ALLOYS. 



63 



and zinc ; so gold and silver, or either of these, with copper. 

 But, in some instances, the properties of the alloy are different ; 

 thus bronze, although intermediate in color between its con- 

 stituents, copper and tin, presents an extraordinary combina- 

 tion of hardness and toughness. A small quantity of tin, 

 lead, or zinc renders gold brittle. By alloying metals, there- 

 fore, we may obtain bodies which, for all practical purposes, 

 are so many new metals. 



Bronze. — The following table exhibits the composition of 

 some ancient and modern bronze and bell-metal, according to 

 recent analyses. 



Title. 



1. Ancient Attic 



bronze 



2. Athenian bronze, 



of the Roman pe- 

 riod 



3. Athenian bronze.. 



4. Coin of a Macedo- 



nian king 



5. Coin of Alexander 



the Great 



6. Coin of Alexander 



the Great 



7. Attic coin 



8. " 



9. Darmstadt chime, 



B, above first line 

 10. Darmstadt chime, 



C, treble clef. 



88.46 



10.04 



7.05 

 10.85 



11.44 



3.28 



10.24 



11.58 

 9-61 



21.67 



21.06 



1.50 



16.54 

 5.53 



0.76 

 2.31 



1.19 

 2.14 



0.27 

 1.18 



0.17 



0.15 



trace 

 trace. 



2.11 

 2.66 



trace, 

 trace. 



Analyst. 



A. Mitsoherlich. 



Schmid. 

 Wagner. 



Monse. 



Schmid. 



Warner. 



Ulich. 



Heldt. 



Heyl. 



Heyl. 



See an excellent article on the alloys of copper and tin, In 

 Technologiste, and in the Lond. Journ. Oct. 1850. 



Speculum Metal. — (Chinese metallic mirrors.) — Copper 

 80.836 + Lead 9.071 + antimony 8.43 = 98.337. It con- 

 tained no trace of arsenic, exhibited a brilliant polish, and 

 did not tarnish in the air. The presence of antimony is in- 

 teresting, as it is not employed for metallic mirrors, and the 

 above metals will probably be well adapted to the mirrors of 

 telescopes. 



