WRITINGS OF JAMES SMITHSON. 33 



The very small quantity which I possess of this ore, and 

 the manner in which it is scattered amongst another sub- 

 stance, and blended with it, have not allowed of more 

 qualities being determined, but I apprehend these to be 

 sufficient to establish its nature. 



This native minium seems to be produced by the decay 

 of a galena, which I suspect to be itself a secondary pro- 

 duction from the metallization of white carbonate of lead 

 by hepatic gas. This is particularly evident in a specimen 

 of this ore which I mean to send to Mr. GREVILLE, as soon 

 as I can find an opportunity. In one part of it there is a 

 cluster of large crystals. Having broken one of these, it 

 proved to be converted into minium to a considerable thick- 

 ness, while its centre is still galena. 

 I am, &c., 



JAMES SMITHSON. 



CASSELL IN HESSE, March 2d, 1806. 



From the Philosophical Magazine, Vol. XXXVIII, 1811, p. 84. 



After I had communicated to the president the account 

 of the discovery of native minium, printed in the Philo- 

 sophical Transactions for 1806, 1 learned that this ore came 

 from the lead mines of Breylau in Westphalia. 



