable. There is, how- ever, a second group of such alloys with 61.54 per cent, of copper and 38.46 per cent, of zinc, which are also malle- able in the heat. The preparation of these alloys requires, however, considerable experience. It is best effected by melting the metals together in the ordinary manner, and heating the fused mass as strongly as possible; it must, however, be covered with a layer of charcoal-dust to pre- vent oxidation of the zinc. By the mass becoming thinly- fluid an intimate mixture of the constituent parts is effected. Small pieces of the same alloy previously prepared are then thrown into the liquid mass until it no longer shows a re- flecting surface, when it is cast into ingots in iron moulds. The ingots while still red-hot are thrown into water, ac- quiring by this treatment the highest degree of ductility. The alloy properly prepared must show a fibrous fracture and have a reddish-yellow color. Az'ck's metal. — This alloy named after its inventor, con- sists of a brass to which a considerable degree of tenacity has been imparted by an addition of iron. It is especially adapted for purposes where the use of a hard and, at the same time, strong metal is required. I58 THE METALLIC ALLOYS. According to analyses of various kinds of this metal, it shows, like other alloys, considerable variations in the quantity of the metals used in its preparation. Even the content of iron, to which the hardening effect is ascribed, may vary within wide limits without the strength, which is the principal property of this alloy, being modified to a considerable extent. The best alloy, which can be called an Aich's metal, is composed of copper 60 parts, zinc 38.2, iron 1.8. The con- tent of iron must be limited to from 0.4 to 3.0 per cent. Another Aich's metal showing excellent properties is com- posed of copper 60.2 parts, zinc 38.2, iron 1.6. The hardness of Aich's metal is claimed to be not in- ferior to that of certain kinds of steel. It has a beautiful golden-yellow color, and is said to oxidize with difficulty, which makes it of great value for articles exposed to the action of air and water. Sterro-metal. — The properties of this alloy approach closely those of Aich's metal. It consists of an alloy of copper, zinc, and iron, but contains a larger quantity of the latter. The composition of the alloy may vary consid- erably, a little tin being sometimes added. We give in the following an analysis of two varieties of sterro-metal of ex- cellent quality : Sterro-metal from Rosthorn s factory in Lower Austria* — Copper 55.33 parts, zinc 41.80, iron 4.66. English sterro-metal ( Gedge's alloy for ship-sheathing) . — Copper 60 parts, zinc 38.125, iron 1.5. The principal value of this alloy is its great strength, in which it is not surpassed by the best steel. While a wrought-iron pipe broke with a pressure of 267 atmos- pheres, a similar pipe of sterro-metal stood the enormous pressure of 763 atmospheres without cracking. Beside its strength it also possesses a high degree of elasticity, and on account of these properties is especially adapted for cylinders of hydraulic presses. As is well known, these COPPER ALLOYS. !59 cylinders begin to sweat at a certain pressure, i. e., the pressure in the interior is so great that the water permeates through the pores of the steel. With a cylinder of sterro- metal the pressure can be considerably increased without the exterior of the cylinder showing any moisture. According to the purpose for which it is to be used, the sterro-metal can be made especially hard and dense, but this change in its properties is less effected by altering the chemical composition than by mechanical manipulation. If cast sterro-metal be rolled or hammered in the heat, it acquires, besides strength, an exceedingly high degree of toughness. In hammering the metal special care must be had not to overheat it, as otherwise it easily becomes brittle, and cracks under the hammer. A sterro-metal containing copper 55.04, zinc 42.36, tin 0.83, and iron 1.77 was tested by Baron de Rosthorn, of Vienna, and gave the following results : * Tenacity. Material. Lbs. per square inch. Kilogrammes per sq. centimetre. Sterro-metal cast 60,480 76,160 83,120 40,320 4252 5354 5984 2834 Sterro-metal forged Sterro-metal cold drawn Gun-bronze cast The specific gravity of this metal was 8.37 to 8.40 when forged or wire-drawn ; it has great elasticity, stretching 0.0017 without set, and costs 30 to 40 per cent, less than gun-bronze. It has been forged into guns, cold from the casting. Delta metal. — This alloy was introduced in 1883, by Mr- Alexander Dick, and on account of its strength and power of resisting the action of chemical influences is much used *Holley. " Ordnance and Armor." l60 THE METALLIC ALLOYS. in the construction of machinery as a substitute for the more expensive bronze. The name "delta" was given to it by Mr. Dick, simply for the purpose of connecting it with his own name, delta being the Greek for the letter D, the initial of his surname. Delta metal is a somewhat ferriferous brass with a fixed content of zinc — 40 to 43 per cent. It is malleable at a red heat and distinguished by its strength. To prevent oxidation in remelting and to keep the composition invar- iable a small percentage of phosphor-copper or, still better, manganese-copper is added, That a content of iron is capable of increasing the strength of brass has been re- ferred to in speaking of similar alloys, but in using such alloys containing iron many failures result because the iron alloys only with difficulty, and not always uniformly, with the other two metals. In making delta metal this drawback is overcome by first preparing an iron-zinc alloy with 8.5 per cent, iron, by dissolving the iron in melted zinc heated to a red heat, and combining this alloy with the rest of the metals. Besides iron, some manufacturers add small quan- tities of tin and lead ; in some samples the presence of nickel has also been established. Examinations of articles of delta metal showed the following composition : Per cent. Per cent. Per cent. Per cent. Per cent. Copper 55-94 55-8o 55.82 54.22 58.65 Zinc 41.61 40.07 41.41 42.25 38.95 Lead 0.72 1.82 0.76 1.10 0.67 Iron 0.87 1.28 0.86 0.99 1.62 Manganese 0.81 0.96 1.38 1.09 — Nickel trace trace 0.06 0.16 0.11 Phosphorus...... 0.113 o.on trace 0.02 — No. I. is cast delta metal, No. II. wrought, No. III. rolled, and No. IV. hot stamped. The advantages claimed for delta metal are great strength and toughness. It produces sound castings of close grain. It can be rolled and forged hot, and can stand a certain COPPER ALLOYS. l6l amount of drawing and hammering when cold. It takes a high polish, and when exposed to the atmosphere tarnishes less than brass,. When cast in sand delta metal has a tensile strength of about 45,000 pounds per square inch, and about 10 per cent, elongation ; when rolled, tensile strength of 60,000 to 75,000 pounds per square inch, elongation from 9 to 17 per cent, on bars 1.128 inch in diameter and 1 inch area.* Wallace f gives the ultimate tensile strength as 33,600 to 51,520 pounds per square inch, with from 10 to 20 per cent, elongation. Durana metal. — The alloy brought into commerce under this name resembles delta metal, but is somewhat richer in copper, and frequently contains tin, as well as antimony and aluminium. Five analyses gave the mean composition as follows : % Tin Copper Zinc Iron Aluminium Antimony 64.78 29.50 1.71 1.70 2.22 Like delta metal the alloy can be worked at a red heat, and is distinguished by its strength. Tobin bronze. — As regards composition and properties this alloy closely resembles delta metal. Analyses of various samples showed the following results : I. II. III. iv. Per cent. Per cent. Per cent. Per cent. Copper 61.203 59-00 61.20 82.67 Zinc 27.440 38.40 37.14 3-23 Tin 0.906 2.16 0.90 12.40 Iron 0.180 0.11 0.18 0.10 Lead 0.359 0.31 0.35 2.14 Silver — — — 0.07 Phosphorus — — — 0.005 * Iron (London) Vol. 21, p. 159. tTrans. of the Institution of Naval Architects, 1888, p. 374. JjZeitschrift fur angewandte Chemie. 1894. II l62 THE METALLIC ALLOYS. The Ansonia Brass and Copper Company are, according to F. Lynwood Garrison,* the sole manufacturers of Tobin bronze. They claim to obtain 79,600 pounds per square inch tensile strength, an elastic limit of 54,257 pounds per square inch, and from 12 to 17 per cent, elongation with best rolled one-inch bars. Tobin bronze, according to the inventor's claim, can be forged and stamped at a red heat as readily as steel. Bolts and nuts can be forged from it by hand or machinery, when cold drawn. Its increased density and high elastic limit, and the facility with which it can be upset, while hot, make it well adapted for special purposes. In forging Tobin bronze, it is stated that particular care must be taken to work it only at a cherry-red heat, and that it should not be worked at a black heat. Alloy No. IV., given in the above table, is brought into commerce under the name of Deoxidized bronze. It seems probable some deoxidizing flux containing phosphorus, similar to that used in the manufacture of phosphor-bronze, is made use of in the manufacture of this alloy. Deoxidized bronze is largely used for wood-pulp digesters, as it is found to resist the action of sodium hyposulphite and sulphurous acid remark- ably well. Deoxidized bronze wire has a tensile strength in the neighborhood of 150,000 pounds per square inch.f Of the mixtures of metals termed brass, the alloys given in the preceding are the most important used in the indus- tries with the exception of aluminium brasses, which will be discussed under " Aluminium Alloys," ChapterXI. It will, of course, be understood that they by no means exhaust the number of alloys which can be included in the generic term, brass, that number being so large that they can scarcely be * New Alloys and their Engineering Applications. Jour, of the Franklin Institute, June and September, 1891. fF. Lynwood Garrison, New Alloys and their Engineering Application. Jour, of the Franklin, Inst., June and September, 1891. COPPER ALLOYS. 163 enumerated. In examining a variety of brass, small varia- tions in its quantitative composition can always be observed. No matter how small these variations may be, they never- theless exert a great influence upon the physical properties of the respective alloys, so that an alloy differing but little in its chemical composition from another one, may never- theless vary very much from it in regard to its physical qualities. Many manufacturers are of opinion that the physical properties of the alloys are also largely influenced by the mode of manufacture, and those whose products are especially distinguished by great uniformity always work according to a determined method. Hence the manufacture of brass is of equal importance with the composition of the alloys. MANUFACTURE OF BRASS. Before zinc was known in the metallic form, brass was prepared by fusing together with zinciferous ores, such as calamine or carbonate of zinc, as well as with cadmia, the zinc reduced by this process combining with the copper to an alloy. As is well known, the chemical composition of even the purest ores from the same locality always vary somewhat and it is almost impossible to obtain a mixture of metals of fixed properties and general uniformity. For the sake of completeness this antiquated process of manu- facturing brass will here be briefly described. Manufac- turers still working according to it, must, on the one hand, use very uniform zinc ore and, on the other, possess a thorough knowledge of the properties of brass so as to be able to tell from the color and fracture of a sample of the fused mass, whether the alloy possesses the requisite quali- ties or whether it requires the addition of a further quantity of zinc ore or of copper. The production of brass with the use of zinc ores is less expensive, but more tedious and troublesome than by the direct fusion of pure metals. a. Manufacture of brass according to the old method with the use of zinc ores. — Previous to melting, the ores 164 THE METALLIC ALLOYS. have to be subjected to a preparatory treatment to remove, as far as possible, admixtures of foreign metals such as lead, arsenic, antimony, which would impair the quality of the brass. The native calamine is calcined to expel car- bonic acid, sulphur and other volatile matter, and forms zinc oxide. The calcined ore is then ground in a mill, the galena contained in it removed by washing, and the dried ore mixed with about one-fourth its volume of charcoal. The mixture is brought into large crucibles with alternate layers of granulated copper. Powdered charcoal is then thrown over the whole and the crucibles are covered and luted. The old form of furnace consisted of a cone with base downward and the apex cut off horizontally. The crucibles were placed upon a circular grate or perforated iron-plate upon the hearth. A sufficient quantity of fuel was heaped around the crucibles, and a perforated cover of bricks or clay was fitted to the mouth which served as a register to regulate the heat. After the alloy is supposed to be formed (the time varying from 10 to 20 hours, ac- cording to the nature of the calamine and the size of the crucibles), the heat is increased, so as to fuse the whole down into one mass. The till is then thrown up, and a workman, standing over the opening, grasps the crucible between the jaws of a pair of tongs and lifts it out of the furnace. The refuse is skimmed off, and another workman then seizes the crucible with a pair of tongs and pours the contents into iron moulds, guiding the stream with an iron rod. During this process there is a considerable combus- tion of zinc, the metal burning with its characteristic blue flame. When the material is good a single fusion is suffi- cient, but the finer sorts undergo a second fusion with fresh calamine and charcoal. The crude brass may show several defects in regard to its composition. It may either contain too much zinc or cop- per, or the reduction of the zinc may not have proceeded in a complete manner. In such cases it is possible to im- COPPER ALLOYS. 165 prove the alloy by a corresponding addition of copper, zinc ore, or charcoal, and by again fusing it. Sometimes pieces of brass or metallic zinc are also added. b. Manufacture of brass by the direct fusion of the metals. — At the first glance this would appear to be a very simple operation ; it is, however connected with many diffi- culties, and considerable skill is required to produce brass answering determined demands in regard to fusibility, ten- acity, etc. In most factories the fusion of the metals is still effected in crucibles heated in reverberatory furnaces. For many years experiments have been made to do away with the crucibles and effect the fusion of the metals di- rectly in special furnaces. It is evident that such a process of production would be considerably cheaper, as there would be no expense for crucibles and the consumption of fuel be considerably less. The use of a furnace in which the metals could be melted down in large quantities would have the further advantage of obtaining at one. operation a large quantity of brass of the same quality. The results of experiments made in this direction have, however, been so unsatisfactory as to force a return to the older and more expensive method of fusion in crucibles. The general introduction of furnaces for melting down the brass cannot, however, be considered as entirely abandoned, as the technical difficulties in the way will, no doubt, be overcome, before long. More recently experiments on a large scale have again been instituted by well-known manu- facturers, which hold out a hope of final success. For the present we must, however, confine ourselves to a descrip- tion of the best constructions of furnaces for crucibles. The manner of constructing these furnaces depends chiefly on the fuel to be used (coal, coke) and on the num- ber of crucibles to be placed in the furnace at one time. Generally speaking, the furnaces for a certain kind of fuel agree in most respects, the variations being chiefly in the arrangement of the crucibles in the furnace, and the man- ner of distributing the flame around them. 1 66 THE METALLIC ALLOYS. We first give a description of a furnace especially adapted for the use of coke. The furnace, Figs. 10 and u, consists of a vault of re- fractory material and is about 3% feet high. On the nar- rowest place of the vault is an aperture through which the furnace communicates with a well-drawing chimney. The Figs, io and u. plate upon which the crucibles for melting the brass stand has seven apertures so arranged that six of them are in the periphery of a circle, while the seventh forms the center of the circle. Between these larger apertures serving for the reception of the crucibles are smaller ones, which admit the air from below into the furnace. The bottom plate consists of a thick cast-iron plate coated with a layer of COPPER ALLOYS. 167 fire-clay. The six crucibles standing on the periphery of the circle have a height of 1.18 feet, with an upper diameter of 0.65 foot, which corresponds to a bottom diameter of 0.55 foot. The crucible sitting in the center hole is called the king crucible, and being more exposed to the heat is generally somewhat larger; it is, as a rule, 1.18 feet high with an Fig. 12. ii|ft|fl! fe - upper diameter of 0.75 foot. The smaller crucibles hold about 92 to 97 pounds of metal each, and the king crucible about 132 pounds. Fig. 12 shows another construction of a brass furnace. As will be seen from the illustration, the space in which the crucibles are placed has the form of two truncated cones touching each other with the basis, a shaft being i68 THE METALLIC ALLOYS. thus formed in which less fuel is consumed than in a fur- nace having the form of a cylinder. In place of coke, char- coal may be used in this furnace if the local conditions are such as to allow of its employment without increasing the cost of the brass. In the preparation of plate-brass the fused metal has to be cast in special moulds to solidify. It is, however, of importance that this solidification should not take place too rapidly, as otherwise the properties of the brass might be Fig. 13. injured. To prevent too rapid cooling the moulds serving for the reception of the fused mass are strongly heated, special furnaces having been constructed for the purpose in which the gases escaping from the actual melting space are utilized for heating the moulds. Fig. 13 shows the construction of such a furnace in cross-section. The crucibles in which the charge is to be melted stand upon a grate; the fuel is introduced from above, and the gases of combustion pass through a flue into a space COPPER ALLOYS. 169 divided into several low stories in which the moulds are placed. With the use of coke or charcoal the work is very convenient, since no smoke is developed which could possi- bly contain combustible combinations. As will be seen from the above descriptions of furnaces for the use of coke or charcoal, no special provisions are required to insure a complete combustion of the fuel, it being sufficient to con- nect the furnace with a chimney producing a moderately strong draught, With the use of coal care must, however, be had to arrange the furnace in such a manner as to insure the complete combustion of all gaseous products evolved from the coal, as otherwise there would be a considerable loss of heat. The arrangement of furnaces for the use of coal is modi- fied in various ways. In one form of construction the coal is burned upon an ordinary grate, the gases of combustion passing through apertures in a vault of refractory material into a space in which the crucibles are placed. In other constructions, the fire-box is entirely separated from the melting-space, being only connected with it by flues led off at the sides through which the flame passes around the crucibles. Other constructions might be advantageously used for melting down brass. By, for instance, arranging the furnace so as to heat the crucibles by gas, the flame could be suitably regulated by a slide, and with the use of a generating furnace a number of melting furnaces could be kept going at one time. The generating furnace would, of course, have to be placed so as to form the center of a circle on the periphery of which the separate melting furn- aces are located and connected with the generating furnace by suitable flues. With, suppose, six such melting furnaces, three could be supplied with heat, while the others, after the removal of the crucibles, would be charged with fresh material. Fig. 14 shows Piat's revolving crucible furnace. The crucible remains stationary in the furnace, at least for 170 THE METALLIC ALLOYS. several meltings. Fusion itself is effected by burning coke heaped around the crucible, combustion being accelerated by a blower. The blast-flue enters below the grate upon which is placed the crucible-stand, and the products of combustion pass through a pipe in the upper portion of the furnace into a chimney, or with larger furnaces into a hot blast-stove. The illustration shows the furnace in a verti- cal (working) position. From this position it can, after shutting off the blast, be brought by revolving around a horizontal axis into the position required for pouring out the metal, a spout with which the crucible is provided fit- Fig. 14. ting accurately to the pouring gutter of the furnace. In case the mould cannot be brought to the furnace, the latter is so constructed as to allow of being raised and being brought to the mould by means of a crane ; the furnace together with its support may also be placed upon a car- riage. With the use of such a furnace lifting the crucibles with tongs is entirely done away with. In conclusion a few words may be said in regard to the construction of furnaces in which the fusion of the brass is effected directly upon the hearth. Generally speaking, they must be so arranged that the copper can be quickly melted down upon a flat hearth, care being had that the gases pass- COPPER ALLOYS. \J\ ing over the copper contain a small excess of unburnt bodies, as the presence of free oxygen in the gases might produce an oxidation of the copper, and the resulting ad- mixture of cuprous oxide injure the quality of the brass. After being fused the copper is to be strongly heated, and the zinc, together with any brass waste, both previously heated, introduced as quickly as possible. It is advisable to connect the furnace with two preparatory heating spaces, showing different temperatures. In the space showing the lowest temperature the zinc is heated as nearly as possible to its melting point, and in the hotter space the brass waste which is to be added to the fused mass. By introducing, as rapidly as possible, the materials thus heated into the heated copper, a too rapid cooling off of the latter by yielding heat to the zinc need not be feared. By this precautionary measure of preparatory heating the metal will remain thinly fluid, even after the introduction of the zinc and the waste brass, and the resulting alloy will be perfectly uniform as regards fracture, hardness, and color. The manner in which fusion is effected varies somewhat in the different works. In furnaces in which the king- crucible stands in the center of a circle and the rest on the periphery, the work is generally carried on as follows : One of the crucibles is lifted from the furnace, and being placed alongside of it is first charged with a small quantity of brass-waste mixed with a certain quantity of pulverized charcoal. Upon this base the mixture of copper and zinc in suitable proportions, previously weighed off for each crucible, is placed and the whole covered with a layer of a mixture of brass-waste and pulverized charcoal. It is also advisable -to cover the surface of the contents of the crucible with as high a layer of pulverized charcoal as possible, this preventing at least to some extent a too strong volatiliza- tion of the zinc. In brass foundries the waste resulting from casting and otherwise is always melted down with a new charge of the crucibles. The centre crucible, the so- 172 THE METALLIC ALLOYS. called king-crucible, is generally charged last. In some foundries it is even customary to leave it entirely uncharged, it forming then, so to say, the inner casing of the furnace. This practice, however, cannot be recommended. The period of the complete fusion of the charge depends on the size of the crucibles, the fuel used, and on the con- struction of the furnace itself, but should not be longer than from two to five hours. After placing the crucibles in the furnace the fuel (if coke or charcoal be used) is heaped around them, or the coal placed upon the grate and ignited. In working with furnaces provided with a movable plate the latter is from time to time lifted off, in order to see that the surface of the melted metal remains covered with charcoal. When by dipping a rod into the crucibles it is observed that the contents are thoroughly liquefied, the casting can be either at once proceeded with, or sam- ples may first be taken to test the quality of the brass, and, if necessary, change its properties by additions to the fused mass. While in the course of fusion care must be had to keep the apertures through which the air is admitted to the fuel free, towards the end of the operation they are covered as much as possible in order to save fuel. It is also of im- portance not to force the heating of the finished alloy further than is absolutely necessary, since by strong over- heating a considerable portion of the zinc volatilizes, and the alloy may acquire properties entirely different from those desired. Casting Brass. The casting of brass requires certain precautionary measures in order to obtain homogeneous pieces as free from flaws as possible. As regards the mode of casting we especially distinguish two different methods, viz : Ingot- casting and plate-casting, the former serving for casting brick-shaped pieces, which are to be remelted for further COPPER ALLOYS. I 73 working or at once brought into the required shape, and the latter for casting plates to be rolled out into sheets. a. Casting of ingots. — If the brass is to be cast in the shape of bricks, or cubes, or is directly to be used for cast- ing various articles, the operation is carried on as follows : The king-crucible is generally left empty, and after the brass in the other crucibles is thoroughly melted down, is lifted from the furnace and placed in a depression in front of it filled with glowing coals. One crucible after the other is then taken from the furnace and its contents emptied into the king-crucible. As soon as it is filled the surface of the fused metal contained in it is covered with charcoal and the whole allowed to stand quietly about 15 minutes in order to bring about a uniform mixing of the masses emptied from the different crucibles. After this period, the charcoal is removed from the surface, and, after vigor- ously stirring the contents of the crucible several times with an iron rod, the fused metal is poured into the moulds. As will be seen from the preceding description, the king- crucible answers here the purpose of a sump, and may be suitably replaced by one. For this purpose another furnace, in which the sump stands free and can be heated to a bright red heat, has to be erected in front of the furnace contain- ing the crucibles. This sump then serves for the reception of the fused brass, and by charging the king-crucible also with metal, the space occupied by it in the center of the furnace can be advantageously utilized. By arranging several melting furnaces around the sump-furnace and with a proper division of the work, only one sump is required, it being charged in rotation with the contents of the cru- cibles from the separate furnaces. The moulds for casting ingots of brass are similar to those used for casting pig-iron. The patterns for the moulds are of wood, and have generally the form of bricks with oblique sides. The patterns are pressed alongside each other in wet moulding sand, a small gutter being left be- 174 THE METALLIC ALLOYS. tween each two moulds through which the metal after one mould is filled runs into the other. The object being not so much to give the ingots a beauti- ful appearance as to obtain them in a handy form, the sand for making the moulds need not be especially fine. The cold ingots of brass have quite a rough surface, and must be freed from adhering grains of sand by rubbing. For casting articles to be subsequently turned or worked with the file, special care is required in making the mould. As a rule the ingots are remelted in a wind furnace, and the quality of the article to be cast is regulated by the addition of pieces of brass or zinc to the fused metal. For remelting brass graphite crucibles are generally used, less dross adhering to their walls than to those of the rougher clay crucibles. The moulds used for casting articles of brass are some- times made of loam, and must be sharply dried before use to prevent cracking. Suitable moulding sand is, however, generally preferred. The condition of the sand is of great importance for the surface of the cast article ; if it be too meager the surface is rough, and requires much after-work in turning or filing. Meager sand is improved by adding a small quantity of ordinary flour paste or some sugar syrup. If the sand is too fat, this property is decreased by the ad- dition of some finely pulverized charcoal. In order to obtain perfect castings great attention must be paid to the temperature of the fused brass. Overheated metal gives, as a rule, porous castings, and if it be too cool the mould is incompletely filled out, which with delicate articles may spoil the entire casting. The metal must be poured in an uninterrupted stream into the mould, other- wise flaws will, as a rule, be formed and the casting be use- less. In conclusion it may be remarked that in making the moulds, vents must be provided for the escape of the aque- ous vapor evolved. b. Casting of plate-brass. — For the preparation of sheet- COPPER ALLOYS. I 75 brass or wire-brass the metal has to be cast in the form of plates of corresponding thickness. It being absolutely necessary for the metal to retain the property of ductility, special precautions must be taken in executing the casting. Many attempts have been made to use iron moulds, but in most cases the castings turned out failures, on account of the brass cooling off too rapidly. This evil might, how- ever, be overcome by heating the moulds in a special furnace previously to casting and returning them to the furnace after casting, where by a suitable regulation of the temperature, the castings could be cooled off as slowly as desired. Such furnace could be built on the same principle as the cooling furnace used in glass houses. Loam moulds give good castings, but have the disad- vantage of breaking readily, which, to be sure, might be overcome by edging the loam plates with band-iron. At present small moulds of sand are frequently used in many foundries, which must, of course, be thoroughly dried in special furnaces previously to casting. With the use of small moulds and careful work, faultless plates can be readily cast, while with large moulds it frequently happens that some places of the plate are defective and have to be cut out. In many places granite moulds are still in use, and yield, according to the statements of many manufacturers, the best results. The preparation of these moulds requires great care, the following points deserving special attention : The granite plates have to be provided with a uniform coating of clay, which must always be kept in such a con- dition as to insure the utmost uniformity in the surface of the plates. To prevent the cracking of the coating of clay, it is covered, after thorough smoothing, with a thin layer of cow-dung. The granite plates thus prepared are arranged in the fol- lowing manner : The upper plate is suspended over the lower one, the space or mould between the two being 176 THE METALLIC ALLOYS. limited by iron bars laid on the lower stone, which is a little longer than the upper one, and projects to the front so as to form a lip or mouth piece for receiving the metal. The plates are bound together with iron, and raised on one side so that they stand at an angle of 45 . As soon as the casting is finished and the metal is supposed to be solidi- fied, the sheet of brass is carefully taken from the mould. With sufficient precautions such granite moulds can be used for a long time without the coating of clay becoming damaged, and the sheets turn out very uniform after the mould has once been heated by several castings. One and the same mould is frequently used continually, in order to keep it warm, and if it has to stand empty for some time it is enveloped in a bad conductor, as a coarse carpet, to pre- vent its cooling. If the mould is damaged it must be care- fully mended, and the mended places sharply dried to prevent cracking. The sheets of brass taken from the mould are subjected to a mechanical cleansing, and at the same time carefully inspected, defective sheets being remelted. At the present time the plate-brass obtained by casting is generally worked into sheet-brass, which was formerly prepared by hammering, but now by rolling. In some cases rolling is succeeded by hammering, as, for instance, in the case of the very thin sheet-brass known as Dutch metal, which is distinguished by the peculiar clear sound it emits on being pressed together. Thicker plates are oc- casionally prepared for rolling by hammering. After each passage through the rolls the sheets are heated in a heat- ing furnace, quenched to obtain greater ductility, and then rolled cold until reduced to the desired thickness. In working brass which is only ductile in the heat, the sheets must of course pass in a hot state through the rolls until reduced to the proper size. Before rolling, the sheets, and sometimes the rolls also, are coated with oil. After passing through the rolls the sheet-brass is finally subjected to a COPPER ALLOYS. I 77 treatment which decides whether it is to be soft and flex- ible, or hard and elastic. For soft sheet the rolled sheet- brass is again heated and quenched, while for hard and elastic sheet the heating is omitted, and the sheet several times more rolled cold. The sheets are generally heated in a reverberatory fur- nace heated by wood or gas. Siemens has constructed regenerative gas reverberatory furnaces for heating. Coal, if used in such furnaces, yields, on account of the sulphur contained in the gases of the fire, a product which after cleansing does not show a beautiful yellow, but a red, color, which is due to the copper having entered into combination with the sulphur contained in the gases of the fire. If coal is to be used as fuel, either furnaces with iron or clay muffles washed by the flame are used, or the coal is con- verted into gases, which before combustion are sucked by means of an exhauster through milk of lime to remove their content of sulphurous acid. Regenerative gas firing is advisable, especially for large heating furnaces, since by directing the flame now to one side and then to the other, a more uniform heat can be obtained and the temperature more readily regulated. Figs. 15 and 16 show a reverberatory furnace for wood firing. It is furnished with a grate, a, 4 feet long and 2 feet wide ; the fire-bridge b projects about 1 ^ feet above the hearth c, which is on a level with the grate ; the hearth is about 9 feet long and 4 feet wide. The arch behind the fire bridge is about 3 feet high, and the flue d opens about 1 foot above the hearth. The sheets rest upon the rails e so that they are also played upon from below by the flame. The sheets to be heated are frequently placed upon a carriage running upon wheels and rails, which when the charge is heated is withdrawn and replaced by another loaded carriage. This plan has the disadvantage that through the intermediate space required for the movement of the carriage and the expansion of the bottom, much cold 12 1 7 8 THE METALLIC ALLOYS. air passes between the bottom of the hearth and the fur- nace into the heating space and cools off the furnace,. Fig. 15. whereby more time, and consequently more fuel, is required for heating. In some brass factories this evil has been overcome as follows : On both sides the entire length of the furnace, run, below the bottom of the hearth, hearth- Fig. 16. plates with their angles turned downward. Corresponding to this, angle-irons turned upward are placed with sufficient COPPER ALLOYS. I 79 play on both sides of the carriage so that on the carriage wheels a sort of gutter is formed which is filled with fine sand. On pushing the carriage into the furnace the angle- irons of the furnace sink into the sand and thus prevent the access of air. This arrangement is said to decrease the consumption of fuel one-third. Cleansing or Pickling of Brass. The finished sheets have a black color, which is partially due to the formation of cupric oxide on the surface and partially to sulphur combinations formed, as previously mentioned, by heating with coal in annealing. As a rule brass is brought into commerce in a bright state, the only exception being the thicker sheets, which retain their black coating. In order to impart to the sheet its characteristic beautiful yellow color, it is subjected to a final operation termed pickling or dipping. This operation simply con- sists in treating the sheet with acid, which removes the layer of oxide to which the black color is due. The pick- ling is commenced by placing the sheets in a fluid consist- ing of 10 parts of water and i of sulphuric acid. The layer of oxide quickly dissolves in the fluid and the sheets show the pure yellow brass color. After this operation the sheets may be at once washed and dried, and brought into com- merce. In most cases the sheets are, however, subjected to a second treatment with acids in order to impart to them a beautiful color ; hence the treatment with sulphuric acid is generally termed preparatory pickling. As the actual pickle, either nitric acid by itself is used, or a mixture of two parts of nitric acid and one part of sulphuric acid. Pickles containing nitric acid possess the property of dis- solving zinc from the brass quicker than copper, the sur- face of the sheet acquiring in consequence of it a warmer tone, shading more or less into reddish. By exercising great care dilute nitric acid by itself may be used as a l8o THE METALLIC ALLOYS. pickle, but the sheets must be immediately washed, since if only the slightest trace of the acid remains, they acquire after some time a greenish color due to the formation of a basic cupric nitrate. It has been observed that nitric acid containing a certain quantity of nitrous acid yields especially beautiful shades of color. To obtain them a small quantity of organic sub- stance is added to the nitric acid or to the mixture of nitric and sulphuric acids. The most curious substances are used for the purpose, snuff, for instance, being highly recom- mended as especially efficacious in producing beautiful colors. The use of such substances is, however, entirely superfluous, there being a number of cheaper organic sub- stances which, when brought together with concentrated nitric acid, evolve nitrous acid. The cheapest of these ma- terials is dry saw-dust, the nitric acid acquiring a short time after its introduction an orange-yellow color, which is due to the products of decomposition of the nitric acid, prominent among which is nitrous acid. After taking the sheets from the pickle they are washed, best in running water, in order to remove the last traces of acid. By quick pickling the articles are obtained bright by the removal of the layer of oxide from the smooth surface of the metal. But sometimes a dull lusterless surface is to be imparted to the brass, which is effected by treating the articles with a boiling pickling-fluid composed also of nitric and sulphuric acids. In many factories this pickle is pre- pared by dissolving I part of zinc in 3 of nitric acid and mixing the solution with 8 parts each of nitric and sulphuric acids. The solution is heated in a porcelain dish, and the articles to be pickled dipped in it 30 to 40 seconds. In dipping the brass articles large masses of red-brown vapors originating from the products of decomposition of the nitric acid are evolved which strongly attack the lungs. The operation should therefore be executed under a well- drawing chimney, or, still better, in an open space. COPPER ALLOYS. l8l The pickled articles have a gray-yellow color, and in order to bring out the pure yellow color are immersed for a few seconds in pure nitric acid. They are then drawn through a weak solution of soda or potash, and finally washed. As the bright metal loses its beautiful color on exposure to the air in consequence of oxidation, the arti- cles after drying must be coated with good varnish. TOMBAC. The term tombac is applied to copper-zinc alloys which on account of their small content of zinc — at the utmost 18 per cent. — have a golden-yellow, reddish to red-brown color instead of the yellow brass color. Articles of such an alloy having the appearance of gold are said to have been brought, in the 17th century, to Europe from Siam, and the Malayan name tambaga (actually copper) was con- verted into tombac. According to other statements the word has been formed by reversing the syllables of the Chinese packfong or packtong (white copper), If such alloys consisting essentially of copper and zinc, have been used for castings, especially machine parts, they are sometimes called red brass to distinguish them from the more zinciferous yellow brass. Pure tombac, i. e., the alloy free from tin, lead and other bodies impairing flexibility, is distinguished by a compara- tively high degree of ductility at the ordinary temperature but, like most all other varieties of brass, cannot be worked at higher temperatures. It is chiefly used for the manufac- ture of fictitious gold articles which possess a gold-like color, and are generally made by " striking up " in a die under a press or a drop-hammer, for which purpose a very flexible and tenacious metal is required, as otherwise the articles would crack. To this class belong cheap jewelry and ornaments, buttons and Dutch gold leaf. The varieties of tombac which contain not less than 10, and not over 18 per cent, zinc possess a color most closely resembling that 182 THE METALLIC ALLOYS. of gold. Articles made from such alloys are generally thinly gilded as otherwise they soon turn black and require frequent cleaning. While tombac generally contains 84 to 85 parts of cop- per and 15 to 16 parts of zinc; the proportions vary con- siderably as may be seen from the following table. Parts. Cast-tombac, German English Tombac, German (Oker) " (Hegermiihl) Paris (red) Copper. Zinc. Lead. 87.00 86.38 85.00 85.30 92.00 for gilding, German ; 97.80 French German (Liidenscheid) French (yellow) golden-yellow 86.00 82.30 80.00 89.97 82.00 13.00 13.62 15.00 14.70 8.00 2.20 14.00 17.70 17.00 9.98 17.50 3-00 0.05 0.50 The best Berlin alloys (so-called bronzes) for lamps and chandeliers contain, as a rule, 80 per cent, copper and 20 per cent. zinc. For ordinary work an alloy with 33 per cent, zinc is used. Castings to be worked with a lathe con- tain 40 per cent. zinc. The so-called Lyons gold is tombac. The color of tombac varies from pure copper-red to orange-yellow, according to the content of copper, though a red color is by no means a criterion as regards the con- tent of copper, since an alloy of 49.3 parts of copper and 50.7 of zinc is redder than one of 4 parts of copper and 1 of zinc. The more copper the alloy contains the more fine- grained and ductile it generally is. Many small articles, as- candle-sticks, inkstands, etc., which are sometimes gilt, are made from a compound designated in commerce as bronze, which is, however, not bronze, but only resembles it in color. Such alloys are also frequently used for casting small statues, for which they are COPPER ALLOYS. 183 well adapted, since they fill the moulds very uniformly. The composition of these alloys varies very much, though zinc and copper are, as a rule, the actual constituents, an admixture of tin occurring only occasionally. We give a few compositions of this (imitation) bronze: Parts. I. II. III. Copper 80 67 76 Zinc 20 23 2 4 Mannheim gold or similar. — This alloy has a beautiful golden-yellow color. Its composition varies considerably : Parts. I. II. Copper 83.7 89.8 Zinc 9.3 9.6 Tin 7.0 0.6 The alloy may also be obtained by melting together 69.6 parts of copper, 29.8 of brass, and 0.6 of finest tin. Mannheim gold was formerly much used in the manu- facture of buttons and pressed articles of a gold-like ap- pearance, but it has recently been superseded by alloys which surpass it as regards beautiful color. Chrysochalk {gold-copper). — This term is applied to several alloys resembling gold, which may consist of copper 90.5 parts, zinc 7.9, lead 1.6, or of copper 58.68, zinc 39.42, lead 1.90. The beautiful color of this alloy soon disappears on ex- posure to the air, but can be preserved for some time by coating articles manufactured from it with a colorless lac- quer. Chrysochalk is generally used for ordinary gold imitations, as watch-chains, articles of jewelry, etc. Chrysorin. — This alloy, prepared by Rauscherber, con- sists of 100 parts of copper and 51 of zinc. Its color re- sembles that of 18 to 20 carat* gold, and does not tarnish in the air. 184 THE METALLIC ALLOYS. Pinchbeck. — The alloy known under this name was first manufactured in England, and is distinguished by its dark gold color which comes nearest to that of gold alloyed with copper. Pinchbeck being very ductile can be rolled out into very thin plates, which can be brought into any desired shape by stamping. The alloy does not readily oxidize in the air, and is, therefore, well adapted for cheap articles of jewelry, for which it is principally used. Pinch- beck answering all demands is composed of — Parts. I. II. Copper 88.8 93.6 Zinc 11. 2 6.4 Or, Brass 1 .0 0.7 Copper 2.0 1.28 Zinc — 0.7 French oreide. — This alloy is distinguished by its beau- tiful color which closely resembles that of gold. In addi- tion to its beautiful color it is very ductile and tenacious so that it can readily be stamped and rolled ; it also takes a very fine polish. The directions for preparing this alloy vary very much, some from Paris factories showing the following compositions : Copper qo.o Zinc 10. o Tin — Iron — 85.5 82.75 1 14.5 16.40 — 0.55 — 0.30 PM According to a special formula, oreide is prepared as fol- lows : Melt roo parts of copper and add, with constant stirring, 6 parts of magnesia, 3.6 of sal ammoniac, 1.8 of lime, and 9 of crude tartar*. Stir again thoroughly, and then add 17 parts of granulated zinc, and after mixing it COPPER ALLOYS. 185 with the copper by vigorous stirring, keep the alloy liquid for one hour. Then remove the cover of froth and pour out the alloy. Talmi or talmi-gold. — Cheap articles of jewelry, chains, earrings, bracelets, etc., were first brought into commerce from Paris under the name of talmi-gold, which were dis- tinguished by beautiful workmanship, low price, and great durability. Later on, when this alloy had required con- siderable reputation, other alloys, or rather metals, were brought into commerce under the same name, which re- tained their beautiful gold color, however, only as long as the articles manufactured from them were not used. The finer quality of talmi-gold retains its pure gold color for some time, and consists actually of brass or copper or tombac covered with a thin plate of gold combined with the base by rolling. The plates thus formed are then rolled out by passing through rolls, whereby the coating of gold not only acquires considerable density, but adheres so firmly to the base that articles manufactured from the metal can be used for years without losing their beautiful appear- ance. In modern times articles of talmi-gold are brought into market which are simply electroplated, the coating of gold being in many cases so thin that by strong rubbing with a rough cloth the color of the base shows through. Such articles, of course, lose their gold-like appearance in a short time. In the following table we give the composition of a few alloys used in the manufacture of articles of talmi-gold ; it will be seen that the content of gold varies very much, the durability of the articles manufactured from the respective alloys being, of course, a corresponding one. The alloys I., II., and III. are genuine Paris talmi-gold; IV., V., and VI. are imitations which are electroplated, and VII. is an alloy of a faulty composition to which the gold does not adhere. 1 86 THE METALLIC ALLOYS. Copper Zinc . . Tin Iron . . Gold . . II. III. ! IV. V. VI. VII. 89.88 j 9 o. 79 | o .oo {g«g {%* {g* „.„ 9-32 8-33 8. 9 5.97 I 12.44 6.60 12.2 11.42 U0.97 1 15-79 — — — 1.1 — 0.3 1.03 | 0.97 i 0.91 { ^°5 j 0^03 j 0^51 _ Tissier s metal. — This alloy is distinguished by great hardness and differs from the previously described com- pounds in containing arsenic. It has a beautiful tombac red color. Its composition is not always the same, the quantities of the component metals varying within wide limits. The alloy actually deserving the name is composed of copper 97 parts, zinc 2, arsenic 1 to 2. According to this composition Tissier's metal may be considered a brass containing r a very high percentage of copper and hardened by an addition of arsenic. It is some- times Used for axle-bearings, but can be very suitably re- placed by other alloys, to be mentioned further on, which are preferable to it on account of lacking the dangerous arsenic. Tournays metal. — This alloy is much used by the Paris manufacturers of bronze articles, and on account of its great ductility can be advantageously employed for the manufac- ture of cheap jewelry to be made from very thin sheet. It is also well adapted for the manufacture of buttons. It is composed of copper 82.54 parts, zinc 17.46. Platina, a white alloy, especially suitable for buttons, contains 80 parts brass and 20 copper. Manilla gold consists of copper and zinc, or lead. Dutch leaf or Dutch gold. Copper 77.75 to 84.5 per cent., zinc 15.5 to 22.25 P er cent. The alloy is pale to dark yellow according to the propor- COPPER ALLOYS. 187 tions of copper and zinc used. Being very ductile it is em- ployed in the manufacture of Dutch leaf or Dutch gold. The alloy is melted in graphite crucibles and cast in iron moulds to semi-circular bars about 24 inches long and >^ or or yi inch wide. The bars are then rolled cold and each resulting ribbon is made into a pile about 2 feet long and beaten under the hammer to a ribbon about 1 >2 inches wide. It is then annealed and beaten into a ribbon 2~%. inches wide, and, after further annealing, into one 3%' to 4 inches wide. This last ribbon is pickled in dilute sulphuric acid, washed, boiled bright in argol solution, washed, brushed and quickly dried. The ribbons are then cut up and 1000 to 2000 pieces made into a pile and beaten under the hammer. The material is then again cut up, the leaves are placed between parchment and reduced by beating to about 5^ inches square. Each leaf is then cut up into 4 pieces, which are placed between gold beaters' skin and beaten by hand to about four times the size of the original leaf. The hammer used weighs 5^2 to 11 pounds, and the work is performed upon an anvil of dolomite by alternately beating with the right and left hand, and turning the package with the free hand. The package is made up of from 800 to 1000 gold beaters' skins, between which the metal leaves are placed ; on top and bottom come six parchment leaves, and the whole is then tied up in parchment. After the above-mentioned hammer has been used for about one hour, beating is continued for about 2 hours with a hammer weighing from 12 to 16^2 lbs. To prevent the leaves from adhering to the skins in consequence of the development of heat, they are coated with gypsum. The leaves when taken from the skins are trimmed and placed in small books be- tween tissue paper rubbed with rouge. Each book con- tains 21 to 25 leaves. Dutch leaf is used for gilding all sorts of articles, and its beautiful color may be preserved for some time by applying a coat of thin colorless or slightly yellow lacquer. By add- ISO THE METALLIC ALLOYS. ing to the latter a small quantity of a pure color — aniline colors being well adapted for the purpose — the color of the leaf can be readily changed to red, green, violet, etc. Bronze powders. — The bronze powders used for coating metallic and non-metallic articles (wood, plaster of paris, oil-cloth, wall paper, etc.), consist of tombac-like alloys. For colors shading strongly into white, metallic mixtures with a high percentage of zinc are used, and for those ap- proaching more closely to a pure red, alloys with a large content of copper. The many shades of color found in commerce are, how- ever, not produced by the employment of different com- pounds, but by heating the alloys converted into an impal- pable powder until the desired shade is obtained by the formation of a thin layer of oxide upon the surface of each particle. In modern times bronze powders are brought into commerce showing beautiful green, blue, and violet colors, which are, however, not obtained by the formation of a layer of oxide, but by coloring the metallic powder with aniline color. The manner of preparing bronze pow- ders has been recently much improved by the use of suit- able machines for the conversion of the alloys into powder. In metal-leaf factories the waste resulting in rolling out and hammering is used for the preparation of bronze pow- der. According to the old method the waste was rubbed with a honey — or gum — solution upon a stone until a mass consisting of fine powder combined to a dough by the honey — or gum — solution was formed. This dough was thrown into water, and after the solution of the agglutinant the metallic powder was dried, and subjected to oxidation by mixing it with a little fat and heating it in a pan over an open fire until the desired shade of color was obtained. At the present time this laborious and time-consuming method has been much shortened by the use of suitable machines, and of alloys prepared by melting together the metals in suitable proportions for powders which do not COPPER ALLOYS. 189 require to be colored by oxidation. These alloys are beaten out into thin leaves by hammers driven by steam. The leaves are then converted into powder by forcing them through the meshes of a fine iron-wire sieve with the as- sistance of a scratch-brush. This rubbing through is effected with a simultaneous admission of oil, and the mass running off from the sieve is brought into a grinding machine of peculiar construction — a steel-plate covered with fine blunt-pointed needles revolving over another steel-plate. In this machine the mass is reduced to a very fine powder, mixed, however, with oil. The powder is first brought into water where the greater portion of the oil separates on the surface. The metallic mass lying on the bottom of the vessel is then subjected to a strong pressure, which removes nearly all the oil, the small quantity remain- ing exerting no injurious influence, but being rather bene- ficial, as it causes the powder to adhere with greater tenacity to the articles to which it is applied. In the following table we give the compositions of the alloys for some colors : — Color. Yellow .... Pale green Lemon Copper-red Orange . . . Pale yellow Crimson . . Parts Copper. 82.33 84.32 84.50 99.90 98.93 90.00 98.22 Parts Parts Zinc. Iron. 16.69 15.02 15-30 0.16 0.63 0.07 0-73 9.60 0.50 0.56 The better qualities of English bronze powders consist of copper 83 parts, silver 4.5, tin 8, oil 4.5, and the poorer qualities, of copper 64.8 parts, silver 4.3, tin 8.7., zinc 12.9, and oil 3. The variety of bronze powder known under the name of "brocade," consists of coarser pieces prepared from the I9O THE METALLIC ALLOYS. waste of metal-leaf factories by comminuting it by means of a stamping-mill, and separating the pieces of unequal size formed, first by passing through a sieve, and finally by a current of air. A certain kind of brocade, however, does not consist of a metallic alloy, but simply of mica rubbed to a fine powder. Some kinds of bronze powder, as pre- viously mentioned, are colored with aniline colors. This is effected by simply pouring a dilute solution of the aniline color in strong alcohol over the powder and intimately mixing. Bronze powders from alloys of copper with 5 to 10 per cent, aluminium and 0.04 to 0.1 per cent, bismuth are, ac- cording to Lehmann, prepared directly from the block of metal by a cutting-machine, heating and boiling the powder, again heating several times, rubbing, washing, drying, sift- ing, and polishing between rolls. As a polishing agent for bronze powders Rosenhaupt uses mercurous nitrate. Metallic powders are now directly produced electrolytic- ally, several methods for this process having been patented in France and Germany. WHITE BRASS. Alloys of copper and zinc containing less than 45 per cent, of copper cease, as previously mentioned, to have a yellow color, the latter being, according to the content of zinc either pure white (silver white) or a pale, but pleasing, yellow. The ductility decreasing considerably with the in- crease in the content of zinc, such ailoys cannot be used for rolling and wire-drawing, but they may be employed for castings which are to be finished by the lathe or file. Being quite cheap they are well adapted for casting statuettes and other small articles not exposed to the weather. In the air these alloys do not acquire the beautiful color of bronze known as patina, but a dirty brown-green. On account of their white color some of these alloys are used for pressed work, such as buttons, etc., but only a moderate pressure can be applied. COPPER ALLOYS. I9I Birmingham platinum or platinum-lead. — This alloy is of a pure, nearly silver-white color, which remains constant in the air for some time. It is, however, so brittle as to be only suitable for casting. Buttons are made of it by casting it in moulds giving sharp impressions, the letter, escutcheon, etc., upon the button being subsequently brought out more by careful pressing. The composition of the alloy varies according to the taste of the manufac- turers as shown by the following examples : I. II. III. Copper 43.0 46.5 20 Zinc 57.0 53.5 80 Other alloys for white buttons consist of : I. II. III. IV. V. Copper 54.0 50.0 60.0 60.0 54.5") >-d Zinc 43.0 45.0 33.5 30.0 45.5 \ 3 Tin 3.0 5.0 6.5 10.0 — > w Sorel's alloy. — This important and valuable alloy possesses properties rendering it especially suitable for many pur- poses. It is chiefly remarkable for its considerable hard- ness, it being in this respect at least equal to good wrought- iron. Its toughness surpasses that of the best cast-iron. In casting it shows the valuable property of .being readily detached from the mould, and it can be mechanically worked with great ease, but it is too brittle to be rolled out into sheets or drawn into wire. It is much used for casting small statues, which after careful bronzing are brought into commerce under the name of cast-bronze. It may also be employed in the manufacture of articles exposed to the in- fluence of the weather, as it rusts with difficulty and finally becomes coated with a thin, firmly-adhering layer of oxide which prevents further oxidation. The following mixtures have nearly the same properties, though they vary very much as regards their composition : — 192 THE METALLIC ALLOYS. Parts. Copper 1 10 Zinc 98 80 Iron 1 10 The iron is used in the shape of cast-iron shavings, which are added to the zinc. The copper is then added and the alloy kept for some time fluid under a cover of glowing coals, in order to insure an intimate combination of the metals without a combustion of the zinc. The alloy being difficult to prepare in the above manner on account of the combustibility of the zinc, it is recommended in preparing large quantities not directly to mix the metals, but to use brass of known composition. This is melted down under a cover of charcoal and slightly overheated ; the zinc is then added, and finally the iron. Bath-metal. — This alloy is used for the manufacture of candlesticks, tea-pots, buttons, etc., and is much liked on account of its beautiful yellowish-white to almost white color. It takes a high degree of polish, and articles manu- factured from it acquire in the course of time a lasting silver luster by simply rubbing them with a soft cloth, Bath-metal is composed of : Brass 32 parts and zinc 9 = copper 55 parts and zinc 45. Guettier s button metals: — 1. Brass 372 (copper 297, zinc 93) zinc 62, tin 31. 2. " 372 ( " 297, " 93) " 47, " 47. 3- " 372 ( " 297, " 93) " 140, — These alloys possess a silver color, No. 1 being the finest quality, No. 2, medium, and No. 3 inferior. Ordinary English white metal. — Brass (copper 360, zinc 120) 480 parts, zinc 45, tin 15. Fontainemoreau s bronzes. — These alloys are claimed to be well adapted for chill-casting, the metal being poured into iron moulds, whereby the alloys become more homo- COPPER ALLOYS. I93 geneous, separation of the constituents being prevented by the rapid cooling. By the addition of copper, iron and lead, the highly crystalline nature of the zinc is changed. Examples of the composition of these so-called bronzes are given below : Parts. ^"i. II. III. IV. V. VI. VII. VIIL Zinc 90.00 91.0 92.0 Q2.0 97.0 97.0 99.0 99.5 Copper 8.0 8.0 8.0 7.0 2.5 3.0 1.0 — Cast iron... 1.0 — — 1.0 0.5 — — 0.5 Lead 1.0 1.0 — — — — — The preceding alloys are those which, strictly speaking, belong to the brasses, the composition of the mixtures as regards their principal constituents — copper and zinc — varying only within certain limits, and the addition of tin, lead, and iron being only made in order to change the properties of the alloys for certain purposes. Besides these alloys there are, however, some which find special applica- tion, and for that reason will be discussed separately ; the alloys known as white metal, etc., belonging to this group. In the following table, originally collated for the Com- mittee on Alloys of the U. S. Board,* the properties of the alloys of copper and zinc as described by the best authorities are exhibited in a concise manner : — * Report, Vol. II., 1881. 13 194 THE METALLIC ALLOYS. c3 ! i Sheet copper. Mean of 9 samples. Tombac for buttons. Red tombac of Vienna. Railway axles, porous. Defective bar. Pinchbeck. Bearings, Austria. Red tombac of Paris. Tombac. Specific gravity of ingot, [8.753. French oreide. Very delicate castings. Ornaments of Hanover. French oreide. Specific gravity of pow- Paris jewelry. [der,8.584. lombac of Oker. 1 CO . ■ ■ . . Q3 W . rQ . . CQ CO • pf . ! & "^ PSD D £3 P '001 = -its 'Ajpi.no joj y£jiAijon =jaA|is 'ji aoj Xjiaijoh I9- v to _ aia 1 1 1 £ 1 1 2 1. 1 1 1 1 1 1 1 1 1 1 1 1 1- 1 1 2 1 1 ! 3 1 I 1 1 -1 1 1 1 3CIO0 1 &> l ~" CM CO 001 1 h io co cn »q 1 1 1 ! 5S 1 g 1 1 1 1 1 1 1 1 1- 1 ! M- 1 1 1 K5 1 1 . 1 § ' 1 1 1 1 1 1 I 1 puoo 1 •(jail's Xjiljqisnj jo J •(nosu pin? jiaAiuo i 'jail'BK) ssau Jg J0 | | 2 1 1 ! 1 1 II 1 1 1 II 1 1 1 3 1 1 1 S 1 a 1 S 1 1 1 S 1 1 1 i 1 qof PJBH i s- 1 g i i i i i i i i i i i i I a i i i § 1 2 rs i i i s; r i . i i i •(lan^N) A.V.VA -■BailBui jo japio |-< 1 1 1 1 1 1 1 1 1 1 1 1 1 MS 1 1 IS 12 l=* 1 1 i 00 1 1 1 M •(uojsjnqx) o||||||||oo|5|||||||S||||||li||||S| Ajuiionp aAijiqan * ^'« » I I I I i I ! i I I I I « I i VjailBH) | co 1 | 1 1 1 1 | | | I I : I 1 1 | so I 1 1 r« 1 oi | ct> it | m i i , i i Xmijonpjojapio ' ' ' ' ' ' ' ' •qouiajBnbs jad oo gj^o o o g s eg spunbd 'A}ioBuax \ W2 \ 1 1 1 -* 1 1^-1^1 1 1 1 L-l 1 1 .ri 1 <» ' oS 1 1 l-I 1 1 1 1 ' OMiO (MCflrH 7 8.921 8.952 8.672 8.791 8.825 8.74C 8.605 8.834 8.773 8.607 8.633 8.587 8.591 8.710 8.656 •sisa'ibu'b A"q a S! 1.88 3.79 7.68 9.60 9.42 10.97 14.90 10.06 unjjisoduio;) o 97.83 96 07 92.32 90.56 88.94 89.80 ojnjxirji SI 3 O lOOOO CO HO O^OOOCO,-! tc a CJ O i.O TfiiOiO Ot CO Ol^^riCl^COSO UOtCl^ T OOOOOCOCM^OiOCM^fKClJ. SlOOO'-HCl^WKT'TTT'Ci^ UO [WUlflUO jo UOljlSOdUiOQ 100 100 100 100 100 100 100 99.15 97.80 97.50 97. .0 95 93.6 92.5 92.5 92 91 90.72 90.65 90 90 89.80 88.-'9 8S.60 87.50 87.30 86.67 86.38 86 85.5 85.34 85.3 85 85 81.6 •Bpnmioj ot [nojy- S3t3 c e 3 3 o o S3 SI S3 SI 3 3 3 3 3 3 OO o o o t - £ ! COPPER ALLOYS, 195 * Remarks. Gold leaf. Tombac for buttons. Bronze powder. Bath metal. Alloy for jewelry. Ornaments. Dutch brass. [der, 8.367. Specific gravity of pow- Vienna gold leaf. Bristol metal. Rolled sheet brass. Brass of 32 copper, 12 zinc. Chrysorin. Tombac. Suitable for forging or [leaf. Suitable for forging. Bristol metal. Chrysorin. Common brass. Suitable for forging. •ijijoqpnv ... i-^ . p3 • . — . i-J . . CQ . P5 i_i . CO . . . CQ • ■ CQ i_; . mfflei d m»^ffl»Sj5m^m»g d ffi^m«ffi<|m^a:«ffiio d (S '00I=.i3A -jis 'Xjioij^oaja joj A^iArjonpuoo •001 =J3ATIS 'jB9q joj XijArjonpuoo 1 1 I 1 1 1 ? 1 1 1 1 1 1 1 1 ' I 1 1 1 1 1 1 1 1 1 2 1 1 1 1 "1 1 1 1 1 71.5 31.1 66.6 63.8 25.8 62 1 •(lailBK; XiniQlsnj jo japjo 1 1=" 1 1 II 1 l x 1 I 1 1 1 II*" 1 1 1 1 1 1 1 1 1 1 1 | |«'| II •(uosuqof puB jjaApao pire 'lan^pj) ssaupji3H 16 427.08 468.75 14 468.75 13 •(lail^R) &mn -■eairBtn jo japjo 1 1 M 1 1 1 1 1 1 M 1 1 1 I 1 1 1 ^ 1 II 1 1 1 i 1 1 1 1 1 1 '-= 1 1 1 •(noisjnqx) Xjiiijonp aATjB[a>j 105.3 113.1 97.5 76.7 88.7 77.8 49.1 "ftBTIBK) XjinPnp J° JapJO 1 1 3 1 1 1 1 1 1 *- 1 1 1 1 1 1 I 2 1 1 1 1 1 1 1 1 1 1 1 1 1 » 1 | | •qout ajimbs jad spuhod 'Xjioeuax 30.688 32.600 32.670 32.928 35.630 30.520 29.344 31.580 30.510 23120 28.00) Z C S3 Finely crystalline Earthy Earthy Finely crystalline Earthy Earthy Finely crystalline Earthy Earthy Earthy Finely crystalline ti O O O Red-yellow Red-yellow Yellow Yellow-red Yellow Yellow Pale yellow Yellow Yellow Yellow Full yellow •a^iauiS ogpadg 8.415 8.673 8.633 8.598 8.650 8.638 8.574 8.528 8.397 8.576 8465 8.444 8.384 z 8.299 S. .92 8.'48- ■sisXiBins Aq uonwodnioo N 16.98 17.90 21.80 22.45 23.08 26.47 28.54 30.06 c 82.93 81.91 77.39 76.65 73.20 71.20 69.74 ■ajnjxpji [miiSjjo jo uotiisodriioo SJ 15.79 17.1 16.98 17.05 17.46 17.5 17.54 17.7 20 20.35 20.44 20.49 22.1 22.5 24.3 25 25.38 25 42 25 52 27.27 27.5 28 28.5 29.9 30 32.26 32.46 32.5 32.8 33.3 33.4 33.82 33.84 33.94 34 c *i- cc ^ d c-i -ri '13[I«W) ssau '(latl'BK) A) -■eailBiu jo j ijor PUB P-TBH II 1 i 1 1 1 1 1 11 11 1 1 1 1 1 1 1 i 1 1 IS§ 1 11 1 1 1 11 11 co 1 !I - q 1 II 1 1 1 1 1 M 1 1 1 1 1 1 1 1 1 1 1 1 1 1'" II ! 1 II 1 1 1 It tapjO ! 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CO O <0 'T I CI H 1 I ifO ?C CC 3D CJ -" O i>- 00 00 3D x 30 as as as [BUt^lJO jo uoiiisodraoo I I 5C --C I I C- CI O O 1 CJ CO »o r^ 1^ r-^ ■^ to -o 3C O CO TO © « l- L- l^ l- ' £» i> i>» 1- K i> *> f» 00 00 00 t TOO 6606 30 JL : os a. as as o o o o o — ' in — — cj o f- cj o — co3Ct-»toioinco *™:'-; u ^'^' :y| " rr< **i r>i CJ ^ <— • O O C X I"* (*■* '-C 11.. ... «COCOCOCOCOCOcOClCJCJCJCJCJCJCJCJCNCJClCJr-i^Hr-l^^-ii-l"r-lr-.^H 'Binnijoj oimo^y NNNN NN (5c5 c c SIS] S3 3 C SJSJ CCS SJSJS) NSl = S S 3 S 3 3 3 3 3 3 3 3 3 3 3 Ow^^ OO OO O;; O OO OOO OO I98 THE METALLIC ALLOYS. LIST OF AUTHORITIES. Bo. — Bolley. Essais et Recherches Chimiques , Paris, 1869. Cr. — Croockewit. Erdmann s Journal, XLV. 1848, pp. 87 to 93. C. J.— Calvert and Johnson. Phil. Mag., 18, 1850, pp. 354 to 359; ibid., 17, i8S9. PP- XI 4 to I2I j ibid., 16, 1858, pp. 381 to 383. Ma.— Matthiessen. Phil. Trans., i860, pp. 161 to 184; ibid., 1864, pp. 167 to 200. ML— Mallet. Phil. Mag., Vol. 21, 1842, pp. 66 to 68. Ri. — Riche. Annales de Chimie, 30, 1873, pp. 351 to 410. U. S. B. — Report of Committee on Metallic Alloys of United States Board appointed to test iron, steel, etc. (Thurston's Investigations.) We. — Weidemann. Pogg. Annalen, 108, 1859, pp. 393 to 407. Prof. Robert H. Thurston, who conducted the investiga- tions of the United States Board, makes the following note on the preceding table : " Alloys having the name of Bolley appended are taken from Bolley's ' Essais et Recherches Chimiques,' which gives compositions and commercial names, and mentions valuable properties, such as are given in the columns of remarks, but does not give results in figures as recorded by other authorities. The same properties and the same names are accorded by Bolley to alloys of different compositions, such as those which in the column of remarks are said to be ' suitable for forging.' It might be supposed that such properties belonged to those mixtures and not to other mixtures of similar composition. It seems probable, how- ever, that when two alloys of different mixtures of copper and zinc are found to have the same strength, color, frac- ture, and malleability, it will also be found that all alloys between these compositions will possess the same properties, and hence that instead of the particular alloys mentioned only being suitable for forging, all the alloys between the extreme compositions mentioned also possess that quality. " In the figures given from Mallet under the heads of 'order of ductility,' 'order of malleability,' 'hardness,' and ' order of fusibility,' the maximum of each of these proper- ties is represented by 1. "The figures given by Mallet for tenacity are confirmed COPPER ALLOYS. I99 by experiments of the author with a few very marked ex- ceptions. These exceptions are chiefly the figures for cop- per, for zinc, and for CuZn 2 (32.85 copper, 67.15 zinc). The figures for CuZn 2 , as given by Mallet, can, in the opinion of the author, only be explained on the supposition that the alloy tested was not CuZn 2 (32.85 copper, 67.15 zinc), but another containing a percentage of copper prob- ably as high as 55. The figure for the specific gravity (8.283) given by Mallet indicates this to be the case as does the color. The figure for ductility would indicate even a higher percentage of copper. The name ' watch- maker's brass ' in the column of remarks must be an error, as that alloy is a brittle, silver-white, and extremely weak metal. "The figures of Calvert and Johnson and Riche, as well as those of the author, give a more regular curve than can be constructed from the figures of Mallet. "The specific gravities in Riche's experiments were ob- tained both from the ingot and from powder. In some cases one, and in some cases the other, gave highest re- sults. In the table under the head of 'specific gravity,' Riche's highest average figures are given, whether these are from the ingot or from fine powder, as probably the most nearly correct. The figures by the other method, in each case, are given in the column of remarks. The figures of Riche, and Calvert and Johnson are scarcely sufficient in number to show definitely the law regulating specific gravity to composition, and the curves from their figures vary considerably. The figures of the author being much more numerous than those of earlier experimenters, a much more regular curve is obtained, especially in that part of the series which includes the yellow or useful metals. The irregularity in that part of the curve which includes the bluish-gray metals is, no doubt, due to blow-holes, as the specific gravities were in all cases determined from pieces of considerable size. If they were determined from powder. 200 THE METALLIC ALLOYS. it is probable that a more regular set of observations could be obtained, and that these would show a higher figure than 7.143, that obtained for cast-zinc. Matthiessen's figure for pure zinc (7.148) agrees very closely with that obtained by the author for the cast-zinc, which contained about 1 per cent, of lead. " The figures for hardness given by Calvert and Johnson were obtained by means of an indenting tool. The figures are on a scale in which the figure for cast-iron is taken as 1000. The alloys, opposite which the word "broke" ap- pears, were much harder than cast-iron, and the indenting tool broke them instead of making an indentation. The figures of alloys containing 17.05, 20.44, 2 5-5 2 > an d 33-94 per cent, of zinc have nearly the same figures for hardness, varying only from 427.08 to 472.92. This corresponds with what has been stated in regard to the similarity in strength, color and other properties of alloys between these com- positions." CHAPTER VII. COPPER-TIN ALLOYS. Bronze in General. The bronzes are the most celebrated of all the alloys. In ancient times, bronze already formed an important ma- terial for weapons, household utensils, and ornaments, and the opinion for a long time held by archaeologists that among the early civilized people bronze was used for these purposes prior to iron gave rise to the term bronze age being applied to an entire period. This opinion is, however, now considered erroneous.* However, the term bronze itself is not very old and seems to have first been introduced in the 15th or 16th century. The Italian author Vannuccio Biringoccio states in his " Pirotechnia," published in 1550, that alloys of copper and tin were termed bronzo, but fails to give the derivation of the word. From the Italian the term passed into the English, French, German, and other languages. Whether the opinion expressed by the French chemist Berthelot, that the alloy was originally called brondision, and that its name was derived from the city Brundusium (Brindisi), is correct, must be left undecided. The term bronze is frequently erroneously applied to mixtures of metals belonging really to the brasses, so that there is actually such a confusion of terms that many whose interest it is to have an accurate knowledge of alloys do not know what bronze actually is. In the widest sense, bronze may be designated as copper, *Complete refutations of this opinion are found in Dr. L. Beck's " Ge- schichte des Eisens," vol. 1, pp. 35, 343, 580. (20I ) 202 THE METALLIC ALLOYS. which by the absorption of other bodies, has become stronger and harder, and capable of being cast. The principal constituent of bronze, therefore, in all cases, is copper, the addition of tin only serving to modify its prop- erties. Tin, though a rather soft metal by itself, possesses, as previously mentioned, the characteristic property of im- parting great hardness to copper, so that genuine bronze takes a fine polish, and castings of it can be worked very clean with the file. On account of these qualities it is es- pecially adapted for a casting material, and its properties can be so changed that it will flow freely, or give a beauti- ful sound, or acquire the utmost degree of hardness. The ductility of bronze being but slight, only that con- taining very little tin can be converted into sheet by rolling, the operation succeeding satisfactorily at a red heat if the content of tin does not exceed 4 to 6 per cent. Bronze, as previously mentioned, being chiefly intended for casting, finds, on account of its hardness, much application in the machine industry for articles which cannot be made of iron or steel. Bronzes consisting of absolutely pure copper and tin show definite properties according to the quantity of the metals contained in them. However, in making a chemical analysis of commercial bronze, it will almost invariably be found to contain a small quantity of other metals. A sharp distinction should, however, be made as to whether these admixtures are accidental or intentional. Besides iron, manganese, nickel, lead, and zinc, very small quantities of phosphorus, arsenic, sulphur, or antimony, are sometimes found, and as a small quantity of these bodies suffices to considerably change the properties of the alloy, it is im- portant to pay some attention to their influence. Before entering on a discussion of these properties, it may, how- ever, be remarked that the difficulties many manufacturers find in obtaining alloys of determined qualities is due to the fact that they do not use as pure metals as possible by COPPER-TIN ALLOYS. 203 themselves, but melt down with them certain quantities of old bronze, which, as a rule, contains zinc, iron, or other foreign metals. A content of zinc acts upon the properties of bronze in various ways. Added to it in a very small quantity it has even a beneficial influence, the moulds being filled out sharper and the castings obtained freer from blow-holes. If, however, the addition of zinc be exceeded above a cer- tain limit, the alloy loses the characteristic properties of bronze, and especially the warm color, which passes into a more or less dull brass yellow. Besides, bronze with too large a content of zinc does not acquire on exposure to the air the beautiful green coloration termed genuine patina, but one shading into black. The addition of zinc must always be kept within very narrow limits, less than one-half per cent, of it contributing so essentially to the strength of the bronze that such an addition should be made in all cases where this property is especially desired. With an addition of up to 2 per cent, of zinc the properties of the alloy remain about the same, its elasticity being also increased to a considerable extent. With a slight increase of over 2 per cent, of zinc, the hardness as well as the tenacity of the bronze decreases to a considerable extent, and the brass-like character of the alloy soon becomes apparent. An admixture of lead has in all cases an injurious effect upon the properties of bronze. With a content of one- half per cent, the lead begins to liquate from the bronze, which makes the castings turn out unequal, and increases the oxidability of the alloy. A content of lead makes the bronze somewhat denser and more malleable, these prop- erties being, however, of little value, as the alloy is ex- clusively intended for casting. The peculiar patina of a velvety-black color found upon old Chinese bronzes is said to be the product of a content of lead ; and it is actually a fact that all Chinese bronzes contain a certain quantity of lead. 204 THE METALLIC ALLOYS. Iron affects the properties of bronze in a manner similar to zinc, imparting great hardness to it, and for this reason is frequently added to bronzes for axle-bearings and wherever they are to show great power of resistance. A content of iron has also considerable influence upon the color and gives a peculiar white tone to the bronze. It further makes it more difficult of fusion, though the cast- ings are faultless. An admixture of nickel increases the hardness of bronze to a considerable extent and decreases its toughness. On account of its costliness many declared the use of this metal as an addition to bronze impracticable. It must, however, not be forgotten that at the utmost only i to i^ per cent, of it are required to impart the desired qualities. Moreover it is not by any means the most expensive metal used as an addition to bronze, tungsten and titanium being also frequently employed for the purpose. These last- mentioned metals seem, however, to possess no special properties exerting a favorable influence upon bronze, and, though the alloys have been frequently mentioned and recommended in various periodicals, they have not gained a foothold in practice, which cannot be ascribed to their costliness, because manufacturers requiring alloys com- pletely answering certain purposes, are always willing to pay a good price for them. An admixture of very small quantities of arsenic, anti- mony, and sulphur, renders the bronze brittle, tV per cent, of either of these bodies sufficing for the purpose. Phos- phorus exerting, as is well known, an injurious influence upon most metals and alloys, acts differently in this respect as regards bronze, and, for this reason, the so-called phos- phor-bronze will be discussed later on. The physical properties of bronze are also materially af- fected by other conditions than the chemical composition, chief among which is the rapid or slow cooling off of the fused material,' which exerts so powerful an influence that COPPER-TIN ALLOYS. 