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XI. New Method of raiderwg Plufhia mallcallc. Bi/ 

 Count Apollos Moussin Poushkin. Made pub- 

 lic, at his Bequest, li/ Charles Hatch ktt, Esq. 

 F. R. S* 



1. JLBECiPiTATE the platina from its solution by muriate 

 of ammonia, and wash the precipitate with a little cold 

 water. 



2. Reduce it in a convenient crucible to the well-known 

 spungy metallic texture; which wash two or three times 

 with boiling water, to carry off any portion of saline matter 

 which may have escaped the action of the fire. 



3. Boil it for about half an hour in as much water mixed 

 with one tenth part of muriatic acid as will cover the mass 

 to the depth of about half an inch in a convenient glass 

 ■vessel. This will carry off any quantity of iron that might 

 still exist in the metal. 



4. Decant the acid water, and edulcorate or strongh' 

 ignite the platina. 



5. To one part of this metal take two parts of mcrcur\', 

 and amalgamate in a glass or porphyry mortar. This amal- 

 gamation takes place very readily. The proper method of 

 conducting it is to take about two drams of mercury to 

 three drams of platina, and amalgamate them together; and 

 to this amalgani may be added alternate small quantities of 

 platina and mercury till the whole of the two metals are 

 combined. Several poHuds may be thus amalgamated in a 

 few hour&, and in the large way a proper mil! might shorten 

 the operation. 



6. Aficr the amalgam is completely produced, it must be 

 quickly moulded in bars or plates, or any other forms that 

 mav be preferred ; taking care that these moulded pieces 

 should at least be half an inch in thickness, and of a pro- 

 per length to manage them afterwards in the fire; it is also 

 requisite that the moulds should be perfectly even and 

 smooth. Half an hour after the pieces are tormcd thcv 

 begin to harden by tlie oxidation of the mercury, and change 

 their brilliant metaliic colour for a dull leaden one. 



7. As soon as the pieces have, acquired a proper degree 

 ^,of hardness to be handled without danger of breaking, 



which commonly takes place in a little more than an hour, 

 place them in a pro]irr furnace, and keep them ignited un- 

 der a muffle or in h small rcverbi-ratory. No other prccau- 



* Vnm Kic'.'.olsoji'- lounin!, vol. ix. Oct. 1804.. 



tieri 



