34 
rorULAE, SCIENCE REVIEW. 
him grind the ore, whilst an attendant sprite is pouring a con- 
tinuous stream of water on the triturated mass. 
This is really what Mr. Readwin lias contrived to do. 
His “ Genius ” is the lovely waterfall which excited our ad- 
miration, and which is formed by the stream as it flows past 
the engine-house. 
Causing a portion of the water to diverge, he lets it flow 
along a wooden conduit that leads it to a little water-wheel, 
which is thus set in motion. This wheel turns a horizontal 
shaft or axle in the engine-shed, and, by means of two vertical 
cog-wheels attached to the shaft, and two other horizontal 
ones, into which these work, two smaller vertical shafts are set 
in motion, and to these are affixed the arms, which cause the 
grinders or pestles to revolve in the mortars containing the 
quartz. This is effected much after the manner in which a 
druggist’s apprentice pounds drugs with a large pestle and 
mortar. The arms attached to the vertical shaft are of iron, 
and the reader may form an idea of then’ shape and mode of 
operation, if he turns the palm of his hands downwards, doub- 
ling his thumb and two last fingers underneath, protrudes his 
first and second fingers, and slightly separates them, lowering 
the points. These two fingers will then represent the “ arms.” 
Let him now suppose that his fingers can be made to revolve 
horizontally, and that they carry round with them a pestle, 
which is held between them, but allowed to roll freely against 
the sides of a mortar, in which it works, and he will thus 
imitate the grinding or pounding process here employed. (See 
Plate IV.) The pestle is shaped iike a peg-top, with the pointed 
end downwards, and weighs about 2 cwt. ; and the mortar is 
a vessel of cast iron, of proportionate size and strength ; of a 
suitable form internally, and externally a hemisphere. The 
quartz is first broken as fine as the hammer can reduce it. It 
is then placed, along with mercury, in the mortar, and a little 
stream of water is allowed to trickle continually through a 
siphon upon the triturated mass. The gold contained in the 
quartz is taken up by the mercury as the trituration proceeds, 
and a lump of amalgam sinks to the bottom of the mortar, and 
is taken out through an opening closed by a plug. It is heated 
in an iron retort over a furnace, the mercury driven off, and 
the residue is pure gold, worth about £3 an ounce. 
In some cases, the gold is visible in the quartz, and Mr. 
Readwin showed us a piece of the latter, so charged with it, 
that he valued it (the crude mineral) at £1,200 per ton ; in 
others, it is scarcely to be detected with the aid of a pocket- 
lens, being disseminated in fine granules throughout the 
matrix. 
There are other processes by which the gold is extracted 