205 the product with an equal chemical composition may ac- quire an entirely different appearance. According to the content of tin the color of bronze varies between red and white, and with a considerable content of tin passes into steel-gray. Generally speaking, tin exerts a greater influ- ence upon the color than zinc, the alloy with a compara- tively small Gontent of tin exhibiting no longer a red, but a white, color. Alloys containing 90 to 99 per cent, of copper retain a pure red color ; with 88 per cent, of copper it rapidly changes to orange-yellow, and with 85 per cent, becomes pure yellow. With a decrease of the content of copper to 50 per cent, the respective alloys show a slightly yellowish- white color. It is a remarkable fact that alloys with a content of copper of between 50 and 35 per cent., are dis- tinguished by a pure white color, while those containing up to 65 per cent, of tin show a steel-gray color. With a still greater percentage of tin the color of the alloys again becomes pure white. Bronze of various compositions being extensively used in the construction of machinery and the manufacture of ordnance, many physicists have occupied themselves with the determination of the propor- tions of ductility and hardness of the various alloys. But, notwithstanding the many full researches, it cannot yet be said with absolute certainty when a bronze is hardest, toughest, most ductile, etc., and we have only approximate numbers for these proportions, which may briefly be summed up as follows : Alloys with 1 to 2 per cent, of tin show nearly the same ductility as pure copper ; they can be worked in the cold under the hammer, but crack more readily than pure cop- per, this cracking showing itself especially in attempting to stretch a plate of the alloy under the hammer. The duc- tility decreases rapidly with an increase in the content of tin; an alloy containing 5 per cent, of tin can only be worked with the hammer at a red heat, but soon cracks 206 THE METALLIC ALLOYS. when it is attempted to hammer it in the cold ; alloys con- taining up to 15 per cent, of tin can no longer be hammered even in a warm state. The figures above given show that tin reduces the ductility of the copper. Its solidity is, however, considerably increased. Alloys with about 9 per cent, of tin show, according to most statements, the great- est strength of all bronzes, and in accordance with this, gun-metal has generally a content of tin approaching that limit. According to other statements alloys with about 15 per cent, possess the greatest hardness and strength. The maximum for hardness and brittleness lies between a con- tent of 28 and 35 per cent, of tin. From the results of more modern researches in regard to the strength and hardness of bronzes, the following may be deduced : The hardness increases constantly until the com- position of the alloy has reached 72.8 parts of copper and 27.2 of tin. With an increase in the content of tin the hardness decreases, it being, in a mixture of 33.33 parts of copper and 66.66 parts of tin, nearly exactly the same as that of pure copper. Above this proportion of tin the hardness decreases considerably, and with a compound of 90 parts of tin and 10 of copper is but little more than that of tin. Alloys rich in copper undergo a peculiar molecular change by forging. By subjecting alloys containing somewhat less than 94 per cent, of copper to continued forging they be- come as hard as steel, but unfortunately acquire at the same time such a degree of brittleness that they can only be used for purposes where they are not exposed to heavy shocks. Though the hardening of bronzes by forging is remark- able, there is another phenomenon yielding still more re- markable results. By quickly cooling off red-hot bronze in cold water it almost completely loses its brittleness, and can then be used for many purposes, an alloy containing 84 parts of copper and 16 of tin being most suitable for the purpose. Even a quite thick article acquires a certain COPPER-TIN ALLOYS. 2.0J flexibility through its entire thickness, which it retains after forging. If it is desired to restore an article after temper- ing to its original hardness, it need only be brought to a red heat and slowly cooled. According to the above the behavior of bronze in this respect is just the reverse cf that of steel, the latter by quick cooling becoming very hard and brittle, and by slow cooling soft and malleable. The density and hardness of bronze decrease with quick cooling and increase with slow cooling, and, hence, bronze articles quickly cooled have a deeper sound, a fact well to be con- sidered by bell-founders. The density and hardness, as well as the power of resist- ance against cracking, depend on the composition of the alloy as much as on the manner of cooling the cast articles. According to practical experience the greatest strength is secured by endeavoring to obtain the crystals of the alloy as small as possible, even the material of the mould in which the casting is effected exerting a great influence upon the grain, and through this upon the strength. Articles must be cast at a higher temperature in iron moulds than in sand moulds, one of 2912 F. (1600 C.) being required with the use of iron moulds, while one of 2552 F. (1400 C.) suffices with the use of sand moulds, especially for larger castings. Alloys suddenly subjected to a high pressure, as is the case with gun-metal, must have an especially high degree of density, the density being, however, not directly pro- portional to the composition, as will be seen from the fol- lowing table : — 208 THE METALLIC ALLOYS. Composition. Density. Copper. Tin. 96.2 3-8 8.74 94.4 5-6 8.71 92.6 7-4 8.68 91.0 9.0 8.66 89.3 10.7 8.63 87.7 12.3 8.61 86.2 13.8 8.60 75-0 25.0 8.43 50.0 50.0 8.05 Bronze bein^ exclusively used for casting, it is important to say a few words in regard to the temperatures at which the various alloys become fluid. According to Kiinzel, to whose researches we are indebted for much information re- garding the properties of bronze, the various alloys show the following melting points : — Composition. Copper. Tin. 95 5 92 8 90 10 89 11 86 14 84 16 80 20 Melting point, degrees C. 1360 1290 1250 1220 1 150 1 100 1020 Articles cast of bronze contract in solidifying, as is the case with other mixtures of metals, the degree of contrac- tion depending on the temperature of the alloy and its composition, and amounts to yio to tt of the bulk of the various mixtures. The difficulty of obtaining perfect castings is, however, COPPER-TIN ALLOYS. 209 more increased by the chemical behavior of the alloys towards the oxygen of the atmosphere than by contraction. In subjecting the bronze to fusion, the tin shows greater affinity for oxygen than the copper, and hence by remelting the bronze several times, it becomes sensibly richer in cop- per by a portion of the tin being lost by oxidation. To prevent a change in the qualities of the alloy, a larger quantity of tin than the finished product is to contain is generally added, so that the tin lost by volatilization is equal to the excess added, and the alloy obtained shows exactly the desired composition. Another effect of the oxygen of the atmosphere consists in the oxides of the constituent metals of the bronze — ■ stannic oxide and cuprous oxide — dissolving in the allov, whereby its strength and toughness are considerably de- creased. In the manufacture of ordnance a portion of the metal required is generally obtained by melting down old cannon. The mixture of metals thus obtained containing frequently large quantities of the metallic oxides in solu- tion, the toughness and strength of the new alloys are con- siderably impaired. The melted bronze shows another property frequently observed in other metals, especially in gold and silver : it can absorb a considerable quantity of oxygen, but allows it to escape in a gaseous state on cooling. If now, as is done in most cases, the castings are rapidly cooled off, the bronze becomes so thickly-fluid that the absorbed oxvgen cannot escape, and the resulting castings are full of in- numerable, though microscopically small, hollow spaces, which injure the density and strength of the alloy. The absorption of oxygen, as will be seen from the above, being very injurious to the qualities of the bronze, precau- tions have to be taken to protect the metal from the effect of oxygen in fusing as well as in casting. The best pre- ventative against the absorption of oxygen is to protect the alloy by a layer of glowing charcoal, and to effect a reduc- 210 THE METALLIC ALLOYS. tion of any oxides formed by vigorous stirring of the fused alloy with a stick of green wood. Though oxidation is counteracted by these means, it is not possible to remove by them the oxygen reaching the alloy from oxygenous material. Phosphorus has, however, been found an excel- lent agent for the deoxidation of the oxides dissolved in the metal, but it has to be added very carefully, since a small quantity of it in excess exerts great influence upon the properties of the alloy itself. In most cases an addition of tcmTo to t^oot suffices for the reduction of the oxides in solution. The tin oxidizing more readily, it is, as a rule, advisable to fuse the copper first, and then quickly introduce the tin. The heat should at the same time be increased so as to keep the alloy very thinly-fluid, the union of the two metals being accelerated by these means. The melted mass should at the same time be vigorously stirred with wooden rods, which not only accelerates the mixing but also counteracts the oxidation of the tin. Even with the use of all the above-mentioned precautions, the loss in fusing and casting always amounts to several per cent, of the weight of the metals used. Work where the loss is only one to two per cent, may be called excellent, as in many cases it amounts to ten per cent. The loss of metal as well as the qualities of the castings are also considerably affected by the construction of the melt- ing furnace. The more quickly the furnace can be heated to the temperature required for reducing the alloy to a fluid state the better it is for the purpose, for even with perfect protection against the action of oxygen, changes injurious to the homogeneity of the castings take place with long-con- tinued fusion. If a bronze be intentionally kept in a fluid state for a long time, a white alloy very rich in tin is formed in it and is clearly perceptible in the castings. The alloy is no longer homogeneous, but actually consists of a mix- ture of several alloys differing very much in density, power COPPER-TIN ALLOYS. 211 of resistance and strength, which seriously impairs the properties of the entire mixture. This separation or liqua- tion of the alloy into two or more compounds occurs specially in mixtures most frequently used, i. e., such as contain between 5 and 20 per cent, of tin; from alloys con- taining a lower or higher percentage of tin, homogeneous castings are more readily obtained. Most bronzes have a strong tendency towards liquation and it is difficult to make thick castings from them without this liquation becoming perceptible. It is particularly plain to the eye with an alloy containing about 10 per cent, of Fig. 17. tin, the reddish fracture of which, if cooling has not been effected very rapidly, shows white spots, so-called tin-stains, due to an alloy richer in tin. Although the liquation of bronzes has been the subject of numerous investigations, the opinions regarding the con- stitution of the bodies imbedded alongside each other in the solidified bronze have not yet been entirely elucidated. Fig. 17 shows the ground surface, 365 times magnified, of a copper-tin alloy with 12 per cent, tin, after etching with cupro-ammonium chloride and annealing, a are mixed 212 THE METALLIC ALLOYS. crystals of copper and of a copper-tin combination. They form the constituent richest in copper of the structure and, as a rule, show a core somewhat richer in copper and a border somewhat richer in tin in consequence of the im- perfect equilibrium between the separated crystals and the alloy still remaining fluid, b is a constituent 1 of the struc- ture richer in tin which is imbedded between the crystals a, and with a low content of tin appears as the eutectic alloy, while the latter, with the above-mentioned content of tin is formed by the included alloy 3 which is still richer in tin. Since the liquation of an alloy rich in tin is promoted by slow cooling, the melted mass, which has a temperature of about 2552 F., must be cooled down as quickly as possi- ble to 932 F., at which point, according to experience, the alloy richest in tin solidifies. This is, however, connected with many difficulties, especially in casting large pieces, such as cannon and bells, for which a perfect homogeneous metal is an absolute necessity. The behavior of the solidified alloys towards the atmos- phere varies according to their chemical composition, i. e., they oxidize, on exposure to the air, in a shorter or longer time, acquiring thereby a color ranging from a beautiful green to black. This layer of oxide, which contributes much to the aesthetic effect produced by an article of bronze, is an important factor, especially to those occupied with casting statues, etc., and will be referred to later on. Melting and Casting of Bronze. The quantity of bronze to be prepared at one time varies according to the article to be cast, and may amount to a few ounces, or hundreds or thousands of pounds. Though the mode of preparing the bronze is the same in all cases, in the practice certain difficulties occur in casting small articles as well as large ones, which deserve attention. For casting small articles a finished alloy of the desired proportions of metals is generally used, it being very diffi- COPPER-TIN ALLOYS. 213 cult to hit the exact composition required in preparing small quantities of bronze. The fusion, in this case, is al- ways effected in crucibles, special care being required to prevent as much as possible oxidation of the tin. The crucibles are placed in a wind-furnace and the surface of the bronze is kept carefully covered with pulverized coal, anthracite being best for the purpose on account of its great density. Attention has already been drawn to the fact that the temperature of the fused metal exerts a considerable influ- ence upon the quality of the casting. Experience has shown that for small articles the bronze must not be heated too strongly, as otherwise the resulting casting is blown, and one blow-hole suffices to spoil it entirely. Articles to be subjected to hammering or stretching after casting must also not be cast too hot, in order to prevent them from acquiring a too coarsely crystalline structure. Small castings cool off rapidly, but the effect of this, es- pecially if not uniform, is to make portions of the mass considerably harder in some parts than in others, which renders mechanical manipulation difficult. It is therefore advisable to thoroughly heat the moulds before use, and to surround them with a bad conductor, for instance ashes, and also cover them with a layer of the same material after finishing the casting. Moulds of cast-iron or brass are generally used for small castings, which, in order to pro- tect them, are coated with a mass consisting of lamp-black and oil of turpentine. The preparation of large quantities of bronze as required for casting bells, cannon, or statues, is effected in reverbera- tory furnaces capable of holding up to 10,000 pounds of bronze or more. The copper is first melted, and, when fluid, any old bronze to be used is added. When all is con- verted into a uniform mass, the tin, previously heated as much as possible, is introduced in small portions. Immed- iately before the introduction of the tin, the fire must be 214 THE METALLIC ALLOYS. increased in order to compensate for the consequent reduc- tion of the temperature, and to keep the metal in a thinly- fluid state. Figs. 18 and 19 show the arrangement of a reverberatory furnace especially adapted for melting not too large a quantity of bronze. F is the fire-box, and G the ash-pit. The metals to be melted are placed upon the Figs. 18 and 19. trough-shaped hearth H, while the aperture D serves for the introduction of the charge and for taking samples. The finished bronze is run off through the aperture D. For large articles loam moulds are almost exclusively used, sand moulds being but seldom employed. While, as pre- viously stated, it is advisable in casting small articles not to have the bronze too hot, for casting large objects it should COPPER-TIN ALLOYS. 215 be very hot in order to render the production of uniform casting's possible by keeping the mass in a fluid state for some time, and thus giving the gases evolved, as well as the oxides, a chance to rise to the surface. Figs. 20 and 21. Figs. 20 and 21 show the construction of a furnace espec- ially adapted for melting a large quantity of bronze, which is to be as uniform as possible. The furnace, shown in Fig. 20 in section, and in Fig. 21 in ground-plan, has a capacity of about 16,200 pounds of bronze. Its total length 2l6 THE METALLIC ALLOYS. is 13 feet, and it is heated with wood. F is the fire-box and A the ash-pit, while the metals are melted in the space B, between P and G. K is the stoking-channel, which can be closed by the slide 6\ The aperture O serves for the in- troduction of the large pieces of metal, and the openings on the side for adding smaller pieces. G is the tap-hole closed during melting by a plug of clay. The base of the hearth in these furnaces is, as will be seen from the illustrations, trapeziform, though there are other constructions in which it is elliptical or oval, or even circular, the latter form being frequently used, for instance, in casting statuary bronze. Figs. 22 and 23 show the con- struction of such a furnace, 5" being the hearth, A the fire- box, and D the foundry-pit in which the mould is placed. The aperture above 5* serves for the introduction of the metals, and that above D, which is closed during the melt- ing with a plug of clay, for running 'off the fused metal. In a furnace of this kind up to 26,500 pounds of bronze can be melted for one casting. It is possible to construct furnaces of larger dimensions, but, on account of more uni- form heating, it is recommended to use in this case several fire-places arranged on the circumference of the melting hearth. The different kinds of bronze. — It will, of course, be readily understood that the composition of bronze must vary very much according to the purpose for which it is to be used. In practice a large number of alloys are dis- tinguished, which, according to their application, are known by various names. To retain this division would lead to the enumeration of a large number of names, and we must therefore restrict ourselves to those most frequently used, such as gun-metal, statuary bronze, speculum metal, etc. Before proceeding with the description of the prepara- tion of the alloys serving for these purposes, it will be con- venient to briefly refer to the bronzes of prehistoric times. It is well known that bronze was extensively used by the COPPER-TIN ALLOYS. 217 ancients for coins, weapons, tools and ornaments. It might be supposed, at first sight, from the castings of the ancients, that they possessed some very expeditious and simple means of making their enormous and numerous productions Figs. 22 and 23. in this department; but upon closer inspection this con- clusion appears untenable, for many analyses of their alloys have demonstrated the fact that their bronzes were not a 2l8 THE METALLIC ALLOYS. constant composition of copper and tin, but contained fre- quently foreign metals, which cannot be considered as in- tentional additions, but only as accidental contaminations. Hence the success of a bronze of good composition was, no doubt, at that time, more a matter of accident than is possible with our present knowledge in regard to alloys, and the analyses of old bronzes can only give us hints about the behavior of the metals in the presence of sub- stances to be considered as contaminations, without, how- ever, contributing to the advancement of information in regard to the alloys. The researches made in modern times, especially as regards gun-metal, are so exhaustive in respect to the influence of the chemical composition of the alloy upon its physical qualities as to enable us to prepare alloys with any desired properties. While the older bronzes, especially those of Greek origin, consisted almost only of copper and tin, in the older Roman coins considerable quantities of lead are frequently found, which must be considered as an intentional addition. Zinc seems to have first been intentionally added to bronze in the beginning of the present era. The exact composition of bronze has only been determined in modern times with the assistance of chemistry, the effect produced by the dif- ferent elements upon the properties of the bronze, as well as the influence upon its physical qualities by rapid or slow cooling off, being now quite well understood. But that we have not yet arrived at a full knowledge of these properties is well seen from phenomena which in modern times have excited the interest of all technologists, it being only neces- sary to refer in this respect to phosphor-bronze and Uchatius's so-called steel-bronze. COPPER-TIN ALLOYS. 219 Composition of some ancient bronzes : I. II. III. IV. V. VI. VII. VIII. IX. Copper 86.38 80.91 88.70 92.07 68.42 81.76 83.65 88.06 95.0 Tin 1.94 7.55 2.58 1.04 0.94 10.90 15.99 1 1 76 4-5 Zinc 3.36 3.08 3.71 2.65 — — — Lead 5.68 5.33 3.54 — 22.76 5.25 — 0.2 Antimony.... 1.61 0.44 0.10 — 0.67 — — — — Iron 0.67 1.34 1.07 3.64 4.69 0.15 trace trace 0.3 Nickel — — — — 0.78 trace 0.63 trace — Cobalt — — — — — 1.22 — — — Sulphur — 0.31 — — — — — — — Arsenic — — — — 1.48 — — — — Phosphorus . . — — — — — — 0.05 0.03 — Silica 0.10 0.16 0.09 0.04 — — — — — Loss 0.26 0.79 0.21 0.56 0.26 0.72 — 0.15 — Nos. i to 4 are examples from Japanese temples, according to Mauene; No. 5, an Egyptian figure, according to Flight, No. 6, from Cyprus at the time of Alexander the Great, ac- cording to Reyer ; No. 7, an axe from Limburg with a thick coat of green patina, according to Reyer ; No. 8, a chisel of a dark yellow color from Peschiera, according to Reyer; No. 9, old German chisel, according to Boussin- gault. A Japanese bronze statue of Buddha weighing 450 tons is composed of copper 98.06, tin 1.68, mercury 0.21, gold 0.05. Ordnance or Guit-Metal. The use of bronze for casting cannon is said to have been known by the Arabs as early as the commencement of the twelfth century ; in Germany the first bronze cannon were manufactured towards the end of the fourteenth century. Prior to that, after the invention of gunpowder, cannon of wrought-iron bars put together in the shape of a barrel and hooped with iron were used. While wrought-iron guns soon burst in consequence of the crystalline texture formed, cast-iron cannon of mottled iron are much more durable. Modern cannon of cast-steel are lighter, cheaper and gen- erally more durable than bronze. 220 THE METALLIC ALLOYS. More money and labor have been spent on the study of gun-metal than on any other alloy, the governments of several of the larger countries having expended millions of dollars in experiments to find out the best alloys for the manufacture of ordnance. But that, notwithstanding all this, a final result has not yet been arrived at is best proved by the many different opinions, some diametrically opposed to each other, in regard to the value of, for instance, the previously mentioned steel-bronze. The properties demanded from a good gun-metal follow from the use of the cannon themselves. In firing a cannon an immense pressure, amounting to over 2000 atmospheres, is suddenly developed. To resist this pressure the material must possess great toughness, and cannon manufactured from bronze lacking this toughness burst generally with the trial-shots, for which especially large charges of powder are used. Gun-metal must further possess a high degree of hardness, as in firing the projectile strikes once or several times against the walls of the piece, it being impossible to give the same size mathematically accurate to the calibre of the piece and that of the projectile. If the bronze be not sufficiently hard, the interior of the piece loses after a few shots its cylindrical form, which is detrimental to the ac- curacy of the shot. Finally it must be considered that the gases evolved by the combustion of the powder attack the substance of the piece itself, and hence the composition of the bronze must be such that this chemical action is re- duced to a minimum. Briefly stated, good gun-metal must be very tough, capable of resistance, hard, and indifferent towards chemi- cal influences, conditions which vary much from each other and are difficult to combine. In order to obtain these properties all possible additions have been made to the actual bronze (consisting of tin and copper), and analyses of ordnance metal of different cent- uries and various countries plainly show the efforts made COPPER-TIN ALLOYS. 221 to arrive at a correct composition of gun-metal by certain admixtures. In modern times the addition of foreign metals, with the exception of a small quantity of zinc or, in special cases, of phosphorus, seems to have been aband- oned, the quality of the bronze being adapted to the desired purposes by suitable treatment in melting and casting. In older pieces a series of foreign metals is found, some of which as, for instance, nickel and cobalt, must be considered as accidental contaminations, since the preparation of these metals in a metallic form has only been known during more recent times. Iron, if present in a considerable quantity, is, no doubt, an intentional addition, and a content of bis- muth can be explained by the fact that in connection with arsenic it was formerly used as a flux in the bronze mixture. The content of tin in bronze which by experience gath- ered in the course of centuries has been found most suit- able for casting ordnance, varies between 9 and 1 1 parts of it to 89 to 91 parts of copper. This composition corre- sponds quite closely to that used by the Greeks and other nations of ancient times for their weapons. So many details essential for the success of the operation are connected with the melting and casting of alloys for the manufacture of pieces of ordnance, that a special volume would be required for a complete description of the various processes. We can, therefore, only give the merest out- line, and must refer . those especially interested to the treatises published on this subject. The principal requisite of an alloy answering all the demands of a good ordnance- bronze is the production of an entirely homogeneous cast- ing, which it is endeavored to attain by solidifying the alloy under conditions allowing of its uniform cooling off. The moulds are always placed in a vertical position, and as the upper portions of the casting show frequently a different composition from the lower, this drawback is counteracted by using an excess of bronze, so that the finished casting has a long piece on top, the so-called "dead-head" or " sul- 222 THE METALLIC ALLOYS. lage-piece/' which is later on sawed off and remelted with a new charge. This dead-head contains the greater portion of the alloys of dissimilar composition, and also the so- called "waste," consisting of oxidized metal. Figs. 24 and 25 show a double furnace in use in the gun- Fig. 24. Fig. 25. foundry at Spandau, in which 16,000 lbs. of gun-metal can be melted at one„ time, b is an opening through which larger masses may be brought upon the hearth, after which it is bricked up ; a and c serve for the introduction of smaller masses of metal and for stirring ; e is the tap-hole ; d and /, COPPER-TIN ALLOYS. 223 looking holes ; g, flue. The portions indicated by k are constructed of refractory material. In this furnace the fusion of 16,000 lbs. of metal is effected in 3^ hours. In several French foundries a shaft-furnace after the prin- cipal of Herbetz's steam-injector furnace is used, but the furnace works without steam, only the natural draught of Fig. 26. K ir^ iMflf' ^ 1 ! 1 ! 1 ! 1 I 1 I ' /. — [ — 1 — 1 — 1 — 1 — 1 — 1 — 1 — ] — 1 — 1 — I I I h I I I I ' I ! I ! ' 1 I J -I ; I ; I ; -^ ^ a sheet-iron chimney 82 feet high being used. The fur- nace shaft A (Fig. 26), \2% feet high and 2^ to 3 feet in diameter, contains the furnace and is supported in a frame by four cast-iron columes B, to which is also secured the movable hearth C, so that it can be raised or lowered at will by means of screws a, and the operator has it in his 224 THE METALLIC ALLOYS. power to regulate, according to the quality of the coke used, the width of the slit b between the edges of the shaft and the hearth which serves for the admission of air. c, c are looking holes ; d, a Langen apparatus for closing the mouth of the shaft ; e, a pipe conducting the gas into the chimney D. This furnace has the following advantages over a crucible furnace : Omission of crucible and blast, produc- tion of a beautiful fine-grained bronze on account of the evaporation of zinc present as contamination, consump- tion of only about 12 per cent, coke against 40 per cent, with crucible furnaces, more rapid fusion, and production of castings of any desired size with but one tapping. In casting ordnance old cannon are frequently melted in, the practice in the opinion of many experts producing a favorable influence upon the homogeneousness of the re- sulting new material. The loss of tin by oxidation is also smaller, since tin once united with copper does not oxidize so readily as in the preparation of new alloys. But in order to obtain a homogeneous product great experience is re- quired, and after the metals are melted, samples must be taken and examined as to their qualities, so that if the com- position be not correct it can be improved by a suitable addition of copper or tin, or old bronze, as may be found necessary. A considerable time being, however, required for the newly added metals to form a homogeneous com- bination with the material already melted, great precaution is necessary to prevent the oxidation of the metals as much as possible. Strictly taken, it would be best to use gas only for melting bronze mixtures, since with the practice of this mode of firing not only the heat can be regulated at will, but a flame containing no free oxygen, and conse- quently capable of completely preventing the formation of waste, can be passed over the fusing mixture of metals. The temperature at which ordnance-bronze is cast also exerts considerable influence upon its physical properties, one of about 2822 F. appearing to be the most suitable. COPPER-TIN ALLOYS. 225 Cannon cast at this temperature are distinguished by great homogeneousness throughout the entire mass, and besides there need be no fear of the separation of the so-called tin-spots, one of which, if located in a place especially sub- jected to strong pressure in firing, suffices to render the entire piece useless in a short time. Ordnance-bronze should be cooled off rapidly, this also decreasing the danger of the formation of tin-spots. Iron moulds are frequently used, but they must not be too cold, as otherwise the layers of bronze coming in immediate con- tact with the iron solidify so quickly as to prevent the mobility of the still fluid mass in the interior, which would produce an unequal tension of the molecules, in consequence of which the piece might burst with the first shot. In many ordnance-foundries sand moulds are used, there being a great diversity of opinion as to which method of casting is the most suitable. Cannon are now generally cast solid, and the cylindrical cavity is formed by boring out this solid mass. Some, however, consider it preferable to cast the piece over an iron mandrel, which is sometimes so arranged that water can circulate in it in order that the parts nearest to it may quickly solidify and become as hard as possible. Steel-bronze. — The ordnance-bronze known under this name is prepared in the Austrian arsenals, the method of melting and subsequent treatment in casting being kept secret. It is only known that the bronze contains 8 per cent, of tin, and that the casting is effected in cold iron moulds. The peculiarity of the process of manufacturing ordnance from steel-bronze (also called Uchatius-bronze, after its inventor) consists in the piece after being finished to a certain extent being subjected to a peculiar mechanical treatment. The calibre of the piece is made smaller than it is finally to be, and is then gradually enlarged to the re- quired diameter by steel-cylinders with conical points being forced through the cavity with the assistance of hydraulic presses. In consequence of this peculiar treatment the 15 226 THE METALLIC ALLOYS. cavity is, so to say, rolled or forged, the bronze acquiring the greatest power of resistance in those places which in firing are subjected to the greatest pressure. The following table shows the composition of ordnance- bronze of various times and different countries : — Parts. Copper. Tin. Lead. Zinc. Iron. Brass. United States 90 90.09 90.90 89.30 100 100 88.61 88.929 77.18 93-19 71.16 89.58 95-20 10 9.9 9.1 10.7 12.0 10.7 10.375 3-42 5-43 10.15 4.71 0.062 13.22 0.419 5.02 27.36 0.69 0.110 1-.16 1.38 1.40 France (modern) Prussia — England France ( i 780) 61.0 Savoy (Turin, 1771) Russia (1819) 6.0 Lucerne (Switzerland) . . . Cochin China -j China Turkey (1464) < — Bell-Metal. It was known in ancient times that certain alloys which, by reason of their composition, have to be classed with the bronzes, are distinguished by a specially pure tone on being struck. The ancient Hebrews, Babylonians and Egyptians made use of small hand-bells, and cymbals, especially at festivals and dances. The Romans had small bells at their house-doors and in the baths. In the temple of Proserpina at Athens bells announced the hour of the sacrifice ; they sounded as a martial signal, and were secured to the tri- umphal car of the conqueror. The actual church bells were first introduced by Paulinus, Bishop of Nola in Campania.* In France bells were introduced about the middle of the sixth century, somewhat later in England, but in Germany * Hence the word campanile. COPPER-TIN ALLOYS. 227 only in the nth century. The largest bells were cast in the middle ages, bell-founding flourishing especially from near the end of the 15th to the commencement of the 16th cen- tury. The weight of some of such large bells is as follows ; Ivan Weliki at Moscow, Russia cast in- 1653, 528,000 lbs.; this bell, as well as another weighing 316,800 lbs., at the same place, fell down. Two other bells at the same place weigh 176,000 and 156,200 lbs. respectively. A bell in Toulouse, France, weighs 60,500 lbs., one in the Stephan's tower, Vienna, 56,540 lbs., in St. Peter's church at Rome, 41,800 lbs., at Olmiitz, 39,600 lbs., at Notre Dame, Paris, 35,640 lbs., at Milan, 33,000 lbs., and one, at Erfurt, cast in 1497, 30,250 lbs. Older bells in the cathedral at Cologne weigh 24,200 lbs. and 13,200 lbs. respectively, while the new Kaiser bell weighs 59,730 lbs. ; it is 10 feet 8 inches high and n feet 4 inches wide. Bell-metal must be hard to give a sound and not to suf- fer a change in form when the bell is subjected to the fre- quently repeated action of the clapper or tongue. It must therefore contain more tin 'than gun-metal. But notwith- standing the high content of tin it should not be more brittle than can be helped so as not to crack under these effects. For this reason the addition of other metals, besides copper and tin is excluded ; in fact it is useless and in most cases injurious. Experience has shown that the best proportion of the two constituent metals is 20 to 23 parts tin to jy to 80 parts copper. The quantities of inci- dental foreign constituents present, such as lead, iron, nickel, will of course be the greater, the more impurities are contained in the two metals used, and will therefore appear, as a rule, in greater abundance in old, than in new, bells. The content of lead amounts usually to 1 to 4 per cent. In some bells up to 1 per cent, of silver has been found, the opinion being formerly held that an addition of silver adds to the beauty of the sound, though from what has been previously said, it will be understood that such is not the case. 228 THE METALLIC ALLOYS. Bell-metal is brittle and cracks under the hammer, cold as well as heated. If it be repeatedly brought to a dark- red heat and quickly cooled by immersion in water, its brittleness is so far reduced that it can be hammered and stamped. The color of good bell-metal is a peculiar gray- white, differing materially from that of gun-metal and stat- uary bronze. The bell-founder judges the correct composi- tion of the bell-metal by the appearance of the fracture ; if the latter is too fine-grained the alloy is too rich in tin ; if too coarse-grained it contains too little tin. The fracture is generally fine-grained and of a gray color. This is due to the brittleness of the whitish mixture rich in tin which more and more predominates and almost exclusively forms the surface of the fracture. The structure is distinguished from that of gun-metal by the predominance of denditric formations. It is scarcely possible to find upon the ground surfaces traces of net-work, aggregates of crystals resem- bling fir-tree branches appearing almost always, calling to mind by form and fineness chilled 10 per cent, bronze, but of a pale-yellow color and separated by an abundance of an intermediary substance of a grayish or whitish color. Independent of the quality of the material used the tone of a bell depends materially on its size and form, the thick- ness of the walls and the proportion of height to diameter being also of importance for a beautiful and pure tone. The skill of the bell-founder lies not so much in finding the right composition of the alloy, this being thoroughly under- stood at the present time, as in giving the bell a shape cor- responding to a certain tone, which is of special importance for chimes. The melting and casting of bell-metal is not so difficult as that of ordnance-bronze, though great analogy exists be- tween them. The copper is first melted down, and after heating the fused mass as much as possible, the tin is intro- duced and an intimate mixture promoted by vigorous stir- ring. Many bell-founders do not add all the tin at once, COPPER-TIN ALLOYS. 229 but at first about two-thirds of it, and when this has formed a union with the copper, the other third. It rarely happens that only new materials are used in preparing the bell-metal, old bells and ordnance-bronze being worked in large quantities. The composition of these should, however, be known so that the mean of the alloy will be such as to yield a bell of the required quality. For this purpose it is best to melt small portions of the respective metals together in the same proportions in which they are to be fused on a large scale. From the quality of these test-pieces it will then be seen whether a change in the composition of the alloy is necessary. It is still more preferable to ascertain by a chemical analysis the centesimal composition of the metals, since the appearance of the fracture, color, and degree of brittleness give rise to error. It has been frequently observed that bells repeatedly re- melted acquire a disagreeable tone. The principal reason for this change is found in the solution of oxide in the alloy. This evil can be overcome by deoxidizing the mix- ture of metals, to which we will refer later on. While the composition of bell-metal for large bells is always within the above-mentioned limits, the material used for the man- ufacture of small tower-bells, table-bells, etc., varies very much, mixtures being often used which can actually not be classed as bell-metal, they being frequently only tin alloyed with a small quantity of copper and a little antimony. The following table shows the composition of some bell- metals : — 230 THE METALLIC ALLOYS. Normal composition ■< Alarm bell at Rouen Alarm bell at Ziegenhain . Alarm bell at Darmstadt.. Alarm bell at Reichenhall (13th century) Tam-tam r Bells of Japanese origin. -\ I Parts. Copper. Tin. Zinc. Lead. ■ Silver. Iron. 80 20 _ 78 22 — — — — 76.1 22.3 1.6 — 1.6 71.48 33-59 — 4.04 — •: .12 73-94 21.67 — 1. 19 0.17 — 80 20 — — 78.51 10.27 — 0.52 0.18 — 10 4 i-5 — 0-5 10 2-5 0.5 1-33 — — 10 3 1 2 y 2 10 For small clock-bells, table-bells, sleigh-bells, etc., an alloy giving a clear and pure tone has to be used. Ex- perience has shown that bell-metal with about 22 per cent, of tin gives the finest tone, and can therefore be suitably used for small bells. However, it is an object to use as cheap an alloy as possible for these purposes by a reduc- tion of the content of the expensive copper. The following table will suffice to show the composition of such alloys : Parts. Copper. Tin. Zinc. Lead. Silver. Anti- mony. Bis- muth . House-bells 80 75 73 74-5 72.0 84-5 17 20 25 24-3 25 26.56 15.42 800 7 2.7 0.5 1-44 0.1 1 House-bells, smaller. Clock-bells, German . Clock-bells, Swiss . . . Clock-bells, Paris .... Sleigh-bells — White table-bells White table-bells 5 Chinese tam-tams or goiigs are distinguished by a strong, far-reaching sound. The alloy of which they are made con- COPPER-TIN ALLOYS. 23I sists in the mean of 80 parts copper and 20 parts tin. Genuine Chinese tam-tams are made, as shown by their appearance, from a thicker block of metal by forging with the hammer. However, bell-metal of the composition mentioned above is quite brittle at the ordinary tempera- ture as well as at bright red heat, and its brittleness is but slightly decreased by tempering. The secret of the manu- facture of tam-tams is found in the previously mentioned property of these alloys to suddenly become malleable at a perfectly dark red heat, but to rapidly lose this malleability at higher, as well as lower, temperatures. Algiers metal {metal d' Alger). — This metal has a nearly pure white color and takes a beautiful polish. It can scarcely be classed with bell-metal, its composition having nothing in common with it. It is composed of copper 5 parts, tin 94.5, and antimony 0.5. The antimony is very likely added to give greater hardness. Large bells are cast in loam moulds. The figures or de- signs with which the bell is to be ornamented are placed in the mould, the portions which have been left imperfect in casting being mended after the cast bell is cold. Small bells are generally cast in sand moulds, though recently iron moulds are frequently used. Silver bell-metal. — This alloy suitable for small bells is distinguished by a beautiful silver-clear tone, and a nearly white color. It is composed of: Parts. I. Copper 40 Tin 60 Bronzes for Various Purposes. As previously stated the properties of bronze may be varied within very wide limits according to the purpose for which it is to be used. A few of the most important bronzes used in the various branches of industry are here II. in. 41-5 41.6 58.5 58.4 2$2 THE METALLIC ALLOYS. given. To enter on a detailed description of all these alloys is scarcely practicable, since many manufacturers preparing" bronzes for their special purposes use alloys which, as regards their centesimal composition (in respect to copper and tin), show considerable variations, and sometimes con- tain other metals as additions, which, according to the assertions of the manufacturers, impart to them exactly the properties desired. According to the purposes for which the bronzes are to be used they may be designated, besides those already mentioned, as machine bronze (for bearings and pieces sub- ject to severe friction), coin and medal bronze, and ormolu. The last alloy is chiefly used for small articles of art, and is by many classed among statuary bronze, but incorrectly so,, because the latter, as will be explained later on, cannot be termed a bronze in the actual sense of the word. Besides the above-mentioned varieties of bronze, there remains to be mentioned the speculum metal, which was formerly much used for mirrors of optical instruments, but at the present its application is limited, these mirrors being now made by a cheaper process and at the same time of greater power. Medal and coin-bronze. — A bronze suitable for these pur- poses must have a certain degree of ductility, be able to receive a true impression, and wear well. In many countries the baser coin is now made of a bronze-like alloy instead of pure copper as formerly, it being better calculated to resist the injuries it is likely to receive in circulation. The bronze used in casting medals contains a variable proportion of tin, ranging generally from 4 to 10 per cent., according to the depth of the impression. Bronzes containing about 8 per cent, of tin are distinguished by great hardness, but can be rendered sufficiently soft for stamping by heating to a red heat and tempering. This variety of bronze is chiefly used for medals which, besides being distinguished by artistic execution, are to have considerable durability. If the impression is to be quite deep, or if the medals are to be stamped several times, they must be repeatedly annealed- COPPER-TIN ALLOYS. 233 An addition of a very small quantity of lead and zinc has a favorable effect upon the metal to be used for medals. It renders it softer, so that it can be worked with greater ease, and its color and fusibility are also improved. The baser coin of many countries (France, Switzerland, Belgium, Italy, etc.) consists of a bronze of varying com- position. The copper coin manufactured in France since 1852 consists, for instance, of copper 95 parts, tin 4, and zinc 1. This alloy has stood the test of time, coins stamped in 1852 still showing the impression in all its details, which is sufficient proof of its durability. Coin-bronze as made by the Greeks and Romans contained from 96 parts of cop- per and 4 of tin, to 98 parts of copper and 2 of tin. Chaudet has shown that the first of these alloys can be used for fine work, medals of this composition taking a very perfect polish while sufficiently hard to wear well. Many medals, as is well known, do not show the color of bronze, but a pleasant brown, subsequently produced by oxidation. A bronze which, on account of its pale-red color, is especially adapted for medals with figures in high relief, consists of a mixture rich in copper. It is at the same time very flexible, so that the medals can be stamped without an expense of great power. This bronze consists of copper 97 parts, tin 2, and lead 1. Medals whose size does not exceed a certain limit are at present stamped from sheet rolled out to the required thickness, and the blanks thus obtained stamped with the impression, this method being also used in making coins. For large medals with impressions in very high relief plates are prepared by casting, the model of the medal being used in order to obtain plates already somewhat raised or de- pressed on the respective places. As soon as the pieces cast in sand are solidified, they are thrown in cold water to give them the required degree of softness. After subject- ing them to one or two pressures in the stamping-press, they must be again annealed in order to prevent cracking of the edges. 234 THE METALLIC ALLOYS. Ormolu {or moulu). — This alloy is much used for small statues, candlesticks, inkstands, etc., but serves also for purely artistic purposes. It .also finds a very interesting application in the manufacture of articles coated with enamel. The enamel is placed in shallow cavities chiseled in the surface of the bronze and fused by heating the latter. Enamel of various colors can be used, each color being terminated by the edges of the cavities, and the articles after heating appear coated with the tightly-adhering enamel. Such work is termed email cloisonne - . It became known in Europe through Chinese articles, but at present the European product by far surpasses the Chinese. Below we give the composition of a few bronzes which can be classed with ormolu. They are much used in the manufacture of small articles of art, this industry being car- ried on to an enormous extent in Paris and Vienna. Actual ormolu. — This bronze is distinguished by a pure golden-yellow color, and requires but little gold for gild- ing. It is much used for the finest bronze articles of lux- ury. It is composed of copper 58.3 parts, tin 16.7, zinc 25.3. Bronze for small castings. — For articles to be prepared in large quantities, it is desirable to have a bronze which becomes very thinly-fluid in the heat and fills out the moulds. Cast-iron moulds are generally used, and the articles, as a rule, turning out very clean, can be at once brought into commerce after mending imperfect parts. A bronze of excellent quality for this purpose is composed of copper 94.12 parts, tin 5.88. Gold bro?ize. — For many articles which are to present a beautiful appearance without being too expensive, it is scarcely practicable to provide them with a coating of gen- uine gold. An effort must, therefore, be made to impart to the alloy to be used a color resembling as closely as possible that of gold. A mixture possessing these proper- ties in a high degree is composed of copper 90.5 parts, tin 6.5, and zinc 3.0. This alloy retains its beautiful gold color COPPER-TIN ALLOYS. 235 on exposure to the air, but loses it rapidly if exposed to both air and water. Articles manufactured from it, if kept in a room, retain their color, and in the course of time act like all genuine bronzes, i. e., they become covered with the characteristic green coating know as genuine patina, which is so highly valued on account of bringing out the beauty of the contours. According to Marechal and Saunier, a beautiful gold bronze is obtained if the tin be first purified by fusing with nitrate of soda, and the copper by fusing with saltpetre and potassium cyanide, and adding to the fused copper argol and potassium cyanide. The metals thus prepared are fused together with the addition of a mixture of sal am- moniac, potassium cyanide, phosphor-copper and Marseilles (castile) soap ; before pouring out, a small quantity of sodium is added to make the alloy non-oxidizable. Bronze to be gilded. — Every kind of bronze can be gilded, the gold. adhering with great tenacity. An example of this is furnished in the equestrian statue of the Emperor Marcus Aurelius, standing in front of the capitol at Rome, which still showtracess of the gold with which it was at one time entirely coated. In making castings to be subsequently gilded, it is advisable to use an alloy which is distinguished by a beautiful gold color, such alloy, as previously men- tioned, requiring the smallest possible quantity of gold. An alloy answering the purpose is composed of copper 58.3 parts, tin 16.7, zinc 25.3. In many places, especially in Paris, much jewelry is made of bronze. The articles being generally turned out by stamping and finally gilded, the bronze used must have a certain degree of ductility and allow of being readily gilded. A mixture answering these demands, of which the greater portion of the Paris bronze jewelry is made, consists of copper 8 parts, tin 7. Bronze for ship-sheathing . — A bronze containing 4.5 to 7 parts of tin to 100 parts of copper can be readily rolled 236 THE METALLIC ALLOYS. to sheets at a red heat, and in rolled plates with a content of 4.5 to 5.5 per cent, tin, resists the action of sea-water much longer than pure copper. With less than 3 per cent, tin its durability decreases essentially. It has been sought to replace a small portion of the tin by zinc or lead (0.5 to to 1.3 per cent.), it being claimed that the zinc makes the bronze more uniform. French bronze-sheet contains, ac- cording to Pufahl, copper, 91.57 per cent.; tin, 8.17; lead, 0.1 1 ; nickel, 0.08; and iron, 0.04. Machine-bronze. — In this collective term are included a great number of alloys with very variable properties, and which have actually nothing in common except that they are used for certain parts of machinery. Many of these mixtures of metals — for some of them can scarcely be called bronzes — must be as hard as possible in order to resist wear ; others must possess great strength so as not to yield under shocks or pressure, while still others must have the property of showing, even under a heavy load, but little frictional resistance when in contact with other metals. Bronzes of ordinary composition differ but little as re- gards their properties from other cheaper metals and mix- tures of metals, and, on account of their higher price, are but little used in the manufacture of parts of machinery, red brass being more frequently employed. The so- called white metal, which is distinguished by great hardness and comparative cheapness, finds however, much application for bearings. The white metals most frequently used in the manufacture of machines consist of alloys very rich in tin, containing besides this metal, antimony and a small quantity of copper. Machine bronze. — On account of its considerable hard- ness and strength which can be readily regulated, bronze is used in the construction of machinery as a substitute for iron where rust or other influences would soon corrode the latter, or where two parts are subjected to friction and the unavoidable wear caused thereby is to be confined to COPPER-TIN ALLOYS. 237 the part which can be most easily replaced, for instance, piston rings, bearings, etc. The most frequent application of bronze is for such parts which are in constant friction with iron parts. In regard to the choice of a bronze as a substitute for the cheaper iron, it has of course to be taken into consid- ation that by its suitable composition less friction is to be produced than with iron upon iron. The most important point to be observed is, however, the fact that when two parts of the same material rub together, they also are, to approximately, the same extent subjected to wear, and have in a shorter or longer time to be replaced. If, on the other hand, one part is softer than the other, this alone is chiefly subjected to wear and requires to be replaced. Hence that portion of the two parts which can be replaced at the least expense is generally made of bronze, and the composition of the latter is sought to be so regulated that the object of protecting the more expensive part from wear is attained without, however, subjecting the bronze itself to more rapid wear than is absolutely necessary. As such parts are cast, and an excessive degree of hard- ness would in most cases not even answer the purpose, larger or smaller quantities of zinc are generally added so that the composition of the bronze frequently corresponds with that of art bronzes. As with the latter a moderate addition of lead has sometimes been found suitable, casting and working with cutting tools being thereby facilitated, but the brittleness is, of course, increased. For machine parts readily subject to breaking, a large addition of lead is therefore injurious, and the value of antimony, which is also sometimes used, is questionable. From what has been said it follows that the com- position of machine bronze may vary very much and de- pends on the purpose for which it is to be used. Numer- ous formulas tested in practice have been recommended for the composition of machine bronze of which the following may serve as examples : 2 3 8 THE METALLIC ALLOYS. Tough alloy for cocks, valves, etc Very tough alloy for eccentric rings Another alloy for eccentric rings Dense alloy for pump-bodies and valve-boxes. Whistles for locomotives Same with somewhat duller sound Stuffing boxes, valve balls Screw nuts for large threads Piston rings Piston rings Distributing slide-valve Gears in which teeth are cut Gears in which teeth are cut Gearing for spinning frames Alloy for mathematical and physical appar- atus but slightly subject to changes in tem- perature Alloy for more delicate weights, balances and mathematical instruments Propeller blades and boxes Paddle-wheel pins Cog-wheels Parts. Copper. Tin. Zinc. Lead. 88.0 12.0 3-0 90.0 12.0 2.0 — 84.0 14. 2.0 — 88.0 10. 2.0 — 80.0 18.0 2.0 — 81.0 17.0 2.0 — 86.2 10.2 3-6 — 86.2 11.4 2.4 — 84.0 3-0 8-5 4-5 100. 3-0 10. — 82.0 18.0 2.0 — 88.8 8.5 2-7 — 87.7 10.5 i-7 — 90.0 10. ~ 82.0 13.0 5-0 — 90.0 8.0 2.0 — 57-o 14.0 29.0 — 76.8 17.4 5-8. — 91.0 — 9.0 — The following table shows the composition of various approved alloys for bearings. Ordinary bearings Tough bearings Bearing for French railroad cars Bearing for locomotive axles Bearing for locomotive axles * Stephenson's bearing for locomotive axles.. Bearings for very hard axles Bearings for moderately hard axles Bearing of the Penna. Railroad Co Copper. B4.5 86.0 82.0 82.0 73-5 79.0 82.0 70.0 77.0 Parts. Tin. Zinc. 13-3 2.2 14.0 2.0 18.0 2.0 10. 8.0 9-5 9-5 8.0 5-0 16.0 2.0 22.0 8.0 8.0 — ■ | Lead. 7-5 8.0 15-0 *This alloy contains in addition to the other metals 0.5 per cent, of iron, and has stood the test for several years. COPPER-TIN ALLOYS. 239 In the tables below the mixtures employed by a large engineering firm, using scrap and new metal are given. * Bearing brasses. . Eccentric pumps Pumps Cocks and glands Sluice cock-way . Parts. Copper. Spelter. Lead. Tin. Old metal. 38 1 7 54 38 1 — 4 57 38 4 — 3 55 38 6 i-5 r.5 53 38 9 — — 53 Parts. Copper. Tin. Spelter. Old metal. Bearing brasses Eccentric pumps Kingston valve 56 28 112 56 16 8.5 6-5 14 12.5 4 2.5 7-5 3-5 8 45 70 7 40 84 Paddle-wheel pins Propeller blades and boxes . . . Heavy bearings Heavy bearings Main bearings Propeller shaft liner Parts. Ingot Block Zinc. Old copper. tin. brass. 16 2.5 0-75 _. 16 3 — 13 16 2 to 3 — 32 56 6 — 50 Bronze for articles exposed to shocks and very great fric- tion. — Copper, 83 parts; tin, 15; zinc, 1.5; lead, 0.5. Bronze for valve-balls and other constituent parts to *Hiorns. Mixed Metals. 24O THE METALLIC ALLOYS. which other parts are to be soldered with hard solder. — Copper, 87 parts; tin, 12; antimony, 1. This alloy is flex- ible, and of a red, granular fracture. • Bronze resisting the action of the air. — For this purpose Bath recommends a mixture of 576 parts of copper, 48 of brass, and 59 of tin. A bronze for the same purpose can, however, also be obtained by mixing together 26 parts of copper and 2 of tin. A beautiful bronze, which can be used for most purposes as a substitute for brass, and also as hard solder for copper, is obtained, according to Eisler, by mixing together 16 parts of copper and 1 of tin. It is golden-yellow, can be hammered and stretched, is harder and more plastic than brass and copper, nearly as hard as wrought-iron, and runs more easily and thinner than brass. By remelting the quality of the bronzes is impaired, they becoming more thickly-fluid and their brittleness increases. This deterioration is due to the absorption of oxygen by the liquid alloy, the oxygen being chemically fixed. In ad- dition to cuprous oxide, stannic acid and copper stannate have to be taken into account. This deterioration of the bronzes cannot be removed by melting under a cover of charcoal as has been shown by exhaustive experiments. Charcoal, to be sure, has a reducing effect, but only when in direct contact with the oxides. Since the charcoal, how- ever, does not pass into solution with the alloy, the crystals of cuprous oxide, and especially the stannic acid formed, and present in the alloy in the shape of threads and thin skins, do not rise at all or at least very sluggishly, and the charcoal cannot produce a reducing effect or only a very limited one. These drawbacks can only be removed by refining the old material, and old copper to be rendered suitable for the preparation of bronze must also be refined. This is best effected by poling with green wood as sappy as possible, for instance, green birch poles. During the poling samples should at short intervals be taken and examined as COPPER-TIN ALLOYS. 2/j.I to structure and toughness, the latter by hammering and bending tests. Poling too long continued makes the cop- per brittle. The slags are withdrawn from the surface of the metal-bath, and towards the end of the poling operation the melted copper is covered with charcoal. Old bronzes and old copper may also be sufficiently deoxidized by the addition of a small quantity of phosphor- copper. A few words may here be added, regarding defective bronze castings. Such castings can be but seldom, or not at all, recognized from the outside, it only becoming apparent in further working the casting that it is honeycombed with blisters and pores, and unfit for use. This is unfortunately found out only when the work has quite far advanced, and the time and labor spent is thus lost. The formation of blisters and pores is due to the development of gases in consequence of decompositions which take place in the liquid metal, it being, in fact, nearly always dissolved oxides which by acting upon other dissolved constituents, form new liquid oxygen combinations and, in this manner, cause development, of gas. The formation of oxides frequently takes place during melting by the absorption of oxygen from the air or the fire gases, the latter being especially the case when the time of melting is for any reason prolonged or melting is effected in a reverberatory furnace. By the ad- dition of deoxidizing agents it is sought to destroy the oxides present and which may be formed, and, in fact, bronze should not be cast without treating, for the sake of precaution, the contents of the crucible with such a deoxi- dizing agent. For this purpose small additions of phos- phorus in the form of phosphor-copper are very suitable, also small quantities of manganese-copper and magnesia- copper. Quite porous green moulding sand should be used, and the mould be provided with good vent-holes for the passage of the gas. 16 242 THE METALLIC ALLOYS. Spectdum Metal. Alloys, composed of two-thirds copper and one-third tin, take a beautiful polish and can be used as mirrors. At the present time such alloys are only used in the construction of mirrors for optical instruments, especially for large telescopes, though they are being gradually displaced by glass mirrors. Good speculum metal should be perfectly white, without a tinge of yellow, having a fine-grained fracture, and be sound and uniform, and sufficiently tough to bear the grinding and polishing without danger of disintegration. A composition answering all purposes must contain at least 65 to 66 per cent, of copper. The specula made by Mudge contained from 32 parts of copper and 16 of tin to 32 of copper and 14.5 of tin. A little tin is lost in fusion. It has been frequently attempted to increase the hardness of speculum metal by additions of arsenic, antimony, and nickel. With the exception of nickel these additions have, however, an injurious effect, the specula readily losing their high lustre, this being especially the case with a larger quantity of arsenic. According to Bischoff a. mirror com- posed of 66.3 per cent, copper, 32.1 tin and 1.6 arsenic, which possessed a white color and excellent lustre, after some time suddenly tarnished and became coated with a green patina. Sollitt claims that an addition of arsenic during fusion prevents oxidation of the tin. It would seem that the actual speculum-metal is a com- bination of the formula Cu 4 Sn, and has the following cen- tesimal composition : — Copper 66.6 Tin 33.4 According to David Ross the best proportions are: Copper 126.4, tin 58.9, i. e., atomic proportions. He adds the molten tin to the fused copper at the lowest safe tern- COPPER-TIN ALLOYS. 243 perature, stirring carefully, and securing a uniform alloy by remelting. The so-called tin-spots which sometimes separate when ordnance-bronze is incorrectly treated form an alloy similar in composition to speculum metal ; it has, however, not a pure white color, such as is found in those containing 31.5 of tin. By increasing the content of copper, the color shades gradually into yellow, and with a large content of tin, into blue. It is risky to increase the content of tin too much, as besides the change in color the alloy be- comes brittle and cannot be further worked. The follow- ing table shows the composition of some alloys used for speculum-metal. It may, however, be remarked that the standard alloy is undoubtedly the best for the purpose : — Parts. Copper. Tin. Zinc. Arsenic. Other metals. Standard alloy 68.21 68.5 65-3 65 64.6 80.83 63.9 31-79 31.5 30 30.8 31-3 19-05 0.7 2.3 2 1.9 Otto's Richardson's Little's Sollit's 2 silver. 4.1 nickel. Chinese speculum metal . Old Roman 8.5 antimony. 17.29 lead. Other compositions : Copper 32, brass 4, tin 16^2, arsenic 1%. Copper 32, tin 15 to 16, arsenic 2. Copper 32, tin 15%, nickel 2. According to Boedicker, the mirror of the celebrated Ross telescope, which has a diameter of 6 feet and weighs 11,000 lbs., is composed of copper 70.24, tin 29.11, zinc 0.38, iron 0.10, lead 0.01, and nickel 0.01. For the manufacture of concave mirrors an alloy of cop- per 18, tin 18, zinc 18, nickel 36, and iron 10, has been recommended. 244 THE METALLIC ALLOYS. In conclusion the composition of a few recent and old bronze mirrors may be given : ! » Telescope mirror at Birr Castle, Ireland, weighing 5000 kilogrammes (11,000 lbs.): Copper 70.24 per cent., tin 29.11 per cent., and in addition, small quantities of iron, nickel and zinc. A beautiful mirror in the Polytechnikum, Brunswick, Germany: Copper 65.1 per cent., tin 32.8 per cent. Roman metal mirror found in Mayence: Copper 63.4 per cent., tin 19.0 per cent., lead 17.3 per cent. Old Egyptian metal mirror. Copper 85 per cent., tin 14 per cent., iron 1 per cent. Chinese metal mirrors, probably the so-called magic ?nirrors, * contained, besides copper, antimony and lead, for instance, copper 80.8 per cent., antimony 8.4 per cent., lead 9.7 per cent., and therefore cannot be designated as bronzes in the actual sense of the word. Phosphor-Bronze. In the actual sense of the word, phosphor-bronze can- not be considered an alloy containing a fixed quantity of copper, but it is rather a bronze subjected to a peculiar treatment with the use of certain phosphor-combinations. It has been previously mentioned that bronze frequently contains a considerable quantity of cuprous oxide in solu- tion, which is formed by direct oxidation of the copper during fusion, and that the admixture of this oxide impairs to a great extent the strength of the alloy. If now the melted bronze be treated with a substance exerting a power- ful reducing action, as, for instance, phosphorus, a complete * Figures or inscriptions cast upon the back of such mirrors appear more or less plainly in the light reflected from the front. Thicker places — in this case the figures upon the back — turn out porous in casting and being more firmly pressed together by the subsequent grinding and polishing, reflect the light differently from the thinner parts. Such mirrors can also be made from other copper-alloys. COPPER-TIN ALLOYS. 245 reduction of the cuprous oxide takes place, the pure bronze acquiring thereby a surprisingly high degree of strength and power of resistance. If exactly the quantity of phos- phorus required for the complete reduction of the oxide has been used, no phosphorus will be found in the alloy, but the latter must nevertheless be called phosphor- bronze. Hence it will be readily seen that phosphor-bronze is not a special alloy, but that every kind of bronze can be converted into it. With the use of combinations of phos- phorus, phosphor-bronze is therefore deoxidized bronze. Phosphor-bronze has long been known to chemists, but its valuable qualities as a material to be used in construction were first made known by Montefiori-Levi and Kiinzel, who discovered the alloy in 1871. Besides reducing any oxides dissolved in the alloy, the phosphorus exerts another very material influence upon its properties. The ordinary bronzes consist of mixtures in which the copper actually forms the only crystallized constituent, the tin crystallizing with great difficulty, and the alloy in consequence of this dissimilar condition of the two metals is not so solid as it would be if both constituents were crystallized. The presence of phos- phorus is useful in giving the tin a crystalline character, which enables it to alloy itself more completely and firmly with the copper, the result being a more homogeneous mixture. If so large a content of phosphorus be added that it can be identified in the finished phosphor-bronze, the latter must be considered as an alloy of crystallized phosphor-tin with copper. By increasing the content of phosphorus still more, a portion of the copper also combines with the phos- phorus, and the bronze then contains, besides copper and tin, combinations of crystallized copper phosphide with phosphide of tin. The strength and toughness of the bronze do not suffer by a greater addition of phosphorus, but its hardness is considerably increased, so that many phosphor-bronzes are equal in this respect to the best steel, and some even surpass it in general properties. 246 THE METALLIC ALLOYS. Perhaps about the best method of making phosphor- bronze is to line the crucible with a mixture of 18 parts bone ash, 14 parts sand and 4 parts charcoal ; the whole ground up with gum water and the inner surface of the crucible spread with it. Granulated copper is then intro- duced, covered with a layer of the mixture and subjected to fusion. At a temperature sufficient to melt the copper, the silica decomposes the bone ash [Ca 3 (P0 4 ) 2 ], the base of which (calcium) is removed, thus liberating the phosphorus which reacts on the cuprous oxide in the fused copper, deoxi- dizing and purifying it. The products of the reaction rise to the surface and form a slag which can be tapped off. Another, and perhaps the most general, method of mak- ing phosphor-bronze is the addition of phosphor-copper or of phosphor-tin, both of these phosphor-metals being sometimes used at the same time. They must be especially prepared, the best processes being briefly as follows : — Phosphor-copper is prepared by heating a mixture of 4 'parts of super-phosphate of lime, 2 parts of granulated cop- per, and 1 part of fine-pulverized coal in a crucible at not too high a temperature. The melted phosphor-copper, which contains 14 per cent, of phosphorus, separates on the bottom of the crucible. According to another method phosphor-copper is pre- pared by adding phosphorus to copper-sulphide solution and boiling, adding sulphur as the sulphide is precipitated. The precipitate is carefully dried, melted, and cast into ingots. When of good quality and in proper condition, it is quite black. Phosphor-tin is prepared as follows : Place a bar of zinc in an aqueous solution of chloride of tin, collect the sponge- like tin separated and bring it moist into a crucible, upon the bottom of which sticks of phosphorus have been placed. Press the tin tightly into the crucible and expose it to a gentle heat. Continue the heating until flames of burning COPPER-TIN ALLOYS. 247 phosphorus are no longer observed on the crucible. After the operation is finished, a coarsely crystalline mass of a tin-white color, consisting of pure phosphor-tin, is found upon the bottom of the crucible. Phosphor-tin may also be made by heating 3 parts of anhydrous phosphoric acid with 1 part carbon and 6 parts tin. The resulting alloy has a silver-white crystalline ap- pearance, and dissolves in hydrochloric acid with the evolu- tion of sulphuretted hydrogen. According to Pelletier, this alloy appears to possess the composition of Sn 3 P 2 ; it melts at 698 F. Phosphor-bronze is prepared by melting the alloy to be converted into it in the usual manner, and adding small pieces of phosphor-copper or phosphor- tin. For 220 lbs. of bronze 21 to 24 ozs. of phosphor-copper with 15 per cent, phosphorus are used. Whiting prepares phosphor-bronze wire by immersing the alloy in a solution of 0.125 to 5 per cent, phosphorus in ether, carbon disulphide or olive oil, 5 to 10 per cent, sulphuric acid and 85 to 95 per cent, water, and drawing into wire. The properties of correctly prepared phosphor-bronze are as follows : Its melting point is nearly the same as that of ordinary bronze. In cooling it shows, however, the phe- nomenon! of passing directly from the liquid into the solid state without first becoming thickly-fluid. In a melted state it retains a perfectly bright surface, while that of ordinary bronze is always covered with a thin film of oxide. If phosphor-bronze be subjected to continued melting no loss of tin takes place, but the content of phosphorus de- creases slightly. The chief properties of phosphor-bronze are its extraor- dinary toughness and strength. In a cold state it can be rolled, stretched and hammered. According to Kirkaldy phosphor-bronze produced the following results by physical tests : — 248 THE METALLIC ALLOYS. Elastic Limits. Pounds per Square Inch. Cast 23.800 Cast 24.700 Cast 16.100 Tensile Strength. Pounds per Elongation Square Inch. Per Cent. 52.625 8.40 46.100 1.50 44.448 33-40 Drawn Metal {Phosphor Bronze) . Tensile Strength. Twists in 5 Inches. Wire as Drawn. Pounds per Square Inch. Annealed. Pounds per Square Inch. Wire as Drawn. Annealed. Elongation. Per cent. 102,759 120,957 120,950 I39J4I 159,515 i5i,H9 49,350 47,787 53,38i 54,in 58,853 64,569 6.7 22.3 13.0 17-3 13-3 15-8 89 52 124 53 66 60 37-5 34-i 42.4 44.9 46.6 42.8 Besides, as a bearing metal phosphor-bronze is useful for a large number of purposes, such as pump-cylinders, hy- draulic presses, piston rings, eccentric rings, etc.; also for propeller blades, bells, wire, screws, gunpowder machinery, tools, etc. Blast furnaces are sometimes provided with phosphor-bronze tuyeres, which are said to give most satis- factory results. The content of phosphorus varies according to the pur- pose for which the bronze is to be used, an alloy with 8 to 9 per cent, tin containing, as a rule, not over a few tenths per cent. Pufahl found in a bronze of 91 per cent, copper and 8.5 tin not over 0.1 per cent, phosphorus, the remainder being nickel, lead and iron. According to Priwoznick the content of phosphorus ranges from 0.17 to 0.76 per cent, but, according to Kiinkel. it may rise to 2^2 per cent., ac- cording to the purpose for which the bronze is intended. Ledebur found in a phosphor-bronze with 0.004 P er cent, phosphorus 0.038 per cent, oxygen. COPPER-TIN ALLOYS. 249 According to Thurston five sorts of phosphor-bronze are considered to answer all requirements. 0. Ordinary phosphor-bronze of 2 per cent, of phos- phorus. 1. Good phosphor-bronze oi 2% per cent, of phos- phorus. These two numbers are in all cases superior to ordinary bronze and steel. 2. Superior phosphor-bronze of 3 per cent, of phos- phorus. 3. Extra phosphor-bronze of 3^ per cent, of phos- phorus. » 4. Maximum phosphor-bronze of 4 per cent, of phos- phorus. These three, according to Delalot, are superior to any other bronzes. Above No. 4 phosphor-bronze is useless, below No. o it is inferior to common bronze and steel. Nos. 3 and 4 are comparatively unoxidizable. In the following a few analyses of different kinds of phosphor-bronzes are given : Copper 90.34 90.86 94.71 Tin 8.90 8.56 4.39 Phosphorus 0.76 • 0.196 0.053 I. II. III. IV. V. VI. VIL. VIII. Copper 85.55 — — 77-^5 72.50 73-50 74.50 83.50 Tin 9.85 4to 15 4to 15 11.00 8.00 6.00 11.00 8.00 Zinc 3.77 — 8to20 7.65 17.00 19.00 11.00 3.00 Lead 0.62 4toi5 4toi5 — — — — — Iron trace — — — — — — — Phosphorus 0.05 0.5 to 3 0.25 to 2 — — — — — No. I. for axle bearings; Nos. II. and III. for softer and harder axle bearings; Nos. IV. to VIII. for railroad pur- poses, viz. : No. IV. for distributing slide valves for loco- motives ; Nos. V. and VI. for axle bearings for cars ; No. VII. for connecting rods; No. VIII. for piston rods for hydraulic presses. The alloys IV. to VIII. are richer in zinc than ordinary bronze, and hence more homogeneous. 250 THE METALLIC ALLOYS. On account of its toughness, density, elasticity and strength, phosphor-bronze may in many cases serve as a substitute for wrought iron and steel, especially in the con- struction of articles of complicated form, which require much labor, as well as in the manufacture of wire, for in- stance, for non-rusting mine ropes and telegraph wire. It is also suitable for ship-sheathing, for torpedoes instead of welded steel, for cartridge shells, etc. According to Pufahl, Hoper's phosphor-bronze wire is composed of cop- per, 95.59 per cent. ; tin, 3.60 ; lead, 0.50; iron, 0.07; nickel, 0.24; and phosphorus, 0.37; an alloy from Iserlohn was found to contain copper, 92.12; tin, 4; zinc, 3.69; lead, a trace; iron, 0.05 ; nickel, 0.16; and phosphorus, 0.06. The absolute strength of Hoper's cable rope is 212,500 lbs. per square inch, and sheet, for instance for flap valves, is said to surpass even caoutchouc as regards elasticity. Bender, Stockman and Stolzel give the following analyses of Hoper's phosphor-bronze : Copper 90.34 90.86 94.70 93.68 94.11 Tin 8.90 8.56 4.39 5.83 5.15 Zinc — — — 0.34 0.28 Phosphorus 0.76 0.196 0.053 0.17 0.21 No. II. is especially suitable for blast-furnace tuyeres; and No. Ill for bearings. Phosphor-lead bronzes have also been prepared, Lavroff's bronze containing copper 70 to 90 per cent., tin 4 to 13, lead 5.5 to 16, and phosphorus 0.5 to 1. Kiihne's phos- phor-lead bronze contains, according to Pufahl, copper 78.01 per cent., tin 10.63, ' ea d iO-45» iron 0.09, nickel 0.26, and phosphorus 0.57. Phosphor-aluminium b7 r onze.