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in height, and near to a salient angle where the quarry workings 
met at a right angle. The line of least resistance of the first 
charge was 5 ft. 8 in. from the corner ; 4 ft. still further away 
from this first charge was placed the second charge, and at 
4 ft. 8 in. yet again was the third charge. The bores 
were 3 ft. 4 in. in depth, and 1 J in. in diameter. The 
thickness of the bed of rock was 18 in. Each hole was 
loaded with 1 lb. of lithofracteur, and was tamped with water. 
It need scarcely be said that gunpowder in such holes would 
merely shoot its solid tamping out like a shot from a gun, and 
that no work at all would be done in the rock. The middle or 
No. 2 charge was first fired, and blew out a cavern of trian- 
gular form over 1 ft. 6 in. along each of its bounding lines, 
and the depth of which cavern was 3 ft. 6 in. ; the contiguous 
bed was shivered for a distance of 6 ft. on each side, and 
shaken and fissured over a length of 20 ft. From such a 
heading, further convenient workings were at once practicable. 
The other two shots were also similarly effected. We thus set 
the superior action of the violent nitro-glycerene detonation 
over the slower burning explosions of gunpowder. To give 
now an example of floor work, in which gunpowder would 
equally do no more than fire a shot. A flat toe of rock ran 
out from a bight in the Breidden greenstone cliff, and open 
on one side and in front only. This toe was 12 ft. in length, 
5 ft. in width, tapering to a point, with its surface dipping 
from about 5 ft. extreme height at its junction with the cliff 
to the level of the floor at the toe ; the charge, a little over 
1 lb. of lithofracteur, being put midway on the slope in the 
position of the mean height of 2 ft. The bore hole was 
3 ft. 6 in. deep and 1 \ in. in diameter. When the charge 
was fired, splinters of stone were sent into the air more than 
800 ft. up ; and the mass of the floor shattered completely 
over an area of 8 ft. 8 in. by 2 feet 2 in., and 3 ft. 6 in. 
deep, besides which eight considerable fissures were riven 
into the surrounding rock. Some of the blocks disrupted took 
five men with crowbars to move. The line of least resistance 
in this case had been 5 ft. 6 in. ; but the explosion was so 
sudden and effective, that the charge acted in all directions 
alike ; the fissures striking downwards as well as laterally — the 
full effects of the blast, indeed, not being ascertained until a 
considerable time afterwards in the course of the quarry work- 
ings. It has been said that 45 tons of stone were raised 
altogether from this one blast. 
In Germany, lithofracteur has been used for the breaking up 
of pig and waste iron. This was first done at the suggestion of 
Herr Biittgenbach, director of the Neuss Foundry. It has also 
been similarly used at Krupp’s great steel works at Essen. The 
