Intelligence and Miscellaneous Articles. 321 



forms on killas amorphous crests of a greenish-blue colour, with a 

 waxy surface, and about 5 to 8 millims. in diameter. Its composi- 

 tion is as follows : — 



CuO . . 46-87 



SO 3 1250 



APO 3 17-66 



HO 22-86 



99-89 



According to the formula assigned by Mr. Church to this sub- 

 stance, it is a sulphate of copper associated with a hydrate of the 

 same base along with a hydrate of alumina. 



Having this year received from Mr. Tailing, to whose researches 

 we owe the discovery of several interesting minerals in Cornwall, 

 a substance found under the same conditions of deposit as Wood- 

 wardite, and strongly resembling it in aspect and texture, though of 

 a brighter green colour, I thought it interesting to make a compara- 

 tive study of this mineral with that described by Mr. Church. 



The qualitative test gave, besides the elements of Woodwardite, a 

 quantity of silica sufficiently great to produce a jelly with concen- 

 trated hydrochloric acid ; but the colour of the solution shows that 

 it contains much less copper. 



I thought thence that Woodwardite was not a well-defined mine- 

 ral, but merely a mixture in varying proportions of a subsulphate of 

 copper with a hydrate of alumina. Yet on examining for silica, I 

 found it in a quantity too small to constitute a silicate with alu- 

 mina. 



An analysis of Woodwardite gave me the following numbers : — 



Oxygen. Ratio. 

 Oxide of copper .... 46*8 9*4 4 



Sulphuric acid 117 7'0 3 



Alumina \ 13'4 



Silica 1-2 



Water. 



The ratio of the sulphuric acid and the oxide of copper are as 

 3 : 4. This is the same as that I gave for Langite. 



The following is the result of the analysis of the new mineral re- 

 sembling Woodwardite : — 



Oxygen. Ratio. 



Oxide of copper 17*4 3*52 4 



Sulphuric acid 4*7 2*82 3 



Alumina 33-8 



Silica 6*7 



Water 38-7 



lOTS 



It will be seen from this analysis that the quantity of alumina 

 does not correspond to that found in Woodwardite, while the quan- 



