Crystals of Platinum

Abstract

SINCE writing a note on this subject to NATURE (vol. xliii. p. 541) I have found that it is by no means requisite to use topaz in order to obtain crystals of platinum from a ribbon of that metal heated by a current. Thus the ribbon may be dusted over with quartz dust, and if the temperature be raised to that at which this is slowly melting (1430° C. about), crystals of platinum gather upon projecting points on the quartz. Doubtless the presence of fluorine will facilitate, as described in my former letter, the volatilization of the platinum, but there is little doubt that at a temperature some 300° below its melting-point (1750°; Violle) there is a slow volatilization of the metal due either to heat pure and simple, or to this in conjunction with the presence of a current as in high vacua.