304» SCIENTIFIC NEVfS.. 



muriate of ammonia, then wz^flied and dded, and expofed to 

 a graduated red heat for half an hour in a covered crucible. 

 The produft was a grey coagulated powder; confiftingof me- 

 tallic platina in a fiate of extreme divifion. One part of this 

 powder with three parts of mercury did not combine by half 

 kn hour's trituration ; but upon adding two parts more of mer- 

 cury and flightly heating the mortar, he foon obtained a tena- 

 cious amalgam, which was rendered very foft by the addition 

 of two other parts of thelaft mentioned metal. 



A fmall quantity of this amalgam was rubbed upon a plate 

 of copper, which became perfedly covered. The plate was 

 then ignited, and was found to have retained a coating of pla- 

 tina. In the next place he mixed a little of the amalgam with 

 chalk, fprinkled the mixture with water, coated the plate of 

 copper a fecond time, and again ignited it. The coating u'as 

 now found to be very perfe<^, and aflTumed a (hining filver co- 

 lour under the burnither. 



This chemift remarks that his application of platina to cop- 

 per veffels rauft be fuperior to that of tin; not only in its re- 

 liilance to acids and faline matters, but in its durability from 

 the greater hardnefs of platina; and he adds that the procefs 

 here defcribed, is not more difficult to be eflfeded than th^ 

 common operation of tinning. 



TromfdorJ's Journal, 1803, Vol. II, p. 18. 



