226 
ME. EOBEET MALLET ON VOLCANIC ENEEGY. 
or 42303 , 5 X 165-431 = 6998310-31 foot-pouncls per cubic foot of quartz ; and dividing by 
J=772, 6998 y 3 y 1 0 ° 3 - =9065-2 degrees Fahrenheit in 1 lb. water as the equivalent of the 
crushing worJc of 1 cubic foot of quartz-powder of yyy of a square inch of fineness. 
Secondly, we have the lowest data, viz. that 424 lbs. falling 0-5653 foot 52-143 
times per minute produces 6736 lbs. of quartz-powder of a fineness = 6 - 6 ,^ 43 of a square 
inch in 24 hours. 
Assuming in both calculations that the greatest power is consumed in producing the 
smallest quantity in total of the finest powder, then 
424 lbs. falling 0-5653 feet x 52-143 = 29-479 feet per minute, 
or 29-479x1440 = 42449-76 feet per 24 hours, 
which is 424 lbs. X 42449-76 = 17998698-24 foot-pounds, being the work to crush 
6736 lbs. of quartz, 
or 
1799SG98-24 
6736 
= 2672-01 foot-pounds expended per pound of quartz, 
or 2672x165-431 = 442031-632 foot-pounds per cubic foot of quartz; 
and dividing by J = 772, 
442031-632 
772 
= 572 0, 5S Falir. in 1 lb. of water as the equivalent of 
the crushing work of one cubic foot of quartz-powder of ( , 6 4 3 of a square inch fineness. 
We thus come to this : ygy of a square inch, allowing say yy inch for the diameter 
of the wires of the wire gauze or screen, was about yy inch average diameter of the 
largest fragments ; x 16 x 5 7 of a square inch, same allowance, was about yy inch average 
diameter of fragments ; -. 6 .n of a square inch, same allowance, was about yy inch 
average diameter of fragments. 
Then the proportionate foot-pounds to sizes of fragments and equivalent of heat are 
(omitting decimals) : — 
18 - 14 1( j 
Foot-pounds 6998310 1795435 442031. 
Heat, degrees Fahr 9065° 2325° 572°. 
These results are valuable, from the general corroboration they afford of the correct- 
ness of the results as to crushing experimentally given in the body of this paper. The 
friction of the stamping-machinery is, as may be seen, excluded from our calculation; 
and except what small amount of power due to the fall of the “stamp-head” may be 
consumed in splashing about the water constantly flowing over the crushing quartz, there 
is almost no power consumed except directly in the pulverization of the quartz. 