—T\\os. Shaw, of Newark, N. J.,* patents a phosphor-aluminium bronze, making the following claims : First, an alloy of copper, aluminium and phosphorus, containing 0.33 to 5 per cent, of aluminium, *U. S. patent 303,236, Aug., 1884. COPPER-TIN ALLOYS. 25 I 0.05 to i per cent, of phosphorus, and the remainder cop- per. Second, its manufacture by melting a bath of copper, adding to it aluminium in the proportions stated, the bath being covered with a layer of palm oil to prevent ozidation, and then adding a small proportion of aluminium. Silicon Bronze. Copper and silicon, with or without tin, may be alloyed to form silicon bronze. Weiller's alloy is made by the in- troduction of sodium to reduce silica in the crucible. The inventor recommends the following proportions : Fluo- silicate of potash 450 parts by weight, glass in powder 600, chloride of sodium 250, carbonate of soda 75, carbonate of lime 60, and dried chloride of calcium 500. The mixture of these substances is heated in a plumbago retort to a temperature a little below the point when they begin to react on one another, and it is then placed in a copper or bronze bath, when the combination of silicon takes place. Silicon acts upon copper in almost exactly the same manner that phosphorus does, except that it appears to be a more natural alloy, and a flux or reducing agent to the cuprous oxide that is produced when copper is in a melted condition, and it is thereby more active in clarifying, refin- ing, hardening, and strengthening copper and its alloys. In this respect it is more vigorous and pronounced than phosphorus. Silicon bronze possesses great strength and tenacity, high electric conductivity and resistance to corrosion. It is well adapted for telegraph and telephone wires. Early specimens of silicon-bronze wire for telegraph purposes had a conductivity of 97 per cent., and a tensile strength of about 28^2 tons to the square inch; that for telephone purposes had a conductivity of 32 per cent, and a tensile strength of 47 K tons to the square inch. Later on a new type of telegraph wire was developed; which possessed less conductivity than the former, but had 252 THE METALLIC ALLOYS. considerably greater tensile strength which allowed of the wire being more tightly stretched so that the poles could be placed at a greater distance apart. This wire has a con- ductivity of 80 per cent., and a tensile strength from 35 to 37 tons to the square inch. At the same time the character of the telephone wire was also changed, raising its conduc- tivity to 42 per cent., and its tensile strength to 52 tons. These wires have been largely used for telephone lines at Prague, Trieste, Lemberg, and other European cities. The line at Trieste, in particular, has stood the test of violent storms completely, which is due to the small diameter of the conductor. A similar experience has been had at Rheims, where, in one case, a line having a span of more than a thousand feet was exposed to the action of the wind blowing directly across it. Its power of resisting snow has been equally well estab- lished. Thus, on an Austrian railway the engineer at the head of the telegraph department personally examined the wires during a violent storm of damp snow, followed by a sharp frost, at a point where the line crosses hilly ground at a height of about 2,000 feet above the sea. The wires were well covered with snow and sagged considerably more than usual. In several instances by shaking the wire the snow was detached, when the conductors immediately assumed their normal deflections after the snow had melted. The Austrian railway company above mentioned has numerous lines on which the distance between posts varies from 328 to 720 feet across flat country; in hilly districts the distant ranges from 160 to 500 feet. The " Italian General Telephone Co." has employed silicon-bronze wires with spans as great as one thousand feet. In Vienna telephone posts are frequently placed at the same distance apart, and carry as many as 78 wires. Silicon-bronze telegraph wire (I) and silicon-bronze tele- phone wire (II) of Weiller's patent silicon-bronze contain, according to Hampe : COPPER-TIN ALLOYS. 253 I. II. Copper 99-94 97-12 Tin 0.03 1. 14 Iron trace trace Zinc — 1.62 Silicon . 0.02 0.05 The following compositions of silicon-bronze may be recommended : I. II. Copper 97.12 97.37 Tin 1. 14 1.32 Zinc 1. 10 1.27 Silicon 0.05 0.07 Strength of the above alloys, 600 lbs. per 0.001 square inch, extension 46 per cent., contraction 86 per cent. Cast pins 3 inches thick could be readily reduced by rolling to 1 inch thick. Bronze for telephone lines. — E. Van der Ven* has instituted a careful investigation on wires of phosphor-bronze and silicon-bronze. The wires experimented with contained, according to chemical analysis made for him by M. Van Eyndhoven, in the case of the phosphor-bronze : Copper 95.5 per cent., phosphorus 2.6 per cent., with small quanti- ties of tin, manganese, and silicic acid ; in the silicon bronze: Copper 92.2 per cent., silicon 0.91 per cent., together with small quantities of tin, manganese and anti- mony. The practical results of Dr. Van der Ven's researches are that phosphor-bronze has about 30 per cent, of the con- ducting power of copper, silicon-bronze about 70, while steel as used in wires has only about 10.5 per cent. Com- paring their tenacity, as also very carefully determined by him, with that of steel, he finds that a wire of the latter material, of 2 millimeters diameter, with quadruple security and the conventional sag of 0.7 millimeter, can have a *Musee Teyler, and Electrotech. Zeitsch., 1883. 254 THE METALLIC ALLOYS. stretch from pole to pole of 130 meters, while the stretch, under the same conditions of a wire 1 millimeter in diameter would for phosphor-bronze be 106 meters for silicon-bronze 91 meters. These alloys, with a diameter of 1.18, and of 0.77 millimeters respectively, have the same electrical resistance as the steel wire of 2 millimeters resistance.. The relatively short stretch which in general increases the expense of construction and maintenance, is less costly in cities, where at short distances the roofs of buildings offer points of suspension for telephone wires. It is thus self- evident that the bronze wires are preferable to those of steel, whose resistance demands a much larger section; the more, since the net-work of lines suspended in the air can- not be counted among the ornaments of a large city. To this result may be added the statements made by M. Bede, at the Paris Electrical Congress, concerning the practica- bility of the use of phosphor-bronze wire. A phosphor- bronze wire of 0.8 millimeter (costing, too, the same as steel of 0.2 mm.) would, on account of its high elasticity, coil up, before it has fallen 4 meters from its original posi- tion, so rapidly that on breaking it would ordinarily not strike the ground, and hence would be less dangerous. On account of non-oxidation there is no loss of diameter. Manganese bronze. — By the addition of manganese to the melted bronze, the same effect may be produced as by a limited quantity of phosphorus, the dissolved oxides being decomposed and manganous oxide separated. In 1840, Gersdorff prepared cupro-manganese with man- ganese 1 part and copper 4 parts, and shortly afterwards Schrotter prepared it with 10 to 19 per cent, manganese by reducing a mixture of copper scales, pyrolusite and coal. In 1876, Parson obtained ferriferous cupro-manganese by melting ferro-manganese in a crucible and adding copper and, in 1878, Biermann produced cupro-manganese free from iron which contained 74.50 per cent, copper, 25 per cent, manganese, and 0.50 per cent, carbon. By its content of COPPER-TIN ALLOYS. 255 manganese the alloy exerts, in a manner similar to that of phosphorus and silicon, a reducing effect upon the oxides absorbed by melting bronze, etc., mariganous oxide being formed and separated, so that with a moderate addition (3 to 6 per cent, of the weight of the charge) only small quan- tities of manganese remain in the alloy, the strength of the latter being thereby increased. For reducing purposes a quantity of manganese about four times as large as the cheaper phosphorus is required. By a larger addition of manganese, so that more of it remains in the alloy, hard- ness and strength are increased, but brittleness less rapidly than by phosphorus. Cupro-manganese may be prepared as follows : Bring into a graphite crucible of about 35 to 60 lbs. capacity a mixture of powdered manganese ore, coal dust and granu- lated copper, give a cover of fluor-spar, common salt and charcoal dust, expose the crucible to a white heat for several hours, and pour out the liquid alloy ; the result will be a hard, tough, strong, whitish-gray product. By reason of incomplete reduction up to 10 per cent, of manganese is scorified, and the furnace as well as the crucible is strongly attacked. To partly overcome these drawbacks, Allen melts in a reverberatory furnace with regenerative firing a mixture of cupric oxide, coal and manganic oxide, the latter obtained from the manganiferous liquid resulting as a by-product in the manufacture of chlorine, or prepared from manganous carbonate, the result being a malleable, ductile alloy con- taining 5 to 30 per cent, manganese, which is claimed to possess greater toughness than copper. Valenciennes reduces pyrolusite in a magnesia crucible lined with pyrolusite, and melts the resulting metallic man- ganese with copper to alloys containing 3 to 8 per cent, manganese. Such alloys are soft and ductile, while with 12 to 15 per cent, manganese they acquire a gray color, are hard and brittle, and more readily fusible. By an addition 256 THE METALLIC ALLOYS. of zinc, alloys resembling German silver are obtained, which are ductile, cold as well as hot, while German silver has always to be worked hot. Parkes heats yi to 100 parts by weight of manganese ore with 50 parts of cuprous oxide and 75 parts anthracite in a covered crucible to a red heat six to ten hours. After cooling a friable mass is obtained, in which the alloy is found in small globules. The latter are separated by sift- ing, and washed. With a smaller quantity of manganese, for instance, 4 per cent., cupro-manganese has a copper-red color, with a larger content (10 to 15 per cent.) a yellowish-gray color, and with a still larger content, for instance, up to 30 per cent., a gray color. According to Weiller, an alloy with 8 per cent, manganese can be readily rolled, but with 12 to 15 per cent, becomes very brittle. An alloy of copper 75 and manganese 25 resists corrosion better than copper. Ac- cording to Pufahl, two varieties of cupro-manganese con- tained : Copper. Manganese. Iron. Nickel. Lead. Silicoi 68.39 29.24 1.29 0.19 0.06 0.07 56.29 40.86 1-50 0.10 trace 1.08 Cupro-manganese, generally with 10 to 30 per cent, manganese, serves as an addition to copper or metallic alloys to impart to them, by the withdrawal of oxygen, greater density and strength, and, with a larger content of manganese, greater hardness. If in the oxidation of the manganese trimanganic tetroxide is formed, 1 part oxygen requires 2.585 parts manganese, but only 0.646 parts phos- phorus. For the preparation of manganese-bronze, add to ordin- ary bronze melted in a crucible under a cover of charcoal to which potash or soda may be added, small pieces of cupro- manganese previously warmed, heat, stir several times with a rod of retort-graphite, or of burnt wood, and pour out COPPER-TIN ALLOYS. 257 the alloy; or first melt the copper and old metal together with the cupro-manganese in a crucible under a cover of charcoal dust, then add the required tin, and stir thoroughly with the graphite rod. The quantity of cupro-manganese to be added depends on its content of manganese, but if the object is only the withdrawal of oxygen 3 to 4 per cent, suffices. In this case only small quantities of manganese remain in the alloy. However, an excess of a content of manganese impairs the qualities of the alloy less than one of phosphorus, it rather acting similarly to tin, i. e., increases the hardness and strength, but the brittleness less rapidly than phosphorus. Manganese-bronzes in the actual meaning of the word have been made from manganese and copper, or manganese, copper and tin, or manganese, copper, tin, and zinc with a content of up to 10 per cent, of manganese. Such alloys are intended for various purposes, especially for the manu- facture of machine parts, as a substitute for ordinary bronze free from manganese. However they have found but a limited application, and by no means that of phosphor- bronze. The reason for this may be found in the fact that if the object is simply the withdrawal of oxygen, four times more manganese is required than phosphorus and thus the process, notwithstanding the lower price of manganese, becomes more expensive. Furthermore, manganese does not effect the strength of the alloy in the same degree as tin and while a content of the latter decreases the melting point of the alloy, one of manganese increases it and hence bronze containing tin can be more easily cast than man- ganese bronze. According to Cowles, an addition of up to 5 per cent, aluminium increases the strength and elasticity of manga- nese bronze, makes it more easy to cast, and gives it a silver-white appearance. An alloy of manganese 18, copper 67.5, aluminium 1.2, silicon 5 and zinc 13 is said to be superior to German silver for the manufacture of rheostats, 17 258 THE METALLIC ALLOYS. and its electrical resistance is claimed to be 41 times greater than that of copper. By remelting, even under a cover of coal, manganese is oxidized. Tough, malleable manganese bronze of almost a brass- yellow color contained, according to Gintl, copper 75 to 76, manganese 16 to 17, zinc 5 to 6; or copper 15, manga- nese 4, zinc 1. The statements regarding the properties of manganese- bronze vary considerably. It is interesting to find in this connection that, about the year 1868, Messrs. Montefiore- Levi and Kiinzel made a number of experiments with cop- per and manganese alloys, and from their results concluded such alloys to be useless. They obtained great tensile strength and toughness with some of the compositions, but their ready oxidation at high temperatures made the qualities of the castings uncertain and impracticable. More recent experiments are, however, more favorable. According to Biermann, the most advisable addition to bronze is ^3 per cent, manganese = 2^3 per cent, cupro- manganese with 25 per cent, manganese; in many cases an addition of 0.5 to 2 per cent, cupro-manganese suffices, the alloys then containing only a few hundredths per cent, of manganese. While good qualities of ordinary bronze broke under a pressure of 39.6 lbs. per square millimeter, bronze with 2 /i per cent, manganese stood a pressure of 62.15 lbs. with an elongation of 20^ per cent. On account of its great homogeneity such manganese bronze possesses great resisting power against wear by friction ; bearings of bronze with ^2 to Yi per cent, manganese being much more durable than other bearing metals without manganese. An alloy of copper 80, cupro-manganese 7 to 9, tin 6, and zinc 5 has proved especially suitable for bearing metal. Art Bronzes. This term is applied to bronzes which serve for objects of art, such as statuary, vases and various ornaments. Such COPPER-TIN ALLOYS. 259 bronze should be capable of being cast, and of being readily worked with chasing tools and gravers. It should resist the influence of the weather and at the same time, by reason of its hardness resist mechanical wean It should have a beautiful color which, to be sure, soon changes under at- mospheric influences, i. OlO Tt< O ,R | O O = -' o' O* O* O* — 00 CO CO -/*!-' CC CO* CO i") T?" — ' CO CC CN CN CNJ rH r-^rH ^ | O OCO-rO ~CO)C*. ffiCiCTlOlOi O Oi C^OSOCTICX Cs C503 Ci JC- ■Bjncnjoj ot 1 raojv" S • 5 tt i i I I ii I I I 13 I i I IS ii i i 153 i M ii a c cc 03 W oQCC COPPER-TIN ALLOYS. 269 O) •"• 0) w 5^Sbp ^t^§ g g.ts ■g gg g ^ * - a c P fe— ="3 =, 3 o;C 5^3*5 cS Si g B g n o>TS O > 03 * 03,0 booc ■H '3 '5 M s 4) 03 03 CO r « S.O PH ■iiuoqinv c3 cS oS C-'^ o3 o3 o3 o3 . >J ■ .J.-J d «* •00 1 = J9AITS 'XjIOU309[9 joj AjiAiionpnoo I I ■001 = J9AJ1S 'JB91J joj A"jiAijonpuoo X;inqi s,| j .i° japjQ I I I I •CiailBK) AjiiJI I I I -B9[['BUI JO I9pJQ ' I I •(uosuqof ptTB JJ.>AfBO PUB I I I ■(uojsjnqx) Xjurjonp 9Ayji3[9y; I I •(larri'N) I , , ^inii on P .1° jgpjp I I I •iiom aj'Bnbs .i9d spunud 'ijiDBuax I I Color. 1 Grayish- yellow 1 II Hi.| Grayish- yellow Mottled- white and z ' ' '1 ■a'ijia'biS orjioadg IS 1 1 8.669 8.875 8.935 m X 8.313' 8.363 8.84 8.825 8.523 8.648 8.681a 8.9436 X' X 1 1 1 • •sisa-jbub .£q CO 1 1 1 1 9.58 MM 1 II M II 12.73 1 1 1 1 uoinsodrnoo " Cu. 1 1 1 1 90.27 MM ! 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I I S. . -^- - I I S,°^° n b cc c c cdccc c a ccccc caaa J j 0003 CC 03 COcOCOMCO COPPER-TIN ALLOYS. 273 • AH jo inn v cJ — " d. **■- '■ d — > ^ * ~- X ~- s .*5 * s i."*' «i I ° P M3DD ° "0ni=J3A -jis '.Cji.)jj}oa[3 ioj XjiAijonpuoQ '001 I =ja.\jis '?naq joj XjiAJionpnor) I I I I I I I I Annqisnjjo japjQ_ ■(is[ti!u- ) A'lnm -hojIBot jo japjg •Cnosiuiof piI13 1JSAIX?0 pi 103 I I I I ■(noisjnqr,) ^ijiianp 8Ai;B[9a i I tc — ' to --C ci I "(ISIIHIV) I A^unonp jo aapjQ I I I •qoiit sjBnbs jad spuiiod 'A'ipeuax SO M SO O CT: O iC O O -N CCO"CI^O-tt) l-_ _ .O "T'ltO r-i ^ »o *c ^ cc so t^T CM •a^iauiS oijpads ■sisXimre Aq uojiisodmoo •ajnjxjm [BUlSlIO jo uoijisodinoo it? O 1^ i-H in -r -r i~ lO iC "ST tfT iO rf Tt* " |(C'. . I CO^COCNcNOJnsNCO .^ i-» i> t^ 1^ l-^ t^ r^ l-^ t^ t^ I I I I2l 1 II ;5 I IN I M I IS I I I I I I I I I CO i>i^t> : coqiOTji(NiOrH i o 0000000 HHr- 'Ci050iOiOVt^cdTjic4rHO •BinaiJOj oicao^v 18 ouy-jooa Ills' " * I I s c,c, c a = s c* , c*='c3 co a) cc to coco -co co f cococo 274 THE METALLIC ALLOYS. LIST OF AUTHORITIES. Bo. — Bolley. Essais et Recherches Chimigues, Paris, 1869, pp. 345,348. Cr. — Croockewit. Erdmann s Journal, XLV, 1848, pp. 87 to 93. C. J. — Calvert and Johnson. Specific Gravities, Phil. Mag., 1859, Vol. 18, pp. 354 to 359; Hardness, Phil. Mag., 1859, Vol. 17, pp. 114 to 121 ; Heat Conductivity , Phil. Trans., 1858, pp. 349 to 368. De.— S. B. Dean. Ordnance Notes, No. XL. Washington, 1875. La. — Lafond. Dingier s Jour., 1855, Vol. 135, p. 269. Ml.— Mallet. Phil. Mag., 18 2, Vol. 21, pp. 66 to 68. Ma. — Matthiessen. Phil. Trans., i860, p. 161 ; ibid., 1864, pp. 167 to 200. Mar. — Marchaud and Scheerer. Journal fuer Praktische Chemie, Vol. 2J r p. 193 (Clark's "Constants of Nature"). Mus.— Muschenbroek. Ure' 's Dictionary , article "Alloy." Ri. — Riche. Annates de Chimie, 1873, Vol. 20, pp. 351 to 419. U. S. B. — Report of Committee on Metallic Alloys of United States Board appointed to Test Iron, Steel, etc. T. — Thomas Tomscn. — Annates de Chimie, 1814, Vol. 89, pp. 46 to 58. W. Watt's Dictionary of Chemistry . Wa— Major Wade, United States Army. Report on Experiments on Metals for Cannon, Phil., Baird, 1856. We.— Weidemann. Phil. Mag., i860, Vol. 19, pp. 243, 244. Note on the table. — In the preceding table the figures of order of ductility, hardness, and fusibility are taken from Mallet's experiments on a series of 16 alloys, the figure 1 representing the maximum, and 16 the minimum, of the property. The ductility of the brittle metals is represented by Mallet as o. The relative ductility given in the table of the alloys ex- perimented on by the U. S. Board is the proportionate extension of the exterior fibers of the pieces tested by torsion as determined by the autograph strain diagrams. It will be seen that the order of ductility differs widely from that given by Mallet. The figures of relative hardness, on the authority of Calvert and Johnson, are those obtained by them by means of an indenting tool. The figures are on a scale in which cast-iron is rated at 1000. The word "broke" in this col- umn indicates the fact that the alloy opposite which it oc- curs broke under the indenting tool, showing that the rela- COPPER-TIN ALLOYS. 275 tive hardness could not be measured, but was considerably greater than that of cast-iron. The figures of specific gravity show a fair agreement among the several authorities in the alloys containing more than 35 per cent, of tin, except those given by Mallet, which are in general very much lower than those by all other authorities. In the alloys containing less than 35 per cent, of tin there is a wide variation among all the different au- thorities, Mallet's figures, however, being generally lower than the others. Several of the figures of specific gravity have been selected from Riche's results of experiments on the effects of annealing, tempering and compression, which show that the latter especially tends to increase the speci- fic gravity of all the alloys containing less than 20 per cent, tin, to about 8.95. This result is due merely to the closing-up of the blow-holes, thus diminishing the porosity. The specific gravity of 8.953 was obtained by Major Wade by casting a small bar in a cold iron mould from the same metal, which gave a specific gravity of only 8.313 when cast in the form of a small bar in a clay mould. The former result is exceptionally high, and indicates the probability that every circumstance of the melting, pouring, casting, and cooling was favorable. to the exclusion of the gas which forms blow-holes and to the formation of perfectly compact metal. The figures of tenacity given by Mallet, Muschenbroek, and Wade agree with those found in the experiments as closely as could be expected from the very variable strengths of alloys of the same composition which have been found by all experimenters. Mallet's figure for copper, 24.6 tons or 55,104 pounds, is certainly much too high for cast copper ; the piece which he tested was probably rolled or perhaps drawn into wire. Haswell's Pocket Book gives the following as the tensile strength of copper ; the names of the authorities are not given : — 276 THE METALLIC ALLOYS. Pounds per square inch. Copper, wrought 34,000 Copper, rolled 36,000 Copper, cast (American) ' 24,250 Copper, wire 61 ,200 Copper, bolt 36,800 The strength of gun-bronze, as found in the guns, is not given in the table, which is designed to compare the various authorities on the tenacities of the alloys only as cast under ordinary conditions, and not when compressed, rolled, or cast under pressure. CHAPTER VIII. ALLOYS OF COPPER WITH OTHER METALS'. In the preceding chapters the alloys of copper have been described which on account of their easy preparation and the larger proportion of the metals which are combined with the copper are in general use. There are, however, a number of other copper alloys which, though at present seldom employed, possess properties deserving attention. Copper-arsenic alloys. — Arsenic imparts to copper a very beautiful white color and great hardness and brittleness. Before German silver was known these alloys known as zvhite copper, white tombac, argent hache, Chinese peiong, etc., were sometimes used for the manufacture of cast articles which were not to come in contact with iron. On exposure to the air these alloys, however, retain their white color for a short time only, and acquire a brownish tinge. On account of this, as well as the poisonous character of arsenic and the difficulty of working them, these alloys are very little used at the present time. A white, brittle, lustrous alloy capable of taking a high polish is obtained by pressing a mixture of 70 parts copper in the form of fine shavings, and 30 of white arsenic into a crucible, and melting the mixture under a surface coat of glass in a furnace of good draught. Or by melting copper with white arsenic and black flux, or by melting 16 parts copper and 1 part calcium arsenate under a cover of borax, coal dust and glass powder. Copper-lead alloys. An addition of lead to copper renders it softer and more ductile. Alloys of copper and lead are subject to separation or liquation, the lead separat- ing out and leaving the copper in a porous mass, especially ( 277 ) 278 THE METALLIC ALLOYS. if the alloy is not quickly solidified. In preparing the alloys the copper is melted down under a cover of charcoal dust, the fire is then made as hot as possible and the lead quickly introduced into the overheated copper. As soon as all is melted, stir several times with an iron rod to make the alloy homogeneous, and quickly pour the liquid mass into cold metallic moulds. On account of the above-mentioned liquation it is difficult to obtain faultless large castings of these alloys, and hence they are cast into thin plates, which are subsequently rolled out into sheets. The alloy forms a metal of gray color, brittle and of feeble affinity. An alloy of copper 4 parts and lead 1 is sometimes used for large type. For sheets and plates requiring no great durability, Guettier recommends an alloy of equal parts lead and cop- per. For hard solder Domingo recommends an alloy of copper 15.16 parts and lead 20. Copper-iron alloys. In ancient times such alloys in the form of black copper appear to have been employed for castings. A statue of Buddha from Hindostan, about 3500 years old, contains, according to Forbes, 91.502 copper, 7.591 iron, 0.021 silver, 0.005 g°ld, 0.079 arsenic, 0.510 sulphur, 0.292 insoluble matter, and traces of nickel and manganese. An alloy of copper 2 and iron 1 possesses great strength, which decreases with the increase in iron, while the hardness increases. An addition of 3 to 4 per cent, copper to malleable iron gave, according to Holtzer, with decreased strength an elongation of 22.5 per cent, and a decrease in the cross-section of 51 per cent. According to Billings iron with 2 per cent, copper gives a very red- short, dark gray, granular alloy. However, according to the more recent investigations of Ball and Wingham, copper in iron is not so dangerous as generally supposed, and the red-shortness ascribed to copper may be due to sulphur occurring in the ores. The authors named found cuprifer- ous steel stronger, but harder, than steel free from copper. ALLOYS OF COPPER WITH OTHER METALS. 279 Copper-steel. — Some years ago M. Henry Schneider, of Cruezot, France, took out patents for the manufacture of alloys of iron and copper, and steel and copper. In the patent specifications it is stated the alloy of cast iron and copper can be made in a crucible, cupola, or open-hearth furnace. " The furnace is charged with copper scrap and cast iron mixed between layers of coke, or if a cuprous coke be employed then the cast iron is laid in alternate layers with it, and a layer of anthracite is preferably laid over the whole. The alloy thus formed contains, generally, from five to twenty per cent, of copper, according to the purpose for which it is to be employed, and it is re- markable for its great strength, tenacity and malleability — properties which may be still further developed by chilling or tempering." * The alloy thus formed is charged into the bed of a furn- ace, with the ordinary ingredients used in the manufacture of steel, preferably under a layer of anthracite, to avoid oxi- dation. It is important that the copper be introduced at as early a stage in the process as possible. The said alloy may be introduced either while melted or in its hardened condition, or it may be prepared in the furnace itself, where the operation of manufacturing the steel is carried on. In the latter -case, the bed of anthracite is first prepared and the copper placed thereon with a suitable quantity of cast or pig iron. The whole is then covered with anthracite, in order to protect the metal from contact with the air during fusion. When the charge is melted, the excess of anthracite is removed and successive charges of iron or scrap added, the operation being then continued in the ordinary way, care being taken to continually protect the bath from oxi- dation by means of a layer of slag or cinder, which may be renewed as required, and also to prevent red-shortness in the metal before the final introduction of the recarbonizing and manganiferous silico-spiegel iron or ferro-manganese. *U. S. Patent 415,656, Nov. 19. 1889. 280 THE METALLIC ALLOYS. The steel produced by this means contains from two to four per cent, of copper. It is stated in the patent specifications that the steels alloyed with copper are especially useful in the manufacture of ordnance, armor-plate, gun-barrels, projectiles and for other military purposes, or in the manufacture of commercial bars, sheets, etc.* In view of the remarkable elastic limit of copper-steel while maintaining at the same time a very considerable elongation, Mr. F. Lynwood Garrison t is of the opinion that it would not be surprising if its use became very exten- sive in the arts. It has the advantage over aluminium, nickel and tungsten steels in being cheaper to manufacture. Alloys of copper and much zinc. Pure zinc fouls the cut of files, and to decrease this evil it is mixed with small quanti- ties (i to 10 per cent.) of copper or iron, or of both metals. For cheaper bearing metals better able to resist friction, which are harder and stronger than pure zinc and have but a slight coefficient of friction, zinc may be combined with tin, a little copper, and some antimony. The annexed table gives the composition of a few of such alloys : English bearing metal, very good, Yz brass Same for rapidly revolving shafts Rolls for calico printing.. Metal for pump cocks, which does not deposit verdegris Pierrot's metal ....... Kniess' bearing metal Wagner's bearing metal for steam engines Dunlevie and Jones' bear- ing metal Zinc. Copper. 80 5-5 76.14 78.3 5-69 5-6 12 83.33 40 7 2.27 3 24 0-5 52 1.6 Anti- mony. 3-79 3 0.4 Tin. Lead. 14.5 — 17-47 — 15-8 21 7-57 3-03 15 42 18 14-5 46 — Iron. 0.5 *U. S. Patent 415,654, Nov. 19, 1889. The British Patents Nos. 16,568 and 16,569, 1888, seem to have been abandoned in 1890. tjour. of the Franklin Inst., Sept., 1891. ALLOYS OF COPPER WITH OTHER METALS. 28l Dunlevie and Jones' bearing metal is prepared by melt- ing the copper in a crucible, adding \ of the tin and the antimony, and pouring into an ingot-mold. In another crucible the zinc is melted together with the rest of the tin, and, after adding the first alloy, the whole is again melted. Alloys which can be filed are composed of zinc 90 to 99 and copper 1 to 10 ; or zinc 98 to 99.8 and iron 0.2 to 2 ; or zinc 97, copper 2.5, and iron 0.5 ; or zinc 68, copper 11, tin 21. Manganese-brass. — According to Parkes, copper 70. manganese 30 and zinc 20 to 30 give a silver-like alloy which can be forged and rolled at a red heat. If the alloy is not required to stand a high temperature the composition is: Copper 49, manganese 21, iron 5 to 10, and zinc 5 to 10. For soldering the alloy the following composition is suitable : Copper 7, manganese 3, silver 1 to 2, For coins, copper 65, manganese 25 and zinc 10 may be melted together, or copper 65, manganese 15 to 20, zinc 10, and nickel 5 to 10. Copper-tungsten alloys. — Copper and tungsten unite, according to Biermann, to an alloy with 10 per cent, tung- sten which combines hardness and elasticity with tough- ness, and is suitable for axle bearings and telegraph wires. Tungsten-copper combines also with other metals. Bier- mann prepared an alloy with iron 66, nickel 23, tungsten 4, and copper 5. According to Pufahl, Biermann's tung- sten bronze contains copper 95.39, tin 3.04 and tungsten I-57- Copper'-cobalt alloys. — These alloys show a red color and a fracture resembling that of pure copper. They are distin- guished by great ductility and tenacity, and can be forged and stretched in the heat, and cannot be hardened. They are prepared by melting together copper and cobalt in a crucible under a cover of boric acid and charcoal. An alloy cast in grains, which is attracted by a magnet, is composed 282 THE METALLIC ALLOYS. of cobalt 48.20 per cent., nickel 1, copper 50.26, and iron 0.46. It is red, while an alloy containing equal proportions of nickel and copper shows a white color. Alloys with 1 to 6 per cent, of cobalt can be as readily forged, stretched^ and rolled hot as copper, but are considerably tougher. An alloy with 5 per cent, cobalt shows especially valuable properties ; it is non-oxidizable and ductile like copper,, elastic and tough like iron, and will no doubt be applied to many purposes. Cobalt bronze of Wiggin & Co., of Birmingham, is an alloy of copper, cobalt, zinc, tin or lead, and is said to possess all the properties of pure cobalt. Copper-magnesium alloys. — According to Grazel, an alloy of copper and magnesium is used as addition to tom- bac castings, and when of a pale red color and quite brittle contains, according to Pufahl, copper 89.31, magnesium 10.18, aluminium 0.05, nickel 0.21, lead 0.08 and iron 0.07. According to Warren, alloys of copper with magnesium as regards general properties do not surpass the other usual copper alloys, which can be more readily prepared. An alloy with 1 1 per cent, magnesium has a brass-like ap- pearance, is very brittle, and when melted together with copper gives alloys which with an increase in the content of copper become less brittle. An alloy with 4 per cent, magnesium resembles an actual bronze in appearance and physical properties ; 1 yi per cent, magnesium makes the copper somewhat lighter in color, and harder. The French Society industrielle et commercial des metaux has intro- duced alloys of copper with iron, nickel and zinc-mag- nesium. Copper-antimony alloys. — According to Held, a mal- leable gold-like alloy is obtained by adding to 100 parts of melted copper 6 parts of antimony, and, when liquefaction is complete, some wood ashes, calcareous spar and mag- nesium to remove porosity. The alloy is said to be stronger than gold. ALLOYS OF COPPER WITH OTHER METALS. 283 Melted together in equal parts copper and antimony give a hard combination of a beautiful violet color suitable for fancy articles. Mira metal. — The alloy known by this name is distin- guished by great resistance towards acids and is, therefore, especially suitable for cocks, pipes, etc., which come in contact with acid liquids. Mira metal contains according to analysis: Copper 74.755, zinc 0.615, lead 16.350, tin 0.910, iron 0.430, nickel and cobalt 0.240, antimony 6.785. CHAPTER IX. TIN-ALLOYS. Tin is distinguished by its beautiful white color and by its permanency when exposed to the air. Although soft in itself, it has the property of hardening many other soft metals. It is but seldom worked by itself but, as a rule, alloyed with another metal whereby its comparatively slight hardness is increased, and it also becomes more thinly-fluid and more capable of being cast. The metal most frequently used for alloying with tin is lead, which combines with it without difficulty in all proportions by weight. Tin-Lead Alloys. — These alloys are easily made. Lead added to tin increases its malleability and ductility while its properties are not materially impaired ; its tenacity is how- ever decreased. Difficult to break even after successive bendings, tin becomes more brittle when alloyed with lead. The fracture is then more marked than that of lead, what- ever may be the proportions in the alloy, the latter metal being more readily separated than tin but requiring, never- theless, to be torn asunder. The strongest alloy of tin and lead is produced by alloying tin 3 parts and lead 1, the density of this alloy being 8. According to Watson, the densities of tin-lead alloys are as follows : — o 10 32 16 8 4 2 1 11.3 7.2 7-3 7-4 7-6 7-8 8.2 Alloys of tin and lead were formerly much used in the (284) TIN ALLOYS. 285 manufacture of domestic utensils. They are, however, not suitable for this purpose, on account of the solubility and poisonous properties of the lead. Under no circumstances should an alloy of tin and lead used in the manufacture of domestic utensils contain more than 10 to 15 per cent, of lead. Such an alloy is not sensibly attacked by vinegar and fruit acids. But unfortunately there are cases in which the so-called tin contains as much as one-third of its weight of lead. Alloys containing from 10 to 15 per cent, of lead have a beautiful white color, are considerably harder than pure tin, and much cheaper. Many alloys of tin and lead have an especially lustrous appearance and are used for stage-jewelry and mirrors for reflecting the light of lamps, etc. An especially lustrous alloy is known under the name of Pahlun brilliants. It is used for stage jewelry and consists of tin 29 parts, lead 19. The alloy is poured into moulds faceted in the same manner as diamonds. Seen in an artificial light, the pieces of metal thus cast are so brilliant as to produce the effect of diamonds. Other alloys of tin and lead of some importance are those used in the manufacture of toys (tin soldiers). They must fill the moulds well and be cheap, and, consequently, as much as 50 per cent, of lead is used. With the use of sharp iron or brass moulds such an alloy yields good castings. Toys can also be pre- pared from type-metal, which is even cheaper than alloys of tin and lead, but has the disadvantage of readily breaking on sharply bending the articles. In the following table the melting points of alloys of tin and lead as determined by Messrs. Parkes and Martin are given : — 286 THE METALLIC ALLOYS. Composition. Melting Composition. Melting points. Tin. Lead. Degrees F. . Tin. Lead. Degrees F. 4 4 372° 4 28 527° 6 4 336 4 30 530 8 4 340 4 32 532 10 4 348 4 34 535 12 4 336 4 36 538 14 4 362 4 38 540 ib 4 367 4 40 542 18 4 372 4 42 544 20 4 378 4 44 546 22 4 380 4 46 548 24 4 382 4 48 550 4 4 392 4 50 551 4 6 412 4 52 552 4 8 442 4 54 554 4 10 470 4 56 555 4 12 482 4 58 556 4 14 490 4 60 557 4 16 498 4 62 557 4 18 505 4 64 557 4 20 512 4 66 557 4 22 517 4 68 557 4 24 519 4 70 558 4 26 523 For baths used by cutlers and others in tempering and heating steel articles, Parkes and Martin propose the follow- ing alloys : — No. 1 2 3 4 5 6 7 8 9 10 11 12 Lancets Other surgical instruments Razors Pen-knives Knives, scalpels, etc Chisels, garden knives Hatchets Table knives Swords, watch springs Large springs, small saws Hand saws Articles of low temper , Composition. Lead. Tin. 7 4 7/2 4 8 4 8/ 4 10 4 14 4 19 4 30 4 48 4 50 4 Oil bo ding. 1 4 Melting points. Degrees F. 420 430 442 450 470 490 509 530 550 558 600 612 TIN ALLOYS. 287 Britannia Metal. The alloy known under this name consists principally of tin alloyed with antimony. Many varieties contain only these two metals and may be considered tin hardened by antimony. Other alloys, also called Britannia metal, con- tain, however, in addition, certain quantities of copper, sometimes lead, and occasionally, though rarely, bismuth. The Pewterer's Company of England, which has been an incorporated society ever since the reign of Edward IV. (1474), in 1772 attempted to regulate the quality of pewter wares by permitting enough lead to bring the density of pewter from ifiro to tHo", that of tin. Persons who de- parted from this regulation were liable to expulsion from the guild, but it has been so greatly disregarded as to have very little effect in keeping up the standard of pewter. Britannia metal has always a silvery color with a bluish tinge, and, on account of its hardness, takes a fine polish, which it retains on exposure to the air. Though it is quite hard, in strength it only slightly surpasses tin. Good Britannia metal shows a fine-grained, jagged fracture ; if the fracture be quite coarse and strongly crystalline the alloy contains too much antimony, and, as a rule, is too brittle to be worked to advantage. Even with a correct composition, the brittleness of Brit- annia metal is such that in rolling it out to sheet the edges generally become full of cracks. A content of iron or zinc increases this brittleness to a considerable extent, and, in preparing an alloy to be rolled out into sheet or to be used for stamped articles, great care must be had to have the metals to be used entirely free from iron or zinc. A content of copper increases the ductility of Britannia metal, but decreases its fusibility, which is one of its most valuable properties, and besides gives to the color a strong yellowish cast. An addition of lead is of advantage es- pecially to metal to be principally used for castings, it be- coming more fusible thereby and filling out the moulds 255 THE METALLIC ALLOYS. better, but its color acquires a strong brownish cast, and articles manufactured from it lose their luster on exposure to the air much more quickly than those containing no lead. A large content of antimony, to be sure, imparts great hardness and a permanent brilliant luster to Britannia metal, but it also decreases its ductility. And, moreover, the antimony possessing poisonous properties, its use must be restricted, especially if the alloy is to be employed in the manufacture of domestic utensils, such as coffee and tea pots, etc. It need scarcely be said that for sanitary reasons the antimony must be free from arsenic, and besides, a very small content of it renders the alloy ex- tremely brittle, and articles manufactured from it tarnish quickly, especially on exposure to moist air. Alloys con- sisting of tin and antimony alone would seem to deserve the preference, and a composition of tin 90 parts, antimony 10, can be especially recommended as regards resistance to chemical influences and for its facility of working. For most purposes, not requiring a special degree of hardness, this alloy is the most suitable, it being readily fusible and filling the moulds out well. For articles sub- jected to constant wear a harder alloy is required. The following table shows the composition of several varieties of Britannia metal : — TIN ALLOYS. 289 Britannia Metal. English Pewter Tutania Queen's metal German " (cast) Malleable (cast) Birmingham (sheet) '" (cast) . Karmarsch's Koeller's Wagner's (fine) Parts. Tin. Antimony. 81.90 90.62 90.1 85.4 81.2 89.3 83-30 91.4 88.5 72 84 20 48 90.60 90.71 85.0 85.70 85.64 16.25 7.81 6.3 9.66 5-7 7.6 6.60 7-i 24 9 7.80 9.20 5-0 10.40 9.66 Copper. Zinc. 1.84 1.46 — 3-i 0.5 0.81 3.06 1.60 — 1.8 — 1.60 3.06 0.7 0-3 3-5 0.9 4 — 2 5 10 6 3 48 1.50 — 0.09 — 3.60 1.40 1. 00 — 0.81 3.06 Lead. Bismuth. 15 7-6 1.60 1.60 1.80 0.83 Britannia ware made in Sheffield is often composed of block tin 3^ parts, antimony 28, copper 8, brass 8. Dr. Carl Karmarsch, who thoroughly studied the proper- ties of Britannia metal, says that the specific gravity of the alloy is 7.339 for laminated sheets, and 7.361 for casting. He explains this anomaly by the fact that the molecules, under the action of the rolls, have a tendency to become separated, their softness and malleability not being great enough to allow of a regular and uniform compression. This is not an isolated fact. M. LeBrun has also found a lower specific gravity for certain alloys of copper and zinc which had been laminated or hammered. Britannia metal is prepared by first melting the copper by itself, then adding a portion of the tin and the entire quantity of the antimony. The fire can then be quickly moderated, because the new alloy has a much lower melting point than copper. The last quantity of tin is finally added, and the alloy un- 19 29O THE METALLIC ALLOYS. interruptedly stirred for some time to make it thoroughly homogeneous. Britannia metal can be brought into determined shapes by pressing and rolling, which will be referred to later on, but it being always to some extent brittle, it is preferred to prepare many articles by direct casting. To obtain clean and beautiful castings, requiring but little after-manipula- tion, it is best to use brass moulds. Before casting, the moulds have to be strongly heated and the interior lined with a special coating to prevent the alloy from adhering. This is effected by means of a mixture of lamp-black and oil of turpentine, or by lamp-black alone, and, though the first process is the more simple and convenient, the latter is preferable, especially for casting fine articles. The moulds can be so coated as to be beautiful and uniform by using an ordinary lamp, similar to a spirit lamp, filled with oil of turpentine. By holding the cold mould over the dull flame of such a lamp, it becomes coated with a delicate film of a velvety black soot, which, while it preserves all the fine lines of the mould, prevents the alloy from adhering. Instead of lamp-black, some manufacturers use finely elu- triated reddle or red chalk mixed to a uniform mass with water. With moulds having many small, and at the same time, deep turns, it is difficult perfectly to coat the inside with the protecting mass, and the coating with lamp-black is decidedly to be preferred. With ordinary moulds it is, of course, impossible to cast an article which is to have a certain shape, in one piece. The different parts are consequently cast separately, and subsequently put together with a solder of a color as nearly like that of the metal as possible. Such articles can, how- ever, be also cast in one piece. We will take, for example, an article frequently made of Britannia metal : a coffee-pot, whose shape is such that it must consist of several pieces. To cast it in one piece, the mould must be so constructed that it can be completely removed from the finished castings. TIN ALLOYS. 2CjI The separate parts of the mould having been coated with lamp-black, or reddle, are put together, and the whole heated nearly to the temperature of the melted Britannia metal. The latter is then poured into the mould until it seems entirely filled. After waiting until it may be sup- posed that a sufficiently thick layer of metal is solidified, the mould is quickly turned over to allow the still liquid portion of the metal to run out. In order to obtain castings of the right condition, this mode of procedure requires considerable practical skill, it being necessary to hit the exact moment at which the layer of metal has acquired the required thickness, and before succeeding the operator must be prepared to meet with many failures. But by noting by means of a watch the time allowed to pass between pouring the metal into the mould, and pouring the still liquid portion out, the exact time re- quired for the formation of a sufficiently thick layer will soon be learned. The inside of the articles obtained by the above mode of casting is sometimes roughly crystalline. This is due to the metal beginning to crystallize, and the corners and edges of the small crystals being exposed by pouring out the liquid portion of the metal. Care must therefore be had to use for such casting an alloy giving a fine-grained mass. The interior of the articles, as far as accessible, can also be smoothed, while the article is still in the mould, with a burnishing stone or burnisher. For articles to be made by stamping or other mechanical processes, the alloy resulting from melting the metals to- gether is ladled into cast-iron boxes, and the slabs thus made are subsequently rolled into sheet. Spherical vessels are usually "spun up" in halves, which are then united by soldering, and smaller articles are generally pressed in moulds by a stamping press of very simple construction. Cast or stamped Britannia metal has always an unsightly gray-white appearance, the innumerable small crystals of 292 THE METALLIC ALLOYS. which the surface of the article is composed preventing a complete reflection of the light. The articles must, there- fore, be polished, which is effected with a burnisher, or, if their shape permits, upon the lathe by means of wooden disks covered with leather rubbed with emery. A great many articles of Britannia metal are at the present time electro-plated with silver, the same as objects of Ger- man silver, which are so well manufactured in England, Germany, and this country, that it is difficult to distinguish them from pure silver. In some cases the Britannia metal is electro-plated with tombac. Biddery-metal. — The name of this alloy is derived from Biddery, a city in the East Indies. It may be classed among the alloys known under the collective term of Britannia metal, but differs from it in containing lead in- stead of antimony. Genuine Indian Biddery metal, which is frequently imi- tated in England, consists of — Parts. L I?. Copper 3-5 n-4 Zinc .' 93-4 84.3 Tin — 1.4 Lead 3-i 2.9 According to Dr. Hamilton, who had occasion to witness the operation, 123.6 parts of zinc, 4.6 of copper, and 4.14 of lead, together with a mixture of resin and wax to pre- vent oxidation, are melted together in a crucible. The fused metal is poured into clay moulds and the articles finished with the lathe. The Indian artists impart to the articles a beautiful velvety-black color by treatment with a solution of sulphate of copper, and decorate the surface in a very peculiar and original manner. By means of a graver, lines forming frequently very artistic designs, are cut into the surface. The lines are then inlaid with fine gold and silver wire, pressed in by means of a burnishing tool, after 1 10.20, iron 0.55. Anti-friction metal. — Tin 98.13, copper 1.60, iron, trace. White metal. — Lead 87.92, antimony, by difference, 12.08. Metal for lining car brasses. — Lead 84.87, antimony [_/ 15.10, tin, trace. Salgee anti-friction metal. — Zinc 85.57, tin 9.91, copper 4.01, lead 1. 15. Graphite-bearing metal. — Lead 67.73, tin 14.38, anti- mony 16.73, i ron n °t determined, graphite, none. Carbon bronze. — Copper 75.47, tin 9.72, lead 14.57, car " bon, possible trace. Cornish bronze. — Copper 77.83, tin 9.60, lead 12.40, zinc, traces of iron, phosphorus. Magnolia metal. — Lead 83.55, antimony, by difference, 16.45, traces of iron, copper, zinc, and possibly bismuth. American anti-friction metal. — Lead 78.44, antimony 19.60, zinc 0.98, iron 0.65. Tobin bronze. — Copper 59.00, zinc 38.40, tin 2.16, iron 0.11, lead 0.31. Graney bronze. — Copper 75.80, lead 15.06, tin 9.20. *Jour. Franklin Institute, February, 1892. 302 THE METALLIC ALLOYS. Damascus bronze. — Copper 76.41, tin 10.60, lead 12.52. Manganese bronze. — Copper 90.52, tin 9.58, manganese, none. Ajax metal. — Copper 87.24, tin 10.98, lead J.2.J, phos- phorus or arsenic 0.37. Anti-friction metal. — Lead 88.32, antimony 11.93. Harrington bronze. — Copper 55.73, zinc 42.67, tin 0.97, iron 0.68. Car-box metal. — Lead 84.33, antimony 14.38, iron 0.61, zinc, trace. Ex. B. metal. — Copper 76.80, tin 8.00, lead 15.00, phos- phorus 0.20. Dudley's investigations finally resulted in finding an alloy, which wears 13 per cent, more slowly than phosphor bronze. This alloy consists of copper 76.80, tin 8.00, lead 15. To obtain uniform castings 0.20 per cent, phosphorus is added, the alloy being prepared according to the follow- ing formula : Copper 105 lbs., phosphor bronze, new or broken, 60 lbs., tin 9^ lbs., lead 25^ lbs. The resulting alloy is the above-mentioned Ex. B. metal of the Pennsylvania Railroad Company. The following tables of anti-friction metals which em- brace most of the alloys of proved excellence has been selected and compiled by Mr. John F. Buchanan * from the best authorities and practice in the engineering world. *Brassfounders' Alloys. London, 1905. TIN ALLOYS. Anti- Friction Metals. 303 Parts. Copper. Tin. Zinc. Lead. Anti- mony. Ferro- zinc. 1 10 . 1 Babbitt's. 4 82 — — 14 — " No. 2. 1 6 — — 2 — \ " hardening. 1 6 — — 2 — " 10 % tin added. 4 ' 6 — — 8 — Dewrance's. 5 16 7Q — . — — Fenton's. 58^ 39^ — 2 — Parson's. 1 18 — — 3 — Roose's. 1 18 — 3 — — " No. 2. — 46 — 42 12 — Hoyle ; s. 4 19 69 5 3 — Ledebur's. lY* WA 78 — — — Kingston's 4 24 80 — — — Calendonian. 4 18 90 — — — " No. 2. 2 34 58 6 — — American Car Journals. — 5 — 79 16 — " " " 8 83 — — 9 — Tandem. 1 — 80 13 — Magnolium. 1 3 — 80 16 — " 4 88 — — 8 — American railway. ^ 8 75 — 5 12 — Plastic metal. 5 85" — 10 — Admiralty metal. 5 82 — — 13 — " " 10 83 — — 5 2 Plastic metal. — — 80 IS 5 Anti-attrition metal. — 5 — 76 16 3 " " No. 2. 1 94 — — 5 Spinning metal. 3 go — — 7 — No. 2. 2 67 30 — 1 — White marine bronze. 2 42 56 — — — ' " No. 2. 8 70 10 12 — White navy bronze. 3°4 THE METALLIC ALLOYS. A nti- Friction Metals — Contin ued. Parts. Copper. Tin. Zinc. Lead. Anti- mony. Yellow metal. 4 85 44 17 White navy bronze, No. 2. 14 60 26 — — White brass. 6 30 60 — 4 — " No. 2. 10 30 60 — — — " No. 3. 10 82 — 9 9 — " for patterns. 4 10 85 1 — — " Salgee " metal. 15 — 68 17 — "Graphite" metal. 1 40 — 47 12 — " Clyde " metal. 2 63 — 27 8 — " " No. 2. 41 — 47 9 3 Barrow metal. — 43 — 46 11 — No. 2. 12 — — 80 8 — Metallic packing. 10 — — 80 10 — " " — 10 — 70 20 — " French. 10 — — 70 20 — Eccentrics. — 10 — 60 30 — Piston rings. — 30 — 60 10 — " "■ 8 74 — — 18 — Hard plastic. 6 70 — 12 12 — — 76 — 7 17 — 3 77 — 17 3 — — 38 — 38 24 — Light machines. 5 40 — 45 10 — Heavy machines. 8 82 — 10 — Axle boxes. 6 82 — — 12 — Slide valves. 6 14 80 — — — — — 47 47 6 — 4 88 — — 8 — — 53 — 33 10 4 TIN ALLOYS. A 11 ti-Frictio n Met a Is — Co n clu ded. 305 Parts. » _c u ■ h >> a J" § J3 -G ^ (_, ±i -o ftft recommended as being readily cast, and hence very suitable for articles of art. Copper 52 to 50 Nickel :'.., 17 to 15 Zinc 5 to 10 Manganese 1 to 5 Phosphorus — — Copper with 15 per cent, phosphorus 3 to 5 Aphtit. — The alloy known by this name is composed of : Iron 66, nickel 23, tungsten 4, copper 5. Arguzoid. — Copper 55.78, zinc 23.198, nickel 13.046, tin 4.035, lead 3.544. This alloy is silver-white, almost ductile, and suitable for articles of art. Berro-German silver prepared by the Societe anonyme Le Ferro-Nickel of Paris consists of iron, nickel and copper with or without zinc. A silver-like alloy, which can be worked like German silver, is composed of copper, 70; nickel, 20; zinc, $}4 ; cadmium, 4^2. Platinoid. — This alloy, invented by H. Martino, is a kind of German silver with an addition of 1 to 2 per cent, of tungsten. The latter, in the form of phosphor-tungsten, is first melted together with a certain quantity of copper, the nickel is next added, then the zinc, and finally the remainder NICKEL ALLOYS. 317 of the copper. In order to remove the phosphorus and a portion of the tungsten, both of which separate as dross, the resulting compound is several times remelted. Finally an alloy of a beautiful white color is obtained, which, when polished, closely resembles silver, and retains its luster for a long time. Platinoid has the properties of German silver in a pre-eminent degree. It shows great resistance, which changes but little with the temperature, and is about 1 >^ times greater than that of German silver. To determine the dependence of the resistance on the temperature, plati- noid wire was wound upon a bobbin provided with a thread, and uniformly heated in an oil-bath. The results of the experiments are given in the following table, in which the resistance at o° C. is placed = 1. Temperature. Resistance. Temperature. Resistance. o°C 10 1. 0000 1.0024 1 .0044 1.0066 1.0075 1.0097 6o°C 70 .... 1. 0126 1. 0134 1. 0166 20 80 30 90 1. 0188 4 j roo 1.0209 So This shows an average increase of resistance of 0.0209 for i° C. between o° and ioo° C. ; another experiment with wire gave an average of 0.022 for i° C. According to ex- periments by Matthiessen, and the more recent ones, by Erno, the increase in the resistance of copper is 0.38 per cent., and of German silver 0.044 P er cent. Hence platinoid is in this respect far superior to other wire in use. Manganin. Copper, 83; nickel, 4; manganese, 13. Diejtett's German silver. This alloy is said to possess a beautiful white color and the density and toughness of tombac. It is composed of copper, 4, zinc, 2.5, lead, 0.75, nickel, 0.5 and tin, 0.125. 3l8 THE METALLIC. ALLOYS. Pirscli s patented German silver is composed of Anti- Alumin- Copper. Nickel. Cobalt. Zinc. mony. ium. Iron 79-50 16.00 1. 00 1. 00 1. 00 0.50 1. 00 75-00 16.00 2.00 2.25 2-75 0.50 1.50 71.00 16.50 1-25 7-50 2.50 — 1-25 Alfenide, Argiroide, and allied alloys. — The alloys brought into commerce under these and many other names consist in most cases of a mixture of metals closely resemb- ling German silver, but they are always electro-plated with pure silver, the thickness of the plating depending on the price of the respective articles. In many cases the com- position used in the manufacture of these articles is a very ordinary quality of German silver, which by itself would present a mean appearance, but is hid from the buyer by the silver plating. In recent times alloys have been frequently recommended which differ from the actual nickel alloys as represented by German silver, in containing tin and aluminium, which makes them more fusible and more easily worked than German silver. Thus far these alloys have not been gen- erally introduced in practice, and besides they are dearer than German silver. •According to Rochet, alfenide is composed of 59.1 parts of copper, 30.2 of zinc, 9.7 of nickel, and 1.0 of iron. Ac- cording to this, it is actually nothing but an ordinary quality of German silver. It is said to be well adapted for spoons, forks, and other articles with a smooth surface which are to be plated with silver, but it does not answer so well for decorated pieces. Toucas's alloy is composed of copper 5 parts, nickel 4, antimony, tin, lead, zinc, and iron, of each 1. The metals are melted together in a crucible. This alloy has the ad- vantage of being more complex, even if it does not possess other qualities, than similar compounds. According to the inventor, it has nearly the color of silver, may be worked like NICKEL ALLOYS. 319 it, and is laminated by the ordinary processes. It is re- sisting, malleable, suspectible of a fine polish, with a luster of platinum, and can be perfectly silvered. For objects which are to be spun, hammered, or chased, the above alloy is very convenient, but for cast and adjusted pieces it is preferable to increase the proportion of zinc in order to increase the fluidity of the metal. This compound is em- ployed for ornaments, jewelry, etc. According to Trabuk, of Nimes, a beautiful white alloy, which resists the action of vegetable acids, and may serve as a substitute for German silver, is obtained by melting together 875 parts of tin, 55 of nickel, 50 of antimony, and 20 of bismuth. Into a crucible of suitable size introduce first % of the tin and all the nickel, antimony and bismuth, and after covering these metals with the second third of tin, cover the whole with a layer of charcoal powder to prevent oxidation. The lid is then placed upon the crucible and the latter heated to a bright red heat. After ascertain- ing by stirring with a red-hot iron rod that all the nickel is fused, the last third of the tin is added, without, however, removing the layer of charcoal. The mass is then stirred until it is perfectly homogeneous, and cast into ingots. The annexed table gives a number of nickel alloys ar- ranged according to their composition : 320 THE METALLIC ALLOYS. rt Xi O U MM 1 1 1 1 1 1 1 1 1 1 1 1 Silver. 1 1 1 1 1 1 II II II 1 1 a H II 1 1 1 1 II II Mill c o u 1— 1 Mill 1 1" II Mill Lead. *7^. lOOiOOOvdtOco iO(N o oo to od r- y ntNeMco en fi rt u o s "be C CD 'l <1 S rt fa £ Sheffield German silver, very elastic Vienna German silver: Copper 2, zinc i, nickel i, for forks and spoons, not very white, but hard and does not tarnish Copper 5, zinc 2, nickel 2, for forks and knives; resembles silver 0.750 fine. . . Copper 3, zinc 1, nickel 1, resembles silver 0.750 fine; readily rolled and worked Spoon metal, according to Schubarth. . . . English Packfong, according to Eng- strom 00 _c •3 u rt ii" CD j> en C rt B u CD O CO ,— 1 u rn O be *3 Ih O CD U <^S u 'en e a B : u . CD . O : 2 u 6-c O NICKEL ALLOYS. 321 I I I I I I I I I I I q tj- q ro co m cn qoo cn 6* o ■* ro On ■* 000 rx (-OVO On w o 10 6 p. a o U o\ 6 2 32 CD o > PQ - u ° 5^ - +-> > 3 • -. _, 1-1 "o 5 w o 3^ 5 c Sh 3 • 1-1 -U CD . > i-T • • hr • s CJ . CO • CT3 > en en re oj 3 bfi bfl o3 3 ^ In rt « s w -a ^ be re X .3 ^-o ."-o -a — h in en 3 bu o-r;- > "^ s 8 ^ !=j be £•5 rt a O £3 >> y I- - s (U o be -5 1u •-* .S ' O u rt O U 1- ^ 1-1 U o o o o o [in Pxh fe pL, fin NICKEL ALLOYS. 323 O % o U H a N a a o U cu bo c •3 rt J <" C ,-> 5 O _ |s3'u J> rt gg r3 « ^ > £ — r o n > ■"■ O 5 So S^ ro 3 a £ ^ > S N be S3 bflh > c 9^3 .5 a o o b 5 iT-c ■So a > CV] ..h »_ CO *-" s^.s.sjg 324 THE METALLIC ALLOYS. Sperry* gives the following analyses of nickel alloys. Per cent. Berlin alloys: Richest Medium Poorest French alloys: Tableware • ■ Maillechort Copper-nickel alloy of the Soc. de Nickel, Paris Copper-nickel of Wig- gins & Co., Birming- ham Christofle's alloy Austrian alloys: Tableware Sheffield, England, alloys: White silver Electrum Hard alloy English " elastic Chinese packfong Vivian's copper alloy ••• American alloys: Alloy for casting Bearing alloy Explosive bullet-shell • ■ Copper. Nickel. Zinc. Iron. Cobalt. 52.00 22.00 26.00 59.00 11.00 30.00 — — 63.00 6.00 31-00 — — 50.00 18.70 31.30 — — 50.00 20.00 30.00 — — 65.40 16.80 13.40 3-40 — 48.74 49.26 S 0.089 0.610 Si 0.186 47.68 49-87 S 0.041 1.228 Si 0.136 50.00 50.00 — — — 50.00 25.00 25.00 — — 55 .60 22.20 22.20 — ■ — 60.00 20.00 20.00 — — 55-20 20.70 24.10 — — 51.60 25.80 22.60 — — 45-70 31-30 20.00 — — 60.00 18.80 17.38 — 3.40 57.00 15.00 25.00 — 3.00 40.40 31.60 25.40 2.00 — 48.49 50.09 — 0.826 Si 0.303 52.50 17.70 28.80 — — 50.00 25.00 25.00 — — 75-5o 24 10 ~ 0.40 ~ Manufacture of German Silver on a Large Scale. In the manufacture of German silver, the purity of the metal used is of greater importance than in the preparation of any of the alloys previously described. The nickel found at present in commerce is generally sufficiently pure to be used without further preparation, the chief contamination transactions of the American Institute of Mining Engineers, Florida Meeting, March, 1895. NICKEL ALLOYS. 325 being cobalt, which, as previously mentioned, exerts little influence upon the properties of the alloy. Copper is fre- quently contaminated with iron, lead, arsenic, and anti- mony, and, in such case, is only fit for the preparation of German silver of second or third quality. Zinc also con- tains certain contaminations injurious to the qualities of the alloy. The manufacture of German silver is generally carried on according to two methods which, from the countries where they have been perfected, are termed respectively the English and the Gerrnan process. Both yield German silver of excellent quality, and, as will be seen from the de- scriptions of the two methods, differ chiefly in the manner in which the various operations in melting down the alloys are executed. German process. — The alloy is prepared as follows : The zinc and nickel to be used for a certain quantity of copper are divided into three equal portions. Now place upon the bottom of a graphite crucible, capable of holding at the utmost 22 pounds of the alloy, a layer of copper, upon this a layer of zinc and nickel, upon this again a layer of copper, and continue in this manner until all the copper is in the crucible, retaining, however, one-third each of the nickel, and zinc. * The contents of the crucible are now covered with a layer of charcoal powder to prevent volatilization and oxi- dation of zinc, and melted down as quickly as possible in a wind-furnace connected with a high chimney, quite a high temperature being required for the fusion of the alloy. When the contents of the crucible are supposed to be liquefied, they are examined by dipping in an iron rod, and, if the whole is found to be thoroughly melted, an intimate mixture of the metals is effected by vigorous stirring with the rod. The zinc and nickel retained are now added in portions to the melted contents of the crucible, the mass being vigor- 326 THE METALLIC ALLOYS. ously stirred after each addition, and a sharp fire kept up to prevent the alloy from cooling off too much by the newly- introduced metals. After the introduction of the last por- tion, an additional piece of zinc is generally thrown into the crucible to compensate for the loss of zinc by volatilization, and besides experience has shown that a small excess of zinc renders the alloy more thinly-fluid, which materially facilitates the work in the subsequent casting. If the alloy is to be rolled out into thin sheets, it is recommended to keep the finished alloy liquid for some time longer before proceeding to casting. In doing this, however, it is neces- sary constantly to keep the surface of the melted metal covered with charcoal to prevent volatilization of zinc. The casting of the alloy is effected in various ways. It is either 'at once cast into plates, which are subsequently rolled out into sheets, or into very thin sticks, which after cooling are remelted and finally cast into plates. On account of the greater consumption of fuel and labor, the last method is somewhat more expensive than direct casting, but it has the advantage of the alloy becoming more homogeneous by re- melting, and besides it can be worked with greater ease. Only with the use of very pure metals is it advisable to cast the alloy at once into plates. Considerable skill is required for casting the alloy, it being necessary to run it into the moulds at as high a temperature as possible and in an uninterrupted stream. An interruption of the stream can be at once detected by the fact that the plate is not uniform. The moulds used in casting plates consist of two iron plates, one plain and the other with a ledge corresponding to the thickness of the plate to be cast, which varies from 0.50 to 0.59 inch. On account of the great contraction of the alloy in solidifying, the distance between the two plates must be somewhat greater. In order to obtain castings of greater homogeneousness, it is recommended to run the melted metals from below into the moulds. This is effected NICKEL ALLOYS. 327 by providing the lower plate with a lip or mouth-piece, in which is placed a clay-funnel connected with a pipe rising somewhat above the mould. After the plates are tightly screwed together, the mould is highly heated and the casting proceeded with. The metal is heated as intensely as pos- sible, and after being freed from all contaminations floating on the surface is allowed to run in a steady, thin stream into the mould. When the metal appears on the upper end of the mould and the funnel remains filled, the casting is finished. After allowing the filled mould to stand quietly for about half an hour, the solidified plate is removed. To prevent the alloy from adhering to the sides of the mould, these are previously to casting coated with a layer of fine lamp-black. The principal difficulty in casting plates of German silver is to obtain them perfectly homogeneous and free from blow-holes, which is best effected by bringing' the melted metal as hot as possible into the mould. On account of the difficulty of executing the casting so quickly that the contents of the crucible do not cool off, it is recommended to fill only one mould at a time, and replace the crucible in the furnace in order to keep the contents at the highest temperature possible. The plates of German silver thus obtained have to be care- fully examined as to whether they are perfectly homogene- ous. Imperfect plates must be thrown out and remelted. The perfect plates are rolled out into sheets from which the articles to be manufactured are punched out and then further worked. English process. — The English method of preparing the alloy differs somewhat from the German, especially in the manner in which the metals are melted together, no portion of the zinc or nickel being retained, but the entire quantity of metal is melted at one time. Good graphite crucibles are used, which are placed in a furnace capable of produc- ing a high temperature. The metals are used in the form of small pieces. The charge of each crucible generally con- 328 THE METALLIC ALLOYS. sists of 8% pounds of tin, }4 pound of zinc, and, according to the quality of the alloy to be produced, 2 to 3 pounds of nickel. The metals are intimately mixed and quickly intro- duced into the red-hot crucibles. Their surface is immedi- ately covered with a thick layer of coal-dust and the mixture fused as quickly as possible. After ascertaining by stirring with an iron rod that the mass is liquefied, a previously prepared alloy of 1 part by weight of zinc and j4 part of copper is added, the quantity for the above charge ranging from if and 2 pounds. When this alloy is melted and the entire contents of the crucible form a homogeneous whole, 2 pounds of zinc are finally added. The mass, being kept constantly covered with coal-dust, is now heated as strongly as possible, and when thinly-fluid a sample is taken to test its qualities. The alloy always contains a certain amount of oxide, and, if a large quantity of it is present, the casting will be badly blown. To ascertain how the alloy will act in casting, a test casting is made, and, if the fracture of this shows blow- holes, the oxides will have to be reduced. This is effected by throwing pitch into a stoneware pipe pushed through the contents of the crucible to the bottom. The products of destructive distillation evolved from the pitch effect a re- duction of the oxides, which is accelerated by stirring coal- dust into the melted metal. When the reduction of oxides is supposed to be finished, a strong heat is given, and, after the coal mechanically mixed with the alloy has collected upon the surface, the purified metal is cast in a manner similar to that described under the German process. In- stead of coating the moulds with lamp-black alone, many manufacturers use a mixture of lamp-black and oil of turpen- tine. Moulds thus treated must, however, be sharply dried to volatilize the oil of turpentine, as otherwise the vapors evolved from the oil of turpentine in casting might readily cause the formation of blow-holes. The casting of the plates finishes the chemical portion NICKEL ALLOYS. 329 of the process, and the perfect plates are mechanically worked in the same manner as indicated under the German process. Articles of German silver have to be soldered with a solder whose color approaches as nearly as possible that of the alloy. An excellent composition for this pur- pose is prepared by melting 5 to 6 parts of German silver together with 4 parts of zinc. It is, however, better directly to prepare the alloy which is to serve as solder by melting together copper 35 parts, zinc 57, and nickel 8. The alloy is prepared in the same manner as German silver and, after being cast in thin plates, pulverized while hot. If the alloy is too tough and can only be pulverized with difficulty, it contains too little zinc, while too great brittleness indicates too small a quantity of nickel. In both cases the alloy must be improved by remelting and adding the necessary quantity of the respective metals. The alloys of German silver are principally used for the manufacture of tableware, as cups, dishes, forks, spoons, etc., but on account of their beautiful color, and solidity, they are also used for articles of art, and are more and more substituted for genuine silver. For fine mechanical work German silver surpasses all other alloys, it having, besides considerable strength and power of resistance, the valuable property of not changing its appearance in con- tact with dry air, and of expanding but little on heating. Manufacture of German silver sheet. The crystalline plates obtained by casting are very gradually reduced by rolling. Whilst being passed through the rolls, they are repeatedly heated to a cherry-brown heat in a heating fur- nace for direct firing, Figs. 29 and 30, or in a muffle fur- nace, Figs. 31 and 32, and allowed to cool completely, otherwise edge-cracks will be formed. After the destruc- tion of the crystalline structure German silver can be worked like brass. Very thin sheet, -£$ to - 6 -V millimeter thick, is called German silver foil or packfotig foil. The sheets resting upon a carriage with perforated 33° THE METALLIC ALLOYS. bottom, running upon rails, are introduced into the heating furnace, Figs. 29 and 30, through an opening the entire Fig. 29.- Fig. 30. NICKEL ALLOYS. 331 width of the furnace, which can be closed by a cast-iron door. When taken from the furnace the sheets are placed upon a carriage pushed close up to the furnace, the upper edge just level with the bottom of the hearth. Muffle furnaces, Figs 31 and 32, area protection against Fig. 31. the deposit of dust, and allow of slower heating, but their effect is less favorable on account of their yielding the heat with greater difficulty. The cast iron muffle resting upon a fire-brick arch is washed by the gases of combustion as- cending from the grate through the flues a and b. The 332 THE METALLIC ALLOYS. gases then pass into the chimney. The channels d serve for the introduction of air ; c are the supports of the arch. Nickel-zinc alloy. — Powdered nickel i part and powdered zinc 2 parts, when heated, yield an alloy of a blackish-violet powder and brittle metallic globules. A powder of zinc 90 parts and nickel 10 serves in painting, and for silver printing. Nickel-tin alloy. — Such an alloy is obtained by heating 10 to 18 ozs. of nickel to a red heat, adding 2 lbs. of tin heated to 302 F., bringing the combined metals into 217 NICKEL ALLOYS. 333 lbs. of tin heated to 302 F., and stirring. The alloy is hard and brittle. Nickel-aluminium alloy. — An alloy of nickel 20 parts and aluminium 8 parts gives threads suitable for laces, etc. Silver-bronze. — This term has been applied to an alloy for bars, sheet and wire. It is composed of manganese 18 parts, aluminium 1.20, silicon 5.00, zinc 13, and copper 67.50. It electrical resistance is claimed to be greater than that of German silver. Nickel-aluminium alloys. — Solbisky prepares the follow- ing alloys which are distinguished by hardness, resistance to pressure and ductility. An addition of cadmium makes them elastic. Parts. Hardness Aluminium. Nickel. 1 1 0-5 Tin. Copper. Iron = 1000. 90 95 96.5 5 1 0.5 4 3 2.5 580 442 380 Rosein. This alloy is used for jewelry. It is composed of nickel 40 parts, silver 10, aluminium 30, and tin 10. Martino 's hard alloys for drilling and cutting tools. Pig iron 17.25 parts, ferro-manganese 3, chromium 1.5, tung- sten 5.25, aluminium 1.25, nickel 0.5, copper 0.75, wrought iron 70.5; or, pig iron 17.25 parts, ferro-manganese 4.5, chromium 2, tungsten 7.5, aluminium 2, nickel 0.75, copper 1, wrought iron 65. Nickel-steel. In 1889, M. Henry Schneider, of Creuzot, France, took out two patents for the manufacture of alloys of cast iron and nickel, and steel and nickel respectively.* In the specifications of the first patent it is stated that it k V> . S. Patents 415,657 and 415,655, Nov. 19, li 334 THE METALLIC ALLOYS. is very difficult to incorporate nickel with iron and steel, particularly when it is attempted to produce these alloys on a commercial scale. To overcome this difficulty, a pre- liminary product is made of cast iron and nickel in a cruci- ble, cupola, or open-hearth furnace. This product or alloy, while especially useful for the manufacture of iron and nickel and steel and nickel alloys, may be used as castings for a variety of purposes. " In the manufacture of this alloy of cast-iron and nickel, a suitable furnace is charged with nickel scrap and ordinary cast or pig-iron, with carbonaceous matter ; or the nickel may be in the form of nickelized compounds or coke. The operation is best carried on in a reverberatory furnace under a layer of anthracite, to avoid oxidation. "The resulting alloy contains from five to thirty per cent, nickel, and is remarkable for its great elasticity and strength — properties which may be still further developed by chilling or tempering in the usual manner. "This alloy of cast-iron and nickel, containing (say) thirty per cent, of nickel, sixty-three per cent, of iron, three per cent, of carbon, and two of manganese and silicon, is then charged on the bed of an open-hearth furnace, with the iron or scrap used in the ordinary methods of making open-hearth steel, care being taken to protect the bath from oxidation by means of a layer of slag or cinder. A steel, containing about five per cent, of nickel, is thereby obtained. Precautions, however, must always be taken to prevent red-shortness in the metal before the final intro- duction of the recarbonizing and maganiferous silico-spiegel iron or ferro- manganese. " Nickel-steel of this kind, containing five per cent, of nickel is especially adapted or suitable for use in the con- struction of ordnance, armor plate, gun-barrels, projectiles and other articles employed for military or other like pur- poses, or the manufacture of commercial sheets, bars, etc. "The percentages of carbon, silicon and manganese can NICKEL ALLOYS. 335 be regulated according to the degree of hardness required, but in all cases, in order to obtain the best results possible, the product must invariably be tempered in an oil or other bath."* Marbeau s nickelo-spiegel is made by a patented process, which consists in the reduction of the ores of nickel, iron and manganese at the same time and in one operation. The following proportions are stated as affording good re- sults, f Nickel ore or matt, contafning ten per cent, of nickel 2 tons Manganese ore, containing ten per cent, manganese and forty per cent, iron 1 ton Iron ore, containing fifty per cent, iron 12 cwt. An alloy of nickel and iron having thus been obtained, there appears to be but little difficulty in working this nickel- iron into a nickel-steel by means of an open-hearth furnace. Ferro-nickel and nickel-steel alloys for technical purposes are produced by adding metallic nickel to ingot-iron in a crucible, converter, or reverberatory furnace, or by melt- ing in a blast-furnace oxide ores of iron, nickel and man- ganese. The SociHe anonyme le Ferro- Nickel of Paris, prepares in this manner an alloy of 20 per cent, nickel, 5 per cent, manganese, 72 per cent, iron, 2.5 to 3 per cent, carbon, and 0.5 per cent, phosphorus, sulphur and silicon. % For the preparation on a large scale of 5 per cent, nickel- iron, ferro-nickel containing 25 per cent, of nickel is melted in a Martin furnace, ingot-iron is next added, then man- ganese and finally, previous to tapping, aluminium ; for in- stance, 200 lbs. ferro-nickel, 800 lbs. ingot-iron, 6 lbs. ferro-manganese with 75 per cent, manganese and ^ lb. aluminium, total 1006.5 ^ Ds - Leschesne proceeds in a simi- lar manner. *U. S. Patent, 415,655, Nov. 19, 1889. t Engineering and Mining Journal, January 31, \\ % German patent No. 37376. 