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Z. One part os platina and four of brass, covered as be-fore with borax, and exposed to a quick fire, melted toge-ther without loss. This compound proved yellower thanthe preceding, and softer to the file; it bore to be cutsome depth with a chisel before it broke, and received someimpression from the hammer, stretching a little, but sooncracking in various directions.

4. Upon increasing the brass to six times the weight ofthe platina, the compound appeared yellower, though stillvery pale. It proved softer to the file; and stretched moreunder the hammer, and received a deeper impression fromthe chisel, before it broke.

5. A mixture of one part of platina and twelve of brasswas considerably paler, and much harder, than brass. Itbroke under the chisel; and cracked, before it had ex-tended much, under the hammer. Both this and the twopreceding compositions bore a tolerably good polissi, andhave not tarnished so much as brass by itself; though inboth respects they fall short of No. 1 and 2.

XII. Platina with Copper and Pin.

1. Fifty parts of platina, seventeen of copper, and sixof tin, covered with borax, became fluid in a strong fire,and suffered very little loss. The ingot proved consider-ably hard, so as scarce to be touched by the file; and verybrittle, breaking from a moderate blow, of a rough sur-face, and dull bell-metal colour. It bore a good polissi,and continues untarnissied.

2. Platina and copper of each one ounce, and fourounces of tin, melted perfectly together, with little or noloss. This compound filed freely and easily, and bore tobe cut with a knife, but broke readily on the anvil; thefracture was of an irregular surface, and a dull whitish co-lour. Polissied, it looked like polissied iron: the fracture

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