446 Proceedings of the Royal Physical Society. 



sion that the result of analysis would reveal an jthing unusual . 

 Mr Binney proceeded with the analysis under my direction ; 

 and it was only on the completion of it, and inspection of the 

 results, that Mr Gellatly and myself were struck with the 

 disagreement that seemed to exist between the external 

 characters of the mineral and its chemical composition. As 

 it presented the external characters of a steatite, it was re- 

 garded by all who examined it to be a variety of that mineral ; 

 but the analysis showed it to contain only a comparatively 

 small quantity of magnesia, which is the characteristic base 

 of the steatites, while at the same time, the alumina had a high 

 percentage ; in other minor features, also, the composition 

 did not correspond with any of the published analyses of 

 steatites. 



Having arrived at this result, it was needful, to avoid error, 

 to make fresh analyses, which were accordingly made by Mr 

 Binney and myself independently, and the numbers thereby 

 obtained are those which have been put below side by side 

 with each other. The result of these second analyses in a 

 great measure confirmed the first, though they showed a com- 

 position widely different from that of steatites generally. 



The typical composition of a steatite is, that it consists of 

 silica, magnesia, with more or less water : these are the usual 

 constituents enumerated ; but it will be seen that the mineral 

 we have analyzed differs from that type in containing but 

 little magnesia, a good deal of alumina, and protoxide of iron; 

 along with a diminished percentage of silica. There is, how- 

 ever, one variety of steatite, called byHauy "saponite,"* which, 

 by both Klaproth's and Swanberg's analyses, contains con- 

 siderable amounts of alumina as well as magnesia ; but even 

 here the quantity of the former base does not exceed 10, and 

 that of the latter is not set down as less than 25 per cent. 

 To neither of those numbers do the percentages which we 

 obtained approach ; so that from the composition of the mineral, 

 coupled with the following physical characters, we are in- 

 clined to think there are sufficient grounds for concluding that 

 it is a new species. 



* Dana, Ed. 1850, p. 253. 



