358 
/TT' 
hn . 
The above methods of assaying tin ore, by means of 
the fixt alkalies, is due to Klaproth : but the following 
method in the dry way, appears to me sufficient for most 
purposes, and less complicated. 
Pound the ore ; separate it from the stony matters that 
accompany it ; take a piece the size of a pepper corn, and 
roast it on charcoal with the blow pipe ; if any sulphu- 
reous or arsenical fumes should arise on this trial, the 
pounded ore must be well roasted previous to fusion, with 
a little charcoal ; if no such vapours appear, the roasting 
may be dispensed with. Take 400 grains of the ore; 
smear the sides of a crucible with charcoal, and put a 
small quantity of charcoal dust in the bottom ; mix up 
your pulverized ore with pitch and sawdust ; lute a co- 
ver on your crucible ; urge it with a fire quickly raised, 
during fifteen minutes in an air furnace or blacksmith’s 
forge. 
The method of treating the ores of tin in Cornwall, Eng- 
land, is two-fold. The first that we shall mention, is that to 
which the tin-stone from the mines or vein-tin is subject- 
ed ; the second is that by which the stream tin is re- 
duced, 
1. The vein-tin is procured by blasting, and when 
brought to the top of the pit, is in fragments of various 
sizes, and mixed so largely with quartz, argillaceous 
schistus, granite, and other impurities as rarely to contain 
more than 2 per cent, of metal. The first preparation 
that it receives, is being broken by hand hammers, about 
the size of hens’ eggs, after which it is ready to be stamp- 
ed, The stamping- mill is of the usual construction, ex- 
cept that the stampers are only three in number, and in 
front of the trough or coffer, there is inserted a plate of tin 
about a foot square, pierced full of holes, large enough to 
admit a moderate sized knitting-needle ; that surface of 
the plates which is occupied by the rough extremities of 
