296 Major W. A. Ross on Jeypoorite. [May 15, 



matter, or raised by the boiling of fresh P added, the metallic mass or 

 ball rises to or touches the platinum wire. The glass is thus made to 

 act as a miniature test-tube, with this advantage, that any novel reaction 

 or peculiarity can, by removing it from the pyrocone, be immediately 

 preserved for inspection, like a fly in amber. 



(18) (a) 2*4 mgrs. of pure cobalt oxide were taken to standardize an 



assumed 50-mgr. P glass with an apparent red-violet colour. 



(b) It took four Jeypoorite crystals, weighing 3*2 mgrs., to bring 



another 3? glass, also measured only by the eye, to a similar colour*. 



(c) [a] glass weighed 76*5 mgrs., and [6] glass 79-2 mgrs. 



- (d) Then [a]=3-33 (standard of Co), and [ftjfe 4 per cent. 



(e) Therefore 3-3:4:: x (per cent,); and x=~ of 100, =82-5 per 

 cent, of cobalt. 



(19) I have not the means as yet of separating and estimating by my 

 methods small quantities of sulphur and sublimates ; but, assuming the 

 percentage of cobalt oxide in Jeypoorite to be about 82, of the remaining 

 18 I am led to believe there are nearly equal quantities of arsenic and 

 antimony, with very little sulphur — certainly not more than 5 per cent. ; 

 so that I would temporarily, until a sufficient quantity of the pure mineral 

 (not the sand) be obtained to submit it to a regular chemical analysis, 

 estimate the constituents of Jeypoorite to be about 



per cent. 



Oxide of Cobalt 82 



„ Antimony 7 



„ Arsenic 6 



Sulphur 5 



100 



(20) The garlic smell of volatilizing arsenic is only obtainable from 

 Jeypoorite by heating the mineral carefully with a ball of gold upon 

 charcoal. Plattner used gold for separating copper from its arsenide and 

 that of nickel (vide his 'Mckel and Cobalt Assay,' page 616 etseq.); but 

 he fuses the arsenides with the gold in borax, in which condition it would 

 appear that the gold takes up some arsenic and retains it (vide Gmelin's 

 'Chemistry,' vol. vi. p. 238, English translation). My use of gold, on 

 the contrary, is more mechanical than chemical, for the gold ball (weigh- 

 ing about 100 mgrs.) is placed in a round cavity made in a charcoal 

 mortar (" Pyrology," par. 88) slightly larger than its diameter, and a 

 crystal of Jeypoorite put on the offside or rear, i. e. the side away from the 

 blast. The whole front of the mortar is now covered with an H. P. 

 not too strong (fig.. 8, "Pyrology"), when the gold becomes red-hot, but 

 does not fuse. The cobalt of the arsenide has now a tendency to reduction, 

 and to join the gold in a metallic state, while the arsenic is volatilized by 

 * Neither of these glasses was coloured up to the standard of 5 per cent. 



