Besides the binary combinations of copper and zinc and copper and tin, there are _ternary_ combinations of these metals, namely, alloys of copper, zinc and tin. For instance, the metal of which common white buttons are made. I had occasion to analyse a specimen of this metal and found it to be constituted of 4 parts copper, 1 of zinc and 1 of tin; or 4 atoms of copper, 2 of zinc and 1 of tin. It will be proper to subjoin the methods of analysis which I adopted in regard to brass. Twenty grains, more or less, of the particular articles were dissolved in nitric acid, and the metals were precipitated in the state of sulphurets by hydrosulphuret of lime. The copper is thrown down in the state of a black powder, and the zinc in that of a white powder turning to grey. Great care was taken to add the precipitating liquor gradually in order that the copper might be obtained distinctly from the zinc. The whole of the copper is thus thrown down before any of the zinc precipitate appears. The precipitates were collected and dried in a temperature not exceeding 150°, and then weighed. In both cases one third of the weight was allowed for sulphur, and the remaining two thirds were estimated to be metal; which is agreeable to the known constitutions of these sulphurets. Another method I sometimes practised, which also answers very well; namely, to throw down the whole or greatest part of the copper by a plate of lead, then to throw down the lead by sulphuric acid; after this the liquor was tested by hydrosulphuret of lime to precipitate the copper remaining, if any; and lastly to throw down the zinc by hydrosulphuret of lime. 6. _Copper and bismuth._ The alloy is brittle and of a pale colour. It is not much known. 7. _Copper with antimony._ Copper and antimony unite by fusion and form a violet coloured, brittle alloy. 8. _Copper and arsenic._ These metals unite by fusion in a close crucible, the surface of the mixture being covered with common salt to prevent the oxidizement of the arsenic. The alloy is white and brittle, and is known by the names of _white copper_, and _white tombac_. 9. _Copper and manganese._ These may be united by fusion, and form a red coloured, malleable alloy, according to Bergman. 10. _Copper and molybdenum._ These metals may be alloyed in various proportions, but the compounds exhibit nothing peculiarly remarkable. _Alloys of Iron with other Metals._