180 NATURAL HISTORY 
the other at the foot, (by flipping the flake which fupported it) is 
turned eafily from horizontal to perpendicular, and the tin, which 
remained on the frame, runs off, by the afTiftance of a little fprink- 
ling, into a wooden cheft, X, called the coffer, which lies below 
ready to receive it ; the frame is then righted into its horizontal 
pofition, and the fame procefs repeated, till the coffer is full ; the 
contents are then carried to the keeve N, where they are tozed, 
lifted, and packed ; the ore is then carried back again to the frame, 
W, and cazedy which is performed by flopping the lower end of 
the frame with flime and turf that the water may be quite ftill, and 
the tin more eafily fettle upon the frame, and defcend the more 
furely into the coffer ; the coffer is then emptied the fecond time, 
the tin carried again to the keeve, there tozed, fkimmed, and 
packed ; and thus the Himes are finifhed, and brought to as great 
a degree of purity as the fize of the tin (which, being exceedingly 
fmall, will neceffarily have fomewhat more of waft than what is 
larger and heavier) will permit. 
Thus proceeding only upon this Angle principle, that the force 
of water, properly applied and introduced among the particles of 
ore, and the fordes mixed with it, will difperfe the latter, and 
leave the former at reft for them to colleCt and treafure up, they 
vary their operations inconceivably, conducting with great ingenuity, 
leflening, increafing, diffufing, or contracting their water (the great 
inftrument of purity), as the fize, weight, and combinations of the 
metal and its feeders do require; indeed, it is furprizing to fee with 
what eafo, cheapnefs, and regularity all thefe feveral proceffes are 
performed. 
It muft here be remembered, that mundic, and fome other femi- 
metals, being Ipecifically heavier than the tin, whatever tin-ore is 
incorporated with thefe muft firft be burnt, and the lulphur, &?c. 
evaporated, and then, and not otherwife, will the water wafh 
away the remains of the femimetal, and leave the tin behind. This 
bufinefs of dreffmg is a particular trade, entirely different from that 
of the labouring miner, and is beft learned under a mafter-work- 
man, who makes it his foie occupation to follow the ftamping-mill, 
and the works belonging thereto. This mafter- workman hires boys 
from foven or eight years old to eighteen, gives the former about 
three {hillings a month, and raifes their wages as they advance in 
age and workmanlhip, till they have man’s wages, viz. at the leaft 
twenty-four fhillings, at the higheft thirty fhillings per month. 
This is of double benefit to the poor parents; the boys being taken 
in fo young become healthy and hardy by ufing themfelves to cold, 
and to work with wet feet all day ; and, 2dly, they learn early to con- 
tribute to their own maintenance. Each ftamping-mill, which has 
conftant 
i 
