SHORT NOTES ON PROFESSIONAL SUBJECTS. 
138 
into the centre of the debris. The explosion was not characterised by the sharp 
report usual to gun-cotton, and the splinters were not thrown to a greater distance 
than 50 yds. The diameter of the chief debris was about 90 ft. 
The most remarkable feature of this experiment, was the ease, rapidity, and 
safety with which the work was performed. There was no previous preparation, no 
sinking shafts, tamping charges, &c., &c. The Engineer Committee brought a 
few boxes of gun-cotton, a few hundred yards of copper wire, and a small frictional 
machine. In about an hour after their arrival, the tower was a heap of bricks and 
rubbish. 
Elevational Section on the Line AJ3. 
