342 
ME. F. A. ABEL’S CONTEIBTTTIONS TO 
portions, at the extremity most distant from the initiative explosion. With tubes 2 feet 
(•608 m.) in length, the gun-cotton disks being just inserted into each end, perfect 
detonation by transmission was attained. A variation of the mode of arrangement 
furnished the same result. One pound of compressed gun-cotton was placed in a pit 
dug in the ground; one extremity of a tube (T25 inch in diameter and 2 feet long) was 
allowed to rest upon it, and was buried in the ground in this vertical position, the earth 
being firmly rammed round the charge and tube. A perforated disk of gun-cotton, 
weighing 1 ounce (3T2 grms.), and containing a detonating electric fuse, was just 
inserted into the open end of the tube, and exploded ; the charge at the opposite end of 
the tube was detonated, a large crater being produced in the ground, and the iron being 
violently projected to a great height. In a corresponding experiment made with a tube 
3 feet ( , 91 metre) in length, the buried charge was only inflamed by the detonation of 
1 ounce of gun-cotton at the upper extremity. 
With the employment of 2 ounces (62‘4 grms.) of compressed gun-cotton as the 
detonating agent, experiments were made with tubes gradually reduced in length from 
6 feet (1*82 metre) to 5 feet (1‘53 metre) ; with such a tube complete, detonation of 
the gun-cotton at the distant extremity was obtained *. 
These experiments were subsequently repeated with the employment of stouter 
wrought-iron tubes, but of the same lengths and diameter (l - 25 inch, ’031 m.) as 
those before used. In these the shattering and opening-up of the tube at the seat of 
the initiative detonation were less considerable, but increased eflects as regards the 
transmission of detonation were obtained. The detonation of only 0’5 ounce (15*6 grms.) 
of gun-cotton, inserted into one extremity of a tube 2 feet long, detonated a charge in 
the opposite extremity — a result which it required 1 ounce (3T2 grms.) to accomplish in 
the previous experiments, while the latter quantity, employed in the stouter tubes, induced 
detonation through a tube 3 feet 3 inches (1 metre) long. 
Trials were made of wrought-iron tubes only 1 inch (-0254 m.) in diameter, and 
of similar thickness to those first used in the experiments with the wider tubes ; no 
detonation was transmitted, when the disk of gun-cotton was simply placed against the 
opening of one extremity of the tube, on the detonation of 1 ounce just at or within 
the other extremity; but when hoth charges were inserted into the extremities, the 
detonation was transmitted to a distance of 3 feet with the employment of 1 ounce of 
gun-cotton, while with the wider tube of similar thickness complete detonation was only 
obtained with certainty at a distance of 2 feet ( - 608 m.). 
In other experiments wrought-iron tubes of larger diameter were used. A stout 
wrought-iron tube, T75 inch (’45 m.) in diameter and 3 feet (‘91 m.) in length, 
had a charge of 3 ounces of gun-cotton (1 inch, ’025 m. diameter) just inserted 
* In these experiments, when detonation of the distant charge was obtained, the destructive action upon the 
iron tube was always greatest at that extremity ; the sudden obstruction of the wave of gas by the induced 
detonation was evidently productive of greatly increased destructive effects from the point at which the opposing 
columns of gas met. 
