OBSERVATIONS. II 
r 
Stream-Tin. 
Not only the above-mentioned tin- 
ftones, which are taken out of veins, pro¬ 
duce metal, but likewife what are 
obtained from ftream works, fimilar 
to thofe in Germany, yield a con- 
liderable quantity of rich tin ores. The 
manner of ftreaming or collecting the 
tin rubbles, with which the valleys of 
the tin mountains in Cornwall are filled 
in great abundance, and to confide- 
rable depth, is briefly the following; 
the foil of fuch valleys is dug feve- 
ral feet deep to the tin ftratum, and, 
by water led over, wafhed of all the waft. 
It is very probable that violent torrents 
©f water have broke thefe tin rubbles from 
the original veins of the tin mountains, 
and rolled them down the declivities of 
hills into the lower grounds. Mr. Jars, 
indeed, believes thefe fragments to be 
remains of heaps of refufe, from the an¬ 
cient unlkilful working of the mines, 
which by inundations have been wafhed 
down 