336 THE METALLIC ALLOYS. For the preparation of nickel-steel at Homestead, Pa., * nickelous oxide together with lime is brought upon the hearth of a Martin furnace, upon this ingot-iron and the rest of the charge. For alloys poorer in nickel, nickelous oxide and coal are made into bricks and brought into the furnace. In the Bethlehem works reducing coal is used or metallic nickel added for steel with 20 per cent, nickel. Riley states the alloy (nickel-steel) can be made in any good open-hearth furnace, working at a fairly good heat. No special arrangements are required for casting, the ordinary ladles and moulds being sufficient. If the charge is properly worked, nearly all the nickel will be found in the steel — almost none is lost in the slag. No extraordinary care is required when reheating the ingots for hammering or rolling. If the steel has been properly made, and is of correct composition, it will ham- mer and roll well, whether it contains little or much nickel. Riley appears to have obtained the best results with steel containing five per cent, nickel. With this grade rolled, but not annealed, he obtained elastic limit, 69,664 pounds per square inch, tensile strength 116,480 pounds per square inch, with fourteen per cent, elongation in eight inches. When rolled and annealed, elastic limit 72,800 pounds per square inch, tensile strength 104,832 pounds per square inch with thirteen and one-half per cent, elongation in eight inches. Riley states that the whole series of nickel steels up to fifty per cent, nickel takes a good polish and finish. Steels rich in nickel are practically non-corrodible, and those poor in nickel are much better than other steels in this respect. The alloys up to five per cent, of nickel can be machined with moderate ease ; beyond that they are more difficult to machine. The one per cent, nickel-steel welds fairly well, but this quality deteriorates with each addition of nickel. * Stahl und Eisen, 1895. No. 15, p. 119. NICKEL ALLOYS. 337 The tests of some of the nickel steel made by Carnegie, Phipps & Co.,. Pittsburg, for the U. S. Navy Department, gave the following results : Elastic limit (two specimens) 59,000 and 60,000 lbs. per square inch, ultimate tensile strength, 100,000 and 102,000 lbs. per square inch; elonga- tion, 15^ per cent., and reduction of area at fracture, 29^ and 26^ per cent. The test pieces were cut % inch plate. The chemical analysis gave a content of r 6 - per cent, nickel.* The conductivity of nickel steel is extremely poor and low, but the resistance very high. According to Hopkin- son, nickel steel containing less than 5 per cent, nickel is decidedly more magnetizable than wrought iron, particularly for high inductions. On the other hand, when containing 25 per cent, nickel, it is non-magnetic. But if cooled to — 4 F. it becomes very decidedly magnetic and remains so when it again returns to its normal condition. If, finally, it is heated until it reaches its critical temperature, 1076 F., it becomes again non-magnetic and remains so until cooled to — 4 F.f * Engineering and Mining Journal, Dec. 13, 1890. fF. Lynwood Garrison, Journal Franklin Inst., September, 1891. 22 CHAPTER XI. ALUMINIUM ALLOYS. As stated in the general review of the metals, aluminium is distinguished by a beautiful silvery color and great strength. It is, however, especially valuable on account of its low specific gravity, which is about that of glass. Among the alloys of aluminium those with iron and cop- per are of special importance, but before entering on a de- scription of them we will briefly mention the behavior of aluminium towards the other metals. Aluminium unites easily with most of the metals, the combination being usually accompanied by a disengagement of heat, which is particularly active in the case of copper. Lead and antimony appear to be the only metals not alloy- ing with it easily. The practical production of aluminium alloys is, generally speaking, not a difficult operation. The aluminium may be melted in a carbon or magnesia-lined crucible, without a flux, and the other metal simply thrown in ; it falls to the bottom, melts, and is absorbed by the aluminium. In some few cases the alloying metal must be mixed in powder with finely-divided aluminium and heated together in a closed crucible, but this is only exceptionally the case. Again, a bar of aluminium may be taken in the tongs and held under the surface of another metal already melted. This is the best method of introducing small per- centages of aluminium into other metals, unless we may except the adding of a small quantity of rich alloy to pure metal, thus diluting the percentage of aluminium to the desired quantity. Most of the alloys thus produced are improved by careful remelting, the aluminium seeming to become more intimately combined. The alloy made in the (338) ALUMINIUM ALLOYS. 339 first operation is often not entirely homogeneous, but be- comes more uniform, and finally perfectly so, by repeated fusion. Very few of these alloys will liquate, the alloys in general acting as a single metal. However, in some cases where the alloy is not of a very definite or certain composi- tion a liquation may take place, leaving as a residue an alloy with different proportions from the fluid metal running off. In the case of volatile metals they can usually be driven out of the aluminium by keeping the alloy melted and exposed to a heat sufficient to drive off the volatile metal. The properties of the alloys of aluminium with the prec- ious metals, gold and silver, approach nearest to those of the metal present in larger quantity. An alloy of aluminium 90 parts and gold 10 equals in hardness a corresponding alloy of gold and silver, and shows a beautiful yellow color. It can be readily worked under the hammer and rolled out to sheet. An alloy of aluminium with five parts of silver does not differ in its properties from pure aluminium, except that it is somewhat harder and takes a finer polish. It is used in- making balances for chemists. With a content of iron of over five per cent., the aluminium becomes more refractory and, at the same time, brittle. The introduction of 0.1 per cent, of bismuth makes the metal so brittle that it can no longer be worked ; it breaks even if worked directly after annealing. The presence of a small quantity of silicon gives to aluminium a strong crystalline structure, the crystallization being clearly perceptible on the surface by a peculiar net-like appearance of the metal. Aluminium-iron alloys. — A small quantity of aluminium, by changing the structure of iron and steel, improves their strength, sensibly increases their resistance towards cor- roding substances and atmospheric influences, and lowers the fusing point, for instance of cast iron, making the cast- ings more uniform and denser — for instance, Mitis castings. Speaking generally of the application of aluminium to 34-0 THE METALLIC ALLOYS. the manufacture of iron and steel, the usual amount stated to be requisite for producing good results is about o.io per cent., but in many cases this would be too little. Aluminium steel. — A considerable percentage of the total production of aluminium, both in this conntry and in Europe, is used in the manufacture of iron and steel cast- ings. The process consists in adding from o. 10 to 0.15 per cent, of aluminium to iron and steel just before casting, by which blow-holes are prevented and sounder castings produced. The beneficial effect is due in part at least to the deoxidizing action of aluminium upon carbon monoxide at a high temperature, a reaction which has been demon- strated directly between the metal and the gas. A detail of manipulation in the method of applying aluminium, especially in castings for steam and pump cylinders, and other castings intended to resist high pressure, is reported in Dingler's Polytechnical Journal, Vol. 284, No. 11. The addition is made by first forming a mixture of aluminium and iron, which is effected by placing the proper quantity of heated aluminium in the bottom of a small ladle, run- ning some iron into the ladle from the furnace, and wait- ing until the mixture begins to stiffen. Then the iron to be operated on is run into a large ladle and the iron-alumin- ium mixture is poured into it, whereby an intimate mixture of the whole is effected. For 220 lbs. of iron to be opera- ted on, about 7 ozs. of aluminium are used. The iron is not poured at once from the large ladle, but is allowed to stand until it is orange-yellow and a thin film begins to form on the surface. As soon as this occurs the film is removed and the iron is poured. The mould should be kept full. According to a paper read by Mr. J. W. Langley at the Glen Summit meeting of the American Institute of Mining Engineers, the practice in the United States in pouring ingots is as follows : The aluminium in small pieces of % or % pound weight is thrown into the ladle during the ALUMINIUM ALLOYS. 341 tapping, shortly after a small quantity of steel has already entered it. The aluminium melts almost instantaneously, and diffuses with great rapidity throughout the contents of the ladle. The diffusion seems to be complete. The quan- tity of aluminium to be employed will vary slightly, accord- ing to the kind of steel and the results to be attained. For open-hearth steel, containing less than 0.50 per cent, car- bon, the amount will range from 5 to 10 ounces per ton of steel. For Bessemer steel the quantities should be slightly increased, viz., 7 to 16 ounces. For steel containing over 0.50 per cent, carbon, aluminium should be used cautiously ; in general between 4 and 8 ounces to the ton. Aluminium-copper alloys. — These two metals unite readily in any proportions, the union being attended with evolution of heat, which in some cases is very large in amount. The alloys of aluminium with copper show very different properties according to the quantities of alumin- ium they contain. Alloys containing but little copper can- not be used for industrial purposes. With 60 to 70 per cent, of aluminium they are very brittle, glass-hard, and beautifully crystalline. With 50 per cent, the alloy is quite soft, but under 30 per cent, of aluminium the hardness re- turns. The usual alloys are those of 1, 2, 5 and 10 per cent, of aluminium, such alloys being known as aluminium bronze. The 5 per cent, bronze is golden in color, polishes we'll, casts beautifully, is very malleable cold or hot, and has great strength, especially after hammering. The 7.5 per cent, bronze is to be recommended as superior to the. 5 per cent, bronze. It has a peculiar greenish-gold color, which makes it very suitable for decoration. All these good qualities are possessed by the 10 per cent, bronze. It is bright golden, keeps its polish in the air, may be easily en- graved, shows an elasticity much greater than steel, and can be soldered with hard solder. When it is made by a simple mixing of ingredients, it is brittle and does not 34 2 THE METALLIC ALLOYS. acquire its best qualities until after having been cast several times. After three or four meltings it reaches a maximum, at which point it may be melted several times without sensible change. It gives good castings of all sizes and runs in sand-moulds very uniformly. Thin castings come out very sharp, but if a casting is thin and suddenly thickens, small off-shoots must be made at the thick place, into which the metal can run and then soak back into the casting as it cools and shrinks, thus avoiding cavities by shrinkage at the thick part. Its specific gravity is 7.68, about that of soft iron. Its strength when hammered is equal to the best steel. It may be forged at about the same heat as cast steel and then hammered until it is almost cold without breaking or ripping. Tempering makes it soft and malleable. It does not foul a file and may be drawn into wire. Any part of a machine which is usually made of steel can be replaced by this bronze. The melting-point of aluminium-bronze varies slightly with the content of aluminium, the higher grades melting at a somewhat lower temperature than the lower. The 10 per cent, bronze melts at about 1700 F., a little higher than ordinary bronze or brass. In making aluminium bronze great attention must be paid to the quality of the copper used. Ordinary com- mercial copper may contain small amounts of antimony, arsenic or iron, which the aluminium can in no way re- move, and which affect very injuriously the quality of the bronze. The aluminium bronzes seem to be extremely sensible to the above metals, particularly to iron. This necessitates the employment of the very purest copper ; electrolytic copper is sometimes used when not too high priced, but Lake Superior is generally found satisfactory enough. Even the purest copper may contain dissolved cuprous oxide or occluded gases, and it is one of the func- tions of the aluminium to reduce these oxides and gases, forming slag which rises to the surface and leaving the ALUMINIUM ALLOYS. ■ 343 bronze free from their influences. If tin occurs in the cop- per, it lowers very greatly the ductility and strength of the bronzes, but zinc is not so harmful. Care should also be taken as to the purity of the alumin- ium used, though its impurities are not so harmful as they would be if occurring in similar percentage in the copper, since so much more copper than aluminium is used in these alloys. Yet the bronzes are so sensitive to the presence of iron that an aluminium with as small a per- centage of this metal as possible should be used. The silicon in commercial aluminium is not so harmful as the iron, but it does harden the bronze considerably and in- creases its tensile strength. The " Magnesium and Alumin- ium Fabrik " of Hemelingen gives the following directions for preparing the bronzes : Melt the copper in a plumbago crucible and heat it somewhat hotter than its melting point. When quite fluid and the surface clean, sticks of aluminium of a suitable size are taken in tongs and pushed down under the surface, thus protecting the aluminium from oxidizing. The first effect is necessarily to chill the copper more or less in contact with the aluminium ; but if the cop- per was at a good heat to start with, the chilled part is speedily dissolved and the aluminium attacked. The chem- ical action of the aluminium is then shown by a rise in tem- perature which may even reach a white heat ; considerable commotion may take place at first, but this gradually subsides. When the required amount of aluminium has been intro- duced, the bronze is let alone for a few moments, and then well stirred, taking care not to rub or scrape the sides of the crucible. By the stirring, the slag, which commenced to rise even during the alloying, is brought almost entirely to the surface. The crucible is then taken out of the fur- nace, the slag removed from the surface with a skimmer, the melt again stirred to bring up what slag may still re- main in it, and is then ready for casting. It is very injur- ious to leave it longer in the fire than is absolutely neces- 344 THE METALLIC ALLOYS. sary; also any flux is unnecessary, the bronze needing only to be covered with charcoal powder. The particular point to be attended to in melting these bronzes is to handle as quickly as possible when once melted. As with ordinary brass or bronze, two or three remelt- ings are needed before the combination of the metals ap- pears to be perfect, and the bronze takes on its best quali- ties. When the alloy is thus made perfect, the bronze is not altered by remelting, and the aluminium which in the first instance removed the dissolved oxides and occluded gases from the copper, now prevents the copper from tak- ing them up again, and so keeps the bronze up to quality. If, however, the bronze is kept melted a long time, and subject to oxidizing influences, the tendency of the copper to absorb oxygen will cause some loss of aluminium by the action of the latter in removing the oxygen taken up, and a slag consisting principally of alumina will result ; but if the remelting of the bronze is done quickly and the surface covered with charcoal or coke, the loss from this cause will be very trifling, and the percentage of aluminium will remain practically constant. Dilution of a high per cent, bronze to a lower one is practiced on a large scale by the companies which produce aluminium bronze directly in their reduction furnaces. The operation is said to consist simply in melting the high per cent, bronze in a crucible, and stirring into it pure copper in the required proportion, or else melting the two down together on the hearth of a reverberatory furnace. The combined aluminium thus cleanses the added copper and produces a lower per cent, bronze of right quality if the high per cent, bronze is pure and the copper added of the proper quality. It is, of course, quite certain that no diffi- culty can occur in adding aluminium to a low per cent, bronze to increase its percentage other than that of imper- fect combination which may be overcome by one or two remeltings. ALUMINIUM ALLOYS. 345 Aluminium bronze is not an easy metal to cast perfectly until the molder is familiar with its peculiarities. Alumin- ium bronze shrinks about twice as much as brass, and this shrinkage in setting and this contraction in cooling are the obstacles which cause the most trouble. A plumbago crucible, or one lined with magnesite, * is the best to use for melting the bronze, the melt being kept covered with powdered charcoal. Dr. Joseph W. Richards suggests that the stirrers and skimmers used be coated with a wash made of plumbago and a little fire-clay, as the contact of bronze with bare iron tools cannot but injure its quality. The crucible should not be kept in the fire any longer than is absolutely required to bring the bronze to proper heat for casting. In casting it is of considerable advantage to use a casting ladle, into which the bronze is poured, which is arranged so as to tap from the bottom. This effectually keeps any slag or scum from being entangled in the cast- ing. The same result is also obtained by arranging a large basin on top of the pouring gate, which is temporarily closed by an iron or clay stopper. Enough bronze is then poured into this basin to fill the mould, and after the dirt is all well up to the surface, the plug is withdrawn and the mould fills with clean metal. For very small work the ordinary skim-gate will answer the above purpose ; for larger castings the tapping ladle is preferred. Plain cast- ings, such as pump-rods, shafting, etc., and especially billets for rolling and drawing, are cast advantageously in iron moulds, which should be provided with a large sinking head on top to feed the casting as it cools. Rubbing with a mixture of plumbago, kaolin and oil is said to protect the *It is best to use the white Grecian mineral, fully shrunk by calcining at the highest heat of a fire-brick or porcelain kiln; and then ground fine and made into a stiff paste with sugar syrup or molasses. The crucible is care- fully lined, and then heated slowly to redness. On cooling any cracks are carefully filled with more paste, and the crucible is baked again ; when properly prepared, however, one baking is sufficient, and the linings do not shrink from the walls of the crucible. 346 THE METALLIC ALLOYS. iron moulds from sticking. The chilling makes the bronze soft, and the slabs and cylinders thus cast for rolling and drawing are in good condition to be worked at once. For ordinary foundry castings, sand moulds are used. The slower cooling makes the castings more or less hard ; if soft castings are wanted they can be subsequently annealed. * Thomas D. West, the author of "American Foundry Practice," in a paper on " Casting Aluminium Bronze and other Strong Metals," read before the American Society of Mechanical Engineers, says: " The difficulties which beset the casting of aluminium bronze are in some respects similar to those which were encountered in perfecting methods for casting steel. There is much small work which can be successfully cast by methods used in the ordinary moulding of cast iron, but in peculiarly proportioned and in large bronze castings other means and extra display of skill and judgment will generally be required. In strong metals there appears to be a ' red shortness ' or degree of temperature after it becomes soli- dified, at which it may be torn apart if it meets a very little resistance to its contraction, and the separation may be such as cannot be detected by the eye, but will be made known only when pressure is put upon the casting. To overcome this evil and to make allowance for sufficient freedom in contraction, much judgment will often be re- quired and different modes must be adopted to suit vary- ing conditions. One factor often met with is that of the incompressibility of cores or parts forming the interior portion of castings, while another is the resistance which flanges, etc., upon an exterior surface oppose to freedom of contraction of the mass. The core must generally be ' rot- ten ' and of a yielding character. This is obtained by using * Aluminium : Its History, Occurrence, Properties, Metallurgy and Applications, Including Its Alloys. By Joseph W. Richards. Third edition, Revised and Enlarged. 1896.- Philadelphia, Henry Carey Baird & Co. ALUMINIUM ALLOYS. 347 rosin in coarse sand, and filling the core as full of cinders and large vent-holes as possible, and by not using any core-rods of iron. The rosin would cause the core when heated to become soft, and would make it very nearly as compressible as a ' green-sand ' core when the pressure of the contraction of the metal would come upon it. " By means of dried rosin or green sand cores we were able to meet almost any difficulties which might arise in ordinary work from the evils of contraction, so far as cores were concerned. For large cylinders or castings, which might require large round cores which could be ' swept,' a hay-rope wound around a core barrel would often prove an excellent yielding backing, and allow freedom for con- traction sufficient to insure no rents or invisible strain in the body of the casting. To provide means of freedom in the contraction of exterior portions of castings, which may be supposed to offer resistance sufficient to cause an injury, different methods will have to be employed in almost every new form of such patterns. It may be that conditions will permit the mould to be of a sufficiently yielding character, and again it may be necessary to dig away portions of the mould or loosen bolts, etc., as soon as the liquid metal is thought to have solidified. In any metal there may be in- visible rents or strains left in a casting through tension when cooling, sufficient to make it fragile or crack of its own accord, and this is an element which, from its very deceptive nature, should command the closest attention of all inter- ested in the manufacture of castings. " Like contraction, the element of shrinkage is often found seriously to impede the attaining of perfect castings from strong metals. In steel castings much labor has to be expended in providing" risers sufficient to 'feed solid' or prevent ' draw-holes ' from being formed, and in casting aluminium-bronze a similar necessity is found. The only way to insure against the evils of shrinkage in this metal was to have the 'risers ' larger than the body or part of the 348 THE METALLIC ALLOYS. castings which they were intended to 'feed.' The feeder or riser being the largest body, it will, of course, remain fluid longer than the casting, and, as in cast-iron, that part which solidifies first will draw from the nearest uppermost fluid body, and thus leave holes in the part which remains longest fluid. The above principle will be seen to be effec- tive in obtaining the end sought. It is to be remembered that it is not practicable to ' churn ' this bronze, as is done with cast iron. A long cast-iron roll, 1 foot in diameter, can by means of a feeder 5 inches in diameter and a /-£ inch wrought-iron rod be made perfectly sound for its full length. To cast such a solid in bronze, the feeding head should be at least as large as the diameter of the roll, and the casting moulded about one-quarter longer than the length of roll desired. The extra length would contain the shrinkage hole, and when cut off a solid casting would be left. This is a plan often practised in the making of guns, etc., in cast iron, and is done partly to insure against the inability of many moulders to feed solid and to save that labor. A method which the writer found to work well in assisting to avoid shrinkage in ordinary csstings in aluminium bronze was to ' gate ' a mould so that it could be filled or poured as quickly as possible, and to have the metal as dull as it would flow to warrant a full run of casting. By this plan very disproportionate castings were made without feeders on the heavier parts, and upon which draw or shrinkage holes would surely have appeared had the metal been poured hot. "The metal works well in our ordinary moulding sands and ' peels ' extra well. As a general thing, disproportion- ate castings weighing over 100 pounds are best made in 'dry' instead of 'green' sand moulds, as such will permit of cleaner work and a duller pouring of the metal, for in this method there is not that dampness which is given off from a green-sand mould and which is so liable to cause ' cold shots.' When the position of the casting work will ALUMINIUM ALLOYS. 349 permit, many forms which are proportionate in thickness can be well made in green-sand by coating the surface of the moulds and gates with ' silver-lead ' or plumbago. "From 'blow-holes,' which are another characteristic element likely to exist in strong metals, it can be said that aluminium-bronze is free. Should any exist, it is the fault of the moulder or his mould, as the metal itself runs in iron moulds as sound and close as gold. Sand moulds to procure good work must be well vented, and, if of ' dry- sand,' thoroughly open sand mixture should be used and well dried. The sand for ' green-sand ' work is best fine, similar to that which will work well for brass castings. For 'dry-sand-' w r ork the mixture should be as open in nature as possible, and, for blacking the mould, use the same mix- tures as are found to work well with cast iron." Aluminium bronze forges similarly to the best Swedish iron but at a much lower temperature. It works best at a cherry red; if this is much exceeded, the metal becomes hot- short, and is easily crushed. The temperature for rolling is a bright red heat, and it is a curious fact that if the metal were forged at the temperature at which it is rolled, it would be crushed to pieces. If the temperature in the ordinary muffle in which it is heated.be allowed to rise too high, the bronze will frequently fall apart by its own weight. When in the rolls it acts very much like yellow Muntz metal. As it loses its heat much more rapidly than copper or iron, it has to be annealed frequently between rollings. The following examples of rolling are given by the " Cowles Electric Smelting and Aluminum Company": A billet of 10 per cent, bronze about 18" x \%" x \%" was rolled in a Belgian train to quarter-inch rod, at one anneal- ing. The 5 per cent, bronze is harder to roll hot than the 10 per cent., but in cold rolling just the reverse is true; a piece of 5 per cent, sheeting, 8 inches wide, has been re- duced 8 gauge numbers when rolled cold at one annealing ; 350 THE METALLIC ALLOYS. while a 10 per cent, sheet could not be reduced more than half that number. The billets for rolling can be best pre- pared by casting in iron moulds previously rubbed with a mixture of plumbago, pipe-clay; and lard oil. The metal chills very quickly, and very smooth castings can be pro- duced, the smoothness depending considerably on the speed of pouring. With care the 5 and 10 per cent, bronzes can be easily drawn into wire. It is preferable, however, to roll the 5 per cent, to quarter inch rods, and the 10 per cent, to a less diameter, and anneal them. The metal thus prepared is much tougher and less liable to break in draw- ing. The dies must be very hard, or the ordinary wire, and especially the higher grades, are apt to cut them. The speed of the draw blocks must be less than for iron, brass, copper, German silver, or soft steel, and the reduction must be more gradually effected. Aluminium bronze is, in every respect, considered the best bronze yet known. Its rather high cost formerly pre- vented its extensive use in the arts, but since the perfec- tion of processes for the production of aluminium, the cost of manufacture has been greatly reduced. The following results were obtained at the South Boston Iron Works, with pieces of the Cowles Company allovs : Aluminium bronze. 10 per cent, bronze 10 9 7/2 Tensile strength, pounds per square inch. 9i,4D3 92,441 96,434 77,062 71,698 72,019 60,716 Elastic limit. 59,8i5 85,034 51,774 44,025 45,537 Elongation, per cent. 1 9 9 28^ The following tests were made at the Washington Navy Yard of pieces very nearly half an inch in diameter and two inches between shoulders : ALUMINIUM ALLOYS. 351 Aluminium bronze. 10 per cent, bronze 10 " 10 " Tensile strength, pounds per square inch. H4,5I4 95,366 109,823 Elastic limit. 69,749 79,894 Elongation, per cent. 0.45 0.05 0.05 According to Thurston, the alloys of aluminium and copper may be made by fusing together the oxides with metallic copper and enough carbon and flux to reduce them. The oxides as well as the other materials should be as finely divided as possible, and the carbon introduced in excess. Aluminium brass. An addition of aluminium (1.5 to 5.8 per cent.) to brass increases its strength, toughness and elasticity. An alloy of copper 60 parts, zinc 30, and aluminium 2, made by the aluminium factory at Hemlingen near Bremen, can be rolled, forged, stamped, drawn into tubes and wire, is suitable for bells, strings, etc., and es- pecially for cartridge shells, they being not attacked by the gases of the powder. With an addition of 8 per cent, aluminium the brass becomes more ductile, acquires a more beautiful color, and becomes stronger and more resistant towards- caustic fluids. With over [3 per cent, aluminium it becomes hard and red-short, and acquires a reddish color. With a still greater content of aluminium it becomes very brittle and gray-black, but at 25 per cent, the strength, according to Langhove, increases again. According to Kiliani the action of aluminium upon brass is much more powerful than upon bronze ; 1 to 3 per cent, of it producing nearly the same effect in the former as 5 to 10 per cent, in the latter, so that aluminium-brass is the cheaper metal. Compared with aluminium-bronze, alumin- ium-brass has the disadvantage of greater weight and of being more readily oxidized, it being, however, less oxidiz- able than many other metals used at the present time. For 352 THE METALLIC ALLOYS. soft brass alloys % to 2 per cent, aluminium is usually taken ; for hard alloys 2 to 3.5 per cent. While in casting ordinary brass a dirty-green coat of oxide is obtained, with an addition of only % per cent, aluminium the surface re- mains bright and lustrous, and the metal itself becomes more liquid. By the addition of 1 per cent, aluminium the tensile strength of brass with 33 per cent, zinc is greater than that of cast delta metal. The content of zinc exerts an essential influence upon the alloy; the greater it is the smaller the addition of aluminium must be, otherwise the alloy will be too hard and brittle. To brass with 33 per cent, zinc, up to 3.5 per cent, aluminium is generally added, and to brass with 40 per cent, zinc, not over 2 per cent. While alloys with 40 per cent, zinc can, without regard to their content of aluminium, be forged at a dark red heat, those with 33 per cent, zinc must contain at least 2 to 3^ per cent, aluminium to be malleable at a dark red to brown heat. With the decrease in the content of aluminium the forging temperature also decreases, so that brass containing 1 per cent, should be forged only hand-warm, and brass with % per cent. cold. Brass with 33 per cent, zinc and 3 to 4 per cent, aluminium can be forged at a dark cherry-red heat, while at this temperature ordinary brass breaks up under the hammer. The aluminium may be added to the fusing brass either as such, or in the form of a 20 or 25 per cent, aluminium bronze. In remelting aluminium-brass an enrichment of aluminium takes place in consequence of the volatilization of zinc. Casting requires experience, on account of the great shrinkage and the formation of froth, the latter read- ily passing into the alloy. A warm alloy when suddenly cooled becomes brittle and the fracture exhibits a deep golden lustrous color. Messrs. Cowles recommended aluminium brass for the following purposes : "Valve and valve-seats for mining pumps, or pumps ALUMINIUM ALLOYS. 353 working under great pressure, worms and worm-wheels, slide-faces, mining machinery, pinions, screws, hydraulic machinery, dredging machinery, gates for turbine wheels working under a high head, propeller wheels, and as a metal to resist the action of salt water in marine architecture. While aluminium brass is not quite as strong or as tough as the A grade bronze, yet it will answer nearly as well for many purposes that the bronze is used for." The ordinary grades of aluminium brass have about 85,000 pounds per square inch in tensile strength, with nine per cent, elongation. Cowles Bros, report the following series of tests made, at their works in Lockport, their alloys all being made by adding zinc to aluminium-bronze : Composition. Te: nsile strength r square inch Elongation ' * pe Aluminium. Copper. Zinc. (castings). per cent. 5.8 67.4 26.8 95,712 1.0 3-3 63-3 33-3 85,867 7-6 3-0 '67.0 30.0 67,341 12.5 1.5 77-5 21.0 32,356 41.7 1-5 71.0 27-5 41,552 27.0 1-25 70.0 28.0 35,059 25.0 2.5. 70.0 27-5 40,g82 28.0 1.0 57-o 42.0 68,218 2.0 1. 15 55-8 43-0 69,520 4.0 Richards bronze. — The alloy known under this name is the invention of Mr. Joseph Richards, of Philadelphia. It is a very strong and at the same time cheap alloy. It con- tains copper 55 parts, zinc 42 or 43, iron 1, aluminium 1 to 2. This alloy is of a golden-yellow color, is exceedingly fine-grained, and has a tensile strength in castings of 50,000 lbs. per square inch with 15 per cent, elongation. Like all the strong brasses, however, it requires some experience in handling before the ordinary metal-worker can turn out uniform castings with these maximum properties. The worked metal averages 50 per cent, stronger. 23 354 THE METALLIC ALLOYS. Aluminium-nickel- copper alloys. — A number of remark- able and useful alloys are made by mixing aluminium bronzes with nickel in various proportions. These com- positions are said to be very ductile and to have a tenacity of from 75,000 to over 100,000 lbs. per square inch, with about 30 per cent, elongation. Tests made by Kirkaldy on alloys of a similar nature made by the " Webster Crown Metal Company," England, gave results ranging from 82,000 to over 100,000 lbs. per square inch with 20 to 30 per cent, elongation. The alloys are prepared as follows : a. Copper is melted and aluminium added to it until a 10 per cent, bronze is made. There is then added to it 1 to 6 per cent, of an alloy, ready prepared, containing : Copper 20 parts. Nickel 20 " Tin 50 " Aluminium 7 " The alloy thus prepared would contain, as represented by the two extremes : I. II. Copper 89.3 86.4 Nickel 0.3 1.4 Tin 0.4 2.0 Aluminium 10. 10.2 b. The two following alloys are prepared in the usual way, under a flux consisting of equal parts of potassium and sodium chlorides, and are cast into bars : I. II. Aluminium 15 parts Nickel 17 parts Tin 85 " Copper 17 " Tin 66 " 100 parts 100 parts To make the bronzes, equal parts of these two alloys are ALUMINIUM ALLOYS. 355 melted with copper ; the more of the alloys used the harder and better the bronze. The best mixture is of Copper : 84 parts Alloy I 8 Alloy II 8 " 100 parts The copper is first melted, then the alloys put in together and stirred well. As iron is harmful to this bronze, the stirrer should be of wood or clay. This alloy is suitable for art castings, kitchen utensils, etc., or anywhere where durability, hardness, malleability, polish and very slight oxidability are required. A cheaper and more common alloy may be made of Copper 91 parts Alloy I 4 " Alloy II 5 " The two bronzes would contain centesimally : Rich alloy. Poorer alloy. Copper 85.36 94.58 Tin 12.08 6.70 Nickel 1.36 3.85 Aluminium 1 .20 0.60 c. The following alloy is said to withstand oxidation well,. to possess great tenacity, durability, capability to bear vibration, and to take a high polish. A preliminary alloy is made of : Copper 200 parts Tin 80 " Bismuth 10 " Aluminium 10 " The alloy proper is made by melting together : Preliminary alloy 4^ parts Copper 164 Nickel 70 Zinc 6t^ 356 THE METALLIC ALLOYS. The final composition would be by calculation : Copper 55-67 Nickel 23.33 Zinc 20 50 Tin 0.40 Bismuth 0.05 Aluminium 0.05 d. Another alloy patented by Mr. Webster contains : Copper 53 parts = 51.0 per cent. Nickel - 22^ " = 21.6 ■ Zinc 2 " =21.2 Tin 5 " = 4-8 Bismuth = 0.7 Aluminium = 0.7 100.00 Lechesne. — The alloy known under this name has been patented in England by the Societe anonyme la Ferro- Nickel, of Paris. The patent specified two alloys containing : II. parts 600 parts " 400 " Copper 900 Nickel 100 Aluminium i}( " yi Which would give in per cent.: I. II. Copper 89.84 59.97 Nickel 9.98 39.98 Aluminium 0.18 .05 100. co The first of these alloys is the one to which the name " Lechesne " appears to be given. In a description of the manufacture of this alloy, a French magazine states that the nickel is first put into a crucible and melted, the copper stirred in gradually, then the heat raised and the aluminium ALUMINIUM ALLOYS. 357 added. The alloy is heated almost to boiling and cast very hot. This alloy is claimed to be equal to the best quality of German silver, being very malleable, homogeneous, strong and ductile, and stands hammering, chasing, punch- ing, etc. The following alloys have been recommended by G. F. Andrews as being all very hard, fine-grained and possessing great strength. Aluminium. Nickel. Copper. No. I 6% 21% 72y 2 No. II io 24 66 No. Ill 12 33 55 No II. has the color of io-carat gold and takes a fine polish. No III. has a beautiful golden-brown color. No. I. is similar in color but of a richer and deeper tone. These alloys may be very useful for decorative purposes. Sun-bronze. — An alloy known under this name is com- posed of cobalt 6o or 40 parts, aluminium 10, copper 30 or 50. Metalline. — This alloy contains cobalt 35 parts, alumin- ium 25, iron 10, copper 30. Aluminium alloy for dentists fillings* — Silver 12.3, per cent., tin 52, copper 4.7, aluminium 1. It is reduced to a powder and then forms an amalgam with mercury. Alloy for type metalj\ — Lead 65 parts, antimony 20, and 10 parts of an alloy consisting of equal parts of tin, copper, and aluminium. The tin-copper-aluminium alloy is first melted, the antimony added to it, and the mixture is then added to the melted lead. Aluminium alloy for type metal. % — Aluminium 72 to 90 per cent., copper 2 to 10 per cent., and tin 2 to 23 per cent. Aluminium-nickel bronze. § — A small quantity of mag- nesium is added to aluminium-nickel bronze, the following *U. S. patent, 475,382, May 24, 1892. tU. S. patent, 463,427, Nov. 11, 1891. % German patent, 101,020. § English patent, 5,568, 1898. 358 THE METALLIC ALLOYS. proportions being the best: Copper 89 to 98 per cent., aluminium and nickel 2 to 11 per cent. To this is added, phosphorus up to 0.5 per cent, and magnesium up to 1.5 per cent. This alloy is claimed to be especially suitable for locomotive furnaces, fire-tubes, etc., as well as for castings, such as cocks, valves, bearings, etc. Partinium. — The alloy known under this name is an aluminium-tungsten alloy and is extensively used in France in the construction of motors, etc. It is cheaper than aluminium, nearly as light, and possesses greater power of resistance. Cast partinium has a specific gravity = 2.89, and rolled partinium one =2.89. It is claimed to have a tensile strength of 32 to $7 kilogrammes per square milli- meter. Aluminium-bronze alloy.* — Aluminium 12 to 25 parts, manganese 2 to 5, copper 75 to 85. Hercules' metal. — An alloy known under this name con- sists of bronze 88 per cent., aluminium 2^, tin 7J, and zinc 2. Aluminium-chromium alloy. — With chromium alumin- ium forms a beautiful alloy which can be prepared by a rather tedious operation in the form of crystalline needles. It has thus far found no technical application. A lu m in iu m - m agn esiu m a Hoy ca lied m a gn a liu m.f — This alloy which is used for various purposes is made by adding 2 to 10 parts of magnesium to 100 parts aluminium. It forms an exception to the general rule that aluminium alloys are specifically heavier than pure aluminium. Alloys with 6 per cent, magnesium are specifically not heavier than aluminium, and with a higher percentage lighter. Alloys with 3 to 10 per cent, magnesium have two to two and half times the strength of pure aluminium, but a higher percentage of magnesium decreases the strength. Brittle- *U. S. patent, 446,351, Feb. 10, 1891. t German patent 113,935. U. S. patent 62,5084. ALUMINIUM ALLOYS. 359 ness increases quite rapidly with the content of magnesium, and alloys with more than 20 per cent of it are useless by reason of their great brittleness, while those with 3 to 4 per cent, of magnesium are malleable and can be worked. However, like pure aluminium, they possess the drawback of not being readily worked with cutting tools and clogging the file. By subjecting, however, the alloys to a process of compression by rolling, drawing, pressing, etc., the remark- able fact becomes evident that they acquire entirely differ- ent properties. They possess the same properties as pure aluminium treated in the same manner, which otherwise can be attained only with larger additions of magnesium to aluminium, i. e., an alloy with a small content of magne- sium can readily be worked with cutting tools. The pro- cess of rolling is executed as follows: The alloys are first passed ones or several times cold through the ro^s, then heated to about 752 to 932 F., again passed once or sev- eral times, cold, through the rolls and this alternate heating and rolling is repeated till the desired strength has been attained. Aluminium-magnesium alloy for reflectors, * which, when polished, possesses also a strong reflecting power for the ultra-violet rays, consists of aluminium 100 parts, mag- nesium 60 to 200. Alloy of aluminium and tin. — An alloy, the use of which it is claimed overcomes the difficulties of working and welding aluminium, is formed by melting together 100 parts of aluminium with 10 of tin. The alloy is whiter than aluminium and but little heavier, its specific gravity being 2.85. By most substances it is less attacked than pure aluminium, and it can be welded and soldered like brass without any special preparation. Brazing aluminium bronze. — Aluminium-bronze will braze as well as any other metal, using one-quarter brass * German patent 110,178. 360 THE METALLIC ALLOYS. solder (zinc 50 per cent., copper 50 per cent.) and three- quarters borax. Soldering aluminium-bronze. — To solder aluminium- bronze with ordinary soft (pewter) solder: Cleanse well the parts to be joined free from dirt and grease. Then place the parts to be soldered in a strong solution of sul- phate of copper, and place in the bath a rod of soft iron touching the parts to be joined. After a while a copper- like surface will be seen on the metal. Remove from bath, rinse quite clean, and brighten the surfaces. These sur- faces can then be joined by using a fluid consisting of zinc dissolved in hydrochloric acid, in the ordinary way with common soft solder. Mierzinski recommends ordinary hard solder, and says that Hulot uses an alloy of the usual half-and-half lead-tin solder with 12.5, 25, or 50 per cent, of zinc amalgam. Aluminium-bronze for jewelry may be soldered by using the following composition : Hard solder for 10 per cent, aluminium-bronze. — Gold 88.88 per cent., silver 4.68, copper 6.44. Middling hard solder for 10 per cent, aluminium-bronze. ■■ — Gold 54.40 per cent., silver 27.60, copper 18. Soft solder for aluminium-bronze . — Brass (copper 70 per cent., tin 30 per cent.) 14.30, gold 14.30, silver 57.10, cop- per 14.30. Schlosser gives the following directions for preparing solder for aluminium-bronze : White solder is alloyed with zinc amalgam in the proportions of White solder 2 4 8 Zinc amalgam 1 1 I The white solder may be composed as follows : Brass 40 22 18 Zinc 2 2 12 Tin - 8 4 30 ALUMINIUM ALLOYS. 361 The zinc amalgam is made by melting 2 parts of zinc, adding 1 part of mercury, stirring briskly and cooling the amalgam quickly. It forms a silver white, very brittle alloy. The white solder is first melted, the finely powdered zinc amalgam added, and the alloy stirred until uniform, and poured into bars. Soldering aluminium. — Although strictly speaking the subject of soldering aluminium-bronze and aluminium does not belong here, a special chapter being devoted to "Soldering," it is preferred to refer to it in this place. From the articles which occasionally appear in the trade journals, both in Europe and in this country, and the patent list, it appears that the difficulties of soldering aluminium have not been entirely overcome. Some of the solders are here introduced without comment. Mourey s aluminium solders are composed of : — I. II. III. IV. V. Zinc 80 85 88 90 94 Copper 8 6 5 4 2 Aluminium 12 9 7 6 4 In making these solders the copper should be melted first, the aluminium then added, and the zinc last. Stearin is used as a flux to prevent the rapid oxidation of the zinc. When the last metal is fused, which takes place very quickly, the operation should be finished as rapidly as possible by stirring the mass, and the alloy should then be poured into an ingot-mould of iron, previously rubbed with fat. The pieces to be soldered should first be cleaned thoroughly and roughened with a file and the solder placed on the parts in small fragments, the pieces being supported on a piece of charcoal. The place of juncture should then be heated with the blast lamp. The union is facilitated by the use of a soldering tool of aluminium. This last is said to be essential to the success of the operation. Alloy I is recommended for small objects of jewelry ; 362 THE METALLIC ALLOYS. alloy IV is said to be best adapted for larger objects and for general work, and is that most generally used. The successful performance of the act of soldering appears to require skill and experience, but the results obtained are said to leave nothing to be desired. Soldering tools of copper or brass should be avoided, as they would form colored alloys with the aluminium and solder. The skillful use of the aluminium tool, however, requires some practice. At the instant of fusion the operator must apply some fric- tion, and, as the solder melts very suddenly, the right moment for this manipulation may be lost unless the work- man is experienced. Boiirbonze s aluminium solder. Tin 45, aluminium 10. If the soldered articles are not to be subjected to further working, a solder containing somewhat less aluminium may be used. Frishmutli s aluminium solders. I. II. Silver 10 — Copper 10 — Aluminium 20 — Tin , 60 95 to go. Zinc 90 — Bismuth — 5 to 8 Solder No. II. is to be applied with the soldering iron, but on account of its great fusibility it appears to be only suitable for small articles, which after soldering are not to be subjected to further heating. M. H. Lancon has patented* the following method of pre- paring aluminium solder : Pure aluminium is melted, the surface of the melted metal completely covered with a layer of phosphoric acid, acid sodium sulphate, fluorine combina- tions or other salts of an acid reaction, and finally a small quantity of copper and tin is added to the melted metal, or copper, bismuth, zinc and tin, or copper, antimony, bismuth * German patent, 66,398. ALUMINIUM ALLOYS. 363 and zinc, or copper, antimony, bismuth and. tin. The com- position of the solder varies according to the articles to be soldered. For wire and thin articles the solder is composed of pure aluminium 95 parts, copper 1, tin 4. The 4 parts tin may be replaced by bismuth 2 parts, zinc 1, tin 1. For large pieces of aluminium and aluminium sheets, the solder is. composed of: Pure aluminium 95 parts, copper 2, antimony 1, bismuth 1, zinc 1 ; or : Pure aluminium 60, copper 13, bismuth 10, antimony 15, tin 2. Schlosser recommends two solders containing aluminium as especially suitable for soldering dental work on account of their resistance to chemical action. Copper cannot be allowed in alloys intended for this use, or only in very in- significant quantity, since it is so easily attacked by acid food, etc. Since these two alloys can probably be used also for aluminium dental work, their composition is here given : Platinum aluminium solder. — Gold 30, platinum 1, silver 20, aluminium 100. Gold aluminium solder. — Gold 50, silver 10, copper 10, aluminium 20. O. M. Thowless has patented the following solder for aluminium and the method of applying it. * The alloy is composed of: Tin 55 parts, zinc 23, silver 5, aluminium 2. The aluminium and silver are first melted together, the tin added, and lastly the zinc. The metallic surfaces to be united are immersed in dilute caustic alkali, or a cyanide solution, washed and dried. They are then heated over a spirit lamp, coated with the solder, and clamped together, small pieces of the alloy being placed around the joints. The whole is then heated to the melting point of the solder, and any excess of it removed. No flux is used. C. Sauer of Berlin has patented the following : An alloy is made of: Aluminium 9 parts, silver 1, 2, 3, or 4, copper 2, 3, 4, or 5. * English patent, 10,237, Aug. 29, 1885. 364 THE METALLIC ALLOYS. He also claims the above alloy, to which is added 1 to 2 parts of zinc, cadmium, or bismuth, or even a fusible metal such as Wood's alloy. A small proportion of gold may be added. In making, the copper and silver are first melted, melted aluminium added, and the solid zinc last dropped in. In using, the alloy is broken small, spread between the surfaces to be soldered, previously heated, and the joint then made with a soldering iron. No flux is required. Chloride of silver has been recommended as a solder. It is to be finely powdered and spread along the junction to be soldered, and melted with the blow- pipe. Richards s solder. — Mr. Joseph Richards has patented * in the United States and England a composition contain- ing a small amount of phosphorus, and describes as prefer- able a solder composed of : Tin i> 2 parts = 78.34 per cent. tin. Zinc 8 " =19.04 " zinc. Aluminium 1 " — 2.38 " - aluminium. Phosphor tin 1 " = 0.24 " phosphorus. On remelting some of this solder, a liquation was noticed, and it was inferred that the more fusible part was probably a better alloy for soldering, being less likely itself to liquate. It was therefore analyzed, and found to contain 71.65 per cent, of tin corresponding closely to the formula Sn 4 Zn , which would call for 70.7 per cent. The solder as now made contains 1 part aluminium, 1 part phosphor tin, 11 parts zinc and 29 parts tin, giving it 71.2 per cent, of tin. The solder fuses easily at a heat attainable with a copper or nickel bolt, and possesses great ability to take hold on the metal. It is so tough that if a joint is well made the metal will break before the solder. It is very nearly the color of aluminium, but darkens slightly on standing some time ; when the article is in constant wear, however, the solder retains its bright color ; when discolored it becomes bright * United States patent, 478,238, July 5,1892; English patent, 20,208, 1892. ALUMINIUM ALLOYS. 365 again by polishing. The edges to be joined are filed or scraped clean immediately before soldering, then, if the piece will allow, heated to a temperature at which the solder melts, and the edges are tinned by rubbing with a stick of solder. If the whole piece cannot be heated, the edges can be tinned by heating with a tinned bolt and rubbing in the melted solder briskly. Any surplus solder is removed from the edges by a small scraper, while still hot. The prepared edges are then soldered together in any way desired. For a lap-joint, the edges are overlapped, the soldering bolt passed along, and a little extra solder melted in the joint. For a joint at an angle, it is necessary that the bolt be shaped to fit, as the solder must be rubbed in well at the edges. No flux of any kind is to be used either on the bolt or on the joint. In making a lock seam, the edges of the aluminium should be coated with the solder as above-described before being turned over, else the solder cannot soak into the joint. Common sheet-tin does not need such preparation, because the whole sheet is already tinned to start with. In brief, aluminium is similar to cop- per and black-iron, not like tinned iron, and the edges must be prepared for soldering. CHAPTER XII. LEAD ALLOYS. Lead in a pure state is but little used except for pipes, foil, and for certain chemical purposes. Some of its alloys, however, are of great importance, and are generally used, notwithstanding many efforts to replace them, especially for typographical purposes. An addition of other metals generally makes the lead harder and more or less injures its ductility. An addition of copper imparts to the alloy greater hardness without impairing its ductility to a serious extent, and if the content of copper be small such an alloy can be drawn to pipes or rolled out to thin sheet. A content of arsenic, antimony, and tin increases the hardness of lead, but considerably impairs its ductility. Antimony and arsenic especially exert a strong influence in this respect, while the lead-tin alloys retain their ductility. Lead-antimony alloys containing less than 22 per cent, antimony contract on cooling and are therefore not suitable for sharp castings ; only mixtures richer in antimony ex- pand on cooling and reproduce the finest depressions of the mould. The hardness of lead-antimony alloys increases with the content of antimony, alloys with 11 to 17 per cent, antimony being about four times as hard as lead, and alloys with 23.5 per cent, antimony five times. A larger content of antimony makes the alloys still harder (with over 25 per cent, twelve times as hard as lead), but on ac- count of their brittleness they are not suitable for technical purposes. The affinity of zinc and iron for lead being very small it is difficult to prepare alloys with them. The most important alloys of lead are type-metal and shot-metal, the (366) LEAD ALLOYS. 367 first generally an alloy of lead with antimony, and the latter, one with arsenic. Type- Metal. An alloy to serve for type-metal must allow of being readily cast, fill the moulds sharply, and at the same time be as hard as possible. Though it is difficult entirely to satisfy these demands, an alloy consisting of lead and anti- mony answers the purpose best. Antimony increases the hardness of lead and renders it very brittle if present in too large a proportion. An alloy of lead j6 parts, and anti- mony 24, appears to be the point of saturation of the two metals. More fusible than the average fusibility of the two component metals, ductile and considerably harder than lead, this alloy expands in. cooling, and to this property is due its employment for the manufacture of type. But the above compound does not answer perfectly well, especially for small type. When too soft it gets out of shape, when too hard it cuts the paper ; and it happens very often that the founder goes to one or the other extreme. When the alloy is melted in contact with the air antimony is oxidized much more rapidly than lead, and this accounts for the difficulty of obtaining an exact composition. It is a constant subject of study for type-founders to arrive at a fusible and homo- geneous metal with much expansion, resistant as much as possible, and, at the same time, soft enough to be repaired and to bear the action of the press without being soon put out of shape. The alloy of equal proportions is porous, and brittle. These defects increase in the same ratio as the proportion of antimony increases. On the other hand they disappear when the lead takes the place of antimony. An alloy of lead 4 parts and antimony i is compact, much harder than lead, and remains malleable. An alloy of antimony i part and lead 8 is very tough, and has a higher specific gravity than the proportional 3 68 THE METALLIC ALLOYS. specific gravity of the two metals. It is more malleable than the preceding alloy and retains a certain degree of hardness. The hardness imparted by antimony, the in- crease in toughness, and that in the specific gravity are quite perceptible in alloys of antimony i part and lead up to 16 parts. At present a great many receipts for type metal are known, in the preparation of which other metals besides lead and antimony are used for the purpose of rendering the alloy more fusible (additions of bismuth as imparting to them greater power of resistance, as well as copper and iron having been recommended for the purpose). By such admixtures the fusibility of the alloys is, however, impaired, and the manufacture of the types becomes much more diffi- cult than with an alloy of lead and antimony alone. In the following table some alloys suitable for casting type are given : Parts. Metals I. II. III. IV. 10 V. 70 VI. 6o VII. 55 VIII. IX. X. Lead , 3 5 10 55 100 6 Antimony I I i 2 18 20 25 30 30 — Copper 8 4 Bismuth — — — I — — — — 2 — Zinc 00 Tin — — — — 10 20 20 15 20 Nickel 8 French and English type-metals always contain a certain quantity of tin, as shown by the following analysis : English types. French types. Lead 69.2 61.3 55.0 55 Antimony 19.5 18.8 22.7 30 Tin 9.1 20.2 22.1 15 Copper 1.7 — — — 99.5 100.3 99.8 100 LEAD ALLOYS. 369 According to Ledebnr, type-metal contains : — Lead 75 60 80 82 Antimony 23 25 20 14.8 Tin 2 15 — 3.2 I. Ordinary; II. fine quality of type-metal ; III. alloy for sticks ; IV. for stereotype plates. Erhart's type metal. — Erhart recommends the following alloys as being hard and at the same time ductile : Zinc 89 to 93, tin 9 to 6, lead 2 to 4, copper 2 to 4. The tin is first melted and then the lead and zinc are added in succession, and finally the copper. The manufacture of the type from the alloys is seldom effected by cold stamping in steel moulds, the process being verv expensive ; hence they are generally cast. Ac- cording to the old process the types are cast piece by piece by means of a small casting ladle, but for types with a large face and much detail, the motion of the hand is barely suf- ficient to give the momentum required to throw the metal into the matrix and produce a clean, sharp impression. A machine is then used, which may be compared to a small forcing-pump, by which the mould is filled with the fluid metal ; but from the greater difficulty of allowing the air to escape, such types are in general considerably more un- sound in the shaft or body, so that an equal bulk of them only weighs about three-fourths as much as type cast in the ordinary way by hand, and which for general purposes' is preferable and more economical. Some other variations are resorted to in type-founding; sometimes the mould is filled twice, at other times the faces of the types are dabbed (the cliche process), many of the large types and ornaments are stereotyped and either sol- dered to metal bodies or fixed by nails to wooden blocks. The music type and ornamental borders and dashes display much curious power of combination. Plates for engraving music are generally made of tin 5 to 7.5 parts, antimony 5 to 2.5. 24 37° THE METALLIC ALLOYS. Type-metal being easily cast may also be used for candle- sticks, statuettes, etc., sand moulds being generally em- ployed for the purpose, though for decorated articles metallic moulds thoroughly rubbed inside with oil can be advantageously used. An alloy for keys of flutes and similar parts of instru- ments consists of lead 2 parts, antimony 1. Shot- Metal. The mixture of metal used for the manufacture of shot consists of lead and arsenic. The latter, as previously men- tioned, possesses the property of hardening lead, the alloy being at the same time more fusible than pure lead. Shot, as is well known, is prepared by letting fall from an ele- vated place drops of lead into water, and an addition of a very small quantity of arsenic to the lead helps its solidifi- cation and gives to the shot a more spherical shape. On account of the poisonous properties of the arsenious vapors certain precautions have to be preserved in prepar- ing the alloy. In a cast-iron pot provided with a well-fit- ting lid, the lead is first melted and then covered with a layer of charcoal dust. Only after this is done should the arsenic or arsenious combination to be used be introduced. In many shot-factories this precaution is omitted, which, however, deserves censure, as everything should be done to protect the workmen from the injurious effects of the poisonous arsenious vapors. If the metal is covered with a layer of charcoal dust, the vapors cannot reach the air as easily as when the bright metal is in direct contact with the air. White arsenic (arsenious acid) is generally used as an addition to the lead, though in some cases red arsenic (realgar or red orpiment) is employed. Immediately after the introduction of the arsenic the mass is vigorously stirred with a wooden rod, and the pot is then covered with the lid, which is luted around the edges with moist clay. A strong fire is now kept up to render the contents of LEAD ALLOYS. 371 the pot thinly-fluid. After about three hours the lid is re- moved and the charcoal and oxides floating upon the sur- face having been carefully lifted off, the alloy is poured with ladles into moulds. This alloy serves for the preparation of the actual shot-lead, which is prepared by melting lead and adding a certain quantity of the alloy of lead and arsenic. It is in all cases preferable first to prepare the arsenious alloy in the manner prescribed, it being otherwise difficult intimately and homogeneously to combine the lead with the comparatively small quantity of arsenic required for shot-metal. In working by the preceding process generally 1000 parts of lead are alloyed with 20 of arsenic, and equal parts of this alloy and of lead are subsequently melted together. For the direct preparation of the alloy of lead and arsenic for shot, 2.4 parts of arsenious acid are used for 600 parts of refined lead, or 3.0 parts of arsenic to 700 parts of lead. As will be seen the quantity of arsenic is exceedingly small, and should in no case exceed that actually required for hardening the lead and rendering it easy to cast. The quantity considered necessary for this varies much in differ- ent countries. While, for instance, in England 10 parts of arsenic are allowed for 1100 parts of lead, in France 3 to 8 parts are considered sufficient for 1000 parts of lead. This variation in the proportions of arsenic used for hardening the lead is readily accounted for by the difference in the qualities of the lead used ; the purer and softer the lead the greater the quantity of arsenic required. But under no circumstances should good shot-metal contain more than from ToVo to toou - of the weight of lead used. Both a too small or too large content of arsenic is in- jurious ; if the lead contains too little arsenic, the resulting shot has the shape of tears, and the interior is frequently full of cavities, while with too much arsenic the drops are lenticular. As even with much experience it is quite diffi- cult to hit at once the right proportion, it is advisable, be- 3J2 THE METALLIC ALLOYS. fore melting together large quantities of lead and arsenic, first to make tests with small quantities. From the shape of the shot obtained from these samples it can be readily judged whether the proportions are right or in what re- spect they have to be changed. Many manufacturers of shot, it would seem, vary the composition of the alloys used by them, for, besides lead and arsenic, other metals are frequently found in shot, es- pecially antimony and copper, though the latter only in ex- ceedingly small quantities. The content of antimony is, however, larger, reaching in many cases 2 per cent, of the total weight, and from this it would appear that the manu- facturers endeavor to replace the arsenic by antimony. Casting of shot. — According to the old method, shot is prepared by allowing the melted metal to fall in drops from a tower of considerable height. This method is said to have originated with a plumber of Bristol, England, named Watts, who, about the year 1782, dreamed that he was out in a shower of rain, that the clouds rained lead instead of water, and the drops of lead were perfectly spherical. He determined to try the experiment, and, accordingly, poured some melted lead from the tower of St. Mary Redcliffe Church into some water below ; the plan succeeded, and he sold the invention for a large sum of money. For carrying out this invention shot-towers and shot- wells have been constructed. At the top- of the tower melted lead is poured into a colander and the drops are re- ceived into a vessel of water below. The surface of the lead becomes covered with a spongy crust of oxide called cream, which is used to coat over the bottom of the colander to prevent the lead from running too rapidly through the holes, whereby they would form oblong spheroids instead of spheres. The colanders are hollow hemispheres of sheet-iron, the holes in them differing according to the size of the shot. They must be at a distance of at least three times the diameter of the shot from each other, as LEAD ALLOYS. " 373 otherwise it might happen that two or more drops of lead would while falling down, unite to one mass, which, of course, would be useless and have to be remelted. The water serving for the reception of the drops must be frequently changed to prevent it from becoming too hot or boiling. By some it is recommended to pour a layer of oil upon the surface of the water, the shot retaining thereby its spherical shape better than when dropping directly into the water. To prevent the shot, when taken from the water, from losing its metallic appearance by oxidation, a small quantity, (about 0.25 per cent.) of sodium sulphide is dis- solved in the water serving for the reception of the shot, by means of which the drops falling into it are at once coated with a thin film of sulphide of lead of a lustrous, metallic, gray-black color, which is permanent even in moist air. In more recent times the formation of shot by centri- fugal power has been introduced, which does away with the expensive towers. The melted lead is poured in a thin stream upon a rapidly revolving metal disk, surrounded at some distance by a screen against which the shot is thrown. The moment the melted lead falls upon the metal disk it is divided by the centrifugal force into drops, the size of which depends on the rapidity with which the disk re- volves. The drops are hurled in a tangible direction from the disk and are stopped by the above-mentioned screen. David Smith, of New York, has invented and put into practice a mode of manufacturing drop-shot. The chief feature of this invention consists in causing the fused metal to fall through an ascending current of air, which shall travel at such a velocity that the dropping metal shall come in contact with more particles of air in a short tower than it would in falling through the highest towers before in use. Fig. 33 is a vertical sectional elevation of a sheet- metal cylinder set up as a tower within a building, and may be about 20 inches internal diameter and 50 feet high or 374 THE METALLIC ALLOYS. less. This tower, although mentioned in Smith's patent, is now- dispensed with in the middle of the height, so that only an open space remains. Fig. 34 is a plan at the line a b; Fig 35 is a plan at the line q r: Fig. 36 is a section at op; and Fig. 37 is a section at m n, Fig. 33. C is a water cistern beneath the tower. B is a pipe from the blowing apparatus leading into the annular chamber // the upper surface g is perforated as shown in Fig. 35 to dis- perse the ascending air. The outer side of this annular ring / forms the base of a frustrum of a cone, forming the LEAD ALLOYS. 375 tower D, passing the blast through the frame yy, Fig. 36 ; and in Fig. 37 is shown to support a cylindrical standard R, the upper central portion of which receives the pouring pan A. This pan is charged with each separate size of shot. Round the pouring pan A is a. circular waste trough z. The object of this arrangement is that the fluid metal run- ning through the pouring-pan A into the ascending current of air, will be operated upon in the same manner as if it fell through stagnant air of great height. The shot falls Fig. 36. Fie. 27. through the open center of the ring / into the water cistern C, where a chute t carries it into the tub S, which when full may be removed through x, an aperture in the cover of the cistern. Sorting the shot. — Even with the most careful work it happens that drops of unequal size or cornered masses are found among the shot, and the latter, after being taken from the water and dried, must be sorted. This was formerly effected by hand in the following manner : A slab of polished iron is tilted at a certain angle, and the shot are strewed along the upper part cf the inclined plane thus formed. The perfect shot proceed rapidly in straight lines and fall into a bin placed to receive them, about a foot away from the bottom of the slab. The misshapen shot, on the contrary, travel with a slower zigzag motion and fall without any bound into a bin placed immediately at the 37^ THE METALLIC ALLOYS. end of the incline. The perfect shot are then subjected to another sorting by passing them through sieves with meshes of exactly the same size as the apertures in the casting colanders. The finished shot, which are now of dead silvery-white color are polished and made dark in an iron barrel or rumble containing a quantity of powdered plumbago. They are then tied up in canvas bags and are ready for sale. At present the shot are, however generally sorted by means of sorting drums consisting of inclined cylinders perforated with holes whose diameter corresponds to that of the shot. The forward motion of the shot in these drums is effected by means of an Archimedean screw. Large shot are at the present time also frequently pre- pared by casting in moulds like bullets, or by stamping them from thin plates of the alloy. In both cases the re- sulting shot shows a seam which is removed by bringing the shot together with very fine. quartz sand into revolving drums. By the action of the sand the seams are ground off, and a perfectly spherical shape imparted to the shot. Alloys of lead and iron.— Lead, as previously stated, has no affinity for iron. A piece of lead thrown into a bath of melted iron becomes oxidized, or is separated and found at the bottom of the bath after the cast-iron has been run out. As soon as the lead is introduced into the melted cast-iron, a certain agitation appears on the surface, and even through the whole bath, and the cast-iron seems more fluid. When thin or large pieces are to be cast, the founders, who are aware of this phenomenon, often throw a certain quantity of lead into the melted cast-iron in order to prevent it from congealing too soon against the sides of the casting ladle. This want of affinity of lead for iron, and conversely, is made use of for separating iron from other metals, such as silver, for instance. Thus if lead is added in sufficient quantity to a fused alloy of cast-iron and silver, it will com- bine with the silver, and the iron will float on the surface of the bath. LEAD ALLOYS. 377 All the authors who have occupied themselves with the question of alloys agree upon the impossibility of alloying lead and iron. Alloys of lead and other metals. — Lead, as seen from the preceding sections, is much used in the preparation of alloys which have been already partially mentioned under the respective mixtures of metals. Lead is also frequently alloyed with cadmium and bismuth, and forms an important constituent of the so-called soft-solder. In speaking of these compounds, the lead alloys not yet mentioned will be referred to. Only type-metal and shot-metal can be con- sidered as lead alloys, i. e., alloys of which lead forms the greater portion. CHAPTER XIII. CADMIUM ALLOYS. Cadmium shares with bismuth the property of consider- ably lowering the melting points of alloys, but while the bismuth alloys are nearly all brittle, many alloys of cad- mium possess considerable ductility, and can be worked under the hammer as well as between rolls. They act, however, very differently in this respect, there being alloys which are very ductile, and others again, though contain- ing in addition to cadmium the same metals only in differ- ent proportions, which are very brittle. An alloy consisting, for instance, of cadmium and silver,, shows this phenomenon in the most remarkable manner. By melting together one part of cadmium and one to two parts of silver a very ductile alloy is obtained which can be rolled out to a very thin sheet. By taking, however, two parts of cadmium to one of silver, the resulting alloy is so brittle as to break into pieces under the hammer. As cadmium imparts to the alloys a very low melting point, it is frequently used in the preparation of very fusible solders, for casting articles not to be exposed to a high temperature, and, in denistry, for compounds for filling hollow teeth. Alloys of cadmium contain generally tin, lead, bismuth, and sometimes mercury, the latter being chiefly added to lower the melting point still more. Alloys of cadmium and mercury alone (cadmium amalgams) are solid and mal- leable, hence the addition of mercury does not impair their solidity. Lipowitzs alloy. — This alloy is composed of cadmium 3 (378) CADMIUM ALLOYS. 379 parts, tin 4, bismuth 15, lead 8. It is best prepared by heating the comminuted metals in a crucible and stirring", as soon as fusion begins, with a stick of hard wood. This stirring is of importance in order to prevent the metals, whose specific gravity varies considerably, from depositing themselves in layers. This alloy softens at 140 F., and melts completely at 158 F. Lipowitz's metal has a silvery-white color, a luster like polished silver, and can be bent short, hammered, and worked in the lathe. It, therefore, possesses properties adapting it for many purposes where a beautiful appearance is of special importance, but on account of the considerable content of cadmium and bismuth, the alloy is rather ex- pensive and finds but limited application. Castings of small animals, insects, lizards, etc., have been prepared with it, which in regard to sharpness were equal to the best gal- vano-plastic products. Plaster of Paris is poured over the animal to be cast, and after sharply drying, the whole animal is withrawn from the mould and the latter filled up with Lipowitz's metal. The mould is then placed in a vessel containing water, and by heating the latter tc the boiling point the metal is melted and deposits itself in the finest impressions of the mouid. The alloy is very suitable for soldering tin, lead, etc., and on account of its silver-white color is especially adapted for soldering Britannia metal and nickel. But the costliness of the alloy prevents its general use for this purpose, and cheaper alloys having nearly the same properties as Lipo- witz's metal have been prepared. Cadmium alloy {melting point 170 F.) — Cadmium 2 parts, tin 3, lead 11, bismuth 16. Cadmitim alloy {melting-point 167 F.). — Cadmium 10 parts, tin 3, lead 8, bismuth 8. Cadmiitm alloy {melting-point 203° F.). — The follow- ing compositions have all the same melting-point (203°F.). or 4 or 3 or IS or 3 380 THE METALLIC ALLOYS. Parts. 7. II. III? Cadmium 1 1 1 Tin 2 3 1 Bismuth 3 5 2 Very fusible alloy. — An alloy with a melting point of 150 F. is composed of: — Parts. Tin 1 Lead 2 Bismuth 4 Cadmium 1 Wood's alloy or metal melts between 140 and 161. 5 F. It is composed of lead 4 parts, tin 2, bismuth 5 to 8, cad- mium 1 to 2. In color it resembles platinum, and is malle-. able to a certain extent. Cadmium alloy (melting -point 179. 5 F.). — Cadmium 1 part, lead 6, bismuth 7. This alloy, like the preceding, can be used for soldering in hot water. Cadmium alloy (melting-point 300 F.). — Cadmium 2 parts, tin 4, lead 2. This alloy yields an excellent soft sol- der, with a melting-point of about 86° below that consist- ing of lead and tin alone. Cliche metal. — An alloy consisting of lead 50 parts, tin 36, and cadmium 22^, is especially adapted for the prepara- tion of cliches, since with as low a melting-point as the cliche metals (of bismuth alloys) generally used, it com- bining the valuable property of greater hardness. With a cliche of this alloy, a large number of sharp impressions are obtained. According to Hauer, the melting-points of fusible alloys are proportionate to the atomic composition, thus : CADMIUM ALLOYS. Formula. Melting point. I. CdSnPbBi. iSS-i° F. 2. Cd,Sn,Pb 4 Bi,. 153-5° " 3- Cd 4 Sn,Pb 5 Bi 5 . 150. 0° " 4. CdPb (i Bi 7 . 190.4 " 5- CdPb s Bi 2 . 193-0° " 6. Cd,Pb 7 Bi 4 . 203. 