Mr. William Phillips on the OxydofTin. 343 



work, containing it is said the value of ten or eleven guineas in 

 weight of gold. It is in the collection formerly belonging to the 

 late Philip Rashleigh, Esq. of Menabilly. 



Tin is not found mineralized by any other metal, and rarely in 

 intimate combination with any other, except with copper in that 

 mineral which is known by the name of sulphuret of tin. This 

 substance has also obtained the names of bell-metal ore and 

 pyritous tin. It is the Zinnkies of the Germans, the Etain 

 pyriteux of the French, and has hitherto only been discovered in a 

 mine called Huel Rock in the parish of St. Agness, in mass, never 

 crystallized.* According to Klaproth, it contains tin 34, sulphur 

 25, copper 36, iron 2. Its colour is steel-grey, passing into 

 bronze-yellow, in some parts inclining to silvery. Its fracture is 

 unequal and granular. According to Klaproth, its specific gravity 

 is 4.350 ; under the blowpipe it emits a sulphureous odour, and 

 passes into a blackish slag : it gives a yellow tinge to glass of borax. 

 Its lustre is metallic. It is brittle and easily frangible. 



Among the specimens of oxyd of tin in my collection, it may be 

 observed occurring 



In Granite — in minute crystals interspersed through granite, from the 

 south-west side of St. Michael's Mount — in granite, with chlorite 

 and schorl from the south side of Redruth Church-town — with 

 schorl in granite from near St. Just. In decomposing granite 

 from Polgooth mine. 



* Kirwan has described this mineral as " Tin mineralized by sulpliur and associated 

 with copper." On this definition Haiiy has the following remark. " It may be proved 

 by other examples, that this celebrated chemist is of opinion, which appears to me to be 

 well founded, that a principle that presides in regard to quantity, may be only an 

 accessary. Mineralogy will have made a great stride towards perfection, when this 

 distinction between essential principles and those which are only accidental, shall be 

 correctly applied to all minerals to which it strictly appertains." 



