360 NATIVE ARSENIATE OF LEAD. 



The other side of the ship is shown fitted up iti the common 

 way, that the contrast may be observed. 



Fig. 2 is a side view of the mast and rigging, in whicb 

 the same letters refer to the same parts. 



VIII. 



On a native Arseniate of J^ead. By the Rev. William; 

 Gregor. Communicated bt/ Charles Hatciiett, Esq, 



Native arseni- § 1. 1 HAT the oxide of lead and the arsenic acid might 

 ate of lead not ^^^ found in the state of natural combination, is a supposi^ 

 tion highly probable, from the strong affinity which subsists 

 between these two substances. But the existence of such a 

 compound has not, as I conceive, hitherto been established 

 by such proofs, as entitle it to be ranked among the decided 

 cases of mineralogical science. I trust, therefore, that the 

 observations, which I have the honour of submitting to the 

 till lately dis- Society, on a new f ore of lead lately discovered in the 

 covered county of Cornwall, so justly celebrated as well for theva* 



riety as for the richness of its mineral productions, will not 

 be deemed superfluous, 

 in a copper This mineral v/as raised in the mine called Huel- Unity, a 



mine in Corn- ^g^y ^.j^jj copper mine, in the parish of Gwennap. Ac, 

 cording to the information with which I have been favoured 

 by Mr. William Davey, a very intelligent and experienced 

 miner in that district, it was found in a lode south of Huel- 

 Unity principal lode, at the depth of fifty fathoms below 

 the surface, which lode underlay about two feet in the fa- 

 thom south. At the depth abovementioned, this lode fell 

 in, or formed a junction with another small lode or vein to 

 the south, and when the junction took place, this lead ore 



* Philos. Transact, for 1809, p. 195. 



t It is new at least to the miners in Cornwall ; nor was there, 

 previously to this discovery, any ore resembling it to be found in 

 that splendid collection of minerals, which my valuable friend 

 Philip Rashleigh, Esq., has so liberally formed, and as liberally 

 employed in the promotion of science. 