0° " 381 The above formulas correspond to the following percent- age compositions : — Cadmium Tin Lead Bismuth 17.31 18.24 32.00 32.45 13.6 19.0 33-4 34-0 14.3 16.0 33-1 36.6 4.0 44.0 52.0 9-7 54-0 36.3 8.9 57-7 33-4 It is sometimes claimed that cadmium alloys are not con- stant as to their melting-points, and that on account of the volatility of cadmium, the alloy will fuse with greater dif- ficulty the oftener it is remelted. A glance at the above figures shows plainly that cadmium cannot volatilize at these temperatures, and, further, a series of experiments made especially for the purpose, has shown that the alloys can be melted as often as desired without their melting points being sensibly changed. It may, however, happen that the alloys, originally homogeneous, may by liquation separate into several alloys with different melting-points, if a large quantity of it be allowed to Stand in a melted state for a long time. This can, however, be readily prevented by not keeping the alloy in a liquid state until this liquation takes place, which requires many hours, and if it does take place, by vigorous stirring of the melted alloy. The alloys of cadmium with mercury (cadmium amal- gams), will be referred to in speaking of amalgams, and those containing gold, which are for certain purposes used by gold workers, will be mentioned under gold alloys. CHAPTER. XIV. BISMUTH ALLOYS. Like cadmium, bismuth possesses the property of lowering the melting points of metals, and is, therefore, frequently- used in the preparation of fusible alloys, which would be still more extensively used if bismuth could be obtained in abundance and at a small cost. The alloys are now chiefly used in the preparation of delicate cliches, very fusible solders, and in the manufacture of safety-valves of a peculiar construction for steam boilers. The behavior of bismuth towards other useful metals is given by Guettier as follows : — Alloys of bismuth and copper. — These alloys are easily effected notwithstanding the difference in the points of fusion of the two metals. They are brittle and of a pale-red color whatever the proportions employed. Their specific gravity is sensibly equal to the average of the two metals. Alloys of bismuth and zinc. — These alloys are seldom made and produce a metal more brittle, presenting a large crys- tallization with less adherence than zinc or bismuth taken singly. On that account they are useless in the arts. Alloys of bismuth and tin. — The combinations of bismuth and tin take place easily and in all proportions. A very small quantity of bismuth imparts to tin more hardness, sonorousness, luster and fusibility. On that account and for certain applications a little bismuth is added to tin to increase its hardness, However, bismuth being easily oxi- dized and often containing arsenic, the alloys of tin and bismuth would be dangerous for the manufacture of domes- tic utensils such as culinary vessels, pots, etc. The alloys of tin and bismuth are more fusible than each of the metals taken separately. An alloy of equal parts of ( 382 ) BISMUTH ALLOYS. 383 the two metals is fusible between 212 and 302 F. When tin is alloyed with as little as 5 per cent, of bismuth, its oxide acquires the peculiar yellowish-gray color of the bis- muth oxide. According to Rudberg, melted bismuth begins to solidify at 507 F., and tin at 550 F. For the alloys of the two metals the "constant point" is 289 F. Alloys of bismuth and lead. — These two metals are im- mediately alloyed by simple fusion with merely the ordinary precautions. The alloys are malleable and ductile as long as the proportion of bismuth does not exceed that of lead. Their fracture is lamellar, and their specific gravity greater than the mean specific gravity of either metal taken singly. An alloy of equal parts of bismuth and lead has a specific gravity equal to 10.71. It is white, lustrous, sensibly harder than lead, and more malleable. The ductility and mallea- bility diminish with an increased proportion of bismuth, while they increase with the excess of lead in the alloy. An alloy of bismuth 1 part and lead 2 is very ductile, and may be laminated into thin sheets without cracks. Ac- cording to Berthier, its point of fusion is 33 1° F. Alloys of bismuth and iron. — Authorities disagree as to the possibility of combining bismuth and iron. The pres- ence of bismuth in iron renders the metal btittle. It will be seen, from the preceding data, that the alloys of bismuth are not at present of importance in the arts ex- cepting the fusible alloys made of bismuth and certain white metals, such as tin, lead etc., and a few others. Alloys of bismuth with antimony . — The alloys of these two metals alone are grayish, britle, and lamellar. In order to remove the brittleness, varying quantities of tin and lead are added, whereby their fusibility rather increases than decreases. Alloys containing the above metals are much used in the preparation of Britannia and Queen's metals, but they are also employed for some special purposes of which the following are examples : Cliche metal. — This alloy is composed of tin 48 parts, 384 THE METALLIC ALLOYS. lead 32.5, bismuth 9, and antimony 10.5. It is especially- suitable for dabbing rollers for printing cotton goods, and, possessing a considerable degree of hardness, it wears well. For filling out defective places in metallic castings, the following alloy can be used to advantage : Bismuth 1 part, antimony 3, lead 8. Alloys of bismuth, tin, and lead. — The compounds ob- tained by alloying these metals have a somewhat higher melting point than the cadmium alloys. They have, how- ever, been known for a long time, and are used for various purposes. JSiewtori s metal consists of bismuth 8 parts, lead 5, tin 3. It melts at 202 F. Rose's alloys consist of : — I. II. Bismuth 2 8 % ^ Tin i 3 I Ej_ Lead 1 %) V The first of these alloys melts at 200. 75 ° F., and the other at 174.20 F. These alloys were formerly used in the preparation of the so-called safety-plates which were inserted in the tops of steam boilers. The composition of these plates was such that they became fluid at a determined temperature corresponding to a certain steam pressure in the interior of the boiler, thus giving the steam a chance to escape through the aperture formed. Such plates acted as a sort of safety-valve, and were intended to prevent the ex- plosion of the boiler with too high a tension of steam. At the present time their use has, however, been almost entirely abandoned, it having been found that boilers pro- vided with these plates would explode, without a previous melting of the plates. A chemical and physical examination has shown that, by long-continued heating of the plates, alloys are formed whose melting points are much higher than those of the compositions originally used. The fol- lowing table gives the compositions of some alloys which are said to melt, if the pressure of the steam exceeds that indicated : — BISMUTH ALLOYS. 385 Bismuth. Lead. 5 Tin. Melting point. Degrees F. Corresponding pressure of steam in atmosphere. 8 3 212 1 8 8 4 235-9 1% 8 8 8 253.9 2 8 10 8 266 2^ 8 12 8 270.3 3 8 16 14 289.5 y/* 8 16 12 300.6 4 8 22 24 308.8 5 8 32 36 320.3 6 8 32 28 331.7 7 8 30 24 341.6 8 Onion s fusible alloy consists of lead 3 parts, tin 2, bis- muth 5. It melts at 197 F. D' Arcet's fusible alloys. Mr. D'Arcet gives the follow- ing proportions for fusible alloys : — Parts. No. Remarks. Bismuth. Lead. Tin. 1 7 2 4 Softens at 212 F., without melting. 2 8 2 6 Softens at 212 F., easily oxidized. 3 8 2 4 \ Softens more or less at 212 F. No. 4 4 16 4 7 \ becoming softer than either No. 3 or 5 9 2 4 i No. 5. b 16 5 7 Becomes nearly fluid at 212 F. 7 8 3 4 Becomes quite liquid at 212° F. 8 8 4 4 Becomes very liquid at 212 F. 9 8 7 1 Becomes soft at 212 F., but does not melt. 10 16 15 1 Neither liquid nor soft at 212 F. II 8 5 3 Melts at 205 F. 12 8 6 2 Melts at 205 F. 13 16 9 7 Becomes very liquid at 212 F. These alloys are generally hard, but may be cut. Their frac- ture is a dead blackish-gray. They are rapidly tarnished in the air, and more so in boiling water, in which they become covered with a wrinkled pellicle which falls as a black powder. Lichtenbergs metal. — Bismuth 5 parts, lead 3, tin 2. Melts at 197 F. 25 386 THE METALLIC ALLOYS. Bismuth alloys for delicate castings. — For the preparation of castings of delicate articles, and taking impressions from dies, medals, etc., bismuth alloys of the following composi- tions have been recommended : — : Parts. I. II. III. IV. Bismuth 6 5 2 8 Tin 3 2 1 3 Lead 13 3 1 5 On cooling, these alloys expand strongly, and, conse- quently, fill out the finest depressions and elevations. Bismuth alloy for cementing glass. — Most cements in use are dissolved by petroleum, or, at least, softened. The following alloy, which melts at 212 F., is, however, not attacked by petroleum, and is therefore well adapted for fastening the metal parts upon glass lamps : Lead 3 parts, tin 2, bismuth 2.5. The following table, made by Messrs. Parkes and Martin, indicates the various points of fusion of the fusible combi- nations of bismuth, lead, and tin : — Parts. | Parts. Temperature \ Temperature of fusion, t of fusion. Bismuth. Lead. Tin. Degrees F. Bismuth. Lead. Tin. 24 Degrees F. 8 5 3 202° 8 16 3i6° 8 6 3 208 8 18 24 312 8 8 3 226 8 20 24 310 8 8 4 236 8 22 24 308 8 8 6 243 8 24 24 310 8 8 8 254 8 26 24 320 8 10 8 266 8 28 24 330 8 12 8 270 8 30 24 342 8 16 8 300 8 32 24 352 8 16 10 304 8 32 28 332 8 16 12 294 8 32 30 328 8 16 14 290 8 32 32 320 8 16 16 292 8 32 34 3i8 8 16 18 298 8 32 36 320 8 16 20 304 8 32 38 322 8 16 22 312 8 32 40 324 BISMUTH ALLOYS. 387 These alloys are valuable baths for tempering small steel tools. They give a very exact temperature, which may be adjusted to the purpose intended. They are used, according to Thurston,* by placing the article on the surface of the unmelted alloy and gradually heating until fusion occurs and they fall below the surface, at which moment their temper- ature is right ; they are then removed and quickly cooled in water. It is not easy, even if possible at all, to give as uni- form a temperature by the ordinary processes of heating or to obtain the exact heat desired, and the quality of the tool is not so easy of adjustment by any other method. Alloys of lead and bismuth have also been tried. They are too easily oxidized, and are difficult to make on account of the separation of the lead. An alloy of equal parts of bismuth and lead possesses a toughness from fifteen to twenty times that of lead. Alloys of bismuth and tin succeed better; those which are best known are — Bismuth. Tin. Melts at about. 50 parts. 50 parts 310 F. 33 " 67 " 325 20 " 80 " 480 The first alloy (equal parts of bismuth and tin) is called cutlanego, and the oxide of it makes a white enamel. Very fusible alloy. This alloy which is suitable for many applications in the arts is composed of bismuth 48 parts, cadmium 13, lead 19, tin 26. It melts at about 158 F., and, consequently, at a lower temperature than that at which the so-called "magic spoon" melts in a cup of tea. It is said to resist great pressure. * Brasses, Bronzes and other Alloys, p. 196. CHAPTER XV. IRON-ALLOYS (ALLOY STEELS.) The substances which combine with iron, and alloy with it, are derived either from the raw materials — ores, fluxes, reducing material — in short the charge used in the manu- facture of the iron, and are therefore unavoidable and fre- quently troublesome associates of the latter, or they are intentionally added in definite quantities in order to pro- duce an iron-alloy suitable for certain industrial purposes. In the first case it is scarcely possible to regulate as much as would be desirable the quantity of the constituents, and thereby, their influence upon the properties of the iron. Thus, copper, sulphur and phosphorus are to a certain extent associates of commercial iron manufactured on a large scale and cannot be removed, they remaining as troublesome admixtures, and relatively small quantities of them may impair the value of the iron for certain applica- tions. Hence iron as found in commerce may be considered more or less of an alloy. Perfectly pure iron which can be electro-chemically prepared at great expense is not worked at all. The relatively purest iron which can be made by smelting processes on a large scale, contains about 99.6 per cent, of iron and 0.4 per cent, of other con- stituents, chiefly carbon and secondarily, phosphorus, sul- phur, copper, manganese, silicon. The color of such iron is pale gray, its tensile strength in pieces of larger cross- sections is about 30 kilogrammes per square millimeter, and considerably more with smaller cross-sections. It is furthermore very tenacious, has a specific gravity of 7.8, and melts at about 2732 F. The most important, never (388) IRON ALLOYS. 389 wanting constituent of iron is carbon ; it is derived from the reducing material of the charge and exerts a peculiar influence upon the properties of iron. However, there is a limit to the capacity of iron of alloying with carbon, the greatest amount of carbon which pure iron can absorb being about 4 to 4.5 per cent. ; iron with the largest con- tent of carbon melts at about 1922 F. Iron with about 1 per cent, carbon possesses the greatest tensile strength, but its tenacity is not very great. With an increase in the content of carbon, the tensile strength decreases and brit- tleness increases. The content of carbon serves as a distinctive mark of the different varieties of iron. Iron with less than 2.6 per cent, carbon is called malleable iron, and with more than 2.6 per cent., pig iron, the former containing as a rule less than 1.5 per cent., and the latter over 3 per cent. The malleable varieties of iron with more than 0.5 per cent, carbon are distinguished by special hardness and strength, and are called steel, while those poorer in carbon are softer and not so strong, but more tenacious, are termed wrought iron. However, this classification according to the content of carbon cannot always be carried out, other points re- garding the differences in the above-mentioned varieties of iron having to be taken into consideration. Another admixture which frequently occurs, besides carbon, is silicon. It is derived from the raw material used for the production of the iron; in malleable iron it does not exceed 1 per cent., and in pig iron to be used for industrial purposes, not 3 per cent. A comparatively large content of silicon causes in pig iron rich in carbon, when cooling, a separation of carbon in the form of graphite, more of the latter being separated in slow, and less in rapid, cooling. However, in any case, the iron, by this separation of carbon in the form of graphite, acquires essentially other properties. Pig iron rich in graphite is less brittle and hard, and is called gray pig iron or fotmdry pig, while pig iron free 390 THE METALLIC ALLOYS. from graphite is very hard and brittle, has a silver-white fracture and is called white pig iron. With only a moder- ate content of carbon and a comparatively small content of silicon — about 3.5 per cent, carbon and 0.8 to 1 per cent, silicon — the separation of graphite can be entirely prevented by rapid cooling ; the production of chill castings is based upon this possibility. Iron-silicon alloys with up to 20 per cent, silicon are sometimes intentionally produced. They are, however, not directly worked into articles of use but serve for certain purposes in iron works. The manganese which also occurs in iron, is, as a rule, not intentionally added, but is reduced in smelting from manganiferous iron ores and absorbed by the iron. In malleable iron the content of manganese amounts generally to 1 per cent., and in foundry pig to about 1.5 per cent. A larger content of manganese in these varieties of iron would increase their hardness and brittleness, and exert an injurious influence upon their capacity of being worked. For special purposes iron is sometimes alloyed with up to 14 per cent, of manganese in order to produce the so- called manganese-steel, which is distinguished by great hardness. Ferro-manganese with up to 85 per cent, of manganese is intentionally produced to be used as addition in iron works, especially in the manufacture of mild steel. The ferro-manganese is usually added to the melted steel after it is tapped into the ladle. For ordinary steels the ferro-manganese is used for the removal of oxygen from the metal, so that a considerable proportion of the man- ganese finds its way into the slag leaving only 0.5 to 1 per cent, of manganese in the finished steel. This quantity seems to have almsot no influence on the physical properties of the steel except to counteract the tendency to red-short- ness ; but as the percentage of manganese approaches 3 per cent, an excessive brittleness shows itself, rendering the metal almost useless ; and when 5 to 6 per cent, is reached, IRON ALLOYS. 39I the steel is so hard and brittle that it can readily be powdered by crushing. However, when 7 per cent, of manganese is exceeded an extraordinary change takes place immediately, and with from 8 to 20 per cent, man- ganese an alloy known as Hadfield's manganese steel is obtained, which possesses remarkable characteristics. An excellent quality of razors and axes have been made from Hadfield steel containing 13.75 P er cent, manganese and 0.85 per cent, of carbon. This alloy, after forging and water-toughening gave, on testing, a tensile strength of 65 tons per square inch, and almost 51 per cent, elongation. The use of manganese steel is likely to be restricted. on account of the difficulty of machining and filing it, but it can be partially softened by treatment in the following manner: The tool is heated to very little over 1832° F., and suddenly quenched in cold water nearly at the freezing point, when the metal becomes soft enough to be easily filed or even planed. To restore the former hardness, heat- ing to a bright red heat (say 1382 F.) and slowly cooling in the air is sufficient. The main use of manganese steel is confined to purposes where extreme hardness is necessary, such as the working faces of crushing mills and grinding machinery. Car wheels, also railway crossings are frequently made of this alloy.* Chrome-steel. — According to the investigations of Berth- ier, Fremy, Smith and others, iron and chromium unite in all proportions by strongly heating a mixture of the oxides of iron and chromium in brasqued crucibles, adding pow- dered charcoal if the oxide of chromium is in excess, and fluxes to scorify the earthy matter and prevent oxidation. According to Howe,t this is substantially the same method for preparing ferro-chrome as employed at Brooklyn, New * Greenwood " Steel and Iron." t Metallurgy of Steel, p. 75. 392 THE METALLIC ALLOYS. York, and Unieux Works in France, where chrome-steel has been produced in large quantities for a number of years. According to the method of Guetat and Chavanne * a neutral solution of potassium calcium chromate or of sodium calcium chromate is mixed with an equivalent quantity of ferrous chloride, the precipitate of ferric chrom- ate washed, roasted, mixed with a sufficient quantity of coal dust, and heated to a white heat in a well-luted cruc- ible, in which the ferro-chrome fuses together to a regulus. The ferro-chrome from Kapfenberg in Styria contains, according to Schneider, 44.5 per cent, chromium and 48.2 per cent, iron, besides fixed carbon. From this and simi- lar alloys the iron may be extracted with dilute hydrochloric acid, or with chloride of copper, whereby acicular crystals of the composition Fe 4 C.Cri2C 4 remain behind. Chrome-steel is easily made by adding ferro-chrome to nearly finished steel in the furnace. Ferro-chrome with about 40 per cent, chromium is employed, and allowance is made for about 20 per cent, loss in the slag, which must be basic. For high-class tool steels it is preferable to use a refined ferro-chrome alloy containing from 60 to 75 per cent, chromium, made by reducing chrome iron ore in crucibles. The effect of chromium in steel is, in general, to raise the tensile strength as the percentage of chromium increases without diminishing at the same time the ductility seriously. Up to 1 per cent, of chromium has little or no effect, either on the tensile strength or hardness of the steel even on quenching. In the absence of carbon, as much as 4 per cent, of chromium produces no greater hardening than the same quantity of aluminium, but with about 1 per cent, of carbon and from 2 to 3 per cent, of chromium, great stiff- ness with undiminished toughness is attained. Such a ma- terial is suitable for armor-piercing projectiles, if suitably *Jahresberichte der chemischen Technologic 1883, p. 220. IRON ALLOYS. 393 hardened and tempered to give the formation of the in- tensely hard carbides of iron and chromium, suitable for penetration of armor plates. Low-carbon chrome-steels can be forged well with up to about 12 per cent, chromium present but, as the carbon increases, forging makes the steel hard and brittle. This brittleness can, however, be easily removed by annealing, and the steel is rendered excessively hard by quenching in water. In addition to shells, chrome- steel with about 1.2 per cent, of chromium is very suitable for making files. Other uses of this alloy are the manufacture of locomotive springs, tires and axles ; dies and shoes for stamp batteries, and any tools requiring great hardness. Armor plate is frequently now made with a combined chrome-nickel steel. For safes, alternate layers of chrome-steel and wrought iron are welded together and cooled suddenly. The hardness of the quenched chromium steel resists the burglar's drill, while the ductility of the wrought iron resists the blows of his sledge-hammer. . Under the microscope the effect of chromium on steel is seen to be an interference with, the growth of the iron crystals, the granular structure being very minute, and this, no doubt, accounts for the modifications which the chro- mium effects on the mechanical properties of steels. The effect is not proportional to the chromium content, small percentages being more active than larger amounts. At first the chromium seems to dissolve in the steel, but as the amount increases, a double carbide of iron and chro- mium is formed, which possesses great hardness. This occurs in the steel either as isolated globules, or it may be dissolved in the metallic matrix (on annealing at 2192 F.), bestowing a very high degree of hardness on the alloy. Tungsten steel. — Although tungsten by itself melts only with great difficulty, it readily unites with iron, forming an alloy known as ferro-tungsten. Such an alloy containing 394 THE METALLIC ALLOYS. about 80 per cent, of tungsten is, for the preparation of tungsten-steel, added to the steel whilst in the ladle. It is, however, preferable to use crucibles for melting in the alloy for special high-grade tool-steel. Tungsten-steel does not make sound castings except with the addition of a small quantity of aluminium and silicon ; the fluidity of the alloy is slightly less than that of ordinary steel. The general effect of tungsten in steel is to make it intensely hard and brittle. It is very difficult to forge, and it can- not be welded when the content of tungsten exceeds 2 per cent. One peculiarity of tungsten-steel is that in the absence of carbon its strength or hardness is not increased by tempering. With a higher content of tungsten the steel can be worked only with the greatest difficulty. The higher grades cannot be worked with the file, and as none of them can be tempered, they must be shaped at one forging, and then ground to the form desired. Tungsten- steel may be cast in the form of tools which can be ground to a fine edge. Like chrome-steel, tungsten-steel can be readily worked at a red heat, but has to be handled with the greatest care to obtain the best results. An addition of tungsten gives to steel a very fine and uniformly crys- talline structure, and such steel is less affected by the atmosphere than ordinary steel. Tungsten-steel may also be prepared by adding metallic tungsten to the melted steel in a crucible. Bending tests conducted on bars of tungsten-steel show that, as cast, the increase of the percentage of tungsten gradually diminishes the toughness, especially after 3.5 per cent, of tungsten is reached, this point being comparable with 1% per cent, of tungsten if the bars are annealed at about 1652 F., and then water-quenched, when a distinct hardening is noticeable. Unlike either the manganese or nickel steels, which, although brittle during the range from 3 to 7 per cent, for manganese and from 10 to 15 per cent, for nickel, become tough with higher percentages, tung- IRON ALLOYS. 395 sten-steel does not show this peculiar return to toughness, since the angle through which the bars bend decreases with the increase of tungsten. On fracture the tungsten-steels show very marked peculiarity. First a very fine crystalline structure com- mences with 1.5 per cent, of tungsten, and up to 7 per cent., the grain is extremely close, but not silky. This characteristic appearance of silkiness only appears when the carbon content exceeds 1% per cent, and is apparently, therefore due to the presence of a carbide of tungsten in association with the carbide of iron. Tungsten-steels with a high content of carbon are very retentive of magnetism, and an alloy with 5 per cent, tung- sten, with 0.62 per cent, carbon and 0.55 per cent, manga- nese, is found very suitable for the manufacture of perma- nent magnets in electric meters. The highest magnetic power attainable with the greatest retentiveness is reached when the tungsten content is varied between 4 and 7 per cent. Low-carbon steels with tungsten do not show this magnetic retentiveness. The special use of tungsten is for the production of self- hardening steels, that is, those which can be made hard enough to retain a cutting edge by heat treatment alone, without water-quenching. Such steels, if plunged when red hot into water, simply crack or split. They usually contain from 5 to 8 per cent, of tungsten, with 1.5 to 2.5 per cent, of carbon. The following are some typical analyses of special tungsten-steels. * Analysis per cent. Carbon Tungsten Manganese Silicon Chromium Mushet (Osborn) 1.65 5.8 2.12 1.36 0.45 Allevard 0.42 6.22 0.29 0.5 — Mushet (ordinary) 2.0 7.81 0.19 0.9 — Mushet (special) 2.3 8.22 1.72 1.60 — * Greenwood. " Steel and Iron." 396 THE METALLIC ALLOYS. The first mentioned steel is peculiar in that it can be successfully softened for machining by heating to the temperature of incipient redness (about 932 F.) and quenching in water. The second-named steel, of French manufacture, can, by quenching in water at 1112 F., be rendered (a) very hard ; (b) of only medium hardness ; or (c) quite soft, ac- cording as the temperature of the preliminary heating is raised to (a) 2372 F. : (b) 1832 F. ; or (c) 1562 F. The Taylor and White special " quick speed " cutting steels with 5 per cent, of tungsten, 4 per cent, of molyb- denum and 4 per cent, of chromium can be worked at a red heat without losing their cutting edge. The temper of tools made from this alloy cannot readily be destroyed even when the rate of cutting makes the working face of the tool approach a low red heat. Vanadium-steel.— -The element vanadium was discovered about a century ago in a lead ore from Zimapan, Mexico, by the Mexican mineralogist Del Rio who, by reason of its forming red salts, christened it erythronium. This dis- covery, however, was later on discredited, Collet-Descotils declaring erythronium to be impure chromium and the mineral from which it was obtained, a lead chromate. Wohler, however, later on proved the mineral to be lead vanadate. In 1830 the element was re-discovered by Sef- strom, in bar iron from Eckersholm, Sweden, and was called by him vanadium in deference to the Scandinavian deity Vanadis (a by-name of the goddess Freia). The element was isolated, about thirty years later, by Sir Henry Roscoe. While vanadium was formerly considered only of scientific interest, it has during the past few years sprung into the position of a metal which has practically marked an epoch in the history of the steel-trade, its alloy with iron, known as vanadium-steel forming a highly valuable material in the construction of automobiles, locomotives, etc. IRON ALLOYS. * 397 It was already surmised by Dick that a small content of vanadium would increase the ductility of iron, and Helouise* also concluded that by an addition of vanadium, steel would be rendered especially tenacious. He arrived at this con- clusion from the fact that Taberg wrought iron, which con- tains vanadium, is the softest of all Swedish brands of iron, and that many blast-furnace cinders in Staffordshire, Eng- land, where a very ductile iron is produced, show a consid- erable content of vanadic acid. To clear up the matter, he prepared aluminium- vanadium by reducing vanadium by means of aluminium powder, and from this made alloys of vanadium with ferro-aluminium, ferro-nickel and ferro- cyanide, and added them to liquid steel in a crucible. The steel, produced by the basic process, showed a compressive strength of 48 kilogrammes and an elongation of 16.9 per cent. By being previously melted, without an addition, in a graphite crucible, it absorbed much carbon, and then showed a compressive strength of 96 kilogrammes and an elongation of only 2.3 per cent. The basic steel was then treated three different ways : a. The raw material together with 1 per cent, vanadium was remelted in a graphite crucible. The sample when forged, but without being annealed, showed a compressive strength of 109 kilogrammes and an elongation of 7.53 per cent. b. Steel with 0.5 per cent, vanadium in a crucible brasqued with magnesia had a compressive strength of 66 kilogrammes, and an elongation of 16 per cent. c. With 1 per cent, vanadium, a compressive strength of 97 kilogrammes and an elongation of 14 per cent., and when annealed a compressive strength of 71 kilogrammes and an elongation of 20 per cent. The latter material which is very soft by itself acquires, on hardening, an extraordinary degree of hardness. White * Stahl and Eisen, 1896, No. 16. 398 THE METALLIC ALLOYS. iron with a compressive strength of 38 to 39 kilogrammes and an elongation of 19 per cent, showed, with an addition of 0.5 per cent, vanadium, a compressive strength of 61.25 kilogrammes and an elongation of 12 per cent, in an unan- nealed state, and after annealing a compressive strength of 53 kilogrammes and an elongation of 32 per cent. According to J. Kent Smith,* two varieties of steel, otherwise equal, but one of which contains 0.53 per cent, vanadium, show the following properties. Tensile strength Limit of elasticity. Ductility ■ Reduction of cross-section Without vanadium. 62.50 35-70 8.00 7.80 After annealing, Soft steel Same with 1 per cent, vanadium The latter annealed Tensile strength in tons. 30 61 45 Ductility in per cent. 17 14 20 Effect in wrought iron. Wrought iron Same with 0.5 per cent, vanadium, hardened. Thejatter annealed Tensile strength in tons. 24-5 39 33 Ductility in per cent. 19 12 32 Bending tests by Professor Arnold have shown that vanadium-steel will stand a much higher alternating stress than steels containing any of the other alloys. A high *Jour. Soc. Chem. Ind., 20, 1183. IRON ALLOYS. 399 carbon may break at ioo alternations. Steels of the best acid or open-hearth casting will run as high as 290. An excellent quality of nickel-steel ran to 270, while vanadium- steel has attained as high as 570, or nearly 100 per cent, better than a good nickel compound. To get the best results vanadium must be used in ex- tremely small quantities. A little goes a great way, too much being as useless as not enough. In speaking of vanadium in an address before the Central Railway Club at Buffalo, N. Y., March 8, 1907, Mr. J. Kent Smith says: "Its action is very powerful; it may be said that vanadium is to metallurgy what strychnine is to medicine, and therefore it is only used in small quantities." " Vanadium increases the strength of steel ' per se,' but to the greatest extent by acting through another con- stituent (present in such quantities as not to dynamically 'poison' the steel in question), while it confers in itself to steel properties of great dynamic value. This first is ex- emplified by the following table." Comparative effects of chromium and vanadium on static tests. Rolled Bars Untreated. Crucible Steels Plain carbon-manganese ■ + o.s per cent, chromium + 1.0 " " + 0.1 vanadium + O.T5 " + 0.25 4- 1 per cent, chromium 4- ) vanadium | ' chrom'um + ) 0.25 " vanadium J ' Open-hearth Steels Plain carbon-manganese + 10 per cent. "J Chrom'um +0-15 "' >- Vanadium ) .IS Lbs. per sq. in. elastic limit. Lbs. per sq. in. ' 35,840 51.296 56,000 63,840 6?,oq6 ' 76,384 90,496 39,648 77.056 U ten™ne e EI ° n gation Reduction stress. I on2i n- of area. Lbs. per sq. in. 60,480 76,160 85,568 77,052 8i,75o 88, 32 135,296 72,128 116,480 Per cent. 18.5 Per cent. 60.0 60.6 57-3 60.0 590 59-0 56.6 46.3 52.6 55 5 ''Vanadium, however, can be regarded as a 'master' alloy, in that it can act in totally different ways, and by judiciously using it in the line one wishes to follow, steels 40o THE METALLIC ALLOYS. of great dynamic super-excellence, great static super-excel- lence, or with combinations of both, are attainable, such as can be obtained by no other known means." "The following table illustrates type of this :" Automobile purposes are taken owing to requirements of same being of the most exigent nature. Nature. Tests. Yield Point (lbs. sq. in.) Static •• Ultimate Stress- Ratio •• 1 Elongation p. c. on 2 in- I Reduction of Area I Torsional Twists Intermediate Alternating Bends- Resistance to Pendulum Impact Cft. lbs.). Alternating Impact Number of Stresses • Dynamic ••{ Falling Weight on Notched Bar, Number of Blows. Rotary Vibrations, Num- ber of Revolutions I Carbon "Axle" Stock. 2 Nickel "Axle" Stock. 3 Vanadium Axle Steel. 4L330 65,840 .62 42 6i# 2.6 49,27° 87.360 -56 33^ 58/. 3-2 63,570 94,080 .66 6i# 4.2 10 12 18 12.3 960 25 6,200 14 800 35 I0.C00 16.5 2,700 69 67,500 4 I 5 Vanadium Vanadium Ciank- "Continual Shaft I Mesh" Steel. Gear Steel. 110,100 127,800 •87 S8tf 2.5 224.000 232,750 -96 i.3 12 i,8;o 76 6 800 N. B. — All figures obtained under comparative conditions- The initial material for the preparation of vanadium-steel is vanadate (lead vanadate), which in a comminuted state is brought into double its weight of saltpeter-cake. After the, at first, violent effervescence, the mass which becomes gradually thicker is moderately heated for 20 to 30 minutes, and then drawn off. The solidified melt is pulverized, washed with water and for several hours thoroughly stirred, steam being at the same time introduced. Iron plates are then for four to six hours suspended in the vessel, whereby the contents of the latter separate into a white precipitate containing lead sulphate, silicic acid and unchanged ore, and into a dark green to blue fluid which contains the vanadium as sulphate or double sulphate. The fluid is siphoned off and compounded with 25 per cent, soda-lye so IRON ALLOYS. 4OI long - as a precipitate is formed. This precipitate is filtered in a filtering press, washed and dried ; it forms a black mass which contains 18 per cent, vanadic anhydride V 2 O s . The oxide mixture thus obtained may be reduced ac- cording to Goldschmidt's process by igniting, by means of a fulminating pellet, 15 parts of the oxide mixture with 4.5 parts of aluminium whereby a regulus is obtained which contains 14.9 per cent, vanadium, 58.1 per cent, iron, 26 per cent, aluminium ; and 1.5 per cent, silicon. Or the oxide mixture is reduced in an electric furnace by heating 8 parts of it with 2 parts charcoal to the melting point, and introducing into the melt, in small portions at a time, 1 part of aluminium. The regulus obtained according to this method contains 16 per cent, vanadium, 70 per cent, iron, 2 per cent, silicon and 12 per cent, aluminium carbide. According to an article in "The Mining Journal," vana- dium steels may be grouped in three classes: (1) Those containing vanadium alone; (2) Those with vanadium and nickel ; and (3) vanadium and chromium. The following are some interesting results obtained by addition of vanadium : Tensile Limit of Strength in Elasticity in lbs. persq. in. lbs. per sq. in. Mild steel, low percentage of phos- phorus 60,000 35,ooo Mild steel, carbonized with cast iron in graphite crucible 62,000 47,000 Mild steel, with 0.5 per cent, of va- nadium 94,000 74,000 Mild steel, with 1 percent, of vana- dium, not annealed 138,000 112,000 Mild steel, with 1 per cent. of vana- dium, not annealed 102, oco 82,000 This 1 per cent, vanadium steel is usually employed for objects subjected to vibrations, as it resists the effects of traction admirably. The second class of vanadium steels is that containing vanadium and nickel. The proportion is usually 0.2 and 26 402 THE METALLIC ALLOYS. 0.4 per cent, vanadium and 2 to 6 per cent, nickel. With these steels a tensile strength of 78,000 to 87,000 lbs. per sq. in. is obtained; elasticity of 55,000 to 70,000 lbs. persq. in., and elongation varying from 30 to 35 per cent. After tempering, the resistance to tension and limit of elasticity attain 220,000 and 195,000 lbs., and elongation falls from 10 to 8 per cent. Nickel has a peculiar action, as it makes steel hard until 8 per cent., and from 8 per cent, to 15 per cent, so brittle that one can break it with a hammer; from 15 to 25 per cent, extensibility rapidly augments to become almost stationary. Vanadium makes nickel steel more homo- geneous, decreases fragility which nickel tends to give steel, though we must add that it is rarely employed with more than 8 per cent, of nickel. Such steel, from the fact that nickel gives a very great resistance to impact, is specially suited for piston rods, connecting rods, small shafts, etc. In the third class of vanadium steels we have vanadium chrome-steels, the two best proportions for which are as follows : Carbon 0.20 0.40 per cent. Chromium 1 1 Vanadium 0.20 0.20 Chromium augments the resistance to impact and tension, but has a tendency to produce a very hard metal, difficult to work hot, and welding can only be operated successfully by electricity, owing to the tendency of chromium to oxi- dize and form slag. Chromium gives a steel difficult to cut and work cold, and the Carnegie Steel Company could find nothing better to cut this steel plate than a disk re- volving at a very great rate of speed. This disk, 6 ft. in diameter, mounted like a circular saw, cuts plates 6 ins. thick ; a jet of steam plays continually on the part being cut. Vanadium in the proportion of 0.15 to 0.25 per cent, counterbalances the tendency of chromium and facilitates cutting. IRON ALLOYS. 403 The steel is particularly suitable for crank-shafts, cranks, propeller shafts, locomotive and wagon axles, journals, etc. The following are results of experiments which clearly show the influence of vanadium on chrome : Manganese carbon steel The same plus 0.5 per cent, chromium . . " 1 " " " 0.10 " vanadium . . . " 0.15 " 0.25 " 1 per cent, chromium and 0.15 per cent, vanadium . . " 1 per cent, chromium and 0.25 per cent, vanadium.. " 1 per cent, chromium and 0.25 per cent, vanadium tempered " 1 per cent, chromium and 0.25 per cent, vanadium tempered c en £ s 03 U bxr" rt S °* *s c O tfi .2 g p ^ CT.O J5 & 1> & H W rt 56,000 33.ooo 60 71,000 46,000 61 80,000 51,000 57 71,000 60,000 60 75,000 64,000 59 81,000 71,000 59 101,000 75,000 57 128,000 104,000 46 178,000 148,000 48 203.000 188,000 45 35 33 30 3i 26 24 24 19 16 Nickel-steel. — This alloy of iron with nickel has been re- ferred to under nickel alloys. Alloys of iron with other metals will be found under the respective headings. CHAPTER XVI. SILVER ALLOYS. Pure silver possesses but little hardness, and articles manufactured from it would be subject to considerable wear. For this reason silver-ware is never made of the pure metal, but always of alloys with other metals, except- ing certain chemical utensils which must be of pure silver, as alloys would be attacked by the substances to be manipu- lated in them. The alloys of silver are of real interest only when they are made with gold, copper, or aluminium. With the other metals, with very few exceptions, they are of no use in the arts. The alloys of silver and gold, and silver and copper are those employed for articles of luxury and for coinage. The alloys of silver, gold and copper are used for the same purpose. An alloy of silver, copper and tin is made into a solder for plated-ware and false jewelry. In modern times alloys containing silver and nickel, or silver, nickel, and zinc, are much used for table utensils ; they having a beautiful white appearance and being much cheaper than alloys of copper and silver, which were formerly exclusively used for the purpose. Alloys of silver and aluminium. — These alloys have previously been briefly referred to. Aluminium and silver form beautiful white alloys, considerably harder than pure aluminium, and take a very high polish. They have the advantage over copper alloys of being unchangeable on exposure to the air and retaining their white color. It has, therefore, been proposed to alloy coins with aluminium instead of with copper, which would render them much (404) SILVER ALLOYS. 405 more durable, but the results of experiments made on a large scale were not satisfactory. The alloys of aluminium and silver show very varying physical properties according to the content of aluminium. An alloy consisting of ioo parts of aluminium and 5 of silver differs but little from pure aluminium, but is consid- erably harder and takes a beautiful polish. An alloy of aluminium 169 parts and silver 5 possesses considerable elasticity, and is recommended for fine watch-springs and dessert knives. An alloy of equal parts of aluminium and silver shows a hardness equal to that of bronze. Tiers-argent {one-third silver). — This alloy is chiefly prepared in Paris factories for the manufacture of various utensils, and as indicated by its name consists of silver 33.33 parts and aluminium 66.66. The advantages of this alloy over silver consist in the lower price and greater hardness ; it is also stamped and engraved with greater ease than the alloys of copper and silver. Alloys of silver and zinc. — Silver and zinc have great affinity for each other, and consequently are readily alloyed. The alloys are prepared by throwing the required quantity of zinc previously wrapped in paper into the melted and strongly-heated silver, stirring thoroughly with an iron rod, and pouring the fused mass at once into moulds. Alloys of silver and zinc can be obtained both ductile and flexible. An alloy consisting of zinc 2 parts and silver 1 has nearly the color of pure silver and is quite ductile. With a larger proportion of zinc it becomes, however, brittle. In preparing the alloy a small quantity of zinc volatilizes, and hence somewhat more has to be taken than the finished product is to contain. By pouring melted zinc into melted silver, G. H. Godfrey* prepared the following alloys: I. Silver 8.16 Zinc 91.84 *Percy. Gold and Silver. Vol. I, p. 169. II. III. IV. 22.47 49.72 67.58 77-53 50.28 32.42 406 THE METALLIC ALLOYS. The surface of I. was bluish-gray. The alloy was hard, easily frangible, and readily scratched with a knife. Its fracture was bluish-gray, finely granular and feebly lustrous. The surface of II. was bluish-gray, The alloy was harder than I., readily frangible, but less easily scratched. Its fracture was bluish-gray, bright and fibro-columnar. The surface of III. was copper-red after solidification. The alloy was hard, brittle and easily pulverized. The broken surface, when fractured cold, was white and very bright and somewhat columnar. The surface of IV. had a faint reddish-yellow tint. The alloy was hard and easily frangible; its fracture white and very bright, but it soon tarnished ; its fracture was columnar. Alloys of silver and zinc possess valuable properties, especially that of retaining their white color and being more fusible than silver-copper alloys. It has, therefore, been proposed to use them for coinage, and especially for small coins. Alloys with 5, 10, and 20 per cent, of zinc pre- pared with this object in view were white, with a tinge of yellow and the coins made of them more elastic and sonor- ous, and not as easily blackened by sulphuretted hydro- gen as silver-copper alloys. Comparative experiments have, however, shown that for coins it would be preferable to use alloys, which, in addition to silver and zinc, contain copper, the following composition having been especially recom- mended for the purpose : Silver 835 parts, copper 93, zinc 72. The alloy can be readily rolled into a sheet of suitable thickness, and should it become brittle its ductility may be restored by annealing. Alloys of silver, copper, and nickel. — Nickel by itself makes silver very hard and brittle, such alloys being diffi- cult to work into utensils. But by adding some copper the alloys can be cast, rolled, and fused, and the articles manufactured from them are harder than those from silver and copper alloys. Alloys of silver, nickel, and copper are much used by French manufacturers for articles formerly SILVER ALLOYS. 407 prepared from standard silver. These compositions may be considered as an argentan whose properties have been improved by a content of silver. Argent-Ruolz. — The articles manufactured by Ruolz, of Paris, from the so-called Ruolz silver, or argent franqais, have the appearance of pure silver, but are much cheaper and harder. According to the quality of the articles, dif- ferent alloys are used, a few such compositions being given as follows : Parts. I. Silver 33 Copper 37 to 42 Nickel 25 to 30 II. III. 40 20 30 to 40 45 to 55 20 to 30 25 to 35 C. D. Abel, of London, has patented in England several alloys containing silver and nickel. They are divided into two classes, the first consisting of alloys of silver, copper, and nickel, with or without an addition of manganese. The alloys of this class may be composed according to the fol- lowing proportions :■■ — Per cent. A. B. C. Silver .' 33 25 to 30 37 to 42 40 20 to 30 30 to 40 20 Nickel Copper 25 to 35 45 to 55 The second group of these alloys consists of silver, cop- per, nickel and zinc, with or without manganese, and is composed of the following proportions : — 408 THE METALLIC ALLOYS. Silver . Copper Zinc . . Nickel Parts. D. 333 418 163 86 E. F. 340 420 16 ; 80 400 446 108 46 Of the above-mentioned alloys A, D, and E are especially intended for rolled, pressed, or drawn silver articles, C for casting, and F for jewelry. The content of silver in these alloys varies from 20 to 40 per cent., according to the pur- poses for which they are to be used — the proportion of nickel being the less, the greater that of silver. For the alloys of the first group the patentee uses the purest copper found in commerce and purified nickel, the purification of the latter being effected in the following manner : The ordinary impure nickel of commerce is dis- solved in nitric acid or in dilute sulphuric acid, the solution in the latter case being promoted by connecting the nickel with the positive pole of a galvanic battery. The solution is treated with chlorine, and the ferric oxide precipitated by boiling with calcium carbonate. The solution is subse- quently precipitated with soda, the precipitate re-dissolved in hydrochloric acid, the solution diluted with a large quantity of water, saturated with chlorine, and then treated with barium carbonate, and allowed to cool. From the fluid separated from the precipitate the nickel is sub- sequently precipitated by the galvanic method and then reduced. Nickel-speiss can be treated by the dry method by melt- ing 100 parts of it with 20 of saltpeter and 100 of feldspar, whereby the cobalt forms a blue glass. The residue is roasted, washed, and dissolved in sulphuric acid, the result- ing fluid being treated in the same manner as above. But SILVER ALLOYS. 409 no matter how the nickel may have been purified, it is of advantage before preparing the alloys to remelt it in a crucible together with yellow or red prussiate of potash, 50 parts of yellow or 25 to 30 of red prussiate of potash being used for the purification of the commercial nickel. Fre- quently this method alone suffices for the purification of the commercial nickel, which by these means is obtained in well- fluxed, homogeneous pieces of any desired size. The nickel purified in the above or any other manner is melted with the copper and an addition of charcoal and yellow, or better, red prussiate of potash, which when used as flux, is claimed to impart special properties to the alloys. In preparing an alloy which is to contain the highest con- tent of silver and the smallest of copper, it is of advantage to add some manganese to prevent oxidation as much as possible, since the addition of nickel, if exceeded above a certain proportion, would impair the quality of the alloy. For this purpose sufficient oxide of manganese previously glowed with charcoal in a closed crucible is added to the mixture of copper and nickel before melting so that a pre- liminary alloy, consisting of 80 to 90 parts of copper and nickel and 10 to 20 parts of manganese, is obtained — borax, red or yellow prussiate of potash, and charcoal being used as Auk. The manganese readily combines with the copper, and the nickel and silver form with them a ductile alloy readily worked. For the preparation of the alloys D, E, and F, the patentee employs the purest commercial copper and zinc and nickel purified by one of the methods above described. He first melts the copper and zinc together in the right proportions, and adds to the alloy thus obtained, the nickel by remelt- ing, using the above-mentioned fluxing agents. For an alloy with a large percentage of silver, manganese is added in the same manner as above described. The preliminary alloys thus obtained are subsequently melted together with the necessary quantity of silver, either 410 THE METALLIC ALLOYS. yellow or red prussiate of potash, charcoal or borax, to- gether with phosphorus being added. For the production of an alloy of phosphorus and copper the use of phosphor- copper deserves the preference. ■ Its content of phosphorus having been previously determined by an analysis, it is added to the argentiferous alloy in such a quantity that the content of phosphorus of the latter amounts to ^ to 2 per cent. The phosphor-copper is best prepared by heating 8 parts of comminuted copper with 1 part of a mixture of 40 parts of charcoal and 27 of superphosphate of lime. The final silver alloys can also be at once fused with this mixture of char- coal and superphosphate of lime previously heated to a slight red heat, using 1000 parts of the alloy to 100 of the mixture. By this process the content of phosphorus in the alloys will be the greater the longer the heating has been continued. The introduction of phosphorus makes the alloys more fusible and more homogeneous, and at the same time imparts to them a white color. To retain these advantages and to restore to the alloy its ductility lost by the addition of phosphorus, the latter is almost entirely re- moved, after homogeneous ingots have been obtained, by heating the alloy with charcoal powder in a closed crucible for several hours. Alloys of silver, copper, nickel, and zinc. — These alloys have been used for the preparation of small coins, especially in Switzerland. The coins while wearing well, however, soon lose their original beautiful white color and acquire a disagreeable yellowish shade resembling the color of poor brass. For coinage these alloys have the further disad- vantage of the silver contained in them being only regained by a very tedious process. SILVER ALLOYS. Alloys for Swiss fractional coins. 411 , 20 centimes. 10 centimes. 5 centimes. Parts. Parts. Parts. Silver Copper 15 50 25 10 10 55 25 10 5 60 Nickel Zinc 25 10 Mousset's silver alloy. — Copper 59.06 parts, silver 27.56, zinc 9.57, nickel 3.42. Color, yellowish with a reddish tinge, but white upon the fractured surface. The argent-Ruolz sometimes contains also certain quan- tities of zinc. The following alloys can be rolled into sheet or drawn out into wire : — Parts. II. III. 34 40 42 44.6 8 4.6 18 10.8 I. Silver 33.3 Copper 41 .8 Nickel 8.6 Zinc 16.3 Alloys of silver and arsenic. — These alloys may be formed by direct fusion, and the silver will retain a certain pro- portion of arsenic even when the temperature is very high. The compound made of 86 parts of silver to 14 of arsenic is of a dead grayish-white color, brittle, and acquires a metallic luster by friction. It is very fusible. An alloy composed of silver 49 parts, copper 49 and arsenic 2, is very ductile and has a beautiful white color. It was formerly used for the manufacture of table-ware, for which it is, however, not suitable on account of the poisonous properties of the arsenic. Alloys of silver, copper and cadmium. — Cadmium imparts to silver alloys great flexibility and ductility, without im- 412 THE METALLIC ALLOYS. pairing their white color. Some of the more important alloys of this group are composed of — Silver . . . Copper . . Cadmium Parts. I. II. III. IV. V. VI. VII. gSo 950 900 860 666 667 500 15 15 18 20 25 50 50 5 35 82 180 309 283 450 In preparing these alloys the great volatility of cadmium must be taken into consideration. The silver and copper are, as a rule, first alloyed ; the cadmium wrapped in paper is then brought into the fused mass, the whole quickly stirred and at once poured into moulds. By this mode of procedure volatilization of cadmium is best prevented. Silver is also used in the preparation of other alloys, par- ticularly in connection with platinum, which will be referred to later on. No true alloys of silver and iron have been made, only more or less intimate mixtures, in which silver appears in the shape of drops or filaments. The alloys of silver with cobalt and chromium are generally very hard and brittle, and thus far have found no application in the industries. Alloys of silver and copper. — These alloys are more used than any other compounds of silver, and in most countries form the legal composition of coins and silverware. Silver and copper are easily alloyed in all proportions, the com- bination taking place with expansion, and its specific gravity is less than that calculated from the proportions of the component metals. The copper imparts to silver greater hardness, strength, and toughness, the alloys acquiring the property of giving out a beautiful sound. The presence of copper does not modify the color of silver so long as the proportion of copper does not exceed 40 to 50 per cent. ; a SILVER ALLOYS. 413 greater proportion imparts to the alloy a yellowish tint similar to that of brass, and if the compound contains from 65 to 70 per cent, of copper the color is reddish, approach- ing that of pure copper. The alloys of copper and silver, though easily prepared by the ordinary process of fusion, are, nevertheless, subject to the defect of separation, or " liquation," which necessitates certain precautions when running the metal into moulds. When such an alloy is run into a cold ingot mould, the center of the ingot shows a lower degree of fineness than the portion nearer the sides of the mould; and even in the monetary alloys all the portions are not of the same degree of fineness. Formerly the silver used for coinage frequently contained small quantities of gold, and for this reason nearly all the older coins are treated in the mints by the wet method to regain the gold. At the present time the fineness of all coins is deter- mined by thousandths, the standard varying according to the size of the coins, and the laws of the different coun- tries, from -Atto to iW.r. In the following table the com- positon of the silver coins of various countries is given: — 414 THE METALLIC ALLOYS. Country. Austria Belgium Brazil Denmark East Indies. . . Egypt France Germany Great Britain. Greece Holland Italy Mexico Norway Portugal Prussia Russia Spain , Sweden Switzerland . Turkey United States Coins. Pieces of 3 and 2 guldens 5-franc piece '. 2-franc piece Milreis, pieces of 500 and 200 reis Dobbelt rigsdaler, rigsdaler, halvdaler Mark ( % rigsdaler) Pieces of 1, J4> }£, Y% rupee Pieces of 20, 10 and 5 piastres Pieces of 1 piastre Pieces of Y and % piastre Pieces of 5, 2 and 1 franc, and 50 and 20 cen- times Mark piece Crown, half-crown and shilling Pieces of 5, 1, l /z and Y drachme Pieces of 2Y2, 1 and y 2 gulden Pieces of 5, 2, 1, Y and %. lira Peso (average by U. S. Mint assay) Peso of Maximilian (average by U. S. Mint assay) Pieces of 1, Vz, \, rs specie daler Pieces of 500 reis (by U. S. Mint assay) Thaler pieces Old Thalers before 1857 Pieces of 1 , Y an d X ruble Pieces of 1, T ^, ^V ruble Dollar of 5 pesetas Peseta (present, by U. S. Mint assay) Riksdaler, crown and Y riksdaler Pieces of 2, 1 and Y francs 1 Pieces of 20, 10, 5 and 2 piastres Dollar, half dollar, quarter dollar, dime, half dime and three-cent piece Fineness. 900 897 • 835 916 875 500 Q16.66 833^ 755 750 835 900 925 900 945 835 901 902^ 875 912 900 750 768.5 750 900 835 750 800 830 900 The various silver-copper alloys employed in England for manufacturing purposes are given by Gee * as shown in the following tables : — I. II. III. IV. Silver Copper oz. dwt. gr. 18 020 oz. dwt. 16 4 gr. oz. dwt. gr. 15 050 oz. dwt. gr. 14 060 *Gee. Silversmith's Handbook. SILVER ALLOYS. 415 V. VI. VII. VIII. Silver Copper oz. dwt. gr. 13 12 6 12 oz. dwt. gr. 13 070 oz. dwt. gr. 12 12 7 12 oz. dwt. gr. 12 080 Alloy No. VIII. is about the commonest alloy possible to make without the color showing a perceptible yellow cast. The fineness of silver used in the manufacture of silver- ware in different countries varies from r^i to tWVi as shown by the following table: — Countries. Fineness. Prussia, Saxony, Brunswick 780 Austria, Bavaria 812 England 925 France, Italy, Belgium j ^ 5 ° Silver alloyed with copper in the preceding proportions has, in form of wire or sheet, a hardness equal to that of cold-forged copper. By continued mechanical manipulation the hardness increases, however, and may be made equal to that of wrought-iron. Silver is also sometimes used for casting small articles of art, but it is difficult to obtain castings entirely free from blow-holes. This evil can, how- ever, be readily prevented by adding to the alloy a small quantity of zinc, about 1 per cent. The resulting castings will be homogeneous, and free from blow-holes, while the ductility of the alloy is not in the least impaired by such a small percentage of zinc. In consequence of the frequent annealing required in working articles of silver, they gradually acquire a steel- gray color, which is due to the oxidation of copper. Hence the finished articles must be subject to a special manipula- tion called "blanching." This is effected by boiling the articles in a fluid consisting of 40 parts of water and one 4l6 THE METALLIC ALLOYS. part of sulphuric acid. The oxide of copper readily dis- solves in the mixture, leaving the surface of the article coated with a layer of chemically pure silver. The Japanese have a remarkable series of alloys, in which the precious metals replace the tin and zinc of ordinary bronze, but really their main alloys with the exception of bronze are comprised in the following example given by Prof. W. C. Roberts-Austen in a paper read before the Society of Arts, June 13, 1890. The first is called Shakii-do. — It contains : I. II. Copper 94.50 9577 Silver 1 .55 0.08 Gold 3-73 4-i6 Lead 0.11 — Iron and arsenic traces — 99.89 100.01 As will be seen from the analyses, the alloy contains in addition to about 95 per cent, of copper as much as 4 per cent, of gold. It has been used for very large works. Colossal statues are made of it, one cast at Nara in the seventh century being especially remarkable. The quantity of gold is, however, very variable, and certain specimens contain only 1.5 per cent, of the precious metal. The next important alloy used by the Japanese is called Shibu-ichi, the following being typical analyses of it : Copper 67.31 51-10 Silver 32.07 48-93 Gold traces 0.12 Iron 0.52 — 99.90 100.15 There are many varieties of it, but in both these alloys — skaku-do and shibu-ichi — the point of interest is, that the precious metals are, as it were, sacrificed in order to pro- duce definite results, gold and silver, when used pure, be- SILVER ALLOYS. 417 ing employed very sparingly to heighten the general effect. In the case of shaku-do, it will be seen presently that the gold appears to enable the metal to receive a beautiful rich purple coat or patina when treated with certain pickling solutions, while shibu-ichi possesses a peculiar silver-gray tint of its own, which, under ordinary atmospheric influ- ences, becomes very beautiful, and to which the Japanese artists are very partial. These are the principal alloys, but there are several varieties of them as well as combinations of shaku-do and shibu-ichi in various proportions, as, for instance, in the case of kin-shibu-ichi, the composition of which would correspond to one part of skaku-do rich in gold, and two parts of shibu-ichi, rich in silver. With regard to the use of pickling solution, they are made up respectively in the following proportions, and are used boiling : — Verdigris 438 grains 87 grains 220 grains Sulphate of copper • • 292 grains 427 grains 540 grains Nitre — 87 grains — Common salt — 146 grains — Sulphur — 22,2, grains — Water 1 gallon — 1 gallon Vinegar — 1 gallon 5 fluid drachms The most widely employed is No. I. When boiled in No. III. solution, pure copper will turn a brownish-red, and shaku-do, which contains a little gold, becomes purple. The effect of small quantities of metallic impurity as affecting the color resulting from the action of the pickle will be appre- ciated from the following remarks : Copper containing a small quantity of antimony gives a shade very different from that resulting from the pickling of pure copper. But the copper produced in Japan is often the result of smelting complex ores, and the methods of purification are not so perfectly understood as in the West. The result is that the so-called "antimony" of the Japanese art metal-workers, which is present in the variety of copper called " kuromi," is really a 27 418 THE METALLIC ALLOYS. complex mixture containing tin, cobalt, and many other metals, so that a metal-worker has an infinite series of materials at command with which to secure any particular shade; and these are used with much judgment, although the scientific reason for the adoption of any particular sam- ple may be hidden from him. It is strictly accurate to say that each particular shade of color is the result of minute quantities of metallic impurity. The action of the above-mentioned solutions is remark- able. Take copper to which a small amount of silver and a small amount of gold are added. The amount of gold may be variable, and artificers often take credit for putting in much more than analysis proves to be present, but a small amount of gold, it may be only i per cent., is sufficient to entirely change the character of copper, and when it is treated by pickling solutions the result is entirely different from that if copper alone is employed. The Japanese also take copper and dilute it, sometimes half copper and half silver, sometimes only about one-third silver and all the rest copper, and that gives the lovely series of gray alloys, which, either by exposure to atmospheric influences, by handling or by treatment with suitable pickles, gives the beautiful series of light and dark grays of which the Japanese are so particularly fond, and to grays to which the name shibn ichi is given. Then again they have copper in which small amounts of impurities may be present, and the nature of such impurity and the amount, which seldom exceeds two-tenths per cent., is quite sufficient to change the char- acter of the copper. The Japanese working in no small measure by rule of thumb, find that certain varieties of copper are best suited for definite processes, and store them up and use them in definite ways. Other Japanese alloys of special interest are those to which the names moku-me (wood-grain) and niyu-nagashi (marbled) are given. The characteristic alloys which the Japanese employ are taken in thin sheets and soldered to- SILVER ALLOYS. 4 2i Clark's patent alloy consists of shot-copper i ounce, nickel 3 dwts. 18 grains, spelter 1 dwt. 22 grains, tin 12 grains, cobalt 12 grains. Pirsch-Baudoiris alloy. — This alloy, resembling silver, is composed of copper 71 parts, nickel 16.5, cobalt (in the form of oxide) 1.75, tin 2.5, and zinc 7. Some aluminium (about % per cent.) may also be added. Prepare first an alloy of all the nickel, an equal quantity of the copper and the zinc ; then melt this alloy together with the iron, the remainder of the- copper, the cobalt, and some charcoal powder under a surface covering of charcoal powder in a graphite crucible at a strong heat. Allow the melted mass to cool and then add the zinc, previously alloyed with cop- per, at a temperature just sufficient for its fusion. Now take the crucible from the fire, stir/ the contents with a wooden stick, add the tin previously wrapped in paper, stir the mass once more, and pour out into moulds. But a small quantity of zinc remains in the alloy, the greater portion of it volatilizing during fusion. CHAPTER XVII. GOLD ALLOYS. Gold has been known and used by every nation, both uncivilized and civilized, from the earliest period down to our time. It is found among the old Egyptian monuments, and semi-barbarous nations have used it in the form of dust as the principal medium of exchange, the instrument of as- sociation. When America was discovered by Columbus gold was well known to its inhabitants ; the Chinese have used it from time immemorial ; the Medes and Persians were remarkable, even more than other Asiatics, for their love of gold ; jewels of costly description were employed to indicate the rank of the wearer, and this custom is still continued in the East at the present time. To show the sacred value the Egyptians in ancient times placed on gold, it was represented by a circle with a dot in the middle, this circle amongst that nation being the symbol of divinity and perfection. Gold is one of the metals which most readily enter into combination with other metals. But this property is with- out importance when we consider the inutility of the ma- jority of the compounds, and the necessity of not debasing its value or impairing its properties. Moreover, it is certain that excepting its alloys with copper, silver, iron, and plati- num, the latter two being without actual utility, gold loses part of its ductility, resistance, and cohesion, when it is combined with other metals such as zinc, tin, lead, etc. Therefore, it is entirely useless to experiment on those alloys where gold loses not only a part of its money value, but also those valuable properties which participated in making it a noble metal. (422) GOLD ALLOYS. 423 The principal alloys of gold used at the present time are those with copper or silver, or, in rare cases, with both these metals. Gold .and copper have great mutual affinity and may be alloyed in all proportions. The alloys are harder and more fusible than gold alone. Copper diminishes the ductility of gold when it enters into the combination in a proportion over 10 to 12 per cent. The specific gravity of an alloy of gold and copper is less than the average of the two metals. The color of the alloy varies between dark yellow and red, according to the quantity of copper. Pure copper must be used in the preparation of the alloys, as the impure metal alters the malleability of gold and may render it brittle. Gold and silver may be easily mixed together, but do not appear to form true combinations. These compounds are more fusible than gold and are generally greenish-white, more ductile, harder, more sonorous and elastic than gold or silver considered singly. One-twentieth of silver is suffi- cient to modify the color of gold. Silver, like copper, increases the firmness of gold, and on that account it is employed at various degrees of fineness for jewelry work. These alloys are known by jewelers under the names of yellow gold, green gold, and pale gold, according to the proportion of silver. As previously mentioned, the alloys of gold with other metals are of no practical utility and need only be briefly referred to. Gold alloyed with iron forms pale gray masses, brittle, and somewhat magnetic. An alloy holding \ of iron is employed in jewelry under the name of gray gold. Lead shows a peculiar behavior towards gold. Both metals are very soft and ductile, but when alloyed they form an exceedingly brittle metal of a pale yellow color, strongly crystalline, and hard as glass. According to Ber- thier, one-half of one-thousandth of lead alloyed to gold is sufficient to render the latter metal entirely brittle and without ductility. 424 THE METALLIC ALLOYS. Arsenic or antimony alloyed with gold gives a brittle, very crystalline alloy of a white or gray color. Accidental admixtures of arsenic or antimony can, however, be re- moved in a simple manner, it being only necessary, to keep the metal in a melted state for some time, whereby the arsenic and antimony volatilize, the pure gold remaining behind. Alloys of gold and palladium. — By alloying palladium i part with gold i part a gray alloy is formed. It has the color of wrought-iron, is less ductile than either of the com- ponent metals, and of a coarse-grained fracture. A hard, ductile alloy is formed with i part palladium and 4 parts gold, and an almost white alloy with 1 part palladium and 6 parts gold. Alloys of gold, copper, silver and palladium have a brownish-red color and are as hard as iron. They are sometimes used for bearings of the arbors in fine watches as they cause the minimum of friction (less than the jewels used for the same purpose) and do not rust. A typical alloy for watches consists of gold 18 parts, copper 13, silver 11, palladium 6. For parts of watches which re- quire to be very hard an alloy of So parts gold and 20 parts palladium is also used. Alloy of aluminium and gold. — This alloy, also known as N2ire7nberg gold, is frequently used in the manufacture of cheap gold ware, it being well adapted for the purpose as its color exactly resembles that of pure gold and remains unchanged in the air. The composition of most articles of Nuremberg gold is according to the following proportions : Copper 90 parts, gold 2.5, aluminium 7.5. An addition of cadmium to an alloy of gold and silver imparts to it a beautiful green color. These alloys will be referred to in speaking of colored gold. Preparation of Gold Alloys. The preparation of the alloys varies according to the pur- pose for which they are to be used, this difference being es- GOLD ALLOYS. 425 pecially apparent in the moulds employed for casting. The manufacturers of gold articles rarely use moulds for shap- ing the articles, excepting such as have considerable thick- ness, as seal-rings, medals with especially high relief, etc. The casting of such articles is generally effected in moulds of very fine sand, or finely pulverized and elutriated cuttle- fish. For coinage the gold is always cast into ingots or bars, iron moulds being generally used for the purpose. The bars are either rolled out to sheet or drawn into wire, the larger part of jewelry being also manufactured from such sheet or wire. The shape of the moulds used for casting varies according to the shape the ingot is to have ; for in- gots to be drawn out into wire it is best to use cylindrical tubes open on top and closed on the lower end by an iron plug. The gold contracting strongly in solidifying can be removed from the tubes without difficulty. Ingots to be used for the preparation of gold plates are best cast in the form of four-sided prisms, casting ladles with a corresponding bowl being used for the purpose. For casting very thin plates upright ladles covered with a level plate are also used. The melting of the metals constituting the alloys is always effected in graphite crucibles, the gold being in all cases first melted, and as it does not oxidize even at a red heat a protecting cover is not required. The gold being entirely melted, it is heated as strongly as the furnace will permit, and the other metals previously converted into small pieces are then introduced. On account of the great density of gold as compared with that of the other metals, the mixture of the metals is promoted by stirring with an iron rod sharpened on the point and made previously red hot. The crucible is then quickly withdrawn and its contents poured into a suitable ingot mould, previously warmed and greased to prevent adhesion. The warming of the mould is quite indispensable, but if made too hot the metal on 426 THE METALLIC ALLOYS. being turned into it will spit and fly about, and besides in- curring great loss of gold, dangerous results might thereby happen to the person in charge. The same remark applies when the ingot mould is cold. It is hot enough when the hand will just stand touching it for a second or so. The melting point of gold being very high, the furnace used should have a good draught. In some mints which Fig 40. alloy daily large quantities of gold and silver, furnaces heated by gas are used. The furnace used by most manufacturers of gold-ware is, however, the wind-furnace, one admirably suited for the purpose being shown in Fig. 40. The crucible and fuel are introduced through an oblique iron door lined inside with fire-clay. These furnaces can also be used for the prepara- GOLD ALLOYS. 42/ tion of granulated gold, frequently used by gold-workers in the manufacture of jewelry. For. this purpose thin sheet- gold or wire is cut with scissors into small pieces, which are enveloped in charcoal dust in a graphite crucible, and heated in the furnace. The pieces of gold melt to small balls of corresponding dimensions, which, after being freed from adhering foreign bodies by washing, are separated into sizes by passing through a sieve. When it is desired to produce very tough gold, use as flux a tablespoonful of charcoal and one of sal ammoniac, adding it to the gold just before melting ; the sal ammoniac burns away while toughening the gold. The employment of this mixture of sal ammoniac will bring the ingots of gold up bright and clear ; it will also prevent them from splitting or cracking when rolled and in subsequent working. In remelting scrap-gold from the work-shop and old gold, care should be taken that they are not too much contaminated by solder and are free from organic matter, wax, etc. The solder used in soldering gold-ware contains tin, lead, bismuth, and sometimes zinc, and the presence of these metals has an injurious effect upon the ductility of the gold. It is recommended to separate much-contaminated gold from the foreign metals by the wet process, and alloy the resulting chemically pure gold. In most countries there are legally fixed standards for gold alloys. Generally such alloys are considered as con- sisting of so many carats to the unit, the pound, or half pound being divided into 24 carats, each of which contains 12 grains. What is termed 18 carat gold is a unit of 24 carats of alloy containing 18 carats gold and 6 of copper. Since the introduction of the decimal system in many countries the fineness of gold alloys has been determined by thou- sandths, the fineness of the' alloys being officially expressed in this manner. Notwithstanding the simplicity of the system, many manufacturers still hold to the old method and calculate according to carats and grains. To save 428 THE METALLIC ALLOYS. calculation the conversion of carats and grains into thou- sandths is given in the following table : 1 gram = 2 " 3 " 4 " 5 " 6 " 7 " 8 " 9 io " ii " 12 " i carat = 2 " 3 " 4 " 5 " 6 " 3-47 7 can 6-95 8 " 10.42 9 " 13.89 10 " I7-36 11 " 20.84 12 " 24.31 13 " 27.78 14 " 31-25 15 " 34-73 16 " 38.19 17 " 41.67 18 « 41.667 19 ' 83-334 20 ' 125.001 21 ' 166.667 22 " 208.333 23 " 250.000 24 ' 7 carats= 291 .666 333-333 • 374-999 416.667 458.630 500.000 54I-667 583-333 624.S55 666.667 707-333 750.000 791.666 833.333 874.999 916.666 958.333 1000.000 Use of Gold Alloys. Gold alloys are principally used for coinage and orna- mental articles. They are further employed in the manu- facture of genuine gold-leaf, in the preparation of genuine Leonis wires (which consist of silver coated with gold), and in filling teeth. Standard gold. — The alloy used at present in all coun- tries for gold coins consists of gold and copper. Many coins contain a small quantity of silver, but this is due to a contamination of the copper with this metal, many copper ores containing silver, but in such small quantities that the separation of the two metals would not pay. As coins are subjected to considerable wear through frequently passing from hand to hand, the amount of loss occasioned thereby is worthy of some little consideration. Of course, this amount will be in proportion to the length of time the coins have been in circulation. To provide against this the English government allows a sovereign to be a legal tender GOLD ALLOYS. 429 till it is reduced not below 122.5 grains, the difference be- tween this and the full standard weight of 123.147 grains being the, remedy allowed by English law for abrasion or loss by wear. The depreciation of a coin depends upon its hardness, wearing much more when soft, and also upon the rapidity of circulation. In most countries the fineness of gold coins is fixed by law, and though, as will be seen from the following table, the differences are slight, com- merce would be greatly facilitated if all countries would adopt a universal standard of fineness : Ducats, Hungarian 989 thousandths. Austrian 986 ' ' " Dutch 982 " English sovereigns .• , 916 ' ' Prussian Friedrichsd'or 902 ' ' 1 900 thousandths. German gold coins Austrian crowns French gold coins Belgian Italian Swiss Spanish Greek United States Chinese J Older German gold coins (pistoles) 895 " In the manufacture of jewelry alloys of gold with copper, or with silver, or with both metals are used. The alloy with copper alone is termed red, while if silver is used it is termed white, and if both metals are alloyed with gold the caratation is termed mixed. In most countries there are legally fixed standards for gold jewelry. In England 16, 18, and 22 carat gold is stamped, or, as it is termed Hall marked, in France 18, 20, and 22 carat, in Germany 8, 14, and 18 carat, and, also, under the term jonjou gold, a 6 carat gold used for jewelry to be electro-gilt. Though this is intended as a protection to the buyer, the price of the articles does not depend alone on the quantity of gold used, 430 THE METALLIC ALLOYS. but to a great extent on the labor expended on its pro- duction, and, therefore, these legal regulations are, in many cases, illusive. In the following table the gold alloys legally fixed by the various governments are given, but it may be remarked that for certain ornamental articles distinguished by their color some deviation, though within certain limits, is per- mitted : Fineness. Parts. Color. Gold. Silver. Copper. 583 14 6 4 yellow. 583 14 3 7 dark yellow. 