178 Transactions.—Miscellaneous. 
Stamp boxes are generally constructed to hold five stamps ; they are 
of castiron in one piece, are three inches thick at the bottom and aninch and 
a half to one inch at the sides. The bottoms and sides are protected from 
the corroding action of the stamps and quartz by cast iron dies and linings. 
The boxes have two hoppers behind for feeding, and two openings in front 
for the gratings, to screen the crushed quartz. It has been attempted to 
have grating openings behind the box as well, but found not to answer, 
there being greater trouble to regulate the flow of water over the two tables. 
This remark applies to side openings also. The stamp boxes used at 
present are excellent, the only improvement I can suggest in them is that 
the openings for the gratings, which are now made vertical, should have a 
forward inclination on the top. This, I think, would allow the erushed 
material to escape more freely. 
The shoes of the stamps and dies in the boxes, as well as the linings, 
are at present made of comparatively soft iron. They should be made of 
the hardest white iron, and chilled. If battery proprietors took the trouble 
of sending to England for their shoes, dies, and linings, they would find it 
to their advantage, not so much in cost as the great saving in material and 
time lost in changing the different parts when worn out. 
The cams for raising the stamps are very seldom of a proper shape ; 
they are either too curved or too straight. They should be so constructed 
that the motion of the stamp be uniform, and, as soon as the stamp is 
raised to its greatest height, it should drop, and not for one moment before 
it is elevated for the next stroke. There is no trouble in constructing a 
cam with the necessary curve to do exactly as required, and, if so con- 
structed, a battery may be driven up to 80 strokes a minute, without the 
risk of the discs striking the cams. Z 
The screens or grates for sifting the crushed quartz usually used are 
perforated iron plates; the number of perforations are from 100 to 132 
holes to a square inch, the greater the number the finer the holes. It is 
surprising how this kind has not been superseded by the iron wire grating, 
which is superior in many respects, especially in allowing more material to 
pass through in a given time, thus causing a great saving in cost of 
crushing ; and I am further convinced more gold would also be saved, as, by 
the present use of quicksilver in the boxes, 
sarily battered and converted into black 
pulverised with base minerals. This sickened amalgam will pass over silver 
the amalgam formed is unneces- 
but generally in two or 
: The quicksilver ripples 
eighths of an inch deep at the top, and half an 
