306 Prof. J. Joly on the Apophorometer. 



(2) No further black sublimate could be obtained at the 

 former temperature. Raised to a full red, a white sublimate 

 collected. The sublimate after 20 minutes' heating was 

 removed and weighed : weight 6*4 mgrms. 



If the black sublimate be TeO and the white be Te0 2 , the 

 weight of Te is 7*3 mgrms. 



The residue on the ribbon was of a yellow colour and was 

 fluid at the final temperature. The \s eight of it was found 

 to be 24*7 mgrms. Assuming that it is Bi 2 3 the weight of 

 Bi is 22'2 mgrms. The added weights are about 8 per cent, 

 too great. As for the proportions, the mineral is variable 

 in composition, and species exist closely resembling it in 

 appearance which are also bismuth telurides but with largely 

 preponderating amounts of bismuth, e. <j. joseite and 

 wehrlite. 



Smaltite. CoAs 2 . Co 282; As 71*8. Weight taken 15'2 mgrms. 



A white sublimate at very low red heat. The lower glass 

 broke before the experiment was quite completed. Weight 

 of sublimate 9*8 mgrms. This is As 4 6 and contains 7 '3 

 mgrms. of As, or 49 per cent. This being too little ac- 

 cording to the formula, a second experiment was made on 

 the same specimen : 



Smaltite, as above ; weight taken 25 mgrms. Care was 

 taken to complete the sublimation. Result 54*4 per cent, 

 of As. 



Hence the first experiment is sustained. A borax bead 

 made with the residue on the platinum gave a muddy brown 

 colour. The substance, although labelled smaltite and greatly 

 resembling that ore, cannot be the cobalt arsenide. This 

 specimen was from the collection in Trinity College. It was 

 resolved to try one from another source. 



Smaltite, specimen recently purchased from an American 

 dealer and labelled with the formula (Co, Ni) As 2 which 

 should give the same proportion of As as before. 



Weight taken 22*1 mgrms. Total weight of sublimate 

 obtained after raising to a yellow heat, 15'6 mgrms. or 11*8 

 mgrms. of As. This is 54 per cent. The weight of the 

 residue was found to be 12*4 mgrms. This, which is black 

 in colour, is doubtless C03O4 and contains 9*3 mgrms. of the 

 metal. The added weights come to 21*1 mgrms. It is 

 noteworthy that this corresponds very nearly to the formula 

 (Co, Ni) As. It seemed possible that these smaltites corre- 

 spond to the highly nickeliferous varieties having the 

 formula RAs-t-RAs 2 which have been recorded with as 

 little as 58 per cent, of As. As it was desirable to deal with 