583 14 1 9 very red. 666 16 4.66 3-33 yellow. 666 16 1.60 6.40 red. 750 18 3-50 2.50 yellow. 750 18 2.50 3-50 red. Gold alloys which can be legally used in various countries. Fineness. England 750 France ~v highest standard 920 Belgium \ second 840 Italy J third " 750 Austria, No. 1 326 " No. II 545 No. Ill 767 Pforzheim gold-ware. Fineness. Ordinary ware (joujou) 130 to 250 Finer quality 563 Finest quality 583 to 750 Gold. Silver. Copper. Parts. Parts. Parts. Elastic gold alloy (spring gold) 2.66 2.66 5.33 The following table shows the proportions of various metals incorporated in the gold alloys used by jewelers ; GOLD ALLOYS. 431 Carats. Parts. Copper. Silver. Gold. 23 22 : Y I 2 3 6 8 sy 10 10)4 ioy 2 9 Y 1 2 3 3 3 3^ 4 4K sY 8 23 22 20 20 18 18 15 13 12 10 15 13 12 10 9 8 9 8 7 7 Colored gold. — As previously remarked, the color of gold alloys varies according to the proportions of copper or sil- ver used. Manufacturers of jewelry and other gold-ware make extensive use of the various colors of alloys, one arti- cle being frequently composed of several pieces of different colors. The appended table gives the composition of the alloys most frequently used, with their specific colors : — Parts. Color. Gold. Silver. Copper. Steel. Cadmium. 2 to 6 1.0 _ green. 75-o 16.6 — — 8.4 " 74.6 11.4 9-7 — 4-3 " 75-0 12.5 — — 12.5 " 1,0 2.0 — — — pale yellow. 4.0 3-0 1.0 — — dark yellow. 14.7 7.0 6.0 — — ' ' 14.7 9.0 4.0 — — " 3-0 1.0 1.0 — — pale red. 10. 1.0 4.0 — — 1 ' 1.0 — 1.0 — — dark red. 1.0 — 2.0 — — ' ' 30.0 3-0 — 2.0 — gray. 4.0 — — 1.0 — ' ' 29.0 II'.O — — — " 1 to 3 — — 1 — blue. 432 THE METALLIC ALLOYS. The alloys containing cadmium, given in the above table, are malleable and ductile, and can be used for plating. To prepare them the constituent parts must be carefully melted together in a covered crucible .lined with coal dust. The resulting alloy is then remelted with charcoal, or powdered rosin and borax in a graphite crucible. If, notwithstanding these precautions, a considerable portion of the cadmium volatilizes, the alloy must be again remelted with an ex- cess of cadmium to bring it up to the required percentage. In modern times certain alloys of gold are also prepared by the galvanic process, and articles showing various colors are now manufactured by this method. It is generally done by immersing the article of gold in a diluted bath of chlo- ride of gold in which is a plate of silver connected with the positive pole of a battery; silver separates upon the gold, a certain alloy being formed which is used as a basis for fur- ther coloring. When the desired color has made its appear- ance, the plate of silver is replaced by one of colored gold, whose color corresponds to the shade the article is to have. In many factories it is customary to color the finished gold articles, i, e., to impart to them, by treatment with agents capable of dissolving copper, a color approaching that of chemically pure gold. By this operation the alloy of gold and copper is decomposed on the surface of the article, the copper being dissolved out. By allowing the surface of the article to remain in contact with the bath for some time the copper is entirely dissolved, a layer of pure gold with its characteristic color remaining behind. By allowing the bath to act for a shorter time only a portion of the copper is dissolved, and, by skilful manipulation, the various shades between red and yellow can be imparted to the articles. CHAPTER XVIII. ALLOYS OF PLATINUM AND PLATINUM METALS. Platinum alloys readily with most metals, and some of these alloys are of technical importance as they offer greater resistance to chemical influences than platinum itself. The ductility of the latter is, as a rule, decreased by other metals, but its hardness is increased, and alloys of a deter- mined color may be prepared from cheaper metals. Pure platinum, as well as its alloys with iridium and palladium, is used in the manufacture of standard weights and scales. The platinum vessels used in chemical laboratories, in the manufacture of sulphuric acid and other chemical products, consist generally of platinum alloyed with one of its allied metals. The ordinary technically pure commercial platinum con- tains about o.i to i per cent, iridium. Chemically pure platinum is as soft and ductile as gold ; traces of iridium impart to it the hardness and greater resistance against chemical influences required for most purposes. Platinum melting only at a very high temperature, a furnace of peculiar construction heated with oxy-hydrogen gas is required for the preparation of the alloys. The melt- ing-points of the latter are, however, frequently so low as to allow of their being melted in ordinary furnaces. In the following we will briefly describe a platinum furnace ex- hibited by the French government at the Paris Exhibition in 1878, which is used for melting the platinum required in the manufacture of standard meters. This furnace, or, more correctly, melting apparatus, con- sists of an oblong bowl of lime with a cavity capable of holding 440 pounds of melted platinum. Upon this bowl 28 (433) 434 THE METALLIC ALLOYS. a lid of lime can be lowered by means of a lever mechanism. In this lid are so-called Daniell's cocks, used for ordinary oxy-hydrogen blow-pipes. The products of combustion escape through apertures in the periphery of the bowl. The oxy-hydrogen gas used in this apparatus does not con- sist of oxygen and hydrogen, but of oxygen and illuminat- ing gas. For the preparation of platinum alloys on a small scale an apparatus resembling the above in its main features may be used. A bowl holding several pounds of platinum can be fashioned from chalk over a wooden mould, and is, be- fore use, converted into caust'ic lime by heating to a white heat. An ordinary oxy-hydrogen blowpipe is used, the compressed oxygen and hydrogen being contained in strong vessels, or in bags of strong canvas made gas-proof by several coats of rubber varnish. In preparing alloys of platinum with base metals in such a bowl, it must be taken into consideration that the latter are at once oxidized by the smallest excess of oxygen, and hence care must be had to set the cocks of the oxy-hydrogen blow-pipe so that the flame receives a small excess of hydrogen. In pre- paring the alloys the quantity of platinum required is first brought into flux, and then the other metals are added all at once through an aperture in the lid of the bowl which otherwise is closed with a lime-plate. Immediately after the introduction of the metals into the fused platinum, the flame can be modified or in some cases entirely extinguished, the alloys having, as a rule, much lower melting points than platinum. The melted alloy is cast in ingots or cylindrical bars in moulds of lime. The ingots are especially adapted for rolling out into sheet, while the bars are more suitable for wire. Platinum-iridium alloys. — Heraus treated pure platinum alloyed with only o.oi per cent, iridium, and with 5 and 10 per cent iridium for forty days with boiling sulphuric acid of 98 per cent. By taking the loss in weight of pure plati- ALLOYS OF PLATINUM AND PLATINUM METALS. 435 num = 100, the alloys of platinum 95 and iridium 5 were = 73 and of platinum 90 and iridium 10 = 58, the decrease of the latter being therefore little more than one- half of that of pure platinum. Hence platinum-iridium alloys are better adapted for sulphuric acid concentration apparatus than pure platinum. Siebert recommends for laboratory use crucibles of an alloy of 70 to 75 parts platinum and 25 to 30 parts iridium. The hardness and solubility in aqua-regia increase with the content of iridium ; if the latter is not below 20 per cent., the alloy is almost completely resistant. The alloys take a high polish and with a large content of iridium are some- what harder than gold of 916 fineness. Examples of alloys which can be readily worked are as follows : I. II. Plarnmn 91.2 92.6 per cent.- Iridium 5.4 7.0 " Rhodium 3.4 0.4 " Alloy No. II. can be readily rolled and is suitable for the preparation of patterns. Meter-rules manufactured for the French government by Johnson & Matthey of London contained 89.41 platinum, 10.17 iridium, 0.17 rhodium, 0.10 ruthenium, and 0.06 iron. A ductile and malleable alloy of specific gravity 21.614, consists of platinum 8o.65o, iridium 19.078, rhodium 0.122, ruthenium 0.046, and iron 0.098. According to Wille the alloy for kilogrammes consists of platinum 89.90, iridium 10.09, rhodium a trace, and iron 0.01. Platinum-palladium alloys. — With palladium platinum forms a gray alloy. An alloy of platinum with 30 per cent, rhodium is according to Chapius, not attacked by aqua-regia, and after melting can be readily worked. According to Heraus an alloy of pure platinum with up to 50 per cent, rhodium can be drawn into wire, and an alloy of 90 per cent, platinum and 10 per cent, rhodium is used in Le Chatelier's thermo-electric pyrometer. 43^ THE METALLIC ALLOYS. Platinum-gold alloys. — The two metals may be alloyed in all proportions, but on account of the refractory nature of the platinum the combination takes place only at a very high temperature. A very small quantity of platinum suf- fices to change the properties of gold to a considerable ex- tent. With a very small percentage the color becomes sensibly lighter than that of pure gold, and the alloys show a high degree of elasticity, which they nearly lose, however, if the content of platinum exceeds 20 per cent. The melt- ing point of the alloys is very high, and those with 70 per cent, platinum can be fused only in the flame of oxy- hydrogen gas. Alloys containing less platinum may be prepared in a furnace which must, however, be capable of producing the strongest white heat possible. The applica- tion of platinum-gold alloys is limited ; one containing from 5 to 10 per cent, platinum is used in the form of sheet and wire in the manufacture of artificial sets of teeth. According to Percy a platinum-gold alloy resists the action of alkalies better than pure platinum. When platinum-gold alloys are cast in the form of balls in iron moulds, the content of platinum concentrates, on cooling of the alloy, towards the center. Platinum-gold alloys are used for pyrometric measure- ments. By taking the melting-point of gold at 1967 F., and that of platinum at 3137 F., then alloys with 950 gold and 50 platinum melt at 201 2° F. 900 ' 100 " " 2066 F. 850 ' 150 " 2117 F. 800 200 ' ' " 2172 F. 750 250 " 2228 F. 700 ' 300 " 2291 F. 600 400 " 2408 F. 500 500 " 2525°F. However, above 2192 F. platinum-gold alloys with more than 15 per cent, platinum cannot be recommended, as they do not melt uniformly, an alloy richer in gold first liquating out. ALLOYS OF PLATINUM AND PLATINUM METALS. 437 Platinum-silver alloys. — By an addition of platinum the hardness of silver is increased, its ductility decreased, and its pure white color changed to gray, an alloy containing but a few per cent, of platinum, showing a much darker color than pure silver. The alloys obtained by melting the metals together in suitable proportions, for instance, i part platinum and 2 parts silver, are as fusible as 20 carat gold, as ductile and malleable as 18 carat gold, and no more oxi- dizable than 14 carat gold. Equal weights of platinum and silver yield a hard and brittle alloy with little luster. White alloys called Platine au litre, contain 35 parts platinum and 65 parts silver; or 17^3 parts platinum and 82^ parts silver. With an addition of 2 to 3 per cent, copper, these alloys are used for soldering platinum articles. Such alloys are also used by dentists, for instance, plat- mum 2 parts, silver 1 ; or platinum 2 parts, silver 1, and palladium 1. Platinum-gold-silver alloys. — These alloys are used by dentists in the form of fine wires and plates. The silver and gold are first melted, the platinum is then added, and occasionally palladium. Examples of such alloys are : Platinum • Gold Silver • • . Palladium Parts. I. II. III. IV. V. VI. VII. 4 2 9 6 14 10 2 1 1 2 2 4 6 1 1 1 1 1 6 — — ~ ~ — ~~ - — 8 VIII. The alloy most suitable for the purpose as regards light- ness, elasticity, and color is selected, and pure gold or an alloy of gold and silver used as solder. Platinor. — The alloy known under this name in commerce has a beautiful golden-yellow color (hence its name) without containing any gold. It consists of varying quantities of 438 THE METALLIC ALLOYS. platinum, silver, copper, zinc, and nickel, the variations in the percentage of copper and zinc being very likely due to the fact that the two metals are not used directly, but in the form of brass. The use of the latter has the advantage of making the alloy more homogeneous and preventing, to some extent, the loss of zinc. An alloy with a color closely resem- bling that of pure gold and quite constant in the air may be made as follows : Melt i part of silver with 5 of copper, add to the melted mass 2 parts of brass, then 1 of nickel, and, after raising the temperature to the highest point the fur- nace is capable of producing, 2 parts of platinum, which is best used in the form of a very fine powder, the so-called platinum-black. Platinum- bronze. — This alloy deserves attention, it pos- sessing properties not to be found to the same extent in other alloys, and besides it is not very expensive. Plati- num-bronzes are indifferent to the action of air and water, and, once polished, retain their bright luster for a long time. Up to the present time they have only been used for table-ware and articles of luxury, and occasionally, on account of their sonorousness, for bells. Besides tin, plati- num-bronze always contains platinum and, some composi- tions, a certain quantity of silver, which, however, can be replaced by a corresponding quantity of brass without im- pairing the resistance against atmospheric influences. The following table gives the composition of some varieties of platinum-bronze : Uses. For table utensils For bells For articles of luxury- . . For tubes for spy-glasses For ornaments Parts. Nickel. Platinum. Tin. Silver. Brass. 100 1 10 100 1 20 2 — 100 0-5 15 — — 100 20 20 — — 60 10 — 120 ALLOTS OF PLATINUM AND PLATINUM METALS. 439 Alloys of platinum with the base metals. — Among the alloys of platinum with the base metals only those with copper and iron are of importance. The other metals also form alloys with platinum, which, however, are not suitable for technical purposes. The alloys with iron are also of secondary interest, since platinum-iron and platinum-steel have not found the general application in the industries which was at one time prophesied by many. It may, however, be said that a certain addition of platinum imparts to steel many excellent properties, an alloy consisting of i part of platinum and 70 of steel being, for instance, on account of its great hardness, very suitable for the manu- facture of cutting tools. For knives with especially sharp edges, an alloy containing only one-half per cent, of plati- num is claimed to be the most suitable. With pure iron, platinum forms a steel-gray mass very difficult to fuse, and so hard as to be scarcely scratched by the best file. Berthier tried alloys made of 1 part platinum with from 4 to 10 parts of iron. The fracture of the alloy was gray and granular, and it was possible to flatten the metal with a hammer before breaking it. Alloys of platinum and copper. — These alloys, possess- ing with great ductility and toughness a very beautiful color, can be advantageously used for some technical pur- poses. The color of the copper is modified by the presence of a comparatively small quantity of platinum, copper con- taining but 4 per cent, of it showing a rose color, which, in the presence of more platinum, soon changes to golden- yellow. The alloys of copper with platinum are very ductile, malleable, and easily worked. By adding zinc, a mixture of metals is obtained which, as regards color and durability of luster, is equal to gold, and, for this reason, is used in the manufacture of ornaments. The properties of the alloys vary very much according to the quantity of metals they contain, and, hence, they are adapted for many tech- nical purposes. 44-0 THE METALLIC ALLOYS. Golden-yellow alloys of platinum and copper. — Alloys so composed that their color approaches that of pure gold are suitable for the manufacture of jewelry and other orna- ments, and as regards the price of metals can be prepared for about twice the cost of silver. With an equally beau- tiful color they surpass gold, on account of their much lower price, and, especially, their durability. The composition of the alloys used in the manufacture of ornaments varies within very wide limits. The follow- ing are, however, the most important : Parts. I. II. III. IV. Platinum 2 20 7 3 Copper 5 — 16 13 Zinc — — 1 — Silver 1 20 — — Brass 2 240 — — Nickel 1 120 — — The alloy No. IV., which is known as Cooper's gold, is especially adapted for ornamental articles, it having a color which cannot be distinguished from that of 18 carat gold, even by a close comparison. It can be drawn out to the finest wire, and rolled out to very thin sheet. Other alloys suitable for ornaments, on account of their gold-like appearance, are composed of — Parts. I. II. III. IV. Platinum 15 16 7 6 Copper 10 7 16 26 Zinc 1 1 1 — The success in preparing these alloys depends, however, on using metals entirely free from iron, experiments having shown that the yifoo part of the weight of the alloy of iron suffices to render it sensibly brittle. If any one of the con- stituent metals contains iron, the alloy, though showing a ALLOYS OF PLATINUM AND PLATINUM METALS. 44I beautiful color, will be too hard, and besides so brittle as to make it impossible to draw it out into fine wire or roll it out to thin sheet. Cooper has thoroughly examined the properties of plati- num alloys, and to his researches we are indebted for some important compositions which he has termed mirror-metal and pen-metal, they being especially suitable for these pur- poses. Cooper s mirror-metal. — Copper 35 parts, platinum 6, zinc 2, tin 16.5, arsenic 1. This alloy being entirely indif- ferent to the action of the weather, and taking a beautiful polish on account of its hardness, is especially adapted for the manufacture of mirrors for optical instruments. Cooper s pen-?netal. — The preceding alloy is aiso very suitable for the manufacture of pens, but is too expensive to compete successfully with steel. An alloy frequently used for the preparation of pen-metal consists of : Copper 1 or 12 parts, platinum 4 or 50, silver 3 or 36. Their great hardness and resistance against atmospheric influences make Cooper's pen alloys very suitable for the manufacture of mathematical and other instruments of pre- cision. It can, for instance, scarcely be calculated how long a chronometer, whose train of wheels is constructed •of such an alloy, can run before it shows any irregularity attributable to wear. Palladiui7i alloys. — Palladium occurs associated with platinum, and is .obtained as a by-product in refining plat- inum. Pure palladium is but little used. It is sometimes employed in the preparation of mirrors by the galvanic process, or of semicircular protractors for fine mathematical instruments. The pure metal is, however, more frequently used in the preparation of alloys which are chiefly employed in dentistry and in the manufacture of fine watches. The most import- ant of these alloys are the silver alloys and the so-called palladium bearing-metal. 442 THE METALLIC ALLOYS. Alloys of palladium and silver. — This alloy, which is almost exclusively used for dental purposes, consists of 9 parts of palladium and 1 part of silver. It does not oxi- dize, and is, therefore, very suitable for plates for artificial teeth. The following alloy is still more frequently used: Platinum 10 parts, palladium 8, gold 6. Palladium-bearing metal. — This alloy is uncommonly hard, and is said to produce less friction upon arbors of hard steel than the bearings of jewels generally used for fine watches. This alloy has the following composition l Palladium 24 parts, gold 72, silver 44, copper 92. Pa II a diu m a Hoys . I. II. Palladium 20 6 Uold 80 18 Silver • — 11 Copper — 13 Alloy No. I. is white, hard as steel, unchangeable in the air, and suitable for dental- purposes. Alloy No. II. is red brown, hard, has a very fine grain, and is especially suitable for pivot bearings of watch-works. The alloys of the other platinum metals are but little used, particularly on account of their rarity and costliness. The alloys of platinum and iridium are only used for special scientific purposes, for instance, for standard scales, etc. Iridium as well as rhodium possessess the property of im- parting great hardness to steel, but the rhodium and iridium steel found in commerce contain, in many cases, not a trace of either. The alloy of iridium with osmium is distinguished by great hardness and resistance, and has, therefore, been recommended for pivots, for fine instruments, and points for ships' compasses. Alloys for watch manufacturers. — For the manufacture of parts of watches which are to be insensible to magnetism, the following very tough and hard alloys may be recom- mended : ALLOY'S OF PLATINUM AND PLATINUM METALS. 443. I. II. III. IV. V. VI. VII. Platinum ••• 62.75 62.75 62.75 54-32 0.5 0.5 — Copper ..... 18.00 16.20 16.20 16. co 18.5 18.5 25.0 Nickel 18.00 18.00 16.50 24.70 — 2.0 1.0 Cadmium ••• 1.25 1.25 1.25 1.25 — — — Cobalt •• — r. 50 1.96 — — — Tungsten... — 1.80 1.80 1.77 — — — Palladium... — — — — 72.0 72.0 70.0 Silver — — — — 6.5 7.0 4.0 Rhodium ...— — — — 1.0 — — Gold — — — — 1.5— — Phosphor-iridium . — For preparing larger pieces of iri- dium than found in nature for making points for stylo- graphic pens, Mr. John Holland, of Cincinnati, has devised the following ingenious process: The ore is heated in a Hessian crucible to a white heat, and, after adding phos- phorus, the .heating is continued for a few minutes. In this manner a perfect fusion of the metal is obtained, which can be poured out and cast into any desired shape. The material is about as hard as the natural grains of iridium, and, in fact, seems to have all the properties of the metal itself. Phosphor-iridium, as this metal may be called, possesses some very remarkable properties. It is as hard, if not harder, than iridosmine, from which it is prepared. It is somewhat lighter, owing to its percentage of phosphorus and increase of volume. It is homogeneous and easy to polish, and forms some alloys impossible to prepare in any other manner. It combines with small quantities of silver and forms with it the most flexible and resisting alloy of silver. With gold or tin no alloy has thus far been obtained. Added in small quantities to copper it furnishes a metal possessing very small resist- ance to friction, and is especially adapted for articles subjected to great pressure. This alloy seems to possess more than any other metal the power of retaining luhricants. With iron, nickel, cobalt, and platinum, phosphor-iridium forms com- binations in all proportions, which are of great importance. With iron an alloy is obtained which retains the properties 444 THE METALLIC ALLOYS. of phosphor-iridium, although its hardness decreases with a larger addition of iron. The alloy is slightly magnetic, and is not attacked by acids and alkalies, and the best file pro- duces no effect upon it, even if it contains as much as 50 per cent, of iron. With more than 50 per cent, of iron the power of resistance decreases gradually, and the nature of the metal approaches that of iron. CHAPTER XIX. ALLOYS OF MERCURY AND OTHER METALS OR AMALGAMS. Mercury, as is well known, is the only metal which is liquid at an ordinary temperature. It solidifies at — 40 F., forming a ductile, malleable mass, and boils at 662 F., forming a colorless vapor ; it volatilizes, however, even at ordinary temperatures. With other metals it forms alloys which are called amalgams. According to Thomas Aquino and Libadius the term amalgam is derived from the Greek fidiay^a (softening body), and according to others from the Arabic word Algamals. The properties of the amalgams vary very much according to the metals used. In most cases they are at first liquid and after some time acquire a crystallized form, the mercury in excess being thereby eliminated. The amalgams offer an excellent means of studying the behavior of the metals toward each other, the examination being facilitated by the low temperature at which these combinations are formed. If a metal be dissolved in mer- cury, and the latter be present in excess, a crystalline com- bination will in a short time be observed to separate from the originally liquid mass. This crystalline combination forms the actual amalgam, and is composed of proportions which can be expressed according to determined atomic weights, and can be readily obtained by removing the ex- cess of mercury by pressure. Many amalgams require considerable time to pass into the crystalline state, and are at first so soft that they can be kneaded in the hand like wax, but harden completely in (445) 446 THE METALLIC ALLOYS. time. They are especially adapted and much used for filling hollow teeth. Before the action of the galvanic current upon solutions of metals was known, amalgams were of great importance for gilding and silvering, which was effected by coating the article to be gilt or silvered with the amalgam and volatil- izing the mercury by the application of heat, whereby the gold and silver remained behind as a coherent coat (fire gilding). Mercury unites readily with lead, zinc, tin, bismuth, cad- mium, copper, gold, silver, magnesium, potassium and sodium, while iron, nickel, cobalt, manganese and platinum in the compact state combine with it with difficulty. Though the amalgams are of considerable theoretical in- terest and of great importance for a general knowledge of alloys, only a limited number of them are used in the in- dustries, which will be somewhat more closely described in the following : Gold amalgam. — Gold and mercury alloy freely, and the amalgam can be prepared by the direct union of the two metals. If the gold to be used has been obtained by the chemical process (by the reduction of salts of gold) it dis- solves with difficulty in the mercury, it being in a finely divided state, and the finer particles are apt to float upon the surface of the mercury. If, however, the gold is reduced in the form of larger crystals, the solution takes place in a comparatively short time. Such small gold crystals can be readily obtained by dissolving chloride of gold in amyl alcohol and heating the solution to boiling, whereby the gold is separated in the form of very small, lustrous crystals. In gaining gold from auriferous sand, gold amalgam is prepared in large masses, and by subsequent heating in iron retorts the combination is destroyed, the mercury volatiliz- ing, while the pure gold remains behind. Gold forms with mercury a chemical combination of the formula Au 4 Hg, MERCURY AND OTHER METALS OR AMALGAMS. 447 showing great tendency towards crystallization, which, in preparing the amalgam, must be prevented as much as pos- sible, it being difficult to apply a crystalline amalgam to the articles to be gilded. An amalgam suitable for fire gilding is best prepared as follows : Heat in a graphite crucible, rubbed inside with chalk to prevent adhesion, the gold to be alloyed, to a red heat. It is not absolutely necessary to use chemically pure gold, but it should be at least 22 carat fine, and preferably alloyed with silver instead of copper. Gold amalgam con- taining .copper becomes stone hard in a short time, and a small content of it impairs its uniform application to the metals to be gilded. It is best to use the gold in the form of thin sheets, which is cut into small pieces by means of scissors, and brought into the crucible. When the gold is heated to a red heat, introduce about the eighth or ninth part of the weight of the gold of mercury previously heated to boiling. Stir constantly with an iron rod, and after a few minutes remove the crucible from the fire. If the finished amalgam were allowed to cool in the crucible, it would become strongly crystalline and be unsuitable for fire gilding. To prevent this it is at once poured into a larger vessel cooled on the outside by water. By keeping this amalgam for some time, crystallization takes place nevertheless, the amalgam separating from the mercury in excess, and it is therefore advisable to prepare it fresh a short time before use. Crystalline amalgam can be restored by heating it in a crucible with an excess of mercury. Gold-amalgam containing silver gives a green gilding and as this color is frequently desired argentiferous gold is used in preparing the amalgam. The color may be inten- sified by the application of a mass consisting of 17 parts .saltpeter, 14 parts sal ammoniac and 2 parts alum, and heating. In preparing the amalgam, as well as in using it for gild- ings a wind-furnace connected with a well-drawing chimney 448 THE METALLIC ALLOYS. should be used, as otherwise the vapors evolved from the mercury exert an injurious effect upon the health of the workmen. A native gold amalgam containing 39.02 to 41.63 per cent, gold and 60.98 to 58.37 per cent, mercury is found in California. It has the formula Au 2 Hg 2 . Silver amalgam. — The properties of silver amalgam are nearly the same in most respects as those of gold amalgam, it having, however, a still greater tendency towards crystal- lization. Only pure silver can be used for its preparation, a content of copper producing the same injurious effect as in gold amalgam. Silver amalgam is best prepared by using pulverulent silver obtained by the reduction of silver solution. It may be prepared by bringing a solution of nitrate of silver in 10 to 15 parts of water into a bottle, adding a few small pieces of sheet zinc and vigorously shak- ing a few minutes. The silver separating in the form of a very fine black-gray powder need only be washed and dried to be suitable for the preparation of amalgam. This finely divided powder can be directly dissolved in the mercury, though it requires some time. The object is more quickly attained by heating the mercury nearly to boiling in a cru- cible, then throwing in the pulverulent silver and quickly combining the mass by vigorous stirring with an iron rod. Silver amalgam can also be prepared without the use of heat, it being only necessary to compound a concentrated solution of nitrate of silver (1 part of nitrate of silver in 3 of distilled water) with four times the quantity of mercury and combine the liquids by shaking. The silver is reduced from the nitrate by the mercury and dissolves immediately in the excess of it. If the amalgam is to be used for fire- silvering, the presence of the small quantity of nitrate of mercury adhering to it is of no consequence, and it can be at once applied. Fire-gilding. — Fire-gilding, as well as fire-silvering, is always effected with a pure amalgam, i. e., such as is freed MERCURY AND OTHER METALS OR AMALGAMS. 449 as much as possible from an excess of mercury. For this purpose the amalgam is tied in a bag of strong chamois leather and subjected to a gradually increasing pressure, whereby the mercury is forced through the pores of the leather while the amalgam remains in the bag. The pressed- out mercury contains a considerable quantity of gold or silver in solution, and is used in the preparation of fresh amalgam. Fire-gilding as well as silvering is, of course, only ap- plicable to articles of metals which, without melting, will stand a temperature near that of the boiling point of mercury. The amalgam adhering only to absolutely bright metals, the articles before gilding are subjected to a pre- paratory operation. This consists in heating them to a glowing heat, whereby the grease, dust, etc., adhering to the surface are burnt, and the metal becomes covered with a layer of oxide. The articles are then dipped in a mixture of 3 parts of nitric acid and i of sulphuric acid, whereby the oxide is rapidly dissolved and the metal acquires a bright surface. Articles to be heavily gilded must remain for some time in the acid mixture, a rougher surface being required for the adherence of a larger quantity of amalgam. The pickled articles are then rinsed in water without touching them with the hands, and, to prevent oxidation, placed in water until they are to be amalgamated, which consists in covering the bright articles with a layer of metallic mercury. This so-called amalgamating water is prepared by dissolving ioo parts by weight of mercury in no parts by weight of strong nitric acid, and compounding the solution with 25 parts by weight of water. This amal- gamating water is applied to the metals by mean of a brush of fine brass wire. By .the action of the metal upon the mercury salt the latter is reduced to metallic mercury in the form of very small drops, whereby the articles acquire a white color. The articles being thoroughly amalgamated, the amalgam 29 450 THE METALLIC ALLOYS. is quickly and uniformly applied with a stiff scratch-brush and the articles placed upon glowing coals, whereby the mercury vaporizes while the gold or silver remains behind in a coherent layer. While heating the articles must, how- ever, be frequently taken out and defective places provided with amalgam. This process is very injurious to health; the mercury volatilized by the heat insinuates itself into the body of the workman notwithstanding the greatest care, and those who are so fortunate as to escape for a time absolute disease are constantly liable to salivation from its effects. Though fire-gilding is the most durable, it is more and more abandoned and electro-plating substituted for it. Many articles are not finished by one gilding, and have to be subjected to the same process twice and frequently three times, whereby the layer of gold becomes, of course, thicker. By suitable treatment during the heating and by burning off the so-called gilder's wax, various shades can be given to the gilding. But, as these operations belong to another branch of industry, we cannot enter upon a further description of them. Copper amalgam. — On account of its peculiar properties copper amalgam finds quite an extensive use in several branches of industry, an amalgam of copper, tin, lead and antimony serving for the production of axle bearings. It crystallizes with great ease, and on solidifying becomes so hard that it can be polished like gold. It can also be worked under the hammer and between rolls, be stamped, and retains its metallic luster for some time on exposure to the air, but tarnishes quickly and turns black on being brought in contact with air containing sulphuretted hydro- gen. A peculiar property of amalgam of copper is that it becomes soft on being placed in boiling water, and so flexible that it can be used for molding the most delicate articles. In a few hours it again solidifies to a fine-grained mass which is quite malleable. Copper amalgam, on account of its peculiar properties, MERCURY AND OTHER METALS OR AMALGAMS. 45 I was formerly recommended for filling hollow teeth, but is no longer used for that purpose, there being other amal- gams just as suitable and free from poisonous copper. An important application of copper amalgam is for cementing metal, it being only necessary to apply it to the metals to be cemented, which must be bright and previously heated to from 176 to 194 F., and press them together; they will be joined as tightly as if soldered. Many directions have been given for preparing amalgam of copper, but it is effected with the greatest ease as fol- lows : Place strips of zinc in a solution of sulphate of cop- per and shake vigorously. The copper thus obtained in the form of a delicate powder is washed, and, while still moist, treated in a rubbing-dish with a solution of mercur- ous nitrate. Hot water is then poured over the copper, the dish kept warm, and the mercury added. The contents of the dish are then kneaded with a pestle until the pul- verulent copper combines with the mercury to a plastic mass; the longer the kneading is continued the more homogeneous the mass will be. The best proportions to use are 3 parts of copper and 7 of mercury. When the amalgam has the proper consistency, the water is poured off and the soft amalgam moulded in the shape in which it is to be preserved. For the purpose of cementing it is recommended to roll it into small cylinders about % inch in diameter and ^ to 1^ inches long. A composition of 25 parts of copper in fine powder, ob- tained by precipitation from solutions of the oxide by hydro- gen, or of the sulphate by zinc, washed with sulphuric acid and amalgamated with 7 parts of mercury, after being well washed and dried, is moderately hard, takes a good polish, and makes a fine solder for low temperatures. It will adhere to glass. An imitation of gold, known as Vienna metallic cement, which, on account of its golden-yellow color and capability for taking a fine polish, is suitable for the manufacture of 452 THE METALLIC ALLOYS. cheap jewelry, consists of copper 86.4 parts, mercury 13.6. The color of the alloy being, however, very easily affected by sulphuretted hydrogen, it is recommended to provide the articles with a thin coating of pure gold by the galvanic method. Dr onier s malleable bronze is made by adding 1 per cent, of mercury to the tin when hot, and this amalgam is care- fully introduced into the melted copper. Tin-amalgam. This amalgam was formerly of much greater importance for the manufacture of mirrors and looking-glasses than at present, when mirrors coated with a thin layer of silver surpass those coated with amalgam in beauty and cheapness. The great affinity of tin for mer- cury renders the preparation of the amalgam easy; all that is necessary being to combine the tin, best in the form of fine shavings, or foil, with the mercury. According to the quantity of mercury rubbed together with the tin, an amal- gam solidifying in a shorter or longer time is obtained. Tin-amalgam for filling teeth. — This amalgam is pre- pared by intimately rubbing together 1 part of tin with 4 of mercury, removing the excess of mercury by pressing in a leather bag, and kneading or rubbing for some time. It is obtained in a flexible mass which hardens in a few days. Amalgam for mirrors and looking-glasses. — The amal- gam which serves for silvering mirrors is a complete satura- tion of the two metals. It is, however, not prepared by itself, but directly upon the plate of glass which is to form the mirror. The operation is as follows : The glass plate having been thoroughly cleansed from all grease and dirt with putty-powder and wood ash, the workman proceeds to lay a sheet of tin foil of larger dimensions than the plate to be silvered smoothly upon the silvering table, pressing out with a cloth-dabber all wrinkles and places likely to form air-bubbles. A small quantity of mercury is then poured upon it and uniformly distributed by means of a fine woolen cloth. When the surface is uniformly covered more mercury MERCURY AND OTHER METALS OR AMALGAMS. 453 is added so as to attain a height of 2 or 3 lines ; the coating of oxide is removed with a wooden rod and a brilliant sur- face produced. The plate of glass is then pushed slowly forward from the side with the longest edge foremost, and dipping below the surface of the mercury so as completely to exclude the air. In this way the glass is brought into contact with the metals and a brilliant surface produced. The plate may now be said to be floating on a bed of mercury. To get rid of the excess of metal the mirror is loaded with weights and the table inclined io° or 12 , when the excess of mercury drains off. A further portion is got rid of by setting the plate up on edge, and in the course of three or four weeks a dry, permanent coating of tin amal- gam is left upon the plate. If curved glass plates are to be converted into mirrors, the amalgam is prepared by itself, and after spreading it as uniformly as possible upon the glass the latter is heated until the amalgam melts. This method of silvering has many objections : The vapor of mercury is poisonous to the workmen; the plates are liable to fracture from the heavy load placed upon them, and when set up on edge drops of mercury sometimes trickle down, carrying the amalgam with them, thus render- ing it necessary to resilver the whole mirror. Moreover, the amalgam is liable to spoil by crystallization or carriage. For these reasons this process has been almost entirely abandoned and that of silvering by precipitation substituted for it. Amalgam for coati7ig rubbers of electric machines. — This amalgam, known as Kienmayer's consists of zinc 1 part, tin 1, and mercury 2. It is prepared by bringing the metals in the form of fine shavings free from oxide into a previously heated iron mortar and rubbing it with the mercury to a homogeneous mass. The amalgam has a tendency to become crystalline, even if kept in well-stop- pered glass-vessels, but it can be readily pulverized and if 454 THE METALLIC ALLOYS. mixed with a very small quantity of tallow does excellent service. By this method of preparation the disadvantage of the otherwise unadvoidable melting of the solid metals is avoided. Singer s amalgam for the same purpose consists of tin i part, zinc 2, and mercury 3^ to 6. Bottger melts in an iron spoon 2 parts zinc and carefully adds, with constant stirring, 1 part mercury. Musiv silver. — This is a combination of tin 3 parts, bis- muth 3 and mercury 1%, and serves for the spurious silver- ing of brass and copper, the amalgam mixed with 6 parts bone ash being applied by rubbing the articles with it. For silvering paste-board, wood, paper, etc., the mass is triturated with white of tgg, gum solution, glue-water, or varnish and applied to the articles. Amalgam for tinning. — Small iron articles, pins, etc., may be tinned by pickling them in an acid, dipping in tin amalgam made liquid by means of hot water, blanching, washing, drying with coarse bran, and polishing. Zinc amalgam. — Zinc unites with mercury at the ordi- nary temperature, but more readily at a higher one. Triturate 1 part zinc filings, 4 parts chloride of mercury and 2 parts of water, adding a few drops of mercury, or, mix two parts mercury with two parts zinc melted in an iron spoon, stirring constantly with a clay rod. The very brittle amalgam is powdered, triturated with tallow, and may be used for coating rubbers of electric machines. • Zinc amalgam is electrolytically prepared by connecting by means of a wire the zinc cylinder of a Daniell cell with a small quantity of mercury covered by a zinc sulphate solution, a zinc wire serving as anode of the battery dip- ping into the solution. For the amalga7nation of zinc for voltaic cells brush the zinc with ammonium zinc chloride at 450 to 500 F. and then apply the mercury, when combination will immediately and completely take place. MERCURY AND OTHER METALS OR AMALGAMS. 455 The zinc may also be pickled in sulphuric acid and the mercury applied with a metallic scratch-brush dipped in dilute sulphuric acid. The zinc elements may also be immersed in a fluid pre- pared by dissolving 7 ozs. of mercury in 35 ozs. of aqua- regia and 39 ozs. of hydrochloric acid. With about 1 quart of this fluid 150 elements can be amalgamated. Spurious gilding of copper by the formation of brass is produced by boiling the copper article in a mixture of tar- tar, hydrochloric acid and zinc amalgam (1 part zinc and 12 parts mercury). Cadmium-amalgam. — Cadmium readily combines with mercury to an amalgam which easily becomes crystalline. For the preparation of the actual cadmium-amalgam, whose composition is Cd 5 Hg 8 , proceed in the same manner as already described for other amalgams. Heat the mercury nearly to boiling in a crucible and introduce the cadmium in the form of thin siieet. Cadmium .amalgam remains soft for some time and becomes crystalline only after a considerable period. The mass obtained by heating is, therefore, allowed to stand in the crucible until the excess of mercury sepa- rates out, or it can be separated in the ordinary manner by pressing in a leather bag. Pure cadmium-amalgam forms a tin-white or silver-white mass which softens on being moderately heated and can be kneaded like wax. It is used for filling hollow teeth, either by itself or compounded with other metals, which make it still better for the purpose. An addition of tin or bismuth makes it more pliant in the heat, and for this reason the mass used for filling teeth is at present frequently composed of amalgams containing several metals. A few such com- positions are given in the following. Those containing lead are, however, not recommended, as lead has poisonous properties and is attacked even in the form of an amalgam by organic acids : 456 THE METALLIC ALLOYS. Amalgams for filling teeth. Parts. L II. III. IV. V. Cadmium 25.99 2I -74 1 1 to 2 3 Mercury 74-01 78.26 — — — Tin — — 2 2 4 Lead — — — 7 to 8 15 Amalgam No. I. corresponds to the centesimal composi- tion of the above-mentioned combination of cadmium and mercury, and is well adapted for filling teeth, it acquiring in time such hardness that it can be worked with the lathe or file, and, of course, becomes hard in the mouth. Cad- mium-amalgams being very ductile can, moreover, be used for many other purposes. An amalgam of equal parts 0} cadmium and mercury is extremely plastic and can be stretched under the hammer like pure gold. It is silver- white and constant in the air. Evans s metallic cement. — This alloy is obtained by dis- solving a cadmium-amalgam consisting of 25.99 parts of cadmium and 74.01 of mercury in an excess of mercury, slightly pressing the solution in a leather bag and thor- oughly kneading. By kneading, especially if the amalgam be previously heated to about 97 F., Evans's metallic cement is rendered very plastic, and like softened wax can can be brought into any desired form. On cooling it ac- quires considerable hardness, which is, however, not equal to that of pure cadmium-amalgam. Amalgams of the " fusible alloys." — The fusible alloys already mentioned in speaking of the alloys of cadmium and bismuth possess the property of melting in an amal- gamated state at a still lower temperature than by them- selves. By adding a suitable quantity of mercury to them they can be converted into masses well adapted for filling teeth or for cementing metals. Amalgam of Lipowitz s ?jielal. — This amalgam is pre- pared as follows: Melt in a dish cadmium 3 parts, tin 4* MERCURY AND OTHER METALS OR AMALGAMS. 457 bismuth 15, and lead 8, and add to the melted alloy, mer- cury 2 parts, previously heated to about 212 F. Amal- gamation takes place readily and smoothly. After the in- troduction of the mercury the dish is immediately taken from the fire and the liquid mass stirred until it solidifies. While Lipowitz's alloy becomes soft at 140 F. and melts at 158 F., the amalgam melts at about 143. 5 F. It is very suitable tor the production of impressions of objects of natural history, direct impressions of leaves and other delicate parts of plants being obtained, which, as regards sharpness, are equal to the best plaster of Paris casts, and, on account of the silver-white color, fine luster, and con- stancy of the amalgam, present a very neat appearance. The amalgam can also be used for the manufacture of small hollow statuettes and busts, which can be readily gilt or bronzed by the galvanic process. The manufacture of small statuettes is readily effected by preparing a hollow mould of plaster of Paris, and, after uniformly heating it to about 140 F., pouring in the melted amalgam. The mould is then swung to and fro, this being continued until the amalgam is solidified. After cooling the mould is taken apart and the seams trimmed with a sharp knife. Some experience being required to swing the mould so that all parts are uniformly moistened with the amalgarh, it may happen that defective casts are at first obtained ; in such case the amalgam is simply remelted and the operation commenced anew. With some skill the operator will soon succeed in applying a uniform layer to the sides of the mould and preparing casts with very thin sides. The operation may also be modified by placing the mould upon a rapidly revolving disk and pouring in the melted amalgam in a thin stream. By the centrifugal force developed the melted metal is hurled against the sides of the mould, and in this manner statuettes of considerable .size can be cast. Iron-amalgam. — Iron and mercury do not unite directly 458 THE METALLIC ALLOYS. and can only be combined by means of a third metal, etc., though it is sometimes doubtful whether an actual amalgam is formed. According to Bottger, the amalgam may be prepared by triturating 1 part finely divided iron with 2 parts mercuric chloride and 2 parts water, and adding a few drops of - mercury. Gulielmo triturates in a porcelain dish 4^ parts pulver- ized ferrous sulphate and 1 part pulverized zinc with 12 parts water of 140 to 167 F., and frees the iron amalgam which after some time is formed by washing from the rest. According to Joule a crystalline mass of lustrous iron amalgam, especially beautiful if composed of 100 parts mercury and 47.5 parts iron, is formed by connecting by means of wire the zinc cylinder of a Daniell cell with a small quantity of mercury by a ferrous sulphate solution, an iron wire dipping into the latter serving as anode of the battery. According to the duration and intensity of the current, the amalgams are solid or liquid, crystalline, and with metallic luster with different contents of iron (0.143 to 103.2 iron to 100 mercury). The amalgams are magnetic and when subjected to violent shocks the iron is. superficially separated in pulverulent form. When heated to the boiling point of mercury, ferric oxide remains be- hind, sparks being emitted. When submerged under water the amalgam becomes in a few days covered with rust and, on shaking the vessel, is almost immediately disintegrated, the iron floating in the form of a black powder upon the mercury. Iron articles to be uniformly gilded with gold amalgam are frequently first coated with a layer of mercury by boil- ing them after thorough cleaning, in a porcelain or clay vessel in a mixture of mercury 12 parts, zinc 1 part, ferrous sulphate 2 parts, water 12 parts and hydrochloric acid i>2 parts. A mirror-bright surface is thus obtained to which the gold amalgam can be uniformly applied. Bismuth-amalgam. — By introducing mercury into melted MERCURY AND OTHER METALS OR AMALGAMS. 459 bismuth a combination of the two metals is readily effected. The resulting' amalgam being very thinly fluid can be ad- vantageously used for filling out very delicate moulds. Other amalgams are also rendered more thinly fluid by an addition of bismuth-amalgam, a few examples of which have already been given under cadmium-amalgams, and such combinations, being cheaper than pure bismuth-amalgam, are frequently used. Bismuth-amalgam can be used for nearly all purposes for which cadmium-amalgams are employed. On account of their luster, which is at least equal to that of silver, they are preferred for certain purposes, such as for silvering glass globes and the preparation of anatomical specimens. Amalgams for silvering glass globes, etc. — Glass globes can be readily silvered by either of the following composi- tions : Parts. I~ II. ILL Bismuth 222 Lead 2 2 2 Tin 2 2 2 Mercury 2 4 18 First melt the lead and tin and then add the bismuth. After removing the dross pour the mercury into the com- pound and stir vigorously. Leaves of Dutch gold are sometimes introduced into the mixtures according to the color to be imparted to the globes. For silvering the globes heat them carefully to the melting point of the amal- gam. Then pour a small quantity of the amalgam into the cavity of the globe and swing it to and fro until its entire surface appears covered. Amalgam of bismuth for anatomical preparations. — Col- ored wax was formerly exclusively used by anatomists for injecting vessels. A bismuth-amalgam, being of a silvery- white color, is, however, preferable, and by becoming hard on cooling contributes essentially to the solidity of the 460 THE METALLIC ALLOYS. preparation. The amalgam used for the purpose melts at 169 F. and remains liquid at 140 F., the latter property rendering its use especially suitable for larger preparations. It is composed of: Bismuth 10 parts, lead 3.2, tin 3.5, mercury 2. For use, heat the amalgam in a dish in a water-bath to 212 F., which insures it being forced by the injection-pump into the finest ramifications of the vessels. Metallic pencils may be prepared from an alloy of 70 parts lead, 90 parts bismuth and 8 parts mercury. The lead and bismuth are first melted, and the melt allowed to cool somewhat when the mercury is added, stirring con- stantly. If necessary the whole is again heated and the alloy cast in moulds. Pholin s silver-like alloy consists of 19.23 per cent, bis- muth, 76.90 tin, 3.84 copper and a trace of mercury. Sodium-amalga,7n. — By itself this amalgam is not used, it quickly decomposing on exposure to the air into caustic soda and mercury. It can, however, be used in the prepar- ation of many amalgams which cannot be made by the direct method. By bringing, for instance, amalgam of sodium together with a solution of metallic chloride, the respective metal is generally separated from the chlorine combination by the sodium, and the moment it is liberated unites with the mercury to an amalgam while the sodium combines with the chlorine. The presence of a very small quantity of sodium amalgam exerts, moreover, a very favor- able effect upon the formation of amalgams, and by its use in the process of amalgamation for gaining gold and silver considerable time is saved and the amalgamation becomes more complete. Sodium and mercury unite at the ordinary temperature to an amalgam which in the proportion of 1 part sodium to 80 parts or more of mercury is soft to liquid, but solid with a larger content of sodium. For the preparation of an amalgam as rich in sodium as possible, 35 ozs. of mercury are heated in an iron dish to 300 F. and 1 oz. of sodium MERCURY AND OTHER METALS OR AMALGAMS. 461 in coarser pieces is in rapid succession introduced, the sod- ium pieces being pressed beneath the mercury by means of a rod. Vigorous heating accompanied by fire phenomena takes place, vapors of mercury being at the same time evolved. After cooling the amalgam congeals to a solid brittle mass. It has to be kept protected from moisture. Rosenfeld * uses for the preparation of the amalgam a crucible with a perforated lid. The aperture in the lid is closed by a well-fitting cork and in the latter is secured a pointed wire reaching to the bottom of the crucible. The total quantity of sodium in one piece is fastened to the wire and dips into a mixture of i part amyl alcohol and 9 parts petroleum. When the sodium has acquired a pure silver-white color, it is taken from the fluid and brought into the crucible containing the mercury. The combination of the two metals takes place instantaneously with the emission of a peculiar hissing noise and the appearance of fire. However, as the crucible is at the moment of reac- tion closed with the lid, but little mercury vapor passes into the air. Potassium-amalgam is obtained by the introduction of potassium into heated mercury, the air being as much as possible excluded, or by pressing the freshly cut surface of the metal upon mercury, vigorous heating taking place thereby, and an amalgam is formed which become rigid if it contains over 3 per cent, potassium. By introducing 3 per cent, sodium-amalgam into potash lye a crystallizing combination Hg 24 K 2 is formed in the shape of hard lustrous cubes with octahedron and dode- cahedron faces. The cubes when heated to 824 F. leave behind crystalline HgK 2 which spontaneously ignites in the air. The amalgam decomposes slowly in moist air and. under water, and, like sodium-amalgam, may be used for amalgamating iron and platinum, as well as in the amalga- * Berichte der chemischen Gesellschaft, 24, 1659. 462 THE METALLIC ALLOYS. mation of silver and gold ores, the amalgam taking up gold and silver with greater ease than mercury. Nickel-amalgam is formed in the shape of a kneadable mass by rubbing together concentrated nickel chloride solution and an amalgam formed from 1 part sodium and 99 parts mercury, and treating the nickel amalgam thus formed with water until the latter runs off clear. It may also be formed by the addition of mercury to nickel sulphate solution. Platinum amalgam. A thickly-fluid lead-gray mass is obtained by triturating spongy platinum with heated mer- cury, or by introducing sodium amalgam into a platinic chloride solution. Joule obtained an amalgam of a doughy consistency by allowing mercury to remain for a longer time in platinic chloride solution. After being pressed the amalgam con- tained Hg 2 Pt. By boiling, under exclusion of air, thin platinum sheet in mercury, the former is attacked by the latter and the greater portion of the platinum appears to be suspended in the form of fine black dust in the mercury. If this dust is forced upwards by a current of air and the mercury is iso- lated, only an inconsiderable quantity of platinum remains behind. Makenzie s amalgam. — This amalgam, which is solid at an ordinary temperature and becomes liquid by simple friction, may be prepared as follows : Melt 2 parts of bis- muth and 4 of lead in separate crucibles, then throw the melted metals into two other crucibles, each containing 1 part of mercury. When cold these alloys or amalgams are solid, but will melt when rubbed one against the other. CHAPTER XX. MISCELLANEOUS ALLOYS. Mixture especially adapted for serving as a protective cover in remelting alloys. — This mixture is composed of borax, calcined soda, calcined alum and fluorspar, each I part. Alloy for spoons. — A beautiful alloy closely resembling silver is obtained by melting together 50 parts of copper, 25 of nickel, and 25 of zinc. Alloy resembling German silver consists of copper 58 parts, zinc 27, nickel 12, tin 2, aluminium 0.5, and bismuth 0.5. The separate metals are first melted by themselves and then combined by vigorous stirring. This metal re- tains its polish for a long time. Alloy resembling silver. — Copper 70 parts, manganese 30, zinc 20 to 25. Non-oxidizable alloy. — Iron 10 parts, nickel 36, copper 18, tin 18, zinc 18. This metal has a white color, with a slightly reddish tinge. Calin. — This term is applied to an alloy for metallic foils used by the Chinese for lining tea-chests. It is composed of lead 126 parts, tin 17.5, and copper 1.25, besides a trace of zinc. Alloy for moulds for pressed glass. — An alloy suitable for this purpose is obtained, according to C. H. Knoop, of Dresden, by melting together 100 parts of iron with 10 to 25 parts of nickel. New methods of preparing alloys. — The alloys consist of heavy metals and the sulphides of the alkali metals or metals of the alkaline earths. Preferably sulphide of strontium is alloyed with copper in order to obtain a pro- (463) 464 THE METALLIC ALLOYS. cluct of a constant gold-like color. For this purpose zinc is melted together with 8 to 15 per cent, of calcined stron- tium sulphate and the resulting alloy allowed to cool. To this alloy a varying quantity of copper is added, according to the color and power of resistance required. As much of the zinc as may be desired can be expelled by subsequent cupellation. E. Plazet of Paris has patented the following process.* Chromium is added to metals or alloys, such as copper, nickel, aluminium, gold, silver, zinc, lead, platinum, tin, manganese, tungsten, etc. The chromium must be pure (prepared by electrolysis) and may be coated with copper, etc., to prevent oxidation. It makes the alloy harder and increases electrical resistance. To facilitate the admixture of the chromium certain substances used as oxides, borates, or fluorides of zinc or manganese may be added. Alloys thus prepared are suitable for many purposes, and as non-mag- netic metal for bells, watches, etc. Alloys of indium and gallium. — L. de Boisbaudran, the discoverer of gallium, has experimented with alloys of indium and gallium. They are distinguished by not having a fixed melting point, but soften gradually, like fats. In this semi-liquid condition they form a mixture of melted and crystalline metal. L. de Boisbaudran has prepared the following alloys : 1. Indium 227 parts, gallium 69.9 parts. This alloy is white, granular, and can be readily cut with the knife ; it begins to melt at 132. 8° F., and is viscid at 167 F. 2. Indium 113.5 parts, gallium 69.9. This alloy forsm a white coherent mass, but is sfill softer than the first alloy. It is hard at 60. 8° F., semi-liquid at 113 F., and liquid at from 140 to 176 F. 3. Indium 113.5 parts, gallium 139.8. White; soft. It hardens at 60.8 F., is butyraceous at 64.4 F.; liquid from 140 to 176 F. * English patent 202. 1896. MISCELLANEOUS ALLOYS. 465 4. Indium 113.5 parts, gallium 279.6. This alloy is white, commences to melt at62° F., is semi-liquid at 95 F., and liquid at 122 F. Steel composition. — Steel shavings 60 parts, copper 22.5, mercury 20, tin 15, lead 7.5, and zinc 15, are gradually introduced and dissolved in 860 parts of nitric acid. The resulting reddish-brown paste is dried, melted together with twenty times its weight of zinc, and the mass cast in ingots. After cooling, the alloy is remelted with a corre- sponding addition of tin, according to whether it is to be softer or harder. Alloys for drills, chisels, etc. — These alloys have the ad- vantage over hardened steel in that tools made from them do not require tempering or dressing when in use. Cast- ings are simply made and an edge ground on with an emery wheel. Cast iron Chromium Ferro-manganese Tungsten Aluminium Nickel Copper Wrought iron . . . I. II. For drills, For chisels, etc. cutters, etc. 17.25 17-25 1.50 2.00 3-oo 4-50 5-25 7-50 1-25 2.00 0.50 0.75 0.75 1. 00 70.50 65.00 The alloys are prepared by first melting in a graphite crucible the cast iron and tungsten, then covering the melted mass with charcoal and borax and adding the ferro- manganese and chromium. The alloy thus obtained, to- gether with the wrought iron, is again liquefied in a clay crucible and the copper, nickel and aluminium are added. The contents of the crucible are covered with charcoal, and the alloy is finally cast in sand moulds. Alloys of iron with chromium, tungsten, molybdenum, 30 466 THE METALLIC ALLOYS. etc. For the preparation of such alloys the Electro- Metallurgical Co. of London has patented the following process:* Previous to adding the chromium, etc., to the melted iron or steel its content of oxygen is entirely with- drawn by aluminium. TT12 effect of this is that as all the chromium, etc. added alloys with the iron, and only a very minute portion of it is used for the deoxidation of the iron, the intended percentages of the additions can be accurately maintained. Alloys of copper and iron are prepared according to a method patented by A. F. V. M. Baron, of Paris, t by heat- ing the copper to a cherry or very bright red heat, then adding the required quantity of a mixture of rosin and an oxalate or another similar organic salt which, when decom- posed by the heat, evolves carbonic oxide, carbonic dioxide and water, and finally adding the required quantity of iron. Malleable ferro-cobalt and ferro-nickel. For the direct gaining of malleable ferro-cobalt or ferro-nickel, the " Fon- derie de nickel et metaux blancs " of Paris claims to utilize either the ores themselves, or to prepare first an especially suitable initial product for the final result by melting to- gether corresponding quantities of nickel or cobalt and chromium ores. In melting together the ores the degree of heat at which the liquation of the iron would take place must, however, not be attained. This product of melting, or the raw materials themselves, are melted together in a suitable crucible with potassium ferrocyanide and peroxide of manganese. In running off, a small quantity of alu- minium is added. According to the condition desired for the final product, arid according to the original content of iron of the ores, a larger or smaller quantity of cast-iron or wrought-iron can be added from the start, whereby a more or less soft and malleable product is obtained. If, for in- stance, an alloy of 70 per cent, of nickel and 30 per cent, of * German patent, 90,746. t U. S. patent, 577,182. 1897. MISCELLANEOUS ALLOYS. 467 iron, with a very small content of sulphur, be used, 71.9 parts of fused nickel, 12 of peroxide of manganese, 16 of potassium ferrocyanide, and 0.1 of aluminium are taken for the mass to be melted together. If, however, nickel ore containing only about 25 per cent, of pure nickel, with 64 per cent, of iron and 1 1 per cent, of other admixtures, be used, the melting material is best composed of about 82 parts of fused nickel, 8 of peroxide of manganese, and 10 of potassium ferrocyanide. The alloys thus obtained are claimed to excel in perfect malleability, and completely to retain this .property when remelted, so that, on the one hand, ma'leable ingots are at once produced, and, on the other, all waste and defective castings can be again utilized. Bronze resisting acids. — Debie gives the following re- ceipt : Copper 15 parts, zinc 2.34, lead 1.82, antimony 1. This alloy melted in a crucible can be worked in the ordinary manner, and is claimed to answer as substitute for lead for lining vessels used in the manufacture of sulphuric acid, etc. Zinc-iron, being very brittle, is used very seldom as an alloy, but on account of its brilliant light promises to be- come of considerable value for pyrotechnics. Theoretically it is also interesting as an alloy of a very volatile with a non- volatile metal, and, further, it offers the readiest means of obtaining zinc in a finely divided state for purposes where the presence of iron is not objectionable. The best method of preparing the alloy is as follows : Heat 1 to 2 pounds of zinc in a clay crucible to the melting point, then throw 3 to 3.5 ounces of anhydrous sodium ferrous chloride upon the surface of the melted zinc and immediately cover the crucible. A very vigorous reaction takes place during the formation of the alloy mixed with zinc chloride (Zn + FeCl 2 +Fe). The excess of the zinc alloys with the re- duced iron and forms the exceedingly brittle zinc-iron . which can be readily pulverized. An alloy which expands on cooling is prepared from lead 468 THE METALLIC ALLOYS. 9 parts, antimony 2, and bismuth 2. It is very suitable for filling up small holes and defective places in cast-iron. Spences metal. — This compound is an English invention, and is named after the inventor. Strictly speaking, it is not a metal, but a compound obtained by dissolving metallic sulphides in melted sulphur, which is found to be capable of receiving into solution nearly all the sulphides of the metals. For most purposes Mr. Spence employs in the production of his " metal " the sulphides of iron, lead and zinc, in varying proportions, according to the quality of the product desired, which will depend on the uses for which it is designed. On cooling the mixture solidifies, forming a homogenous, tenacious mass, having ordinarily a specific gravity of 3.37 to 3.7. It is said to be exceed- ingly useful in the laboratory for making the air-tight con- nections between glass tubes by means of rubber and a water or mercury jacket where rigidity is no advantage. The fusing point is so low that it may be run into the outer tube on to the rubber, which it grips, on cooling, like a vise and makes it perfectly tight. It melts at 320 F., expands on cooling, is claimed to be capable of resisting well the disintegrating action of the atmosphere, is attacked by but few acids and by them but slowly, or by alkalies ; is insoluble in water and may receive a high polish. It makes clean, full castings, taking very perfect impressions ; it is cheap and easily worked. It has been used as a solder for gas-pipes and as a joint material in place of lead. Lutecine, or Paris metal. — Copper 800 parts, nickel 160, tin 20, cobalt 10, iron 5, and zinc 5. Alloys for small patterns in foundries. I. Tin 7.5 parts, lead 2.5. II. Zinc 75 parts, tin 25. III. Tin 30 parts, lead 70. The last of these alloys is for patterns which will not be in frequent use and which may be mended, bent, etc. The first gives harder and stiffer patterns ; the second is harder MISCELLANEOUS ALLOYS. 469 than tin and more tenacious than zinc, while at the same time it preserves a certain ductility. Alloys' for calico-printing rollers. — Hauvel considers a semi-hard bronze of the following composition the best material for the rollers : Copper 86 parts, tin 14, zinc 2. Rendel, on the other hand, found an English roller mate- rial composed of: Copper 5.6 parts, zinc 78.3, tin 15.8. Though this compound gives a hard, fine-grained alloy, it is likely to be very readily attacked by the colors used in printing. According to analysis by J. Depierre and P. Spiral, the composition of the scrapers (sometimes called doctors or ductors) intended to remove the surplus of colors from the rollers is as follows : Copper. Zinc. Tin. Yellow French scrapers 78.75 12.50 8.75 Yellow English scrapers 80.50 10.50 8.00 Yellow German scrapers 85.80 9.80 4.90 According to the researches of the above-named scien- tists, three groups are to be distinguished: 1. Copper with 95 to 100 per cent, of copper; 2. Brass with about 60 per cent, of copper and 40 per cent, of zinc ; and 3. Alloys. In the annexed table I, the physical properties of the ex- amined pieces are given, whereby it has, however, to be re- marked that in rollers for printing calico, where the hard- ness of the metal is of considerable importance, the chemical composition alone does not express the characteristics of the metal, they depending also on the manner of hardening and tempering. Table II, shows the chemical composition of the samples. Besides red copper the alloys containing 25 to 30 per cent, of zinc and 75 to 70 per cent, of copper are essenti- ally suitable for rollers. Even as small a content of lead as 0.5 per cent, exerts an injurious influence, and the samples containing lead showed blow-holes. The presence of phos- phorus could not be detected in any of the samples, but 47° THE METALLIC ALLOYS. Messrs. Depierre and Spiral are of the opinion that rolls of copper, containing I to 2 per cent, of phosphorus, would yield excellent results as regards resistance against chemical influences, as well as hardness, fineness of grain, homo- geneousness and durability. An addition of one per cent, of phosphorus might also be recommended for varieties of brass containing 30 to 35 per cent, of zinc. Table I. en '33 a Color. Grain. Hardness. Remarks. rt in O I P 8.82 1 red coarse hard 2 " 1 8.83 fine " 3 " 1 8.82 coarse very soft 4 " 1 8.83 very fine medium 5 yellow 3 8.40 coarse hard blow-holes. 6 28.25 very fine, horac- 1 geneous 7 C i 38.58 fine, not homo- very brittle 1 1 geneous 8 red 1 8.*8 very fine hard burnt. 9 1 8.80 coarse 1 ! soft suitable for print- ing. 10 yellow 28.15 very fine [ous hard very unequal. 11 " 3 8.45 coarse, homegene- ' ' 12 3 8.50 fine, not very homogeneous very brittle many blow-holes (i«35). 13 red 1 — | — very good. 14 " 1 8.90 fine hard bad. IS yellow 3 8.35 " " very good. 16 " 38.20 " " blow-holes. 17 i ( 28.10 fine, homogeneous " very bad. 18 red 1 8.90 fine 1 good. 19 — 20, yellow 2 8.20 coarse, not very soft homegenet us 21 ' ' 28.15 fi ne > homogeneous hard 22 i c 28.22 middling soft 23 red 18.85 fine hard 24 yellow 2 — — 25 gray-yellow 3 attacked by colors. MISCELLANEOUS ALLOYS. Table II. 471 No. of the samples. Copper. Tin. 3 OQ.II 0.05 4 • 99 16 0.02 8 99-13 0.03 . 5 74.12 2-37 15 79-42 4-17 < 10 72.15 3.27 24 70 40 — '25 15-0 Lead. 0.12 0.12 0.19 0.12 0.14 0.07 48 traces Zinc. o.=;7 0.58 0-45 0.L0 O.67 o.£8 0.C4 2. to o.39 o.43 0.42 2.18 i.fc8 1 23 1. 71 o.co 38.68 37-51 51.88 30.53 41.02 41.41 19.85 17*3 17.10 ^c.5; 14.49 22.10 28.0 C4.0 Remarks. some aluminium. seme aluminium and sulphur. all contain traces of arsenic and iron. Alloy for compensation balances. For this purpose Ber- guet uses the following alloy : Silver 2 parts, copper 2 parts, zinc 1 part. The silver is first melted and the zinc, in small pieces, is then thrown in. The metals are stirred together and, to prevent the volatilization of zinc, are left on the fire for as short a time as possible. The mixtuie is poured out and allowed to get cold. The^copper is then melted, the cold alloy of silver and zinc added, and the whole intimately mixed by stirring. The alloy is then poured out, when cold cut into pieces, and the latter are remelted to obtain a perfectly homogeneous alloy, care being had, however, not to leave the alloy over the fire longer than absolutely 47 2 THE METALLIC ALLOYS. necessary. The resulting alloy is hard, elastic, very ductile, and quickly melts in the furnace. Black bronze. Tin 5 parts, copper 83 parts, lead 10 parts, zinc 2 parts. Castings made of this alloy, when heated in a muffle after finishing, assume a dead black appearance. Sideraphite. The alloy known under this name resem- bles . silver, and is very ductile and malleable. It is com- posed of iron 63 parts, nickel 23, tungsten 4, aluminium 5, and copper 5. The iron and tungsten are melted together and then granulated by being thrown into water. The water used for this purpose should contain 1 lb. of slaked lime and 1 lb. of potash for every gallon. The nickel, copper and aluminium are also melted together, and the product thus obtained is also granulated in water contain- ing the same proportion of lime and potash. During melt- ing the metals in the two crucibles must be kept covered with a flux made of 2 parts each of borax and saltpeter. A piece of soda or alkali, weighing about the ttoo part of the whole mass, is to be put in the crucible containing the copper, nickel and aluminium to prevent oxidation of the last-named metal, and to prevent the same action taking place with the copper a small piece of charcoal is added. Previous to the operation of granulation the contents of the two crucibles should be well stirred. The granulated metals are dried, melted in the proportions given above, well shaken, and then run into bars. This alloy is claimed not to be more expensive than ordinary white metal. It will resist the action of sulphuric acid, is not attacked by organic acids, and but slightly so by the inorganic acids. Violet-colored alloy. An alloy of a beautiful violet color is obtained by melting together equal parts of antimony and copper. Gold-like alloy. This is a French alloy and in many re- spects very closely resembles gold, especially as regards color. It can be forged, welded, rolled, and pressed. It possesses the special advantage of its color not being at- MISCELLANEOUS ALLOYS. 473 tacked by ammoniacal salts and vapors containing nitric acid. It consists of copper 96 per cent, and antimony 4 per cent. ' The two metals are melted together and to in- crease the density of the alloy, a small quantity of mag- nesium and of, calcium carbonate is added. Pyrophorous alloys for illuminating purposes. In the Auer von Welsbach works such metallic alloys have been prepared from rare earths with the addition of other metals, especially iron. An alloy consisting of about 50 per cent, lanthanium, 30 per cent, of other rare earths, such as neody- mium, praseodymium, cerium, and 20 per cent, iron, is very suitable for the production of light, and an alloy consisting of 60 per cent, cerium, 10 per cent, other rare earths and 30 per cent, iron is particularly well adapted for the for- mation of sparks. Alloy for silvering. This alloy consists of tin 80 parts, lead 18, silver 2 ; or tin 90 parts, lead 9, silver 1. Melt the tin, and when the bath is lustrous white add the granulated lead and stir the mixture with a pine stick ; then add the silver and stir again. Increase the fire for a short time until the surface of the bath assumes a light yellow color, then stir thoroughly and cast the alloy into bars. The operation of silvering is executed as follows : The article, for instance a knife blade, is dipped in a solu- tion of hydrochloric or sulphuric acid, rinsed in clean water, dried, rubbed with a piece of soft leather or dry sponge, and then exposed in a muffle five minutes to a temperature of 158 to 176 F. The effect of this treatment is to render the surface of the iron or steel porous. With iron not very good and coarsely porous the silvering process is difficult to execute. With steel, however, the process is easy ; the article heated to about 140 F. is dipped into the alloy melted in a crucible over a moderate fire. The bath, which must be completely liquid, is stirred with a pine or poplar stick. The surface of the bath should show a fine silver- white color. One or two minutes' dipping suffices for a 474 THE METALLIC ALLOYS. knife blade. When taken from the bath the article is dipped into cold water, or, if necessary, hardened and tempered in the usual manner. It is then rubbed dry and polished without heating. Articles thus treated have the appearance of silver end also possess the sound of silver, and resist oxidation in the air. To protect them from the action of acid liquids they are first dipped in an amalgam bath of 69 parts of mercury, 39 parts of tin, and one part of silver ; then, while hot, in melted silver, and electroplated with silver. This method of silvering is claimed to be very durable and not costly. Robertson alloy for filling teeth. — Gold 1 part, silver 3,. tin 2. First melt the gold and silver in a crucible, and at the moment of fusion add the tin. The alloy, when cold, may be finely pulverized. Equal quantities of the powder and mercury are kneaded together in the palm of the hand to form a paste for filling teeth. American sleigh-bells. — These bells, exceeding in beauty,, fine tone, and small specific gravity, are manufactured by fusing together 10 parts of nickel and 60 of copper. When this alloy has become cold, add 10 parts of zinc and two- fifths part of aluminium, fuse the mass and allow it to cool ; then remelt it with the addition of f part of mercury and 60 parts of melted copper. Alloy for casting small articles. — Fuse a mixture of 79 per cent, of cast-iron, 19.50 of tin, and 1.50 of lead. This alloy has a beautiful appearance, fills the mould completely, and is therefore well adapted for casting small articles. It is malleable to a certain extent. Marlies noji-oxidizable alloy. — Iron 10 parts, nickel 35, brass 25, tin 20, zinc 10. Articles prepared from this alloy are heated to a white heat and dipped into a mixture of sulphuric acid 60 parts, nitric acid 10, hydrochloric acid 5,. and water 25. Alloy for sign-plates. — An excellent metal for engraving firm names, etc., upon plates which are to be attached to MISCELLANEOUS ALLOYS. 