Kc'W Method of rendering Platma mallealle. 77 



tion is necessary In this operation but that of not breaking 

 the pieces during their transport. The mercury flies off 

 during the heat, and the platina remains perfectly solid; so 

 that, after being strongly ignited two or three times before 

 the bellows, it may be forged or laminated in the same 

 manner as gold or silver; care being taken, at the com- 

 mcncemeHit of the forging, or of passing it between 

 rollers, not to apply too'great a force till the metal has ac- 

 cjuired ail its density. It is almost superfluous to add, that 

 in evaporating the mercury from large quantities of amal- 

 g^am, a proper apparatus, such as in the silver amalgama- 

 tion, must be employed to receive the volatilized mercury; 

 but for small quantities, where the loss of this metal is of 

 no consequence, the furnace must have a proper chimney to 

 carry off the metallic vapours. When the platina comes 

 out of the rirst fire its dimensions are about two thirteenth 

 parts smaller every way than the original amalgam from the 

 mould. The whole of this operation seems to be governed 

 by the pressure of the atmosphere and the laws of cohesive 

 attraction; for the air is driven out from between the mole- 

 cules of the platina, which by their solution in mercury 

 are most probably in their primitive and consequently uni- 

 form figure. It is very visible, and at the same time a very 

 anmsing phacnt)mcnon to obseive, (during the process of 

 ignition, which is performed \u four or five minutes) how 

 the platina contracts every way into itself, as if pressed by 

 some external force*. 



I have also lately obtained triple salts of muriate of platina 

 with muriate of ponderous earth; and also with muriate of 

 magnesia; and I strongly suspect that every other earth ex- 

 cept the siliceous, and even the metals, are susceptible of 

 suchtriplccoinbiiiaiions. I havelikcwiseobtainedavery beau- 

 tiful salt of platina by the combination of soJa and platina 

 with the muriatic acid ; a combmalion v/hich Bergnvin and 

 several other chemists deny. Tlie best manner of obtaia- 



'^ In the Count''; letter to Mr. Hatclutt, requesting hiin to publish the 

 method in the tent (communicated 10 Mr. H. some years ago), the fol- 

 lowinK additioii is uivin : (in French.) 



" As soon as my amalj^am of mf.Tciirv h made, I compress the same in 

 tgbes (jf wood, by the pre...urc ot" an iro;i screw upon a cylinder of woo4, 

 adapted to the bore of the tube. This forces out the supcrahunc<ai): 

 mercury from the amalgam, and renders it solid. After two or three 

 hours I Imrn upon the coals, or in a crucible lined with chiircotl, the 

 <heath in which the amalgum is contained, and urj^e the fitc to a white 

 ktat; af er v.liich I take p'lt the platin-i in a \ery sulid stitc, fit tu be 

 tyrgcd." 



itiir 