475 machines, etc., is prepared as follows : Mix ioo parts of pure melted copper in succession with 6 parts magnesium, 57 parts sal ammoniac, 18 parts unslaked lime, and 9 parts cream of tartar, ail the ingredients to be in a finely pulver- ized state. Now, while stirring constantly, add 15 parts of zinc or tin in small pieces, and continue stirring until the whole is thoroughly melted and mixed. Allow the alloy to remain quietly on the fire for half an hour longer, remove the scum, and pour out the metal. This alloy has a golden color, a very fine grain, is ductile, and does not readily lose its color. Victor metal is whiter than German silver, which it can often replace, though less easy to work. It perfectly with- stands the effect of salt water and air, and is frequently utilized for marine engines. It is composed of copper 49.94 per cent., zinc 34.27, nickel 15.40, aluminium 0.11, iron 0.28. Tempe7 r ed lead. — Lead 98.51 per cent., antimony 0.11, tin 0.08, sodium 1.3. It is manufactured by placing small fragments of sodium in the melted metal. This alloy is not so soft as lead, and can be rolled into thin sheets with- out tearing. When the percentage of sodium is rather large, tarnishing is prevented by coating the metal with paraffin. Thus formation of soda is prevented, owing to oxidation of the excess of sodium by atmospheric oxygen. For this reason it is valued for the manufacture of shaft bearings, because the soda formed, as the bearings wear away, saponifies the lubricant and produces a soap which acts even better than the oil. CHAPTER XXI. SOLDERS AND SOLDERING. Soldei-s in General. The so-called solders are alloys in the true sense of the word, but being used for special purposes will have to be separately described. Soldering is the process of uniting the edges or surfaces of metals by means of a more fusible metal which, being melted upon each surface, serves, partly by chemical attraction and partly by cohesive force, to bind them together. There is a great variety of solders known by the names of hard, soft, spelter, silver, white, gold, copper, tin, plumbers , and many others; they may, however, be broadly distinguished as hard solders and soft solders. The former fuse only at a red heat, and are therefore only suit- able for metals and alloys which will stand that temperature ; the soft solders fuse at a comparatively low temperature, and may consequently be used for nearly all metals. Nearly all the principal metals take part in the composition of solder. The metals to be united maybe either the same or dissimilar, but the uniting metal must always have an affinity for both, and should agree with them as nearly as possible in hardness and malleability. When this is the case, as when zinc sol- der is used to unite two pieces of brass or of copper, or one piece of each, or when lead or pewter is united with soft solder, the work may be bent or rolled almost as freely as if it had not been soldered. But when copper or brass is united by soft solder, the joint is very liable to be broken by accidental violence or the blow of a hammer. In all soldering processes the following conditions must be ob- served : i. The surfaces to be united must be bright, (476) SOLDERS AND SOLDERING. 477 smooth, and chemically clean. 2. The contact of air must be excluded during the soldering, because it is apt to oxidize one or other of the surfaces, and thus to prevent the formation of an alloy at the point of union. This latter object is effected by means of fluxes, which will be referred to later on. The process called autogenous soldering takes place by the fusion of the two edges of metals themselves without interposing another metallic alio}'- as a bond of union. The process is possible with the majority of metals and alloys, even the refractory ones, and though it does not actually belong here, the subject being alloys, it will be briefly described. The union of the metals is accomplished by directing a jet of burning, oxyhydrogen gas from a small movable beak upon the two surfaces or edges to be soldered together. Metals thus joined together are much less apt to crack asunder at the line of union by differences of tem- perature, flexibility, etc., than when the common soldering process is employed. This method of soldering is especially of great advantage in chemical works for joining the edges of sheet lead for sulphuric acid chambers and concentrating pans, because any solder containing tin would soon corrode. All soldered work should be kept under motionless re- straint for a period, as any movements of the parts during the transition of the solder from the fluid to the solid state disturbs its crystallization and the strict unity of the several parts. In hard soldering it is frequently necessary to bind the work together in their respective positions ; this is done with soft iron binding wire, which for delicate jewelry work is exceedingly fine, and for stronger work is ^V or t$ inch in diameter ; it is passed around the work in loops, the ends of which are twisted together with the pliers. In soft soldering the binding wire is scarcely ever used, as, from the moderate and local application of the heat, the hands may in general be freely used in retaining most of the work in position during the process. Thick work is. 47§ THE METALLIC ALLOYS. handled with pliers or tongs whilst being soft-soldered, and the two surfaces to be united are often treated much like glue joints, if we conceive the wood to be replaced by metal and the glue by solder, they being frequently coated or tinned whilst separated, and then rubbed together to distribute and exclude the greater part of the solder. Soft Solders. The soft solders serve chiefly for soldering tin-plate, sheet-zinc, and kitchen utensils of sheet-brass. Their melt- ing points lie between 284° and 464 F. For special pur- poses, the two previously mentioned alloys of cadmium and bismuth, with as low a melting point as 140 F., would be very suitable, but their costliness prevents their general use. Pure tin is the simplest of all soft solders, and is fre- quently used for soldering fine utensils of tin. Absolutely pure tin should, however, only be used, as the presence of foreign metals, especially that of iron, considerably increases the melting point. Tin solder is generally employed in the form of semi-cylindrical bars or very thin prisms. For soldering very delicate work tin-foil of very pure tin is frequently used. The surfaces being thoroughly cleansed, and, if necessary, nicely fitted together with a file, a piece of tin-foil is placed between them. They are then firmly bound together with binding wire and heated in the flame of a lamp or a Bunsen burner, or in the fire, until the tin melts and unites with both surfaces. Joints carefully made may be united in this way so neatly as to be invisible. The soft solder most frequently used consists of 2 parts of tin and 1 of lead. A cheaper solder is formed by in- creasing the proportion of lead ; 1^ tin to 1 lead is the most fusible solder, unless bismuth is added. The following table gives the composition of some of these solders with their points of fusion : — SOLDERS AND SOLDERING. 479 Parts. Parts. Mel's at degrees F. No. Melts at No. , degrees F. Tin. Lead. Tin. Lead. i i 25 558° 7 iH i 334° 2 i 10 541 8 2 i 340 3 i 5 en 9 3 i 355 4 i 3 4«2 10 4 i 3&5 5 i 2 441 ii 5 I 378 6 i 1 370 12 6 I 38i For ordinary plumber's work the solders from 4 to 8 are used with tallow as a flux. For lead and tin pipes No. 8 is used with a mixture of rosin and sweet-oil as a flux. For Britannia metal No. 8 is used with chloride of zinc or rosin as a flux. It can also be used for soldering cast-iron and steel, with common rosin or sal ammoniac as a flux. The same solder can also be used for copper and many of its alloys, such as brass, gun-metal, etc., sal ammoniac, chloride of zinc, or rosin being used as a flux. The solder No. 5 is what is called in England plumbers' sealed solder, which is assayed and stamped by an officer of the " Plumbers' Com- pany." The preparation of soft solder is very simple. The tin is first melted, a porcelain or stoneware vessel being best adapted for the purpose, as with the use of iron vessels there is danger of the absorption of iron by the solder. The tin being completely melted, the lead is added, and the two metals are thoroughly combined by stirring. The finished alloy is then poured into suitable moulds. Many manufacturers simply pour the finished solder in a fine stream upon a stone slab, and subsequently break the sheet thus obtained into small pieces. It is, however, recommended to cast the solder in moulds, as it is more handy for working in this shape, and besides its composi- tion can be better controlled. The most suitable shape is that of thin bars about 7^ by 1% inches and }& to % inch thick. 480 THE METALLIC ALLOYS. Experts judge the quality of a solder by the appearance of the surface of the cast pieces, and attach special value to its being radiated-crystalline, which is technically called the "flower" and should have a stronger luster than the dull ground of a dead silver color. If, as it sometimes happens, the solder shows a uniform gray-white color, it contains too little tin, and it is best to remelt it with an addition of a small quantity of tin. Bismuth solder is composed of bismuth 1 part, tin 1, and lead 1. It melts at 284 ° F. As will be seen from the com- position, it is more expensive than ordinary solder on account of the content of bismuth. It is, however, well adapted for certain purposes, as it is very thinly-fluid and considerably harder than ordinary solder. As previously mentioned every readily fusible metallic composition can be used for soldering, and consequently the fusible alloys of cadmium and of bismuth might be classed with the soft solders. They are, however, only used in exceptional cases on account of their costliness. Hard Solders. Under this name many different alloys are used, their composition depending principally on that of the metals or alloys to be soldered. Though hard solders are found in commerce, many large manufacturers prefer to make their own solders in order to have them entirely suitable for the purpose they are intended for. According to the metals or alloys for which they are to be used, hard solders may be divided into brass-solder for soldering brass, copper, etc., argentan-solder for German silver, gold and silver solders for gold and silver, etc., and this division will be retained here. Brass solder is the most fusible of all hard solders and is prepared according to various proportions. It is generally made by melting a good quality of brass together with a determined quality of pure zinc, or sometimes adding some SOLDERS AND SOLDERING. 48.I tin to the mixture. Some solders are composed of brass 8 parts, zinc i. A somewhat more refractory composition consists of brass 6 parts, zinc I, and tin I. And a still more refractory one of brass 6 parts, zinc i,tin i, copper i. The latter solder is the so-called hard brass-solder and is used for soldering iron and copper. In speaking of the respective alloys attention was drawn to the fact that with an increase in the content of tin the color of the brass passes from golden-yellow more and more into gray, and that the ductility .decreases at a corresponding rate. Varie- ties of brass very rich in tin are no longer ductile, but possess a considerable degree of brittleness. By adding tin to such compositions, their hardness and brittleness are still further increased, and mixtures are thus obtained, which, according to their peculiar color, are designated as yellozv, half-yellow or half-white, and white solder. Regarding the quantity of metals to be added to the brass, it has to be taken into consideration that solders containing much tin, though quite thinly-fluid, acquire such a degree of brittleness as to break in most cases on bend- ing at the soldered place. In making solders great care should be taken to secure uniformity of composition ; they are often found in com- merce in a granulated form or cast in ingots. The most suitable mode of their preparation is as follows : Perfectly homogeneous sheet-brass is used, it being preferable to cast brass, as by rolling it has acquired greater homogene- ousness. To prepare the brass for the manufacture of solders directly by melting together copper and zinc, is not advisable, as the unavoidable loss of zinc during the opera- tion can never be exactly determined. By using finished brass it can, however, be readily melted down and com- pounded, if necessary, with zinc, without any sensible volatili- zation of the latter. The brass is first melted in a crucible at as strong a heat as possible, and when thoroughly fused the entire quantity 3i 482 THE METALLIC ALLOYS. of zinc to be used in the manufacture of the solder, and which has previously been highly heated, is added. The contents of the crucible are then vigorously stirred and after a few minutes poured out. The granulation of the solder is effected by pouring the melted metal from the crucible or ladle through a wet broom or from a consider- able height into cold water. The size of the grains thus obtained varies within wide limits, and in order to obtain a uniform product the grains have to be passed through different-sized sieves and all excessively large pieces re- melted. According to another method, the melted metal is poured into a shallow vessel filled with cold water in which lies a large cannon ball so as partially to project from the fluid. The metal falling in a fine stream upon the cannon ball flies into small pieces of nearly uniform size, which fall into the water, where they quickly harden. The finest and most beautiful product is, however, ob- tained in the following manner : At some distance above the level of the water serving for the collection of the grains, a horizontal pipe is arranged which is connected either with a powerful forcing pump or a water reservoir situated at a high level. Before pouring out the melted metal the cock on the pipe is opened so that the jet of water issuing from the pipe is thrown in a horizontal direc- tion over the vessel containing the water ; upon this jet of water the stream of melted metal is poured. The greater the force with which the water is hurled from the pipe the greater also the force with which the stream of melted metal is divided, and by this means it is possible, within certain limits, to obtain grains of a determined size. As will be seen from the above description the scattering of the stream of melted metal is based on the same principle as that employed in diffusing fragrant liquids in the air. Casting being finished, the grains of solder deposited on the bottom of the vessel are collected and quickly dried to SOLDERS AND SOLDERING. 483 prevent them from becoming covered with a layer of oxide, which would exert a disturbing influence in soldering. The following table shows the composition of various kinds of solder which have stood a practical test for various purposes : — Very refractory Refractory Readily fusible Half-white, readily fusible. White Malleable solder Hard solder according to Volk Copper. Zinc. Tin. per cent. per cent. per cent. 57-94 42.06 — 58.33 41.67 50.00 50.00 — 33-34 66.66 — 44.00 46.90 3-30 57-44 27.98 14.58 72.00 18.00 4.00 53-30 46.70 — Lead. percent. Since these solders, as previously mentioned, are gen- erally prepared by melting together brass and zinc, we give in the following table the proportions of brass (in sheet) and zinc required for the purpose. Very refractory Refractory Readily fusible. Half-white . . . . White '.'.'.'. Very ductile. . . For girdlers . . . Brass. Parts; 85.42 7.00 12.58 1. 00 3-oo 1. 00 4.00 5.00 1. 00 2.00 5-oo 12.00 4.00 5-oo 44.00 40.00 22.00 20.00 2.00 2.00 18.00 78.25 81.12 12.00 17.25 18.88 Zinc. Tin. 1. 00 2.00 8.00 4.00 30.00 Zinc. Tin. Lead. 43.10 1.30 c.30 49.90 3-30 I. CO .27.98 14.58 484 THE METALLIC ALLOYS. PrechtV s brass-solders. Parts. Copper. Yellow, refractory 53-30 Half-while, readily fusible . . . <4-C0 White 57-44 Brass-solders according to Karmarsh. Composition of the solder. Brass. Zinc. Copper. Zinc. Yellow, very refractory . 7 1 = 58.33 41.67 " refractory 3 to 4 1 = 50.00 50.00 " readily fusible.. 5 2 to 5 = 33.34 66.66 Half-white 12 4 to 7 and 1 tin 22 10 " 1 " White 20 1 " 4 " ' " 11 1 " 2 " " : 6 4 " 10 " Improved hard solder for brass. Per cent. Copper. Zinc. Silver. 1. Fuses well 50 46 4 2. Fuses readily 43 48 9 3. Fuses rapidly 36 52 12 These solders are said to be thoroughly reliable and though they are somewhat more expensive on account of their content of silver, time and fuel are saved with their use. For general use in workshops No. 2 can be recom- mended, it being suitable for brass of every kind and shape. No. 1 is intended for the first soldering, and No. 3 as a sub- stitute for all hard solders fusing quickly. Brass-solders containing lead are very rarely used at the present time, those containing besides copper, zinc, and perhaps a small quantity of tin, being generally preferred. Argentan-solder. — The metallic mixture to which this term is applied, not only. serves for soldering articles of argentan or German silver, but, on account of its refractory SOLDERS AND SOLDERING. 485 character and considerable toughness, is generally used for soldering articles where the joints are to be especially solid. It is very frequently employed for soldering fine articles of steel and iron. As regards its centesimal composition, argentan-solder is a variety of German silver especially rich in zinc, which must show considerable brittleness, so that it can be mechanically converted into a fine powder. The propor- tions according to which the solder is composed vary, and depend chiefly on the composition of the articles of German silver to be soldered with it. Manufacturers of German silver articles especially rich in nickel, and consequently more difficult to fuse, use, as a rule, a somewhat more re- fractory solder than those manufacturing alloys which con- tain but little nickel, and which are consequently more fusible. As argentan-solder is not only employed for soldering German silver, but also for articles of steel, efforts have been made to prepare compositions answering all demands, of which the following have stood a practical test : — a. Readily fusible argentan-solder. — Copper 35 parts, zinc 57, nickel 8. b. Less fusible argentan-solder (especially adapted for iron and steel). — Copper 38 parts, zinc 50, nickel 12. The alloys are melted in the same manner as German silver and cast in thin plates, which, while still hot, are broken into pieces and converted into as fine a powder as possible in an iron mortar previously heated. If the alloy is readily con- verted into powder, it contains too much zinc, or, if with difficulty, too little zinc. But in either case it does not possess the properties of argentan-solder of the proper pro- portions, and nothing is left but to remelt it. Hence it is recommended first to ascertain by small samples whether the alloy has the correct composition. For this purpose a small quantity of the melted metal is taken from the cruci- ble by means of a ladle and poured upon a cold stone, and 486 THE METALLIC ALLOYS. then tested as to its behavior in the mortar. If it can be readily pulverized, it indicates an excess of zinc. This excess of zinc can be removed by keeping the alloy in flux for some time with the crucible uncovered, whereby a considerable quantity of zinc volatilizes, and, after con- tinuing the heating for some time, an alloy showing the required content of zinc is obtained. This method is, how- ever, expensive, as it consumes time and a considerable quantity of fuel. It is, therefore, more suitable to throw small pieces of strongly heated German silver into the melted alloy, and effect an intimate mixture of the metals by stirring with a wooden rod. If a sample of the alloy cannot be pulverized or broken into pieces by vigorous blows with a hammer, it is a sure proof that zinc is wanting. This defect can be more readily corrected than the preceding one, it being only necessary to throw a small quantity of zinc into the crucible and dis- tribute it as uniformly as possible in the melted mass. After repeating the addition of zinc and testing once, or at the utmost twice, a solder answering all requirements will be obtained. Argentan-solder has a pure, white color and strong luster. It melts at quite a high temperature and for this reason is well adapted for soldering, for instance, lamps used for the production of high temperatures (so-called Berzelius lamps) which were formerly much used in chem- ical laboratories, but which at present are generally re- placed by gas. Solders Containing Precious Metals. Solders containing precious metals — gold and silver — are chiefly used in the manufacture of gold and silver wares, but are also employed for soldering articles of cast-iron, copper, bronze, etc., and by manufacturers of fine mechan- ical works. Generally these solders consist of an alloy of silver and copper, or silver and brass, for silver-solder ; SOLDERS AND SOLDERING. 487 sometimes a small quantity of tin is added, which lowers the melting-point and gives a soft silver-solder. The com- position of silver solders varies according to the purpose for which they are to be used. In the following the com- pounds employed in the preparation of the solders most frequently used are given. Ordinary hard-silver- solder. — Copper I part, silver 4. This alloy is quite tenacious and very ductile. It is pre- ferably used for soldering articles to be worked under the hammer or to be stamped. Brass siiver-solder. — The alloy known under this name shows also considerable hardness and ductility, and has a somewhat lighter color than the preceding. It is prepared by melting together a fine quality of brass with silver, and is consequently an alloy of silver, copper and zinc. It is composed of sheet-brass 1 part and silver 1. Soft silver-solder. — The solders given above have a com- paratively high melting point. To facilitate the working of smaller articles, solders with lower melting points are used. This is attained by the addition of a small quantity of tin, which must, however, be very pure. An excellent soft silver-solder is composed of sheet-brass 32 parts, silver 32, tin 2. Hard silver- solders: a. Very hard. — Silver 40 parts, cop- per 10. b. Hard. — Silver 40 parts, copper 2, brass 18. c. Middling hard. — Silver 40 parts, copper 10, brass 40, tin 10. Soft silver-solders: a. For after-soldering, i. e., for sol- dering articles that have parts already soldered, silver 20 parts, brass 10. b. Quick running and brittle. — Silver 25 parts, brass 30, zinc 10. The last composition is frequently used for soldering silver-alloys with a very small content of silver. In con- sequence of the great brittleness of such solder, the sol- dered places readily spring open. 483 THE METALLIC ALLOYS. Silver solder for jewelry. — Silver 63.3 parts by weight, copper 3.4, brass 33.3. French silver solder. — This solder is used for soldering silver wares of the standard 950. Silver 66.6 parts by weight, copper 23.3, zinc 10. In making this solder it is recommended to previously alloy the zinc with twice its weight of copper, when the following proportions are used : Silver 66.8 parts by weight, brass 30, copper 3.3. Gee * recommends the following solders for special work: oz. dwt. gr. I. Fine silver 100 Shot copper 5 oz. dwt. gr. II. Fine silver •■• ■ 1 Shot copper- • • 10 10 oz. dwt. gr. III. Fine silver o 16 o Shot copper o 12 Ccmpcsiticn 3 12 o oz. dwt. gr. IV. Fine silver- - - 1 Composition - - ] Pure tin ...... o V. Fine silver- • •• Shot copper • • Pure speller -- VII. Fine silver •• Composition Arsenic oz. 1 o dwt. gr. o 12 ' 3 o IS o oz. dwt. gr. 1 o 6 o ■ o 1 o 1 7 oz. dwt. gr. IX. Fine silver 100 Tin o 10 Arsenic o 5 oz. dwt. gr. VI. Fine silver 100 Shot copper- ■• 3 Arsenic 2 o 1 5 oz. dwt. gr. VIII. Fine silver- • -• 100 Composition • • 5 Tin 5 10 X. Fine silver- oz. dwt. gr. 1 Composition-- 15 Arsenic 1 1 15 o *Gee Silversmith's Handbook. 16 SOLDERS AND SOLDERING. 489 The composition mentioned in the above formulas con- sists of a mixture of copper and zinc in the proportions of 2 parts of copper to one part of zinc. It is preferable to employ this composition instead of brass, as the operator then knows of what the solder is composed, and if it should turn out bad he will partly know the cause, and be able to apply a remedy. Nos. I. and II. arc recommended for work to be enameled. No. III. easy solder for filigree work. No. IV. easy solder for chains. No. V. common easy solder. No. VII. easy silver solder. Nos. IX and X. common easy solders. Silver-solder for cast-iron. — Silver 20 parts, copper 30, zinc 10. Silver solder for steel. — Silver 30 parts, copper 10. Flux for hard-soldering used in Vienna. — This substance known as streu-borax (cprinkle-borax) is composed of cal- cined borax 87^ parts by weight, carbonate of coda J%, common salt 5. The ingredients are gently heated to expel the water of crystallization, and the whole is well pounded for use. For soldering articles of silver the alloy itself of which they are manufactured is in many cases used. But the manipulation is somewhat troublesome on account of the difficulty of keeping the places to be soldered clean, and the pieces must be very nicely fitted together. The solder, in this case, is used in the form of fine shavings and is melted by means of a keen flame. For small articles the flame of a blow-pipe suffices as a rule, but for larger articles it is best to use a special small blowing apparatus, by means of which the solder can be applied very uniformly. It offers the further advantage of leaving both hands free, which is of importance for turning the vessel in front of the flame and for the application of the solder. Gold-solders. — In color and fusibility the solders used for articles of gold should approach as nearly as possible the 49° THE METALLIC ALLOYS. alloys of which the article are made ; the smaller the content of gold in the alloy to be soldered, the more fusible the alloy used for soldering must be. Gold-solders consist in most cases of alloys containing, besides gold, copper and silver. By adding, as is sometimes done, small quantities of zinc, solders with a comparatively low melting point are ob- tained, the use of which has, however, the disadvantage of the soldered places frequently acquiring a black color dur- ing the subsequent coloring of the articles. Manufacturers use for articles of gold of various fineness solders which must correspond in regard to color and fusi- bility with the alloy to be soldered. The following table gives the composition of some gold-solders in general use : Parts. Hard solder for fineness 750. Soft " " " 750. Solder " " 583. " " 583. ' ' for less fineness than 583 " 583 " 583 • ' ' readily fusible " for yellow gold- • Gold. 9.0 12.0 3-o 2.0 1.0 1.0 1.0 11.94 10. o Silver. 2.0 7-0 2.0 0-5 2.0 2.0 54-74 5-0 Copper. Zinc. 1.0 _ 3-0 — 1.0 — • 0.5 — 1.0 — 2.0 28.17 S-Oi — 1.0 Solder for enameled work. — Articles which are being fin- ished and are to be decorated with enamel cannot be soldered with every kind of gold solder, since many enamels require so high a degree of heat for fusion as to endanger the dura- bility of the soldered joints. Hence solders with a high melting-point have to be used. The following composi- tions will be found to answer all requirements : — a. Refractory solder. — Gold 74 parts, silver 18. b. More readily fusible solder. — Gold (750 fineness) 32 parts, silver 9, copper 3. SOLDERS AND SOLDERING. 49I Fine gold solder. — For soldering platinum vessels to be used in laboratories chemically pure gold was formerly used, as alloys of gold and silver are attacked by sulphuric acid, etc., at a boiling heat and even below that tempera- ture. Soldering with fine gold is, however, very difficult, as gold requires a very high temperature to become fluid, and even then runs so thick as to require special skill for the production of a perfect joint. In modern times solder- ing with gold has been almost entirely abandoned, the pieces of platinum being now directly united with the assist- ance of the flame of oxyhydrogen gas. Aluminium gold-solder. — This solder is frequently used by dentists for joining together the separate metallic por- tions of sets of artificial teeth. Besides aluminium it gen- erally contains gold and silver, though in the place of the latter platinum and copper are now frequently used. In the following we give two receipts for preparing aluminium gold-solder : I. Gold 3 parts, platinum o.i, silver 2, aluminium 10. II. Gold 5 parts, silver 1, copper 1, aluminium 20. Alloys containing precious metals must, on account of their costliness, be brought into such shape that as little as possible be wasted in using them. In most cases they are cast into thin rods and rolled between steel roils into thin sheet, which is cut with the shears or pressed into thin strips, the so-called "pallions," or filed into dust, which is no doubt the best method of using them. Treatment of the various solders in soldering and soldering fluids, etc. Solders adhere only to bright and clean metal, and the surfaces of the plates to be soldered must consequently be subjected to a special treatment in order to remove any oxide, grease, etc. Many substances are in practice used for this purpose, the most important of which will be briefly discussed 49 2 THE METALLIC ALLOYS. in the following : According to their behavior the chemical preparations used in soldering can be divided into ?ev«ral groups, namely, in those which produce a bright surface of the metals by dissolving the layer of oxide upon them. Dilate mineral acids are generally used for pickling the places to be soldered, hydrochloric (muriatic) acid being chiefly employed for the purpose. By touching the place where the solder is to be applied with a brush dipped in dilute hydrochloric acid, the oxide is at once dissolved and the melted solder spreads rapidly over the surface. Hydro- chloric acid is used upon zinc as well as upon tin. The combination formed by the solution of zinc in hydrochloric acid is, however, very volatile in the heat imparted to the metal by the soldering iron, and a considerable quantity of vapors injurious to the health and also to the metal of the soldering iron are evolved. It is, therefore, recommended to provide the workshop, where much of such soldering is done, with thorough ventilation. Instead of dilute hydrochloric acid, the so-called solder- ing fluid is used in many places. It is prepared by divid- ing a certain quantity of hydrochloric acid into two equal parts, compounding one of these parts with pieces of zinc and leaving it in contact with an excess of zinc until the de- velopment of gas has ceased. The other portion of hydro- chloric acid is compounded with carbonate of ammonia until no more effervescence due to the escape of carbonic acid takes place. The two liquids are then combined. In place of the saturated solution of carbonate of ammonia a solution of sal ammoniac in water can be used, equal vol- umes of the zinc solution and sal ammoniac being in this case taken for the preparation of the soldering fluid. For brass articles ammonia alone is frequently used, which acts by reducing the layer of oxide upon the surface of the metals. As fluxes for coarser work turpentine, colophony, and a mixture of sal ammoniac and olive oil are also used. SOLDERS AND SOLDERING. 493 The composition known under the name of "soldering fat" may be prepared by introducing powdered colophony in melted and strongly heated tallow and adding sal ammoniac. The mass is stirred until homogeneous and then allowed to solidify. For hard soldering, substances are used which dissolve the layer of oxide, and form with it a glass-like combina- tion which is melted by the heat and forced out by pressing the soldered pieces together. The best-known agent of this kind is borax, which readily dissolves the oxides in consequence of the excess of boric acid it contains. For higher degress of temperature, readily fusible glass finely pulverized also does good service, the fused glass dissolv- ing the Oxides. A solution of water-glass also answers the purpose, and is frequently used in hard soldering. Hard-soldering fluid. — The composition known under this name consists of a solution of phosphoric acid in alco- hol. It is prepared by dissolving phosphorus in nitric acid, evaporating the solution to expel any excess of nitric acid and mixing the syrupy mass with an equal quantity of strong, alcohol. The phosphoric acid dissolves the layer of oxide, the combination formed melting under the soldering iron, and is displaced by the melted solder which now comes in contact with the bright metallic surface. The hard-soldering fluid can be advantageously used in solder- ing copper, as well as brass, bronze and argentan. The phosphate of ammonia or of soda is also used in soldering copper. Still more suitable as a flux in hard soldering is the use of quartz-sand and some decomposed soda. Quartz-sand consists of silicic acid and soda or sodium carbonate. Both these substances on coming together in a strong heat com- bine to sodium silicate, which, if silicic acid be present in excess, dissolves the oxides. For very high temperatures, as for instance in welding iron, the use of pure quartz-sand by itself suffices. By strewing the sand upon the red-hot 494 THE METALLIC ALLOYS. iron, placing the other piece of iron also red hot upon it, and uniting both by vigorous blows of the hammer, the combination of the silicic acid with the ferric oxide formed upon the surfaces of the pieces of the metal is pressed out in a fluid form, and the two surfaces of iron having become bright will unite. In soldering copper and brass, or similar metals, with soft solder, many workmen use the soldering iron ex- clusively, whilst in many cases a better joint may be made by carefully filing the places to be soldered, so that they fit accurately one upon the other, applying soldering fluid to them, and laying a piece of thin tin-foil between them. The parts are then bound together with wire and held over the lamp until the tin-foil is melted. Solders 19 and 21 in the annexed table may be recommended for this purpose. The fusing points given in the table may be of advantage to the workman in case the same piece of work requires several soldering joints. If, for instance, a joint has been soldered with tin-solder No. 5, an adjoining joint may, without hesitation, be soldered with solder No. 16, the melting points of these two solders being far apart. SOLDERS AND SOLDERING. 497 soldered, if previously the lower part A of the shirt button was fastened between the screws (see Fig. 43). In Fig 1 . 43 the pan is shown in cross section, to indicate how it is to be used in case a ring with jewel is to be soldered. This is to be fastened as deeply as pos- FlG- 43< sible between the screws, and the pan is then filled to a proper height with sand. Above is placed a layer, O, of small pieces of coal or asbestos, and soldering may then be commenced without danger to the jewel. 32 CHAPTER XXII. DETERMINATION OF THE CONSTITUENTS OF METALLIC ALLOYS, OF THE IMPURITIES OF THE TECHNI- CALLY MOST IMPORTANT METALS, ETC. Since most metals dissolve in nitric acid, pour over the sample in a glass flask chemically pure nitric acid and assist solution by careful heating over a spirit flame.- 1. Gold and platinum dissolve only in aqua-regia ; tin and antimony are only oxidized by nitric acid. Hence if an undissolved residue of the sample remains, it indicates gold, platinum or antimony (or carbon with cast-iron). Filter the residue, which may be termed A, from the solu- tion and treat it further as given under 15. 2. Dilute a sample of the filtrate (or, if filtration be not necessary, a sample of the solution) in a test-glass with dis- tilled water. If turbidity or a white precipitate appears it indicates bismuth, which has been precipitated as basic salt from the solution by water. The non-appearance of this reaction, however, is not conclusive proof of the absence of bismuth, since an excess of nitric acid prevents the precipi- tation of basic bismuth nitrate. To be certain, first evap- orate the sample to drive off the acid and then dilute with water. 3. Another sample of the solution is mixed with dilute sulphuric acid. If a white, granular precipitate is formed, the sample of metal contains lead, because only sulphates of lead are insoluble in acids. 4. If, on mixing a portion of the original solution, or in case the test for lead was successful, a portion of the filtrate free from lead, with pure hydrochloric acid, a white caseous (498) •CONSTITUENTS OF METALLIC ALLOYS. 499 precipitate is formed if the metallic sample contains silver or mercury. In case test No. 3 has not been previously executed, a precipitate of chloride of lead may take place if lead is present. For the further treatment of this precipi- tate, which may be termed B, see under 14. 5. Add to a small sample of the solution in nitric acid a few drops of caustic ammonia. If the solution acquires a fine blue color, the sample of metal contains copper. 6. To test for mercury, evaporate a few drops of the solution in nitric acid to expel the acid, and dilute with water. If a copper wire placed in the aqueous solution turns gray and becomes white with a metallic luster on rubbing with the finger, the presence of mercury is shown. 7. Next conduct into a somewhat larger sample of the solution sulphuretted hydrogen and compound it with water containing sulphuretted hydrogen. All metals men- tioned in 1 to 6 are precipitated as metallic sulphides. Hence, a precipitate, which may be termed C, will gener- ally be obtained. This precipitate is filtered off, thoroughly washed with water containing sulphuretted hydrogen, and further tested for cadmium as given under 16. Since sul- phuretted hydrogen is frequently used, it being a reagent of great value to the chemist, a simple and cheap apparatus, so that a supply may at any time be had, may be made as follows : Cut off the bottom of a long glass-bottle* of small diameter, D, say about two inches, and fit it into a fruit jar E, as in Fig. 44. The top A should be fitted loosely, so that it may be removed to let air pass through. The cork at B must be air-tight. Fit a small tube into the cork after bending it in a spirit-lamp flame — a quarter-inch tube with an eighth- *Cut a nick, with a large file, in the spot where you wish to start a crack near the bottom, then heat a rod or poker nearly red hot, place it on the nick; a crack starts; draw your hot iron and the crack will follow; when nearly cracked around, pull the bottom off. A glass chimney maybe used, but it is rather too small to contain sufficient iron sulphide. 5oo THE METALLIC ALLOYS. inch aperture is sufficiently large and is easily bent. Take an inch rod of iron, let the blacksmith heat it white hot and press it into a small roll of brimstone; this will give you iron sulphide — you need it in pieces as large as bullets ; it melts readily against the brimstone. Place some cotton in the neck of the bottle, and, having fitted a plug of wood with holes in it for the bottom of the bottle, in- vert the bottle and fill it half full of iron sulphide lumps, fasten the wooden plug in the bottom, not very tightly, but tightly in three or four places, so that water can pass freely, and yet the plug be well fixed in. Put the bottle in its place, resting in the jar at A, and somewhat loosely fastened. But this must be after you have half filled the jar with a mixture of equal parts common hydrochloric acid and rain water. Sulphuretted hydrogen will form immediately, and if you have made all connections perfectly as in the figure, the gas will pass from this apparatus into the sample of the solution in the beaker, and precipitation will soon take place. The advantage of this apparatus is, that if you tie two little blocks of wood against the side of the rubber tubes C C, so as to press the sides together and stop the gas from flowing, the gas forming pushes the water out of the interior glass D, and the gas stops form- ing, but is ready at any moment to begin as soon as the string around the blocks is removed. 8. Neutralize the filtrate from the previous experiment and mix it with ammonium sulphide. The precipitate formed, which may be termed D, is washed out with water, containing ammonium sulphide and tested according to 10. Magnesium may also be contained in the filtrate. 9. To determine ?nag?iesium evaporate a small quantity of CONSTITUENTS OF METALLIC ALLOYS. 5OI the filtrate obtained in 8, and add some sodium phosphate and ammonia. If the solution contains magnesium, a crystalline precipitate of ammonium-magnesium phosphate is formed, which is insoluble in ammoniacal water. 10. Pour dilute hydrochloric acid over the precipitate D (from 8). If a black residue — consisting of sulphides of nickel and cobalt — which may be termed E, is formed, it is filtered off and further tested according to n. Boil the filtrate until the sulphuretted hydrogen is completely driven off, then compound it with nitric acid, boil again, and evaporate. Now compound with strong alkaline lye in excess, boil and filter. The precipitate, which may be termed F, is analyzed according to 12. The filtrate may contain zinc or alumina. Both are determined according to 13. 11. The residue is (from 10) is dissolved in hydrochloric acid, a few drops of nitric acid are added and the solution is evaporated nearly to dryness. By adding some sodium nitrate and acetic acid, and after standing for some time in the heat, a yellow precipitate is formed if cobalt be present. After 12 hours filter off and compound the filtrate with caustic soda. Nickel is present when a greenish precipitate is formed, which does not completely dissolve in the excess of the precipitating agent. 12. A portion of the precipitate F (from 10) is dissolved in hydrochloric acid and a sample of it tested : a. With potassium ferrocyanide for iron. b. Melt another sample with potassium carbonate and potassium chlorate, and boil the melted mass with water. If chromium was present it has been converted into chromic acid (yellow solution), and can be readily recognized by compounding the solution with sugar of lead. If chromium is not found, a portion of the sample is tested with the blow-pipe for manganese. c. If chromium was found a portion of the hydrochloric acid solution is neutralized with potassium carbonate, com- 502 THE METALLIC ALLOYS. pounded with caustic soda in excess, and the precipitate tested for manganese and the nitrate for zinc, according to 13. 13. Moisten the solution to be tested for manganese upon a platinum- sheet with some soda and a trace of salt- peter, and let the flame of the blow-pipe act upon it. If the solution contains manganese a green paste is obtained, which on cooling turns blue-green. The filtrate from 10 may contain zinc or alumina. Compound a portion of it with sulphuretted hydrogen; a white precipitate (sulphate of zinc) indicates zinc. Acidulate another portion with hydrochloric acid, add ammonia in slight excess and warm. Alumina, if contained in the solution, is precipitated as aluminium hydrate. 14. The white precipitate B (from 4) may contain chloride of silver, chloride of lead, or subchloride of mercury. Treat it with much water, whereby chloride of lead is dissolved ; the lead may then be determined as in 3, with sulphuric acid. Treat the residue with ammonia. If complete solu- tion takes place, the residue consists of chloride of silver,, and from the solution the silver is again precipitated as chloride of silver by nitric acid. A black residue, insoluble in water and ammonia, consists of chlorine and mercury, (subchloride of mercury). 15. The residue which remained by dissolving in nitric acid is warmed in aqua-regia. If a white insoluble powder is separated it generally consists of chloride of silver, more rarely of chloride of lead. Though silver and lead by them- selves are soluble in nitric acid, by alloying with the more noble metals they are frequently protected from solution,, and may be contained in the residue. They are determined according to 14. A portion of the solution is now mixed with ferrous sulphate solution. A fine brownish separation consists of metallic gold. A yellow precipitate produced by sal ammoniac establishes the presence of piatimim. If the residue A consists of a white powder it is washed CONSTITUENTS OF METALLIC ALLOYS. 503 with water and boiled in a flask with tartaric acid. If it is soluble it consists of oxide of antimony; if insoluble it con- tains tin. 16. The precipitate C (from 7) obtained with sulphuretted hydrogen contains a number of metallic sulphides, a portion of which — antimony, arsenic, tin, gold, platinum — is dis- solved by ammonium sulphide. The residue is boiled with dilute nitric acid and dissolves thereby, separating flaky sulphur, which floats upon the solution. If a portion re- mains undissolved it consists of oxide of mercury. From the filtered solution separate the lead by means of sulphuric acid (see 3), and after settling, filter, and mix with am- monia. A precipitate indicates bismuth; a blue coloration copper. Evaporate the solution completely, add some acetic acid and water, and precipitate the copper with sul- phuretted hydrogen. Cadmium, if present, is precipitated as sulphide of cadmium, and hence the precipitate has to be treated with boiling sulphuric acid. The sulphide of cad- mium is dissolved, while sulphide of copper remains undis- solved. If the alloy contains cadmium yellow sulphide of cadmium is precipitated from the filtrate by sulphuretted hydrogen. 17. Some alloys contain arsenic, it being also found as an impurity in many metals. To complete the analysis, a test for arsenic must therefore be made. Marsh's apparatus is used for this purpose. It consists of a flask a (Fig. 45), in which hydrogen gas is developed from chemically pure zinc and dilute pure sulphuric acid. The tube c ends in a wide glass tube d, which is filled with calcium chloride for dry- ing the gas. The gas escapes through the smaller tube e, running to a point at /. If now through the funnel b a few drops of the metallic solution are brought into the appara- tus, the flame of hydrogen will acquire a blue coloration if the solution contains arsenic, and a white smoke of arseni- ous acid will rise from it. The arsenietted hydrogen formed is very poisonous, a few bubbles of it being sufficient to 5°4 THE METALLIC ALLOYS. cause death. If a piece of glass or porcelain is depressed upon the flame it will acquire a metallic mirror of arsenic. The metallic mirror, however, is not an infallible test, since antimony produces the same phenomenon. To ascertain Fig. 45. whether arsenic or antimony has to be sought for in the metal, drop a little solution of calcium chloride upon the metallic mirror; arsenic is immediately dissolved, while antimony remains unchanged. Testing brass. — Evaporate the alloy with nitric acid to dryness, take up with a few drops of nitric acid and with water, filter the residue {oxide of tin, with or without oxide of antimony), precipitate from the filtrate lead with sulphuric acid, from the filtrate of sulphate of lead copper with sulphuretted hydrogen, from the oxidized filtrate any iron present by ammonia and ammonium chloride, and from another portion of the filtrate by potash lye man- ganese to be tested with saltpetre and soda. For estab- lishing a content of antimony in the separated oxide of zinc dissolve the latter in as little hydrochloric acid as pos- sible, bring the fluid upon a platinum sheet and a small piece of zinc, whereby, if antimony is present, a dark-brown to black stain is formed. In the absence of tin and in the presence of small quantities of antimony in solution, super- CONSTITUENTS OF METALLIC ALLOYS. 505 saturate the solution in nitric acid with potash lye, heat with solution of potassium bisulphide, filter, and precipitate from the filtrate with hydrochloric acid sulphide of anti- mony as well as sulphide of arsenic ; dissolve the precipi- tate in fuming hydrochloric acid and test upon a platinum sheet with zinc for antimony. Dissolve the residue (sul- phide of arsenic), insoluble in the acid, in a little hydro- chloric acid and potassium chlorate, heat until the odor of chlorine disappears, and test for arsenic in Marsh's appara- tus, Fig. 45. A content of bismuth may be detected by dissolving a larger quantity of alloy in as little dilute hydro- chloric acid of 1. 12 specific gravity as possible, heating carefully, filtering off separated oxide of tin, precipitating bismuth from the filtrate with ammonia, dissolving the pre- cipitate in greatly dilute hydrochloric acid and allowing the solution to fall drop by drop into a large quantity of water, whereby a white turbidity appears. Testing Britannia metal. Good qualities of Britannia metal, which can be rolled, contain 90 to 93 per cent, tin, and, at the utmost, 10 per cent, antimony and o to 3 per cent, copper, while inferior qualities contain less than 85 per cent. tin. Hence, the principal point would be the deter- mination of the content of tin. For the purpose of testing whether, besides tin and antimony, other metals are present, oxidize with nitric acid, supersaturate with ammonia, add ammonium sulphide and heat. If the resulting solution is not clear, other metals are present. Testing bronze. Decompose the bronze with nitric acid, evaporate to dryness, heat the residue with water, filter off the stannic acid, separate from the filtrate lead by means of alcohol and sulphuric acid, and from the filtrate thereof copper by means of sulphuretted hydrogen ; filter, add to the filtrate, freed from sulphuretted hydrogen by heating, some potassium chlorate, precipitate iron with ammonia in excess, and from filtrate, supersaturated with acetic acid, zinc with sulphuretted hydrogen ; supersaturate the filtrate 506 THE METALLIC ALLOYS. thereof with ammonia and precipitate manganese with am- monium sulphate. A test for arsenic may be made in Marsh's apparatus by dissolving a sample in hydrochloric acid, with addition of potassium chlorate and heating the fluid to be tested until the chlorine odor disappears. A very sensitive test, according to Gutzeit, is as follows : Pour over zinc in a test-tube hydrochloric or sulphuric acid, add the solution to be tested for arsenic, close the mouth of the tube with a cotton stopper, place filtering paper over the latter and bring upon the center of the paper a drop of a solution of nitrate of silver in equal parts of water. In the presence of arsenic the moistened place acquires, first be- low and then on top, a lemon-yellow color, a brown-black ring being at the same time formed on the periphery, which gradually extends towards the center and finally dis- perses the yellow coloration. In the presence of much arsenic the yellow coloration is only transitory. Antimony gives only a dark brown-red ring on the periphery, w 7 hile in the presence of much antimony the interior space of the ring appears gray-white. To detect phosphorus precipitate from the solution in aqua-regia, copper and tin with sulphuretted hydrogen, supersaturate the filtrate with ammonia, precipitate iron, zinc and manganese with am- monium sulphate, and from the filtrate thereof, ammonium- magnesium phosphate with ammonium chloride, magnesium chloride and ammonia. Testing German silver. — The quality of German silver being dependent on the content of nickel, is recognized by its color, a yellowish coloration indicating an inferior pro- duct. A content of arsenic is detected by dissolving a. sample of the alloy in nitric acid, evaporating with sul- phuric acid until the nitric acid is expelled, diluting with water and testing in Marsh's apparatus, Fig. 45, or accord- ing to Gutzeit's method given above. To test gold-ware. — When a sample of the alloy cannot be taken for a chemical test, the touchstone forms a con- CONSTITUENTS OF METALLIC ALLOYS. 507 venient means of examination. It consists of a species of black basalt obtained chiefly from Silesia. If a piece of gold be drawn across its surface a golden streak is left which is not affected by moistening with nitric acid, whilst the streak left by brass or any similar base alloy would be rapidly dissolved. Experience enables an operator to de- termine by means of the touchstone nearly the amount of gold present in the alloy, comparison being made with the streaks left by alloys of known composition. Resistance of a few metals and alloys to calcium hy- drate. — Filings and turnings of the metals to be examined in quantities of yj grains, were left, at a normal tempera- ture to the action of milk of lime with 4 per cent, hydrate for 14 days; they were then separated from the lime solu- tions by washing until phenolphthaleine showed no longer a red coloration, dried and weighed. The results were as follows : 1. '"Saxonia" pure soft lead: loss of weight, 0.81 1 per cent. The metal was considerably attacked. 2. Antimony regulus : the metal remained entirely un- changed. 3. Lead pipe (with 25 per cent, slag lead): loss of weight, 0.299 per cent.; considerably attacked. 4. Lead plate (12 per cent, slag lead) : loss of weight, 0.658 per cent.; considerably attacked. 5. Pure cast iron : increase in weight, 0.014 per cent.; very much corroded. 6. Brass : loss of weight, 0.686 per cent.; considerably attacked. 7. Phosphor-bronze : no alteration. 8. Pure tin : loss of weight, 0.122 per cent.; the metal was but little attacked. From these results it may safely be concluded that for pumps intended for the conveyance of milk of lime, phos- phor bronze or an alloy of tin and antimony is most suita- ble. 508 THE METALLIC ALLOYS. To distinguish tin-foil from lead-foil. — Treat the foil with concentrated sulphuric acid; tin is dissolved, while lead remains undissolved. To test mercury as to its purity. — Pour nitric acid over a drop of mercury in a dish. If pure, the mercury moves for a moment and then remains quiet and motionless. If it contains foreign metals it commences at once a vigorous circular motion, which is kept up until the mercury is com- pletely dissolved. Tin is generally tested as to its purity by breaking it, whereby it gives out a single, crackling sound (the cry of tin). To recognize the nature of impurities dissolve a sample in aqua-regia ; arsenic and antimony are detected by Marsh's apparatus (see p. 503). Mix another portion of the solution with potassium ferrocyanide ; a white precipi- tate indicates the purity of the tin ; a blue precipitate gen- erally the presence of iron, and a red-brown precipitate that of copper. Lead may be detected by the addition of sulphuric acid or Glauber's salt. Soft solders are tested in the same manner. They should contain only tin and lead. Some soft solders contain bis- muth, which is detected by diluting the solution (see under 2, p. 498). To detect lead in tin. — Make a solution of potassium bichromate in water. Next apply some acetic acid to the tin to be tested, which will produce a whitish coating. Then apply some of the potassium bichromate solution, and if the whitish coating turns yellow the tin contains lead, and the more the yellower the coating becomes. White metals should always be tested with Marsh's appa- ratus, Fig. 45. If the metallic mirror is only partially dis- solved by chloride of lime, the sample contains arsenic and antimony . The other constituents are found in the manner already stated. Nickel has only to be tested for copper, iron and cobalt. The manner of determining copper has been given under 5, CONSTITUENTS OF METALLIC ALLOYS. 509 p. 499. Iron can be recognized by its reaction with potas- sium ferro-cyanide. To determine the presence of cobalt, dissolve the metal in hydrochloric acid, dilute the solution with water, and write with a clean goose-quill upon a strip of white paper. After drying heat the writing ; if it appears emerald-green to blue-green the solution contains cobalt. For other methods see under n, p. 501. APPENDIX. COLORING OF ALLOYS. In many cases alloys are provided with a coating, the object being either to increase their beauty or to protect them from oxidation and discoloration. Articles of ordin- ary alloys, which are not to be exposed to the fire, are fre- quently only provided with a coating of lacquer consisting usually of a solution of shellac in alcohol, that made with " stick lac " being as a rule, the best. The lacquer may be colored by any permanent transparent alcoholic solution giving the desired tint. Dragon's blood, red sanders, or annotto is generally used for red, and gamboge, sandarac, saffron, turmeric, or aloes for yellow; these coloring matters may be replaced by aniline colors. In applying the lacquer care should be had to keep the article to be lacquered warm and of uniform temperature, and to perform the work as quickly and smoothly as possible. Keep the lacquers in well-stoppered bottles, best of opaque material. For use pour them into dishes of convenient size, and apply them with a thin, wide, flat brush. The following is Graham's *• table of lacquers : — * Brass-Founder's Manual, London, 1887. (5IO) COLORING OF ALLOYS. 511 u 0) .£3 B 3 2 n a "t5 .a a •a 01 C U V a '% "o "C 'E in u 01 , Ph a V ft 3 O '5, en 'a u a > a c V a u 3 H 1^ a V 'u 1 p. p. CJ "o u co u o T3 u CO o (LI to 1 a Is 1) 01 I 6 re 3 o <£ o ™ to E a 13 '5 g >>.2 O en j^ re °o "5 a cj a "3 o a >> r2 o B u tt3 CO CJ fc t. Ch Ph 2 H Ph C-, u fc ffi z O I 2 3 4 S 6 7 8 9 TO II 12 13 14 Pt. I dr. 5 16 dr. 5 S pt. i oz. - gr. oz. dr. _ dr. - - oz. Pt. T dr. 2 dr. 16 - dr. i 3 4 cz. I - Brown and every shade to black. Brown and every shade to red. Brownish-red. Dark brown. Yellow to red. Orange. Olive-green. Slate. Blue. Steel-gray. Black. In the preparation of No. 5 the liquid must be brought to boil and cooled. In using No. 13 the heat of the liquid must not be under 180 F. No. 6 is slow in action, some- times taking an hour to give good results. The action of the others is usually immediate. * Brass- Founder's Manual, London, li COLORING OF ALLOYS. 517 II. For copper (by simple immersion} , 1 u 1 L ' -6 ft i.JL a I O M-, C ft a > pt. dr. oz. dr. dr. dr. oz. dr. oz. dr. IS 1 5 -r- Brown, and every shade to 16 I 5 — — — — — 2 — — Dark brown-drab. [black. 17 I — I — — — — — 2 2 " " 18 I — — 2 — — I — — — Bright red. IQ I — — — 1 — I — — — Red, and every shade to 20 I — — — — 1 — — ~l Steel-gray, at i8o°F. [black. III. For zinc (by simple immersion) , u X) S u C O u dr. 5 .5 "o rs IS Ph dr. 1 1 OJ ft ft (J *o u ja< *3 CO dr. 1 4 8 d 4-1 "o 'C dr. 1 1 -a a) "o aj .2 'in oz. * to rt Tl nj dr. 4 O > en K a 'en !s ej '0 c cd I-l TO O * O en 3 -a bo * 21 22 23 24 25 26 27 28 29 30 pt. I I I 2 2 I I dr. 1 dr. 8 Black. Dark-gray. Green-gray. Red (boil). Copper color. (with agita- Purple (boil). [tion) To provide articles of brass or bronze with a very lus- trous gray or black coating, the tendency of certain metallic salts of forming gray or black combinations with sulphur is utilized. For gray dip the article first into a very dilute : Made to the consistency of cream. 5l8 APPENDIX. solution of acetate of lead, or for black into a solution of sulphate of copper, and after drying into a hot dilute solu- tion of hyposulphite of soda. By using the solutions in a very dilute state the articles acquire a peculiar, iridescent appearance similar to soap- bubbles, and it is also due to the same cause. It is well known from the teachings of physics that many bodies show, when in very thin layers, the peculiar color-phe- nomenon termed iridescence, and this is also produced by a very thin layer of sulphide of lead or sulphide of copper. By repeating the treatment of the article in very dilute solutions, the iridescence passes into a red, brownish, or violet coloration. It is impossible to give exact propor- tions for the production of these colors, the success of the coloration depending largely on the skill of the operator. Very beautiful, but not very permanent, iridescent coat- ings can be produced by placing the bright metal in a bath of a heavy metal decomposable by the galvanic current, touching it for a moment with the negative pole of the battery, taking it out, rinsing off, and drying. The metal will show all the colors of the rainbow, but the coating is so delicate that it must be protected by immediately dipping the article after drying into a quick-drying lacquer. There are many means of providing small articles of brass with a coating of one color, various liquids being, for in- stance, used to produce determined shades of color upon brass buttons. For a pure golden-yellow, the buttons are dipped for a few seconds in a perfectly neutral (absolutely free from acid) solution of acetate of copper. A gray-green shade is produced by repeatedly dipping them in a dilute solution of chloride of copper and drying after each dip- ping. A violet tint is obtained by heating the buttons to a temperature at which oxidation does not take place, and rubbing them with a tuft of cotton dipped in a solution of antimony in hydrochloric acid. For the production of the beautifiil gold color possessed COLORING OF ALLOYS. 5IO, by many French articles of brass the following process may be used: Dissolve 1.76 ounces of caustic soda and 1.41 ounces of milk sugar in 2. 11 pints of water. Boil the solu- tion for fifteen minutes, and after taking it from the fire compound it with 1.41 ounces of cold concentrated solution of sulphate of copper. The red precipitate of cuprous oxide, which is immediately formed, deposits on cooling upon the bottom of the vessel. The polished articles rest- ing upon a wooden sieve are then placed in the vessel con- taining the solution. After about a minute the sieve is taken out in order to ascertain how far the operation has progressed ; it is then replaced, and at the end of the second minute the golden color is generally dark enough. The sieve is then taken out, and the articles after washing are dried in sawdust. By allowing the articles to remain for a longer time in the solution they acquire in a short time a greenish tint, which soon becomes yellow and then bluish- green, until finally the iridescent colors are formed. In order to obtain a uniform coloration it is necessary to pro- duce the color slowly, which is best attained at a tempera- ture of from 132 to 136 F. The bath can be repeatedly used and kept for a long time in well-stoppered bottles. If partially exhausted, it can be restored by an addition of 5.64 drachms of caustic soda, sufficient water to replace that lost by evaporation, heating to the boiling-point, and finally adding 14. 11 drachms of cold solution of sulphate of copper. To produce a beautiful silver color upon brass, proceed as follows : Dissolve in a well-glazed vessel 1 yi ounces of pulverized cream of tartar and 2.25 drachms of tartar emetic in 2. 11 pints of hot water, and add to the solution i^/l ounces of hydrochloric acid, 4^ ounces of granulated, or, still better, pulverized tin, and one ounce of pulverized antimony. Dip the article to be coated in the solution heated to the boiling-point. After boiling one-quarter to one-half an hour, they will be provided with a beautiful lustrous coating which is hard and durable. 520 APPENDIX. Browning liquid for copper. — xA.dd acetic acid to 1 1 drachms of spirit of sal ammoniac until blue litmus paper dipped in the liquid turns red. Then add 5^2 drachms of sal ammoniac and sufficient water to make 2. 11 pints. With the solution thus obtained repeatedly moisten the copper surfaces, rubbing after each application until the desired brown tint is produced. For colo7'ing brass Ebermayer, of Niirnberg, gives the following directions : (1) 8 parts of sulphate of copper, 2 of sal ammoniac, and 100 of water give by boiling a greenish color. (2) 10 parts of potassium chlorate, 10 of sulphate of copper, and 1000 of water give by boiling a brown-orange to cinnamon-brown color. (3) By dissolving 8 parts of sul- phate of copper in 100 of water, and adding about 100 parts of caustic soda until a precipitate is formed, and boiling the articles in the solution, they acquire a greenish-brown color, which can be made darker by the addition of rouge. (4) With 50 parts caustic soda, 50 of sulphide of antimony, and 500 of water, and boiling, a light fig-brown color is ob- tained. (5) Boil 29 parts of sulphate of copper, 20 of hyposulphite of soda, and 10 of cream of tartar in 400 of water. The brass first acquires a rose-color, and then a blue color. By adding 20 parts of ammonio-ferric sulphate and 20 of hyposulphite of soda, the colors change from yel- low to rose-color, and blue ; after the latter yellow again makes its appearance, and finally a beautiful gray is formed. (6) 400 parts of water, 20 of potassium chlorate, and 10 of nickel salt give, after boiling for some time, a brown color, which is, however, not formed if the sheet has been pickled. (7) 250 parts of water, 5 of potassium chlorate, 2 of carbon- ate of nickel, and 5 nickel salt give, after boiling for some time, a brown-yellow color playing into a magnificent red. (8) 250 parts of water, 5 of potassium chlorate, and 10 of nickel salt give a beautiful dark brown. (9) 250 parts of water, 5 of orpiment, and 10 of crystallized soda give at first a beautiful red which passes into blue, then into pale blue. COLORING OF ALLOYS. 521 and finally becomes white. .(10) 250 parts of water, 5 of nickel salt, 5 of sulphate of copper and 5 of potassium chlorate' give a well-covering yellow-brown color. (n) 100 parts of water, 1 of liver of sulphur, and 5 of ammonia. The articles being allowed to lie in a closed vessel finally acquire a very beautiful blue color. Coloring of soft solders. — For giving the solder used in soldering copper the same color as the latter, prepare first a saturated solution of pure sulphate of copper and apply it to the solder. By then touching the solder with an iron or steel wire the latter becomes covered with a film of copper, which can be augmented as much as desired by repeated moistening with the solution of sulphate of copper and touching with the wire. If the soldering is to show a yel- low color, mix 1 part of saturated solution of sulphate of zinc with 2 parts of solution of sulphate of copper, apply the mixture to the coppered place and rub the latter with a zinc rod. If the soldered place is to be gilded, copper it as above described, then coat it with a solution of gum or isinglass, and strew bronze powder upon it. This forms a surface which, when the gum is dry, can be polished. Bronzing of copper, bronze-metal, and brass. — Black bronzing is produced by brushing the metals with dilute nitric acid containing a small quantity of silver in solution, and blazing off over the fire. This operation is repeated if after again brushing the articles with the acid and blazing off. the color is not sufficiently deep. Nitric acid which has been used for dissolving fine silver and then poured off is most suitable for the purpose. A bismuth solution may also be used for coloring the above-mentioned black ; after the operations they are coated with lacquer. Brass may be bronzed black as follows : Dissolve copper in an excess of nitric acid, dilute the resulting liquid with a large quantity of rain water, apply it to the warmed brass, allow to dry in a warm place, and finally rub with a brush or with leather. Or amalgamate the brass by brushing it with solution of 522 APPENDIX. mercurous nitrate, and convert the mercury upon the sur- face into black sulphide of mercury by potassium sulphide solution. Brown bronze color is produced in the same manner as black, only besides silver the nitric acid must contain cop- per. Another method is as follows: .Dissolve i oz. of sal ammoniac and % oz. of oxalic acid in % pint of water and brush the metal several times with the solution. Sulphur- etted hydrogen will also produce a brown color. Dissolve liver of sulphur in 30 parts of water, pour the solution into shallow earthen-ware vessels and place the latter in a room protected from draught. Put the articles to be bronzed near the vessels. The object is still more rapidly attained by placing the articles over the vessels containing the liver of sulphur solution. This method of bronzing is especi- ally suitable for articles soldered with soft solder which for that reason cannot be exposed to the fire. Red-bi r own or copper-brown upon copper is produced by brushing the articles with a paste-like bronze consisting of a triturated mixture of horn shavings 1 part, verdigris 4,. rouge 4 and some vinegar, or by placing them in a liquid bronze prepared as follows : Boil a solution of verdi- gris 2 parts, and sal ammoniac 1 in vinegar, remove the scum, dilute with water, allow to settle, pour off the supernatant liquid, boil again in a porcelain dish and quickly pour it over the copper articles. The liquid should be much diluted, the metallic articles carefully freed from grease, and rest upon a wooden grate in a vessel which is immediately placed over the fire and the fluid brought to the boiling point ; finally rinse in clean water. Green bronze color is produced as follows : Dissolve a mixture of sal ammoniac Y%, argol 1 oz., and common salt 2 ozs. in Yz pint of vinegar. To this solution add 2^ ozs. of cupric nitrate solution, brush the articles with the result- ing liquid and allow to dry. Coloring of zinc. — The direct coloring of zinc, according COLORING OF ALLOYS. 523 to existing- directions, does not yield satisfactory results and it is therefore advisable to first copper the zinc and then color the coppering. Experiments in coloring zinc black with alcoholic solution of chloride of antimony ac- cording to Dullos's process gave no useful results. Puscher's method is better. According to it the objects are dipped in a boiling solution of 5 ozs. of pure green vitriol and 3 ozs. of sal ammoniac in 2)2 quarts of water. The loose black precipitate deposited upon the objects is removed by brushing, the objects again dipped in the hot solution, and then held over a coal fire until the sal ammoniac evaporates. By repeating the operation three or four times a firmly ad- hering black coating is formed. Gray, yellow, brown to black colors upon zinc are ob- tained by bringing the articles into a bath which contains 6 to 8 quarts of water, 3^2 ozs. of nickel-ammonium sulphate; 3^ ozs. of blue vitriol and 3% ozs. of potassium chlorate. The bath is to be heated to 140 F. By increasing the content of blue vitriol a dark color is obtained, and a lighter one with the use of a larger proportion of nickel salt. The correct proportions for the determined shades will soon be learned by practice. When colored, the articles are thor- oughly rinsed, dried, without rubbing, in warm sawdust, and finally rubbed with a flannel rag moistened with linseed oil, whereby they acquire deep luster, and the coating be- comes more durable. A sort of bronzing on zinc is obtained by rubbing it with a paste of pipe-clay to which has been added a solution of 1 part by weight of crystallized verdigris, 1 of tartar, and 2 of crystallized soda. Red-brown on zinc. — Rub with solution of chloride of copper in liquid ammonia. Yellow-brown shades on zinc. — Rub with solution of chloride of copper in vinegar. Browning gun barrels. — Apply a mixture of equal parts of butter of antimony and olive oil. Allow the mixture to 524 APPENDIX. act for 12 or 14 hours, then remove the excess with a woolen rag, and repeat the application. When the second application has acted for 12 to 24 hours, the iron or steel will be coated with a bronze-colored layer of ferric oxide "with antimony, which resists the action of the air, and may be made lustrous by brushing with a waxed brush. A lustrous black on iron is obtained by the application of solution of sulphur in spirits of turpentine prepared by boiling upon the water-bath. After the evaporation of the spirits of turpentine a thin layer of sulphur remains upon the iron, which on heating the article immediately combines with the metal. A lustrous black is also obtained by freeing the iron articles from grease, pickling, and after drying, coating with sulphur balsam,* and burning in at a dark-red heat. If pickling is omitted, coating with sulphur balsam and burning-in must be twice or three times repeated. The same effect is produced by applying a mixture of three parts flower of sulphur, and one part graphite with turpentine and heating in the muffle. According to Bottger a durable blue on iron and steel may be obtained by dipping the article in a ^ per cent, solution of red prussiate of potash mixed with an equal volume of a ^ per cent, ferric chloride solution. A brown-black coating with bronze luster on iron is ob- tained by heating the bright iron objects and brushing them over with concentrated solution of potassium bi- chromate. When dry, heat them over a charcoal fire, and wash until the water running off shows no longer a yellow color. Repeat the operation twice or three times. A sim- ilar coating is obtained by heating the iron objects with a solution of 10 parts by weight of green vitriol and 1 part of sal ammoniac in water. * Sulphur dissolved in linseed oil. COLORING OF ALLOYS. 525 To give iron a silvery appearance with high luster. — Scour the polished and pickled iron objects with a solution prepared as follows : Heat moderately i ^ ozs. of chloride of antimony, 0.35 oz. of pulverized arsenious acid, 2.82 ozs. of elutriated bloodstone with 1 quart of 90 per cent, alco- hol upon a water-bath for half an hour. Partial solution takes place. Dip into this fluid a tuft of cotton and go over the iron portions, using slight pressure. A thin film of arsenic and antimony is thereby deposited, which is the more lustrous the more carefully the iron has previously been polished. O11 tin a bronze-like patina may be produced by brush- ing the object with a solution of 1^ ozs. of blue vitriol and a like quantity of green vitriol in 1 quart of water, and moistening, when dry, with a solution of 3^2 ozs. verdigris in 10^2 ozs. of vinegar. When dry polish the object with a soft waxed brush and some rouge. The coating thus ob- tained is, however, not very durable, and must be pro- tected by a coat of lacquer. Warm sepia-brown tone upon tin and its alloys. Brush the object over with a solution of 1 part of platinum chlor- ide in 10 parts of water, allow the coating to dry, then rinse in water, and after again drying, brush with a soft brush until the desired brown luster appears. The coating is quite durable. Oxidizing silver. A blue-black color is produced by placing the articles in a solution of liver of sulphur diluted with spirits of sal ammoniac. Allow to remain until the desired dark tone is produced, then wash, dry and polish. A brownish tint is obtained by using a solution of equal parts of sulphate of copper and sal ammoniac in vinegar. A yellow color is imparted to silvered articles by immer- sion in a hot concentrated solution of chloride of copper, rinsing and drying. 526 APPENDIX. Recovery of Waste Metals. Gold. Besides dust, the sweepings accumulating in gold workers' shops contain gold and silver as well as other metals alloyed with the gold or silver. To obtain the gold and silver proceed as follows : Burn the sweepings, with the addition of some saltpetre, in a red-hot crucible, lixiviate the residue with water, dry- it, and melt it with an addition of 2 per cent, of dehydrated borax. Dissolve the metallic mass thus obtained in aqua regia. The precipitate formed thereby consists of chloride of silver, and is worked into silver. The solution in aqua regia is then evaporated until it commences to become vis- cous. It is now diluted with water, and a bright sheet of copper immersed in the fluid whereby the gold in solution separates in the form of a brown powder, which is filtered off, washed, dried, and melted with a small quantity of borax, the product obtained being chemically pure gold. The precipitate of chloride of silver, mentioned above, is filtered off, thoroughly washed with water, and brought into a ves- sel. Water compounded with 10 per cent, of hydrochloric acid is then poured over it, and a sheet of zinc immersed in the fluid. After some time the chloride of silver is thereby converted into a gray powder of metallic silver, which is filtered off, washed with distilled water, dried, and melted with a small quantity of borax. The water used by the workmen in gold-workers' shops for washing their hands contains gold and silver. The water is collected in a tank, and from time to time drawn off from the sediment. When a sufficient quantity of the latter has accumulated, it is dried, the residue mixed with 5 per cent, of saltpetre, the mass decrepitated in a red-hot crucible, washed with water, dried, and melted with a small quantity of borax. The metallic mass thus obtained is treated in the same manner as that from the sweepings. For the recovery of gold from coloring baths a solution of two parts by weight of ferrous sulphate (green vitriol) RECOVERY OF WASTE METALS. 527 in 18 parts by weight of hot water, may be used. The waste water as well as the exhausted coloring salts should be preserved in a large stone-ware jar kept for the purpose. Add the solution of ferrous sulphate to the contents of the jar and stir well, when the gold will begirt to precipitate. Repeat this each time after coloring, and as the jar becomes full add a little more ferrous sulphate and thoroughly stir the contents. If this produces no effect upon the solution the gold has all been precipitated. Now allow to settle, and then draw off the supernatant water, being very careful not to disturb the precipitate, which forms a dark spongy mass at the bottom. Wash the precipitate several times with hot water to free it from every trace of acid, then dry it in an iron vessel, and then fuse it in a covered crucible with a flux, which for i lb. of prepared sediment consists of carbonate of potash, 8 ozs. ; common salt, 4 ozs. ; common bottle glass, 4 ozs. Reduce all the ingredients to a fine powder and mix them well together. In order to effect a complete reduction of the gold great heat is required. According to Boettger, gold may be recovered from aurtfefotis fliudsby the following process : Heat the fluid in a porcelain vessel to the boiling-point, and then mix it with sodium stannate solution. Keep the mixture boiling until all the gold — in combination with tin — is separated in the form of a fine precipitate of an intense black color. This precipitate is washed and then dissolved in aqua-regia. The solution thus obtained consists of a mixture of chlor- ide of gold and chloride of tin. By slightly evaporating the solution, diluting with distilled water, mixing with a suffi- cient quantity of potassium and sodium tartrate (Rochelle salt), and heating, every trace of gold is precipitated in the form of a very delicate, brownish powder, while the tin re- mains in solution. Recovery of gold from old cyanide solutions. — Evaporate the solution to dryness, reduce the residue to a fine powder, mix it intimately with an equal weight of litharge (oxide of 528 APPENDIX. lead), and fuse at a strong heat. From the resulting button of gold and lead alloy, the lead is extracted by warm nitric acid, the gold remaining behind as a loose, spongy mass. By the wet process the gold may be recovered from old cyanide solutions as follows : Acidulate the solution, which contains gold, silver and copper, with hydrochloric acid, whereby hydrocyanic acid is disengaged. This gas being extremely poisonous, the operation should be carried on in the open air, or where there is a good draught or ventila- tion to carry off the fumes. A precipitate consisting of the cyanides of gold and copper and chloride of silver is formed. This is well washed and boiled in aqua-regia, where the gold and copper are dissolved as chlorides, while the chloride of silver is left behind. The solution contain- ing the gold and copper is evaporated nearly to dryness in order to remove the excess of acid, the residue is dissolved in a small quantity of water, and the gold precipitated therefrom as a brown metallic powder by the addition of ferrous sulphate (green vitriol). The copper remains in solution. Finely divided zinc — so-called zinc dust — is an excellent agent for precipitating gold in a pulverulent form from old cyanide solutions. By adding zinc dust to an exhausted gilding bath and thoroughly shaking or stirring from time to time, all the gold is precipitated in two or three days. The quantity of zinc required for the precipitation depends of course on the quantity of gold present, but, generally speaking, yi lb. or at the utmost 1 lb. of zinc dust will be required for 100 quarts of exhausted gilding bath. The pulverulent gold obtained is washed, treated first with hydrochloric acid to remove adhering zinc dust, and next with nitric acid to free it from silver and copper. Separating silver. — Dissolve the alloy or metal contain- ing silver in the least possible quantity of nitric acid. Mix the solution with a large excess of ammonia and filter into a tall glass cylinder provided with a stopper. Introduce RECOVERY OF WASTE METALS. 529 into the liquid a bright strip of copper, which should be long enough to project above the liquid. Pure metallic silver will be quickly separated. Reduction is complete in a short time, and the reduced silver is then washed first with ammoniacal solution and next with distilled water. The more ammoniacal and concentrated the solu- tion, the more rapid the reduction. The strip of copper should not be too thin, as it is considerably attacked, and any little particles which might separate from a thin sheet would contaminate the silver. Any accompanying gold remains behind during the treatment of the metal or alloy with nitric acid ; chloride of silver, produced by im- purities in the nitric acid is taken up by the ammoniacal solution like the copper, and is also reduced to the metallic state, and whatever other metal is not left behind, oxidized by the nitric acid, is separated as hydrate on treating with ammonia. Any arseniate which may have passed into the ammoniacal solution is not decomposed by the copper. Recovery of silver from old cyanide solutions. — The solu- tion may be evaporated to dryness, the residue mixed with a small quantity of calcined soda and potassium cyanide and fused in a crucible, whereby metallic silver is formed which, when the heat is sufficiently increased, will be found as a button upon the bottom of the crucible ; or if it is not desirable to heat to the melting point of silver, the fritted mass is dissolved in hot water, and the solution containing the soda and cyanide quickly filtered off from the metallic silver. According to the wet method the old cyanide solution is strongly acidulated with hydrochloric acid, observing the precaution to provide for the effectual carrying-off of the hydrocyanic acid liberated as given under gold. Remove the precipitated chloride of silver and cyanide of copper by filtration and after thorough washing, transfer it to a porcelain dish and treat it, with the aid of heat, with hot hydrochloric acid, which will dissolve the cyanide of copper. 34 530 APPENDIX. The resulting chloride of silver is then reduced to the metallic state by mixing it with four times its weight of crystallized carbonate of soda and half its weight of pulver- ized charcoal. The whole is made into a homogeneous paste which is thoroughly dried, and then introduced into a strongly heated crucible. When all the material has been introduced the heat is raised to promote complete fusion and to facilitate the collection of the separate globules of silver into a single button at the bottom of the crucible, where it will be found after cooling. If granulated silver is wanted, pour the metal in a thin stream, and from a cer- tain height, into a large volume of water. ■ Utilization of nickel waste. — For the utilization of waste from rolled and cast nickel anodes, and of the nickel sand gradually collecting upon the bottoms of vats used in plat- ing, the following method is recommended : Wash the waste repeatedly in clean, hot water, and then boil in dilute sulphuric acid ( i part acid to 4 parts water) until the water poured upon the waste is no longer clouded by it. Then pour off the liquid, and treat the waste or sand with con- centrated nitric acid. This must be done very carefully, and a capacious porcelain vessel should be used to prevent the solution from running over. When the solution is sufficiently concentrated, so that it contains little free acid, it should be filtered and slowly evaporated to dryness over a water-bath. The product is nickel nitrate. This nickel nitrate is dissolved in hot distilled water, and the^ solution precipitated with caustic soda carefully and gradually added. The precipitate of hydrated nickel oxide is then carefully filtered and washed, and next treated with dilute sulphuric acid with the assistance of heat until solution has taken place. The solution is concentrated by evaporation, and an excess of concentrated solution of ammonium sulphate is added. The precipitate is the double sulphate of nickel and ammonium, or Adams' nickel-plating salt, which is commonly used for nickel-plating. RECOVERY OF WASTE METALS. 53 1 Recovery of copper. — In works where great quantities of copper are operated upon, it is advantageous to recover the metal dissolved in the cleaning baths, which can be done by an easy and inexpensive process. All the liquids holding copper are collected in a large cask filled with wrought or cast-iron scraps. By the contact of the copper solution with the iron a chemical reaction immediately takes place, by which the iron is substituted for the copper to make a soluble salt, while the copper falls to the bottom of the cask as a brown powder. The cask should be of sufficient capacity to hold all the liquids employed in a day's work. The liquids are decanted every morning. The old iron scrap is generally suspended in a wicker basket near the top of the liquid, and by occasionally moving it about in the liquid, the metallic powder of copper alone falls to the bottom of the cask. The copper thus obtained is quite pure, aud by calcining it in contact with the air a black oxide of copper is obtained. To separate silver fro?n copper. Boil the metal in a mix- ture of sulphuric acid, nitric acid and water, of each i part, until it is completely dissolved, adding fresh liquid from time to time as the action ceases. When solution is com- plete throw in a little common salt dissolved in water, stir vigorously, and allow the precipitated salt to settle. When no more precipitate is formed by the addition of salt water, allow to settle, collect and wash the precipitate on a filter, and fuse in a crucible. Recovery of tin from tin-plate waste. Treat the waste with dilute chlorine at a temperature above the boiling- point of chloride of tin, so that the latter immediately after its formation is carried aw r ay in the form of vapor, since if it remains in the form of fluid in contact with the residues, it gives rise to the formation of chloride of iron, chloride of tin being reduced. The vapors of chloride of tin are pre- cipitated by steam or by contact with moist surfaces in roomy condensing chambers, or are absorbed by chloride of tin solution of medium concentration. 532 APPENDIX. Another method is as follows : Bring the waste into con- tact with sulphur in a boiling-hot solution of sodium sul- phide, whereby the iron is completely freed from tin. The waste thus freed from tin is thoroughly washed and dried, heated to a welding heat in tubes of rolled iron, taken out and hammered into rod iron. The solution of sodium sulphide holding the tin is evaporated, the residue calcined in a reverberatory furnace, and the calcined mass reduced to tin, at a raised heat, by means of a mixture of small coal, charcoal, and calcined soda, or burnt lime. To separate lead from zinc. Melt the alloy. The spec- ifically heavier lead collects in the lower portion of the cru- cible while the lighter zinc stands over it and can be poured off. Recovery of brass from a mixture of iron and brass turn- ings. This may be effected by means of magnets which attract the iron and steel turnings while the brass remains behind. The same object may be attained in a very simple and economical manner by a melting process. Mix the iron and brass turnings and the slag from brass-casting with limestone, powdered coal and ferric oxide, and melt the mixture, whereby the brass separates from the liquid slag formed, settles on the bottom and is run off into ingot moulds. INDEX. ABEL, C. D. 407-410 alloys patented by, Aicb's metal, 157, 158 Ajax metal, 301 Alchemy, influence of, upon chemistry, 3,4 Alfenide, 318 Algiers metal, 231 Alkalies, metals of the, 23, 24 Alkaline earths, metals of, 24 Allevard steel, 395, 396 Alloy, additional increase in the strength of an, by the addition of a third metal, 97-99 change in the properties of an, by remelting and renewed cooling, 67 constitution of an, 5, 6 definition of an, 1 eutectic, 62 for type metal, 357 non-oxidizable, 463 resisting the action of vegetable acids, 319 Sorel's, 191, 192 steels, 388-403 very fusible, 387 which expands on cooling, 467, 468 Alloys, actual constitution of, 8 behavior of, in cooling, 63 casting capacity of, 107-116 color of, 118-121 coloring of, 510-525 condensation in, 70 conductivity for heat and electricity of, 116-118 crystallization of, 93, 94 crystallizing power of, 5 crystals of, 7 separated from, 6 determination of the constituents of, 498-509 development of gases in casting, 113-115 division of, according to specific gravities, 91-93 ductility of, 104-106 earliest historical data in reference to, 2 (533) Alloys, early preparation o 1 ', 4 effect of degree of fluidity of, in casting, 112 expansion in, 70 flexibility of, 104-106 formation of, 9, 10 without fusion, 11 fusible, 112 melting points of, 380, 381 general properties of, 62-127 hardness of, 101-104 historical order of, 3 liquation of, 62-69 metals principally employed for, 134 miscellaneous, 463-475 new method of preparing, 463, 464 of copper with other metals, 277- 283 mercury and other metals, 445- 462 platinum and platinum metals, 433-444 oldest, 2 preparation of, in general, 128-136 protective cover in remelting, 463 remelting of, 132 resembling silver, 420, 421 resistance of, to calcium hydrate, 507 to chemical influences, 121-127 shrinkage of, 115, 116 specific gravity of, 70-93 strength of, 95-101 variation in, 8 very fusible, 380 which can be filed, 281 Alpaka. 307 Aluminium, 17, 24-28 action of, upon brass, 351 alloy for dentists' fillings, 357 type metal, 357 alloving power of, 338 alloys, 338-3U5 of, with the precious metals, properties of, 339 production of, 338, 339 brass, 351-353 534 INDEX. Aluminium brass, tests of, 353 uses of, 352, 353 bronze, 341-351 alloy, 358 brazing of, 359, 360 casting of, 345-349 dilution of a high per cent., to a lower one, 344 forging of, 349 melting point of, 342 preparation of, 342-344 rolling of, 349, 350 soldering of, 3(50, 361 tests of, 350, 351 -chromium alloy, 358 commercial, analyses of, 27 conductivity of heat of, 25 -copper alloys, 341-351 elongation of, 100 strength of, 96 distribution of, 26 effect of iron on, 27 on metals, 27, 28 electric conductivity of, 25 -gold alloys, 424 solder, 491 increase in the strength of copper by an addition of, 96 -iron alloys, 339, 340 -magnesium alloy, 358, 359 -nickel bronze, 357, 358 -copper alloys, 354-356 preparation of, 26, 27 reduction of, by electrolysis, 26, 27 soldering of, 361-365 specific heat of, 25 -steel. 340, 341 -tin alloy, 359 titaniferous, behavior of, 49 -titanium alloys, 48, 49 Amalgam, definition of an, 1 Amalgams, 445-462 early use of, 3 American anti-friction metal, 301 sleigh bells, alloy for, 474 Anatomical preparations, bismuth amal- gam for, 459. 460 Andrews, G. F. , alloys recommended by, 357 Anti-friction brasses, alloy for, 300 metal, 301 for hydraulic ma- i chinery, 300 metals, table showing com- positions of, 302-305 Antimony, 57, 58 alloys of, with g^old, 424 -bismuth alloys, specific gravities of, 81 82 | Antimony, effect of, on brass, 149, 150 lead, 366 increase in the hardness of lead by alloying with, 103 indication of, 498 -lead alloys, specific gravities of, 82, 83 -tin alloys, specific gravities of, 80,81 -zinc alloys, crystallization of, 94 Aphtit, 316 Arabs, development of chemistry by the, 3 use of amalgams by the, 3 Argentan, 312-315 solder, 484-486 Argent-Kuolz, 407 Argiroide, 318 Arguzoid, 316 Arnold, Prof , bending tests of vana- dium-steel by, 398, 3d9 Arsenic, 58, 59 alloys of, with gold, 424 determination of, 503, 504 effect of, on bronze, 204 lead, 366 Art-bronze, furnace for melting, 266, 267 melting and casting, 266, 267 moulds for casting, 267 bronzes, 258-267 Ashberry metal, 293 Atomic weight. 21 weights, 135 Austrian Northwest Railroad, white metal bearings used by, 297 Autogenous soldering, 477 Axle-boxes for locomotives and cars, alloy for, 300 BABBITT'S anti-friction metal, 298, 299 Barium, 17 Base metals, 16 alloys of platinum with, 439-441 Bath metal, 192 Bearing metal, Dulevie and Jones', 281 palladium, 442 metals, 294-305 analyses of, 301, 302 cheaper, 280 Bearings, alloys for, 238, 239 _ composition of white metals for, 298 white metals for, 298 Bell-metal, 226-231 additions of other metals to, 227 melting and casting of, 228, 229 INDEX. 535 Bell-metal, properties of, 228 metals, composition of some, 229, 280 Bells, disagreeable tone of, 229 early use of, 226 large, weight of some, 227 moulds for casting, 231 Berlin alloys, composition of, 182 Railroad, white metal bearings used by, 296, 297 Berthier's alloy, 308 Biddery metal, 292, 293 Binding wire, 477 Birmingham platinum, 191 Birr Castle, Ireland, telescope mirror at, 244 Bismuth, 57 alloy for cementing glass, 386 alloys, 382-387 for delicate castings, 386 -amalgam, 458, 459 -antimony alloys, 383 -bronze, 315 -copper alloys, 382 effect of, on copper, 140 flexibility of metals, 106^ -gold alloys, specific gravities of, 89,90 group, 57, 58 indication of, 498 -iron alloys, 383 -lead alloys, 383, 387 specific gravities of, 88, 89 _ -tin alloys, fusing tempera- tures of, 386 -silver alloys, specific gravities of, 88 solder, 480 -tin alloys. 382, 383, 387 -lead alloys, 384 Black bronze, 472 Blanching, 415, 416 Block tin, 46 Bobierre's metal, 157 Borax, 130 Bourbouze's aluminium solder, 362 Brass, action of aluminium upon, 351 bronze substitute for, 240 bronzing of, 521, 522 liquids for, 516 cast. 151-153 casting of, 172-179 change in the molecular structure of, 147 cleaning or pickling of, 179-181 coloring of, 520, 521 Brass, composition of, 144 crystalline structure of, 145 dull, lustreless surface on, 180 early manufacture of, 142 effect of an addition of tin on, 148 for sheet and wire, composition of, 151 furnaces, 165-170 for the fusion of, directly upon the hearth, 170, 171 gold color on, 518, 519 improved hard solder for, 484 ingots, casting of, 173, 174 introduction of the manufacture of, 143, 144 iridescent coatings on, 518 Japanese, 151 lustrous gray or black on, 517, 518 malleable, 155, 156 manufacture of, 163-179 by direct fusion of the metals, 165- 172 with the use of zinc ores, 163- 165 melting point of, 147, 148 moulds for casting, 173, 174 pickles for, 179, 180 plate, casting of, 174-179 properties, manufacture, and uses of, 143-181 recovery of, from a mixture of iron and brass turnings, 532 sheet, 149-151 production of, 176, 177 silver color on. 519 solder, 487 solder, 480-484 preparation of, 481-483 soldering of, 494 strength of, 147 superiority of German silver to, 309 table showing the properties of, as affected by its composition, 149 testing of, 504, 505 tough, for tubes, 153, 154 use of old copper in the manu- facture of, 148 very ductile, 147 Brazing aluminium bronze, 359. 360 Bristol brass, 155 Britannia metal, 287-292 composition of several varieties of, 288, 289 preparation of, 289, 290 536 INDEX. Britannia metal, properties of, 287, 288 shaping of, 290, 291 testing of, 505 Brocade, 189, 190 Bronze age, 201 basin, Turkish, 2G5 behavior of, towards the atmos- phere, 212 black, 472 castings, defective, 241 change in the molecular structure of, 206, 207 Chinese, 203 color, brown, 522 green, 522 definition of, 201, 202 deoxidized, 162 derivation of the term, 201 different kinds of, 216-219 difficulty in obtaining perfect cast- ings of, 208, 209 ductility of, 205, 206 early use of, 3, 141,142 effect of admixtures on, 203, 204 eutectic alloy of, 212 for articles exposed to shocks and very great friction, 239 ship-sheathing, 235, 236 small castings, 234 telephone lines, 253, 254 valve balls. 239, 240 formation of blisters and pores in, 241 fused, effect of cooling on, 204, 205 furnaces for melting, 214-216 imitation, 183 in general, 201-212 iridescent coatings on, 518 lustrous gray or black on, 517, 518 melting and casting. 212-216 moulds for casting, 241 poling of, 240, 241 powders, 188-190 preparation of large quantities of. 213, 214 resisting acids, 467 action of the air, 240 securing the greatest strength of, 207 -sheet, crystallization of, 146 statuary, alloys of different colors suitable for, 262 table of density and composition of, 207, 208 testing of, 50), 506 to be gilded, 235 upon French bronze figures, 514- 516 Bronze, use of, as a substitute for iron, 237 variations in the color of, 205 weapon, antique. 265 Bronzes. Chinese, 263, 264 deterioration of, by remelting, 240, 241 Fontainemoreau's, 192, 193 for various purposes, 231-244 Japanese, 265 melting points of, 208 prehistoric, 216-219 properties of, 202. 203 strength and hardness of, 206 tendency towards liquation of, 211 Bronzing liquids, 516, 517 Brunswick, Germany, telescope mirror at, 244 Buttons, alloys for, 191, 192 C ADMAN, A. W., Babbitt ' metal patented by, 299 Cadmium, 40-42 alloving power of, 41 alloys, 378-381 constancy of, 381 -amalgam, 41, 42, 455, 456 -bismuth alloys, specific gravities of, 87 determination of, 503 -lead alloys, specific gravities of, 87,88 properties of, 41 pure metallic, preparation of, 40, 41 Calcium, 17 Calico-printing rollers, alloys for, 469- 471 Calin, 463 Camelia metal, 301 Cannon, early use of bronze for casting, 219 old, use of. in casting ordnance, 224 Carats and grains, conversion of, into thousandths, 428 Car-axle-boxes, alloy for, 300 -box metal, 301 -brasses, metal for lining, 301 Carbon. 60, 61 absorption of, by iron, 11 -bronze, 301 effect of, on iron, 389 Carty, specific gravities of bismuth-lead alloys ac- cording to, 88,89 tin-b i s m uth alloys ac- cording to, 83,84 INDEX. 537 Cassiterite, 45 Cast-brass, 151-153 fine, 153 French, for fine castings, 154 ordinary, 152, 153 -iron, 61 silver solder for, 489 Casting aluminium bronze, 345-349 brass, 172-179 capacity, 107-116 development of gases in, 113-115 plate brass, 174-179 shot, 372-376 small articles, alloy for, 474 Castings, delicate, bismuth alloys for, 386 small, bronze for, 234 Celestite, 17 Charpy's experiments with zinc-copper alloys, 97 investigations of copper-zinc alloys, 143 Chemical combination, definition of a, 21 formulas, 22 influences, resistance of alloys to, _ 121-127 Chemistry, development of, by the Arabs, 3 influence of alchemy upon, 3, 4 preparation of alloys, a branch of, 4 China silver, 307 Chinese bronze, 203 bronzes, 263, 264 metal mirror, 244 tam-tams or gongs, 230, 231 Chisels, alloys for, 465 Cliristophle metal, 307 Chrome steel. 391-393 Chromium, 37 experiments showing influence of vanadium on, 4u3 indication of, 501 Chrysochalk. 183 Chrysorin, 154, 183 Church bells, introduction of, 226, 227 Cinnabar. 53 Clark's patent .alloy, 421 Cleaning brass, 179-181 Cliche metal, 380, 383, 384 Clock-bells, small, alloy for, 230 Cobalt, 34, 35 alloying power of, 35 bronze. 282 indication of, 501 naturally occurring compounds of, 34 Coin bronze, 232, 233 Coinage, silver-zinc alloys for, 406 Coins, gold, fineness of, 429 manganese brass for, 281 silver, composition of, 413, 414 Swiss fractional, 411 use of nickel for, 37 Cologne, weight of large bell in, 227 Color of alloys, 118-121 Coloring of alloys, 510-525 Colors, temperatures corresponding to different, 14 Common salt solution, formation of ice in a, 62, 63 Compensation balances, alloy for, 471. 472 Conductivity for heat and electi'icity, 116-118 Copper's mirror metal, 441 pen metal, 441 Copper, 52, 53 alloying power of, 53 -alloys, 137, 200 most important, 140 of, with base metals, 141, 142 other metals, 277- 233 -amalgam, 450, 451 and much zinc, alloys of, 280 -antimony alloys, 282, 283 melting tempera- tures of, 111 -arsenic alloys, 277 black on, 514 blue-black on, 514 -gray on, 514 bronzing liquids for, 517 of, 514, 521, 522 brown color on, 513 browning liquid for, 520 -cobalt alloys, 281, 282 commercial, sources of, 140 conductivity of, 117 early alloys of, 2 effect of foreign bodies on, 137- 140 silicon on, 251 flexibility of, 105 formation of cuprous oxide in, 8 -gold alloys, 140. 141 specific gravities of, 78 increase in strength of, 96 of, by an addition of aluminium, 96 of, by an addition of zinc, 97 538 INDEX. Copper, indication of, 499 -iron alloys, 27S, 466 Japanese, 417 -lead alloys, 277, 278 liquation of,"69 -magnesium alloys, 282 matt-black on, 514 melting point of, 108 -nickel-silver alloys, 322, 323 old, use of, in the manufacture of brass, 148 recovery of, 531 red-brown on, 513, 522 separation of silver from, 531 -silver alloys, 141 resistance of, to chemical influ- ences, 125 specific gravities of, 77, 78 wear of, by abrasion, 103 soldering of, 494 -steel, 279, 280 tensile strength of, 275, 276 test for the quality of, 150, 151 -tin alloys, 201, 276 crystallization of, 93 determinations of the specific gravities of, 71-76 hardness of, 102 liquation of, 68 resistance of to acids and salts, 123 strength of, 99, 100 table of mechanical and physical properties of, 267-273 -nickel alloys, with or without zinc. 322 -tungsten alloys, 281 varying intensity of coloration pro- duced by, 119", 120 -zinc alloys, 142-'_00 behavior of, 144, 145 crystallization of, 93, • . 94 influence of sea-water upon, 123, 124 liquation of, 69 melting temperatures of,_109 physical properties of, 145-149 resistance of, to acids and salts, 123 specific gravities of, 76,77 Copper-zinc alloys, table of the properties of. 193-197 _ -nickel alloys, composition of. ■ 320, 321 -iron allovs, composi- tion of, 321, 322 -lead alloys, composi- tion of, 321 -tin alloys, influence of sea- water upon, 123, 124 Cornish bronze, 301 Crucible furnace, revolving, 169, 170 Crucibles, 128, 129 for melting brass, 166, 167 furnaces for, 165-170 Crystallization. 93, 94 Cuivre-fume, 514 Cupro-manganese, preparation of, 254-. 256 properties of, 256 Cuprous oxide, effect of, on copper, 138 formation of, in copper, 8 Cutting tools, hard alloys for, 333 Cymbals, early use of, 226 DAMASCUS bronze, 301 D'Arcet's fusible alloys, 385 gilding metals, 155 Dead-head. 221 Dechenite, 43 Delalot's alloy, 420 Delta metal, 159-161 strength of, 98 Dentists' fillings, aluminium alloy for, 357 Deoxidized bronze, 162 Dewrance^ patent bearing for loco- motives, 300 Dutch leaf, 186-188 Dienett's German silver, 317 Drilling tools, hard alloys for, 333 Drills, alloys for. 465 Dronier's malleable bronze, 452 Ductility, 104-106 Dudley, C. B. . investigations of bearing metals by, 301, 302 Dulevie and Jones' bearing metal, 2S1 Durano metal, 161 Dutch gold, 186-188 EGYPTIAN metal mirror, 244 Electric furnace, Moisson and Violle's,47, 48 of Deutsche GoldundSil- berscheide- anstalt, 50, 51 INDEX. 539 Electricity and heat, conductivity of alloys for, 116-118 Elements, classification of, 12 combination of, 135 groups of, 12 names, symbols and atomic weights of, .21," 22 Enameled work, solders for, 490 England, introduction of the manu- facture of brass in, 144 silver-copperalloys employed in, for manufacturing purposes, 414, 415 English metal, 293, 294 process of manufacturing German silver,.327-329 sterro-metal, 158, 159 type metals, 368 white metal, 300 ordinary, 192 Erfurt, weight of large bell in, 227 Erhart's type metal, 369 Erythrine. 31 Eutectic alloy, 62 lead-tin alloy, 66 silver copper alloy, 65, 66 Evans's metallic cement, 456 Ex. B. metal, 301 PAHLUN brilliants, 285 Fat, use of, in melting metals, 130 Fenton's alloy for ade-boxes for loco- motives and cars, 300 Ferro-chrome, preparation of, 391, 392 -cobalt, malleable, 466, 467 -German silver, 316 -manganese, 390, 391 -nickel, 466, 467 production of, 335, 336 -tungsten, 393, 394 Fire-gilding, 448-450 early knowledge of, 3 gold amalgam for, 447 Fireworks, magnesium alloys for, 29, 30 Fleitman, Dr., process of, for refining and toughening nickel, 36 Flexibility, 104-106 Fluidity, 112 Flutes, alloy for keys of, 370 Flux for hard soldering, 489, 493, 494 Fontainemoreau's bronzes, 192, 193 Forging aluminium bronze, 349 Foundry pig, 389 French bronze figures, bronze upon, &14-516 ordnance, analyses of, 68 oreide, 184, 185 silver solder, 487 type metals, 368 Frishmuth's aluminium solder, 362 Furnace for melting art-bronze, 266, 267 platinum. 433, 434 reverberatorv, for wood-firing, 177 used by gold-ware manufacturers, 426. 427 Furnaces, brass, 165-170 for heating German-silver sheet, 329-332 melting bronze, 214-216 gun-metal 222-224 Fusible alloys, 112 amalgams of the, 456, 457 D' Arcet's, 385 melting points of, 380, 381 GALLIUM, 42 Gases, development of, 113-115 origin of, 114 Gedge's alloyforship-sheathing,158,159 Geitner, Dr., invention of argentan by, 307 General properties of alloys, 62-127 German admiralty specifications for Babbitt metal, 299 process of manufacturing German silver, 325-327 silver, 312-315 additions to, 310, 311 alloy resembling. 463 analyses of, 313, 314 foil, "329 invention of, 307 manufacture of, 324-332 mechanical manipulation of, 312 sheet, manufacture of. 329-332 substitutes for, 315-319 superiority of, to brass, 309 testing of, 506 Germany, introduction of the manu- facture of brass in, 144 Gilding metals, D'Arcet's, 155 spurious. 455 Glass, 130 bismuth alloy for cementing, 386 globes, amalgams for silvering, 459 pressed, alloy for moulds for, 463 Godfrey's silver-zinc alloys, 405, 406 Gold, 55, 56 alloys, 422-432 colors of, 429 melting temperatures of, 109 preparation of, 424-427 by the galvanic process, 432 proportions of various metals . incorporated in, 430, 431 standards of, 427 540 INDEX. Gold alloys, use of. 428-432 which can be legally used in various countries, 430 -aluminium alloys, 424 properties of, 339 solder, 363 amalgam, 446-448 containing silver, 447, 448 for fire gilding, 447 native, 448 behavior of lead towards, 423 bronze, 234, 235 coins, composition of, 141 fineness of, 429 colored, 431 coloring finished articles of, 432 power of, 121 -copper, 183 alloys, 423 flexibility of, 106 liquation of, 69 early alloys of. 2 granulated. 427 group, 55-57 increase in the strength of, by alloying, 97 -iron alloys, 423 -like alloy, 472, 473 -palladium alloys, 424 recovery of, by the wet process, 528 from auriferous fluids, 527 cyanide solutions, 527, 528 wash-water, 526 scrap, remelting of, 427 separation of silver from. 528, 529 -silver alloys, 423 crystallization of, 94 liquation of, 69 resistance of, to chemical influences, 125 solders, 489-491 -tin alloys, crystallizations of, 94 -ware manufacturers, furnace used by, 426, 427 testing of, 506, 507 waste recovery of, 526-528 wires, strength of, 98 Gongs, Chinese, 230. 231 Graham's bronzing liquids, 516, 517 Grain tin, 46 Graney bronze, 301 Granite moulds for plate-brass, 175, 176 Granulated gold, 427 Graphite, CO -bearing metal, 301 Gray gold, 423 Gray pig iron, 389 Greek coin-bronze, 233 Greeks, knowledge of the art of mixing metals by the, 2 use of amalgams by the, 3 Green gold, 423 Greenockite, 40 Guettier's button metals, 192 Gun-barrels, browning of, 523, 524 -metal, 219-226 effect of casting temperature on, 224. 225 furnaces for melting, 222-224 properties of good, 220, 221 HALF- WHITE solder," 481 -yellow solder, 481 Hamilton's metal, 154 Hampe's researches on the effect of ad- mixtures on copper, 139, 140 Hard silver solder, 487 soldering fluid, 493 flux for, 4S9 solders, 480-486 Hardness, 101-104 determination of the degree of, 102 Harrington bronze, 301 Heat and electricity, conductivity of alloys for, 116-118 development oi, in alloying metals, 10,11 Heavy metals, 16, 30, 59 groups of, 18, 19 Helouise's investigations of the effect of vanadium on steel, 397, 398 Henniger Bros. , invention of Neusilber by, 307 Holland, John, process of, for making phosphor-iridium, 443 Holzmann,specificgravities of antimony- bismuth alloys ac- cording to, 81, 82 bismuth-gold alloys according to, 89, 90 bismuth-silver al- loys according to, 88 . cadminm-lead al- loys according to, 87,88 tin-gold alloys ac- cording to, 86 tin-mercury alloys according to, 90, 91 tin-silver alloys ac- cording to, 84, 85 INDEX. 541 Homestead, Pa., preparation of nickel- steel at, 336 Hoper's phosphor-bronze, 250 Hoyle's patent alloy for pivot bearings, 300 Hydraulic machinery, anti-friction metal for, 300 ILLUMINATING purposes, pyro- phorous alloys for, 473 Imitation bronze, 183 Indium, 42 -gallium alloys, 464, 465 Iridium-osmium alloy, 442 -steel, 442 Iron, 30-33 absorption of carbon by, 11 nickel by, 11 addition of, to German silver, 310, 311 affinity of, for lead, 366 alloying power of, 32 alloys, 388-403 technical importance of, 33 amalgam, 457. 458 and brass turnings, recovery of brass from a mixture of, 532 blue on, 524 brown-black coating with bronze luster on, 524 chemically pure, preparation of, 31, 32 cold-short, 20 commercial, 1, 388 constitution of, 31 derivation of substances which com- bine with, 388 determination of, 509 effect of, on aluminium, 27 on bronze, 204 on copper, 138 phosphorus on, 61 group, 30-38 hot-short, 20 increase in the hardness of, 103, 104 influence of carbon on, 60, 61 lustrous black on, 524 -manganese alloys, crystallization of, 94 most important constituent of, 389 native, 30, 31 pure, 20 red-short, 20 reduction in the melting tempera- ture of, U8 - silvery appearance with high luster on. 525 solution of, in zinc, 33 Iron-tin alloys, crystallization of, 94 use of bronze as a substitute for, 237 varieties of, 389 with chromium, tungsten, molyb- denum, alloys of, 465, 4C6 JAPANESE brass, 151 bronzes, 265 remarkable series of alloys of, 416-419 Jewelers, proportions of various metals incorporated in gold alloys used by. 430, 431 Jewelry, soldering of, 496, 497 Joujou gold, 429 KAPFENBEEG ferro-chrome, 392 Kalischer, S., researches of, in regard to metals becoming crys- talline, 145-147 Karmarsch, brass solders, according to. 484 determinations of specific gravities of copper-silver alloys by, 77, 78 . investigations of Britannia metal by, 289 Kerl on the effect of antimony on brass, 150 Keys of flutes, alloy for, 370 Kilogrammes, alloy for, 435 King crucible, 167 Kingston's metal, 300 Kuromi, 417, 418 LACQUERS, table of, 510, 511 Lancon's aluminium solder. 362, 363 Langley, J. W. , on aluminium-steel, 340, 341 Lead, 51, 52 addition of, to German silver, 314, 315 alloying power of, 52 alloys, 366-377 -amalgams, specific gravities of, 91 behavior of, towards gold, 423 detection of, in tin, 508 determination of, 502 effect of, on bronze, 203 copper, 137, 138 -foil, to distinguish tin-foil from, 508 -gold alloys, specific gravities of, 79,80 group, 51, 52 increase in the hardness of, by alloying with antimony, 103 indication of, 498 542 INDEX. Lead- iron alloys, 376, 377 melting point of, 107 -mercury alloys, specific gravities of, 91 rolled, crystalline structure of, 146 separation of, from zinc, 532 -silver alloys, crystallization of, 94 liquation of, 69 tempered, 475 -tin alloys, action of acids and salt solutions upon, 125- 127 hardness of, 103 melting temperatures of, 107, 108 eutectic alloy, 66 Lead vanadate, 400 Lechesne, 356, 357 Ledebur, type metal according to, 369 Lichtenberg' s metal, 385 Light metals, 16, 17 Lipowitz's alloy, 378, 379 metal, amalgam of, 456, 457 Liquation, 62-69 definition of, 66 effect of, in working metals, 66, 67 Lithium, 17, 24 Loam moulds for plate-brass, 175 Locomotive axle-boxes, alloy for, 300 Locomotives, Dewrance's patent bear- ing for, 300 Long, specific gravities of antimony-tin alloys, according to, 80, 81 of tin-lead alloys, according to, 85, 86 Looking glasses, amalgam for. 452, 453 Lutecine, 468 Lyons gold, 182 MACHINE-BRONZE. 236-240 composition of, 237, 238 Macht's yellow metal, 157 Mackenzie's amalgam, 462 Magic mirrors. 244 spoon, 387 Magnesium, 17, 28-30 alloys for fireworks, 29. 30 preparation of, 29 amalgamation of, with mercury, 29 determination of. 50(), 501 -potassium alloys, 29 properties of, 28, 29 -sodium alloys, 29 Magnolia metal, 301 Maillechort, invention of, 307 Malleable brass, 155, 156 iron, 389 Manganese, 33, 34 alloying power of, 34 brass, 281 -bronze, 254-258, 301 preparation of, 256, 257 effect of, on iron, 390 German silver, 316 steel, 390, 391 testing for, 501, 502 Manganin, 317 Manilla gold, 186 Mannheim gold, 183 Marbeau's nickel-spiegel, 335 Marbled alloy, 418-420 Marcus Aurelius, statue of, 3 Marlie's non-oxidizable alloy, 474 Marsh's apparatus, 503, 504 Marshasila, 38 Martino's hard alloys for drilling and cutting tools. 333 platinoid, 316, 317 Matthiessen, A., investigation of the conducting power for electricity of metals by, 116, 117 specific gravities of antimony-lead alloys ac- cording to, 82, 83 cadmium - bis- muth alloys acco r d i n g to. 87 lead-gold al- loys accord- ing to, 79, 80 silver-lead al- loys accord- ing to, 80 silver-gold al- loys accord- ing to, 79 tin - cadmium alloys ac- cording to, 83 Medal bronze, 232, 233 Melting and casting art-bronze, 266, 267 bell-metal, 228, 229 bronze, 212-216 in a reverberatory furnace, 129, 130 temperature, effect of, in casting, 107-112 utensils, 128 Mercury, 53, 54 INDEX. 543 Mercury, alloying or amalgamating power of, 54 alloys of r and other metals, 445- 462 amalgamation of magnesium with, 29 early knowledge of, 3 indication of, 499 testing of, 508 Metal castings, alloy for filling out de- fective places in, 3S4 changes in the properties of a, by alloying, 1 definition of a, 13 for lining car brasses, 301 Metallic cement, Evans's, 456 Vienna, 451, 452 pencils, 460 Metalline, 357 Metalloids, 8,9, 12 Metals, 12 addition of, to bell-metal, 227 affinity of, for oxygen, 15, 16 alloying larger quantities of one, with smaller quantities of an- other, 133, 134 alloying power of, 9 base, alloys of copper with, 141 , 142 bases, 16 bismuth group of, 57, 58 chemical relations of the, 15-22 combination of, with non-metals, 135,136 sulphur, 59, 60 common characteristics of, 15 development of gases in casting, 113-115 heat in alloying, 10, 11 early knowledge of mixing, 2 effect of aluminium on, 27, 28 bismuth on the flexibility of, 106 degree of fluidity of, in casting, 112 different, on bronze, 203, 204 liquation on working, 66, 67 phosphorus on, 61 gold group of, 55-57 groups of, 17 heavy, 16, 30-59 groups of, 18. 19 increase in the limit of elasticity of, by alloying, 99 iron group of, 30-38 Metals, law regarding the influences ex- erted upon the strength of, by alloying, 95 lead group of, 51. 52 light, 16, 17 liquid, solidification of, 67, 68 most important, determination of impurities of, 498-509 noble, 16 preparation of alloys from, 131 of the alkalies, 17, 23, 24 alkaline earths, 17, 24 _ earths, 17, 18, 24, 30 physical and chemical relations of the, 12-22 relations of the, 13-15 principally employed for alloys, 134 properties of, 13, 14 resistance of, to calcium hydrate, 507 scale of the coloring power of, 119 shrinkage of, 115, 116 silver group of, 52-55 special properties of, 23-61 strength of, 95 tendency of, to become crvstalline. 145-147 tin group of, 45-51 tungsten group of, 42-45 use of fat, in melting. 130 white, 294-305 zinc group of, 38-42 Meteorites, 31 Meter rules, alloy for, 435 Mierzinski's solder for aluminium bronze, 360 Milan, weight of large bell in, 227 Minargent, 420 Minofor metal, 293 Mira metal, 283 Mirror, Chinese, 244 composition of a, 242 Egyptian, 244 -metal, Cooper's, 441 Roman, 244 Mirrors, amalgam for, 452, 453 concave, alloy for. 243 magic, 244 Mitis castings, 339 Moissan and Violle's electric furnace. 47, 48 . Moku-me, 418-420 Molybdenum, 43 Mosaic gold, 154 Moscow, Russia, weight of large bell in. 227 Moulds for Britannia metal, 290 casting art-bronze, 267 articles of brass, 174 544 INDEX. Moulds for casting bells, 231 bronze, 241 ingots of brass, 173, 174 pressed glass, alloy for, 463 Mourey's aluminium solders, 361, 362 Mouset's silver alloy, 411 Mudge. specula made by, 242 Muffle furnace for heating German silver sheet, 329-332 Muntz metal, 156, 157 Mushet steel, 395, 396 Music, composition of plates for engrav- ing, 369 Musiv silver, 454 NEWTON'S metal, 384 Nickel, 35-37 absorption of, by iron, 11 alloying power of, 36, 37 alloys, 306-337 analyses of, 324 composition of, 319-323 properties of. 311 -aluminium alloy, 333 amalgam, 462 arsenic in, 309, 310 -bronze, 315 coloring power of. 120, 121 -copper alloys, 307-309 -zinc alloys, 309-322 effect of, on bronze, 204 indication of, 501 ores, reduction of, 310 refining and toughening of, 36 purification of, 408 source of, 309 -speiss, treatment of, 408, 409 -spiegel. Marbeau's, 335 -steel, 333-337 alloys, 37 conductivity of, 337 tests of, 337 testing of. 508 -tin alloy, 332, 333 use of, for coins, 37 waste, utilization of, 530 Noble metals, preparation of alloys from, 131 Non-metals, 8,9, 12, 16 combination of, with metals, 135, 136 Non-oxidizable alloy, 463, 474 0LMUTZ, weight of large bell in, 227 Onion's fusible alloy, 385 Ordnance-bronze, 219-226 composition of, 226 cooling of, 225 Ordnance-bronze, effect of casting tem- perature on, 224, 225 French, analyses of, 68 or gun metal, 219-226 use of old cannon in casting, 224 Oreide, French, 184, 185 Ormolu, 234 Oxygen, affinity of metals for, 15, 16 effect of, on bronze, 209 PACKFONG, 306 foil, 329 Pale gold, 423 Palladium alloys, 441, 442 bearing metal, 442 Paris metal, 468 weight of large bell in, 227 Partinium, 358 Patina, 124, 260. 261 coating, similar to, 511, 512 Patterns, small, alloys for, 468, 469 Pattinson's desilverizing process, 6 Pen'-metal, Cooper's, 441 Pennsylvania Railroad Co. , Ex-B metal of, 301 Pforzheim gold, 430 Pholin's silver-like alloy, 460 Phosphor-aluminium bronze, 250, 251 -bronze, 61, 244-251 analyses of, 249 content of phosphorus in, 248 grades of, 249 preparation of, 246 properties of correctly-pre- pared, 247 results of phvsical tests of, 247, 248 uses of, 248 wire, 247 -copper, 246 -iridium, 443, 444 "-lead bronzes, 250 -tin, 246, 247 Phosphorus, 61 content of, in phosphor-bronze, 248 effect of, on bronze, 210 on copper, 139 Physical and chemical relations of the metals, 12-22 Piat's revolving crucible furnace, 169, 170 Pickling brass, 179-181 solution, 417 Pig iron, 389 Pinchbeck, 184 Pirsch's German silver, 318 -Baudoin's alloy, 421 Pivot bearings, alloy for, 300 INDEX. 545 Platina, 186 Platine au titre. 437 Platinoid, 316, 317 Platinor, 437, 438 Platinum, 56, 57 alloys of, with the base metals, 439-441 preparation of, 434 aluminium solder, 363 amalgam, 462 and platinum metals, alloys of, 433-444 -bronze, 438 -copper alloys, 439-441 furnace. 433-434 -gold alloys, 436 melting points of, 436 -silver alloys, 437 indication of, 498 iridium alloys, 434, 435 -iron alloys, 439 -lead, 191 -palladium alloys, 435 properties of, 433 -silver alloys, 437 Plumbago, 60 Plumbers' sealed solder, 479 Potassium, 17, 23 -amalgam, 461, 462 -magnesium alloys, 29 Potin gris, 152, 153 Potinjaune, 152, 153 Prechtl brass solders, 484 Preparation of alloys in general, 1 28-136 Prince's metal, 155 Pyrometric measurements, use of plati- num-gold alloys for, 436 Pyrophorous alloys for illuminating purposes, 473 /QUICKSILVER, 53, 54 "DEFLECTORS, aluminium-magnes- Xi ium alloy for, 359 Reverberatory furnace for melting bronze, 214 for wood firing, 177 melting in a, 129, 130 Revolving crucible furnace, 169, 170 Rheostats, alloy for, 257, 258 Rhodium-steel, 442 Richards' aluminium solder. 364, 365 bronze, 353 Riche, determinations of specific gravi- ties of copper-zinc allovs, by, 76, 77 Riche and Thurston, determinations of the specific gravities of copper- tin alloys, by, 71-76 Riley, James, on nickel-steel alloys, 37, 336 Roberts, determination of specific gravi- ties of copper-gold alloys by, 78 Robertson's alloy for filling teeth, 474 Rolling aluminium-bronze, examples of, 349, 350 Roman coin-bronze, 233 Roman metal mirror, 244 Rome, weight of large bell in, 227 Ronia metal, 155 Rose's alloys, 384 metal, 112 Rosein, 333 Ross, composition of speculum metal ac- cording to, 242, 243 telescope, composition of the mirror of, 243 Rubbers of electrical machines, amalgam for coating, 453, 454 Ruolz alloys, 322,323 SAFETY-PLATES for steam boiler*, 334 Salgee anti-friction metal, 301 Salt, common, solutions, 6, 7 Sauer's aluminium solder, 363, 364 Scheelite, 43 Schlosser's solder for aluminium bronze, 360, 361 Schneider, M. Henry, patent of, for cop- per-steel. 279 patents of, for manufacture of alloys of cast- iron and nickel, steel and nickel, 333-335 Scrap-gold, remelting of, 427 Shaku-do, 416 Sheet brass, 149-151 crystalline, structure of, 146 production of, 176, 177 -copper, crystalline structure of, 146 -iron, crystalline structure of, 146 -tombac, crystalline structure of, 146 Sheffield Britannia metal, 289 Shibu-ichi, 416, 417 Ship-sheathing, bronze for, 235, 236 Gedge's alloy for, 158, 159 Shot, casting of, 372-376 formation of by centrifugal power, 373 large, manufacture of, 376 -metal, 370-376 546 INDEX. Shot, mixture of metals for, 370 preparation of, 371 sorting of, 375, 376 -towers, 372 -wells. 372 Shrinkage, 115. 116 Sideraphite, 472 Sign-plates, alloy for, 474, 475 Silicon-bronze, 251-254 properties of, 251 telegraph wire, 251-254 effect of, on copper, 138, 139, 251 iron, 389 Silver, 54, 55 addition of, to German silver, 311 alloy resembling, 463 alloying power of, 55 alloys, 404-421 melting temperatures of, 109 resembling, 420, 421 solder for, 487 aluminium alloys, 404, 405 properties of, 339 amalgam, 448 -arsenic alloys, 411 bell-metal, 231 bronze, 333 coins, composition of, 413, 414 -copper alloy, magnified surfaces of a, 64, 65 alloys, 412, 416 flexibility of, 106 liquation of, 69 -cadmium alloys, 411, 412 eutectic alloy, 65. 66 -nickel alloys, 406, 407 -zinc alloys, 410, 411 crystals, separation of, from a melted silver-copper alloy, 63 early allovs of, 2 flexibility of, 105, 106 -gold alloys, specific gravities of, 79 group, 52-55 increase in the strength of, by alloying, 97 indication of, 499 -lead allovs, specific gravities of, 80 -like alloy,316, 460 melting point of, 108 -mercury alloys, crystallization of, 94 oxidizing of, 525 prize offered for the invention of a substitute for, 306, 307 recovery of, from cyanide solu- tions, 529, 530 separation of, from copper, 531 Silver, separation of, from gold, 528, 529 solder for cast-iron, 489 for steel, 489 French, 487 hard, 487 ordinary hard, 487 soft, 487 solders for special work, 488, 489 -waste, recovery of, 528-530 -zinc alloys, 405, 406 Silverine, 307 Silvering, alloy for, 473, 474 Similor, 183 Singer' s amalgam for coating rubbers of electrical machines, 454 Sleigh bells, alloy for, 230 American, alloy for, 474 Smaltine, 34 Smith, David, invention of, for manu- facturing drop-shot, 373-375 Smith. J. Kent, on vanadium steel, 399, 400 tests by, of steel with and without vanad- ium, 398 Sodium, 17, 23 alloys of magnesium with, 29 amalgam, 460, 461 Soft silver solder, 487 solders, 478-480 coloring of, 521 Solbisky's nickel-aluminium alloys, 333 Solder for manganese-brass, 281 soft, preparation of, 479, 480 Soldering aluminium, 361-365 bronze, 360, 361 autogenous, 477 fat, 493 fluids, 491-497 jewelry, 496, 497 pan, 496, 497 processes, conditions to be observed in, 476, 477 treatment of solders in, 431-497 Solders and soldering, 476-497 constituents of, 476 containing precious metals, 486-491 for aluminium, 361-365 enameled work, 490 hard, 480-486 in general, 476-478 soft, 478-480 coloring of, 521 composition and melting points of, 478, 479 testing of, 508 treatment of, in soldering, 491-497 varieties of, 476 INDEX. 547 Solutions, change in the physical prop- erties of, 6 Sorel's alloy, 191, 192 Special properties of the metals, 23-61 Specific gravity of alloys, 70-93 rule for calculating the, 71 Speculum metal, 242-244 actual, composition of, 242 various compositions used for, 243 Speiss, 35 Spelter, 39 Spence's metal, 468 Sperry, E. S., analyses of nickel alloys by, 324 investigations of, on the influence of antimony on brass, 149, 150 Spoons, alloy for, 463 Statuary bronze, alloys of different colors suitable for, 262 Statues, best bronze for, 262' celebrated, composition of, 262, 263 mixture of metals for casting, 259, 260 Statuettes, small, manufacture of, 457 Steam boilers, safety plates for, 384 Steel, 20, 61, 389 articles, baths used in tempering and heating, 286 -bronze, 225, 226 comparative effect of chromium and vanadium on, 399 composition, 465 effect of chromium in, 392, 393 Helouise's investigations of the effect of vanadium on, 397, 398 results obtained by the addition of vanadium to. 401 silver solder for, 489 tools, tempering of, 387 with and without vanadium, tests of, 398 Sterling metal, 152, 153 Sterro-metal, 158, 159 Stopcocks, alloy for, 300 Stream-tin, 45 Strength of alloys, 95-101 tensile, 95 Strontianite, 17 Strontium, 17 Suhl white copper, 306 Sullage piece, 221, 222 Sulphur, 59, 60 effect of, on copper, 138, 139 Sulphuretted hydrogen, apparatus for preparing, 499, 500 Sun-bronze, 357 Swiss coins, composition of, 311 Swiss fractional coins, 411 Symbols, formation of the, 21 TABLE bells, alloy for, 230 for conversion of carats and grains into thousandths, 428 of analyses of German silver, 313, 314 nickel alloys, 324 of names, symbols and atomic weights of the elements, 21. 22 showing comparative effect of chro- mium and vanadium on steel, 399 composition and melting-points of soft-solders, 478, 479 and melting-points of sol- ders, 495 of alloys for bearings, 238, 239 of alloys for calico printing rollers, 476, 477 of alloys of different colors suitable for statuary bronze, 262 of ancient bronzes, 219 of anti-friction metals, 302- 305 of Britannia metal, 289 of bell metals, 229, 230 of brass for sheet and wire, 151 of brass solders, 483 of cast-brass, 152 of celebrated statues, 262, 263 of gold alloys most fre- quently used, with their specific colors, 431 of gold solders, 490 of machine bronze, 238 of nickel alloys, 319-323 of ordnance-bronze, 226 of silver coins of various nations, 414 of silver-copper alloys em- ployed in England for manufacturing purposes, 414, 415 of tombac, 182 of white metals for bear- ings, 298 density and composition of bronze, 207, 208 fusing temperatures of bismuth- lead-tin alloys, 386 influence of vanadium on chrome, 403 548 INDEX. Table showing mechanical and physical properties of copper-tin alloys, 267-273 melting points of tin-lead alloys, 286 properties of brass as affected by its composition, 149 of copper-zinc alloys, 193- 197 proportions of various metals incorporated in gold alloys used by jewelers', 430, 431 results obtained by the addi- tion of vanadium to steel, 401 Talmi gold, 185, 186 Tambago, 181 Tam-tams, Chinese, 230, 231 Taylor and "White special "quick speed " cutting steels, 396 Teeth, amalgam for filling, 456 Robertson's alloy for filling, 474 Telegraph wire, silicon bronze, 251-254 Telephone wire, silicon bronze, 251-254 Telescope mirror at Birr Castle, Ireland, 244 Temperatures corresponding to different colors, 14 Tempered lead, 475 Tetmajer, experiments of, with alumin- ium-copper alloys, 96 Thallium, 52 Thowless' aluminium solder, 363 Thurston, Prof. R. H., investigation by, of the strength of copper-tin alloys, 99, 100 Tiers-argent, 405 Tin, 45, 46 addition of, to German silver, 311 alloying power of, 46 alloys, 284-305 warm sepia-brown on, 525 amalgam, 452 -amalgams, specific gravities of, 90, 91 -bismuth alloys, specific gravities of, 83, 84 bronze-like patina on, 525 -cadmium alloys, specific gravities of, 83 commercial, analyses of, 45 detection of lead in, 508 effect of, on brass, 148 lead, 366 -foil to distinguish from lead-foil, 508 -gold alloys, specific gravities of, 86 Tin group, 45-51 -lead alloys. 284-286 densities of, 284 melting points of, 285, 286 specific gravities of, 85, 86 melting point of, 107 -mercury alloys, specific gravities of, 90, 91 properties of, 45, 46 recovery of, from tin-plate waste, 531, 532 -silver alloys, specific gravities of, 84,85 -spots, 243 stains, 68 -stone, 45 testing of, 508 unmanufactured, varieties of, 46 use of, as a solder, 478 warm sepia-brown tone on, 525 Tinning, amalgam for, 454 Tissier's metal, 186 Titaniferous aluminium, behavior of, 49 Titanium, 46-51 -bronze, 48 metallic, preparation of, 47 Tobin bronze, 161, 162, 301 Tombac, 181-190 color of, 182 composition of, 182 derivation of the term, 181 properties of, 181 Tools, tempering of, 387 Toucas's alloy, 318, 319 Touchstone, 506, 507 Toulouse, France, weight of large bell in, 227 Tournay's metal, 183 Tournu-Leonard's alloy, 420 Tubes, tough brass for, 153, 154 Tungsten, 42, 43 group, 42-45 -steel, 393-396 analyses of, 395, 396 fracture of, 395 magnetic retentiveness of, 395 tests of, 394, 395 Type, alloys suitable for casting, 368 manufacture of, 369 metal, 367-370 alloy for, 357 UCHAT1US bronze, 225, 226 experiments of, 98, 99 United States, zinc in the, 38 Uranium, 38 INDEX. 549 T7ALVE-BALLS. bronze for, 239, 240 V Vanadate, 400 Vanadite, 43 Vanadium, 43-4-5 alloying power of, 44, 45 -chrome steels, 402, 403 discovery of, 396 experiments showing influence of, on chrome, 403 -nickel steel, 401, 402 preparation of, 44 properties of, 44 results obtained by the addition of, to steel, 401 -steel, 396-403 bending tests of, 398, 399 classes of, 401-403 initial material for the prepara- tion of, 400 tests of steel with and without, 398 Van der Ven, E., investigation by, of bronze for telephone lines, 253, 254 Victor metal, 475 Vienna, flux for hard soldering used in, 489 metallic cement, 451, 452 weight of large bell in, 227 Volborthite, 43 WARNE'S metal, 420 Waste metals, recovery of. 526-532 Watch manufacturers, alloys for, 442, 443 Watches, palladium-bearing metal for, 442 Watts, invention of shot-towers by, 372 Webster's bismuth bronze, 315 Webster Crown Metal Co. , alloys made by, 354-356 Weilei-'s alloys, 251 West, Thomas D., on casting alumin- ium bronze, 346-349 White brass, 190-193 metal, 301 metallo-graphic examination of, 295, 296 metals, 294-305 for bearings, 398 White pig iron, 390 solder, 481 Wolfram, 43 Wood's metal, 112, 380 Wood-grain alloy, 418-420 Wrought iron, 61 YELLOW gold, 423 metal, 156, 157 solder, 481 Zinc, 38-40 affinity of, for lead, 366 alloying power of, 40 amalgam, 454 black on, 523 brands of, 150 brassing of, 523 bronzing liquids for, 517 change in the molecular structure of, 145, 146 coloring of, 522, 523 -copper alloy, pure, strength of, 98 alloys, elongations of, 101 value for the tensile strength of, 97 crystalline structure of, 145, 146 effect of, on bronzes, 203 on copper, 142, 143 for voltaic cells, amalgamation of, 454, 455 gray, yellow, brown to black colors on, 523 group, 38-42 increase in the strength of copper by an addition of, 97 -iron, 467 ores, manufacture of brass with the use of, 163-165 properties of, 39, 40 separation of an alloy in refining. 32,33 lead from , 532 solution of, in iron, 33 testing for, 5U2 -tin alloys, hardness of, 103 liquation of, 69 -white, 39 CA-TAJLOQ-'CnES OF practical and Scientific Boo^ PUBLISHED BY Henry Carey Baird & Co. INDUSTRIAL PUBLISHERS, BOOKSELLERS AND IMPORTERS. 810 Walnut Street, Philadelphia. •S" Any of the Books comprised in this Catalogue will be sent by mail, free d? postage, to any address in the world, at the publication prices, *®" A Descriptive Catalogue, 90 pages, 8vo., will be sent free and free of postag% to any one in any part of the world, who will furnish his addressi t IW Where not otherwise stated, all of the Books in this Catalogue are bouttd in muslin. AMATEUR MECHANICS' WORKSHOP: A treatise containing plain and concise directions for the manipula* tion of Wood and Metals, including Casting, Forging, Brazing, Soldering and Carpentry. By the author of the " Lathe and Iti Uses." Seventh edition. Illustrated. 8vo. . . . $2»5« ANDES.— Animal Fats and Oils: Their Practical Production, Purification and Uses; their Properties, Falsification and Examination. 62 illustrations. 8vo. . ANDES.— Vegetable Fats and Oils: Their Practical Preparation, Purification and Employment; their Properties, Adulteration and Examination. 94 illustrations. 8vo. ARLOT. — A Complete Guide for Coach Painters : Translated from the French o r M. Arlot, Coach Painter, for eleven years Foreman of Paining to M. Eherler, Coach Maker, Paris. By A. A. Fesquet, Chemist and Engineer. To which m added an Appendix, containing Informatics resoecting the Materials and the Practice of Coach and Car Painting w..d Varuishing in the United States and Great Britain i2mo. . . . $I>2$ (I) i HENRY CAREY BAIRD & CO.'S CATALOGUE. 4RMENGAUD, AMOROUX, AND JOHNSON.— The Practi- cal Draughtsman's Book of Industrial Design, and Ma- chinist's and Engineer's Drawing Companion : Forming a Complete Course of Mechanical Engineering and Archi tectural Drawing. From- the French of M, Annengaud the elder, Prof, of Design in the Conservatoire of Arts and Industry, Paris, and MM. Armengaud the younger, and Amcroux, Civil Engineers. Re- written and arranged with additional matter and plates, selections from and examples of the most useful and generally employed mechanism of the day. By William Johnson, Assoc. Inst. C. E. Illustrated by fifty folio steel plates, and fifty wood-cuts. A new edition, 4to . cloth. #600 ARMSTRONG.— The Construction and Management of Steam Boilers : By R. Armstrong, C. E. With an Appendix by Robert Mallet, C. E., F. R. S. Seventh Edition. Illustrated. 1 vol. i2mo. .60 ARROWSMITH.-The Paper-Hanger's Companion: Comprising Tools, Pastes, Preparatory Work ; Selection and Hanging of Wall- Papers ; Distemper Painting and Cornice-Tinting ; Stencil Work; Replacing Sash-Cord and Broken Window Panes; and Useful Wrinkles and Receipts, By James Arrowsmith. A New, Thoroughly Revised, and Much Enlarged Edition. Illustrated by 25 engravings, 162 pages. (1905) .... $1.00 \SHTON. — The Theory and Practice of the Art of Designing Fancy Cotton and Woollen Cloths from Sample : Giving full instructions for reducing drafts, as well as the methods of spooling and making out harness for cross drafts and finding any re- quired reed; with calculations and tables of yarn. By Frederic T. Ashton, Designer, West Pittsfield, Mass. With fifty-two illustrations. One vol. folio $5.00 &SKINSON —Perfumes and their Preparation : A Comprehensive Treatise on Perfumery, containing Complete Directions for Making Handkerchief Perfumes, Smelling-Salts. Sachets, Fumigating Pastils; Preparations for the Care of the Skin, the Mouth, the Hair; Cosmetics, Hair Dyes, and other Toilet Articles. By G. W. Askinson. Translated from the German by IsiDOK Furst. Revised by Charles Rice. 32 Illustrations. 8vo. $3.00 BR0 ° DAVIES. — A Treatise on Slate and Slate Quarrying: Scientific, Practical and Commercial. By D. C. Davies, F. G. S., Mining Engineer, etc. With numerous illustrations and folding plates. J2mo. $1.20 DAVIS. — A Practical Treatise on the Manufacture of Brick, Tiles and Terra-Cotta : Including Stiff Clay, Dry Clay, Hand Made, Pressed or Front, and Roadway Paving Brick, Enamelled Brick, with Glazes and Colors, Fire Brick and Blocks, Silica Brick, Carbon Brick, Glass Pots, Re> IO HENRY CAREY BAIRD & CO.'S CATALOGS. torts, Architectural Terra-Cotta, Sewer Pipe, Drain Tile, Glazed and Unglazed Roofing Tile, Art Tile, Mosaics, and Imitation of Intarsia or Inlaid Surfaces. Comprising every product of Clay employed in Architecture, Engineering, and the Blast Furnace. With a Detailed Description of the Different Clays employed, the Most Modern Machinery, Tools, and Kilns used, and the Processes for Handling, Disintegrating, Tempering, and Moulding the Clay into Shape, Dry- ing, Setting, and Burning. By Charles Thomas Davis. Third Edi- tion. Revised and in great part rewritten. Illustrated by 261 engravings. 662 pages ....... $12.50 DAVIS. — A Treatise on Steam-Boiler Incrustation and Meth- ods for Preventing Corrosion and the Formation of Scale: By Charles T. Davis. Illustrated by 65 engravings. 8vo. DAVIS.— The Manufacture of Paper : Being a Description of the various Processes for the Fabrication, Coloring and Finishing of every kind of Paper, Including the Dif- ferent Raw Materials and the Methods for Determining their Values, '.He Tools, Machines and Practical Details connected with an intelli- gent and a profitable prosecution of the art, with special reference to the best American Practice. To which are added a History of Pa- per, complete Lists of Paper- Making Materials, List of American Machines, Tools and Processes used in treating the Raw Materials, and in Making, Coloring and Finishing Paper. By Charles T. Davis. Illustrated by 156 engravings. 608 pages, 8vo. $6.00 DAVIS. — The Manufacture of Leather: Being a Description of all the Processes for the Tanning and Tawing with Bark, Extracts, Chrome and all Modern Tannages in General Use, and the Currying, Finishing and Dyeing of Every Kind of Leather; Including the Various Raw Materials, the Tools, Machines, and all Details of Importance Connected with an Intelligent and Profitable Prosecution of t tie Art, with Special Reference to the Best American Practice. To which are added Lists of American Patents ( 1884-1897) for Materials, Processes, Tools and Machines for Tanning, Currying, etc. By Charles Thomas Davis. Second Edition, Revised, and in great part Rewritten. Illustrated by 147 engravings and 14 Sam- ples of Quebracho Tanned and Aniline Dyed Leathers. 8vo, cloth, 712 pages. Price $10.00 DAWIDOWSKY— BRANNT.— A Practical Treatise on the Raw Materials and Fabrication of Glue, Gelatine, Gelatine Veneers and Foils, Isinglass, Cements, Pastes, Mucilages, etc. : Based upon Actual Experience. By F. Dawidowsky, Technical Chemist. Translated from the German, with extensive addition-. including a description of the most Recent American Processes, by William T. Brannt. 2d revised edition, 350 pages. (1905.) Price .......... $j.oo DE GRAFF.— The Geometrical Stair-Builders' Guide: being a Plain Practical System of Hand-Railing, embracing all it= necessary Details, and Geometrically Illustrated by twenty-two Ste& Engravings; together with the use of the most approved principle nf Practical Geometry By SlMON De Graff, Architect (deuce. 1 HENRY CAREY BAIRD & CO.'S CATALOGUE. rt DE KONINCK— DIETZ.— A Practical Manual of Chemical Analysis and Assaying : As applied to the Manufacture of Iron from its Ores, and to Cast Iroa, Wrought Iron, and Steel, as found in Commerce. By L. L. Db KONINCK, Dr. Sc, and E. Dietz, Engineer. Edited with Notes, hy Robert Mallet, F. R. S., F. S. G., M. I. C. E., etc. American Edition, Edited with Notes and an Appendix on Iron Ores, by A. A, Fesquet, Chemist and Engineer. i2mo. . . . #1.50 UNCAN.— Practical Surveyor's Guide: Containing the necessary information to make any person of corm mon capacity, a finished land surveyor without the* aid of a teacher. By Andrew Duncan. Revised. 72 engravings, 214 pp. i2mo. $1.50 DUPLAIS.— A Treatise on the Manufacture and Distillation of Alcoholic Liquors : Comprising Accurate and Complete Details in Regard to Alcohol from Wine, Molasses, Beets, Grain, Rice, Potatoes, Sorghum, Aspho del, Fruits, etc. ; with the Distillation and Rectification of Brandy, Whiskey, Rum, Gin, Swiss Absinthe, etc., the Preparation of Aro- matic Waters, Volatile Oils or Essences, Sugars, Syrups, Aromatic Tinctures, Liqueurs, Cordial Wines, Effervescing Wines, etc., the Ageing of Brandy and the improvement of Spirits, with Copious Directions and Tables for Testing and Reducing Spirituous Liquors, etc» etc, Translated and Edited from the French of MM. DuPLAIS s By M. McKennie, M. D. Illustrated 743 pp. 8vo. $15.00 DYER AND COLOR-MAKER'S COMPANION: Containing upwards of two hundred Receipts for making Colors, on the most approved principles, for all the various styles and fabrics now in evistence ; with the Scouring Process, and plain Directions for Preparing, Washing-off, and Finishing the Goods. i2mo. $1 00 EIDHERR.— TheTechno-Chemical Guide to Distillation: A Rand-Book for the Manufacture of Alcohol and Alcoholic Liquors, including -the Preparation of Malt and Compressed Yeast. Edited from the German of Ed. Eidherr. EDWARDS.— A Catechism of the Marine Steam-Engine, For the use of Engineers. Firemen, and Mechanics. A Practical Work for Practical Men. By Emory Edwards, Mechanical Engi- neer. Illustrated by sixty-three Engraving--, including examples of the most modern Engines. Third edition, thoroughly revised, with much additional matter. 12 mo. 414 pages ... $2 Ofi EDWARDS. — Modern American Locomotive Engines, Their Design, Construction and Management. By Emory EDWARDS*, Illustrated i2mo $2.00 EDWARDS.— The American Steam Engineer: Theoretical and Practical, with examples of the latej: and most ap- proved American practice in the design and construction of Steam Engines and Boilers. For the use of engineers, machinists, boiler- w^kers, and engineering students. By Emory Edwards. Fully illustrated, 419 pages. i2mo. - $2.jO 12 HENRY CAREY BAIRD & CO.'S CATALOGUE. EDWARDS. — Modern American Marine Engines, Boilers, and Screw Propellers, Their Design and Construction. Showing the Present Practice ot the most Eminent Engineers and Marine Engine Builders in the United States. Illustrated by 30 large and elaborate plates. 4to. $5.00 EDWARDS.— The Practical Steam Engineer's Guide In the Design, Construction, and Management of American Stationary, Portable, and Steam Fire- Engines, Steam Pumps, Boilers. Injectors, Governors, Indicators, Pistons and Rings, Safety Valves and Steam Gauges. For the use of Engineers, Firemen, and Steam Users. By Emory Edwards. Illustrated by 119 engravings. A20 pages. l2mo ^3 5 finding the Discharge of Water from Orifices, isiotehes Weirs, Pipes, and Rivers : Third Edition, with Addi dons, consisting o! JNew Formulae for the Discharge from Tidal and Flood Sluices and Siphons ; general infor nation on Rainfall, Catchment-Basins, Drainage, Sewerage, Watei Supply for Towns and Mill Power. Bv Tohn Nevtixk. C. E. M R I. A. ; Fellow of the Royal Geological Society of Ireland. Thicl I2mo #5.50 1EWBERY- Gleanings from Ornamental Art of every style : Drawn from Examples in the British, South Kensington, Indian, Crystal Palace, and other Museums, the Exhibitions of 1S5 1 and 1862, and the best English and Foreign works. In a series of 100 exquisitely drawn Plates, containing many hundred examples. Bjf Robert Newbery. 410. .... . (Scarce.) NICHOLLS. -The Theoretical and Practical Boiler -Maker and Engineer's Reference Book: Containing a variety of Uselul Information for Employers of Labor. Foremen avl Wurkiuji Boiler-Makers Irei, Copper, and Tinsmith* 2 o HENRY CAREY BAIRD & CO.'is CATALOGUE. J>raughtsmen, Engineers, the General Steam-using Public, and for th« Use of Science Schools and Classes. By Samuel Nicholls. Ulu* trated by sixteen plates, i2mo. ..... $2.50 NICHOLSON.— A Manual of the Art of Bookbinding : Containing full instructions in the different Branches of Forwarding, Gilding, and Finishing. Also, the Art of Marbling Book-edges and Paper. By James B. Nicholson. Illustrated. i2mo., cloth #2.25, NICOLLS.— The Railway Builder: A Hand-Book for Estimating the Probable Cost of American Rail- way Construction and Equipment. By WILLIAM J. NlCOLLS, Civil Engineer. Illustrated, full bound, pocket-book form . $2.00 NORMANDY. — The Commercial Handbook of Chemical An- alysis : Or Practical Instructions for the Determination of the Intrinsic 01 Commercial Value of Substances used in Manufactures, in Trades, and in the Arts. By A. Normandy. New Edition, Enlarged, and to a great extent rewritten. By Henry M. Noad, Ph.D., F.R.S., thick i2mo Scarce NORRIS.— A Handbook for Locomotive Engineers and Ma- chinists: Comprising the Proportions and Calculations for Constructing Loco- motives; Manner of Setting Valves; Tables of Squares, Cubes, Areas, etc., etc. By Septimus Norris, M. E. New edition. Illustrated, l2mo JM.5C NYSTRGM. — A New Treatise on Elements of Mechanics : Establishing Strict Precision in the Meaning of Dynamical Terms 1 accompanied with an Appendix on. Duodenal Arithmetic and Me trology. By John W. Nystrom, C. E. Illustrated. 8vo. NYSTROM. — On Technological Education and the Construe- tion of Ships and Screw Propellers : For Naval and Marine Engineers. By John W. Nystrom, lah Acting Chief Engineer, U. S. N. Second edition, revised, with addi tional matter. Illustnued by seven engravings, izmo. . $1. O'NEILL. — A Dictionary of Dyeing and Calico Printing: 1 Containing a brief account of all fhe Substances and Processes], C use in the Art of Dyeing and Printing Textile Fabrics ; with Practte Receipts and Scientific Information. By Charles O'Neill, Anal)" tical Chemist. To which is added an Essay on Coal Tar Colors and their application to Dyeing and Calico Printing. By A. A. Fesquet, Chemist and Engineer. With an appendix on Dyeing and Calid Printing, as shown at the Universal Exposition, Paris, 1S67 8vo., 491 pages . . $3.00 ORTON. — Underground Treasures-. • How and Where to Find Them. A Key for the Ready Determination rf ail the Useful Minerals within the United States. By James ORTON, A.M., Late Professor of Natural History in Vassar College, N. Y ; author of the "Andes and the Amazon," etc. A New Edi- tion, with An Appendix on Ore Deposits and Testing Minerals (1901). Illustrated #1.50 HENRY CAREY BAIRD & CO.'S CATALOGUE. 21 QSBORN.— The Prospector's Field Book and Guide. In, the Search For and the Easy Determination of Ores and Other Useful Minerals. By Prof. H. S. Osborn, LL. D. Illustrated by 66 , Engravings. Sixth Edition. Revised and Enlarged. 360 pages, i2mo. (Dec, 1903) ........ $1.50 DSBORN — A Practical Manual of Minerals, Mines and Min ing: Comprising the Physical Properties, Geologic Positions, Local Occur- rence and Associations of the Useful Minerals ; their ^Methods ■ of Chemical Analysis and Assay; together with Various Systems of Ex- cavating and Timbering, Brick and Masonry Work, during Driving, Lining, Bracing and other Operations, etc. By Prof. H. S. Osborn, LL. D., Author of " The Prospector's Field- Book and Guide." 171 engravings. Second Edition, revised; 8vo. . . .- $4-50 OVERMAN— The Manufacture of Steel : Containing the Practice and Principles of Working and Making Steel. A Handbook for Blacksmiths and Workers in- Steel and Iron, Wagon Makers, Die Sinkers, Cutlers, and Manufacturers of Files and Hard- Ware, of Steel and Iron, and for Men of Science and Art. By Frederick Overman, Mining Engineer, Author of the " Manu- facture of Iron," etc. A new, enlarged, and revised Edition. By A. A. Fesqwt, Chemist and Engineer. !2mo. . . $1.50 OVERMAN. — The Moulder's and Founder's Pocket Guide : A Treatise on Moulding and Founding in Green-sand, Dry-sand, Loam, and Cement; the Moulding of Machine Frames, Mill-gear, Hollow- ware, Ornaments, Trinkets, Bells, and Statues; Description of Moulds for Iron, Bronze, Brass, and other Metals ; Plaster of Paris, Sulphur, Wax, etc. ; the Construction of Melting Furnaces, the Melting and Founding of Metals ; the Composition of Alloys and their Nature, etc., etc. By Frederick Overman, M. E. A new Edition, to which is added a Supplement on Statuary and Ornamental Moulding, Ordnance, Malleable Iron Castings, etc. By A. A. Fesquet, Chen> ist and Engineer. Illustrated by 44 engravings. l2mo. . $2.00 PAINTER, GILDER, AND VARNISHER'S COMPANION. Comprising the Manufacture and Test of Pigments, the Arts of Paint- ing, Graining, Marbling, Staining, Sign- writing, Varnishing, Glass- staining, and Gilding on Glass ; together with Coach Painting and Varnishing, and the Principles of the Harmony and Contrast of Colors. Twenty-seventh Edition. Revised, Enlarged, and in great part Rewritten. By William T. Brannt, Editor of " Varnishes, Lacquers, Printing Inks and Sealing Waxes." Illustrated. 395 pp. i2mo. . . . , $i-50 PALLETT. — The Miller's, Millwright's, and Engineer's Guide. By Henry Pallett. Illustrated. i2mo. . . . £2.00 *2 HENRY CAREY BATRD & OVS CATALOGUE. PERCY. — The Manufacture of Russian Sheet-Iron. Bv John Percy, M. D., F. R. S. Paper. . . . 25 eta. PERKINS.— Gas and Ventilation: Practical Treatise on Gas and Ventilation. Illustrated. I2mo. $1.25 PERKINS AND STOWE.-A New Guide to the Sheet-iron and Boiler Plate Roller : Containing a Series of Tables showing the Weight of Slabs and Pilei to Produce Boiler Plates, and of the Weight of Piles and the Sizes of Bars to produce Sheet-iron ; the Thickness of the Bar Gauge in decimals ; the Weight per foct, and the Thickness on the Bar or Wire Gauge of the fractional parts of an inch; the Weight per sheet, and the Thickness on the Wire Gauge of Sheet-iron of various dimensions to weigh 112 lbs. per bundle; and the conversion of Short Weight into Long Weight, and Long Weight into Short. $1.50 POSSELT. — Recent Improvements in Textile Machinery Re- lating to Weaving : Giving the Most Modern Points on the Construction of all Kinds of Looms, Warpers, Beamers, Slashers, Winders, Spoolers, Reeds, Temples, Shuttles, Bobbins, Heddles, Heddle Frames, Pickers, Jacquards, Card Stampers, etc., etc. 600 illus. . . $3 00 POSSELT.— Technology of Textile Design: The Most Complete Treatise on the Construction and Application of Weaves for all Textile Fabrics and the Analysis of Cloth. By E. A. Posselt. 1,500 illustrations. 4to $500 POSSELT.— Textile Calculations: A Guide to Calculations Relating to the Manufacture of all Kinds of Yarns and Fabrics, the Analysis of Cloth, Speed, Power and Belt Calculations. By E. A. POSSELT. Illustrated. 4to. . #2.00 REGNAULT.— Elements of Chemistry: By M. V. Regnault. Translated from the French by T. Forrest Betton, M. D., and edited, with Notes, by James C. Booth, Melter and Refiner U. S. Mint, and William L. Faber, Metallurgist and Mining Engineer. Illustrated by nearly 700 wood-engravings. Com- prising nearly 1,500 pages. In two volumes, 8vo., cloth . $6.00 RICHARDS.— Aluminium : Its History, Occurrence, Properties, Metallurgy and Applications, including its Alloys. By Joseph W. Richards, A. C, Chemist and Practical Metallurgist, Member of the Deutsche Chemische Gesell- schaft. Illust. Third edition, enlarged and revised (1895) . #6.00 RIFFAULT, VERGNAUD, and TOUSSAINT.— A Practical Treatise on the Manufacture of Colors for Painting : Comprising the Origin, Definition, and Classification of Colors; the Treatment of the Raw Materials; the best Formulae and the Newest Processes for the Preparation of every description of Pigment, and the Necessary Apparatus and Directions for its Use; Dryers; the Testing, Application, and Qualities of Paints, etc., etc. By MM. Rifkaitlt, Vergnaud, and Toussaint. Revised and Edited by M. HENRY CAREY BAIRD & CO.'S CATALOGUE. *3 F. Malepeyre. Tranuated from the French, by A. A. Fesqu*^ Chemist and Engineer. Illustrated by Eighty engravings,. In one vol., 8vo., 659 pages . . . . . $ 5.00 ROPER. — Catechism for Steam Engineers and Electricians: Including the Construction and Management of Steam Engines, Steam Boilers and Electric Plants. By Stephen Roper. Twenty' first edition, rewritten and greatly enlarged by E. R. Keller and C. W. Pike. 365 pages. Illustrations. i8mo., tucks, gilt. #2.00 ROPER.— Engineer's Handy Book: v Containing Facts, Formulae, Tables and Questions on Power, its Generation, Transmission and Measurement; Heat, Fuel, and Steam; The Steam Boiler and Accessories ; Steam Engines and their Parts ; Steam Engine Indicator; Gas and Gasoline Engines; Materials; their Properties and Strength; Together with a Discussion of the Fun- damental Experiments in Electricity, and an Explanation of Dynamos, Motors, Batteries, etc., and Rules for Calculating Sizes of Wires. By Stephen Roper. 15th edition. Revised and enlarged by E. R. Keller, M. E. and C. W. Pike, B. S. (1899), with numerous illus- trations. Pocket-book form. Leather &j.50 ROPER.— Hand-Book of Land and Marine Engines : Including the Modelling, Construction, Running, and Management of Lan^ and Marine Engines and Boilers. With illustrations. By Stephen Roper, Engineer. Sixth edition. i2mo.,h'cks, gilt edge. ROPER.— Hand-Book of the Locomotive : 3 ' 5 ° Including the Construction of Engines and Boilers, and the Construc- tion, Management, and Running of Locomotives. By Stephen Roper. Eleventh edition. i8mo., tucks, gilt edge . $2.50 ROPER.— Hand-Book of Modern Steam Fire-Engines. With illustrations. By Stephen Roper, Engineer. Fourth edition, i2mo., tucks, gilt edge #3-50 ROPER. — Questions and Answers for Engineers. This little book contains all the Questions that Engineers will be asked when undergoing an Examination for the purpose of procuring Licenses, and they are so plain that any Engineer or Fireman of or dinary intelligence may commit them to memory in a short time. By Stephen Roper, Engineer. Third edition . . . # 2 .oo ROPER. — Use and Abuse of the Steam Boiler. By Stephen Roper, Engineer. Eighth edition, with illustrations. i8mo., tucks, gilt edge « 2 00 ROSE.— The Complete Practical Machinist: Embracing Lathe Work, Vise Work, Drills and Drilling, Taps and Dies, Hardening and Tempering, the Making and Use of Tools Tool Grinding, Marking out Work, Machine Tools, etc. By JOSHUA Rose. 395 Engravings. Nineteenth Edition, greatlv Enlarged with New and Valuable Matter. i2mo., 504 pages. '. . #2.50 ROSE. — Mechanical Drawing Self-Taught : Comprising Instructions in the Selection and Preparation of Drawing T nstruments, Elementary Instruction in Practical Mechanical Draw- 24 HENRY CAREY BAIRD & CO.'S CATALOGUE. ing, together with Examples in Simple Geometry and Elementary Mechanism, including Screw Threads, Gear Wheels, Mechanical Motions, Engines and Boilers. By Joshua Rose, M. E. Illustrated by 330 engravings. 8 vo, 313 pages .... $4.00 ROSE. — The Slide- Valve Practically Explained: Embracing simple and complete Practical Demonstrations of th> operation of each element in a Slide-valve Movement, and illustrat- ing the effects of Variations in their Proportions by examples care- fully selected from the jnost recent and successful practice. By Joshua Rose, M. E. Illustrated by 35 engravings . $i.oa ROSS. — The Blowpipe in Chemistry, Mineralogy and Geology: Containing all Known Methods of Anhydrous Analysis, many Work- ing Examples, and Instructions for Making Apparatus. By Lieut.- Colonel W. A. Ross, R. A., F. G. S. With 120 Illustrations. i2mo. . $2.00 SHAW. — Civil Architecture : Being a Complete Theoretical and Practical System of Building, con- taining the Fundamental Principles of the Art. By Edward Shaw, Architect. To which is added a Treatise on Gothic Architecture, etc. By Thomas W. Silloway and George M. Harding, Architects. 'The whole illustrated by 102 quarto plates finely engraved on copper. Eleventh edition. 4to. $6.00 SHUNK. — A Practical Treatise on Railway Curves and Loca- tion, for Young Engineers. By W. F. Shunk, C. E. 121110. Full bound pocket-book form $2.00 SLATER.— The Manual of Colors and Dye Wares. By J. W. Slater. i2mo $3-oo SLOAN. — American Houses : A variety of Original Designs for Rural Buildings. Illustrated by 26 colored engravings, with descriptive references. By Samuel Sloan, Architect. 8vo. ...... .75 SLOAN. — Homestead Architecture: Containing Forty Designs for Villas, Cottages, and Farm-houses, with Essays on Style, Construction, Landscape Gardening, Furniture, etc., etc. JUustrated by upwards of 200 engravings. By Samuel Sloan, Architect. 8vo. ..-,.... $2.50 SLOANE. — Ho.re Experiments in Science. By T. O'Conor Slc\ne, E. M., A. M., Ft. D. 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VAILE. — Galvanized- Iron Cornice-Woiker's Manual: Containing Instructions in Laying out the Different Mitres, and Making Patterns for all kinds of Plain and Circular Work. Also, Tables of Weights, Areas and Circumferences of Circles, and other Matter calculated to Benefit the Trade. By Charles A. Vaile. Illustrated by twenty-one plates. 4to (Scarce.) VILLE. — On Artificial Manures : Their Chemical Selection and Scientific Application to Agriculture. A series of Lectures given at the Experimental Farm at Vincennes, during 1867 and 1874-75. By M. Georges Ville. Translated and Edited by William Crookes, F. R. S. Illustrated by thirty-one engravings. 8vo., 450 pages #6.00 VILLE.— The School of Chemical Manures : Or, Elementary Principles in the Use of Fertilizing Agents. From the French of M. Geo. Ville, by A. A. Fesquet, Chemist and En- gineer. 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