THE EOYAL ARTILLERY INSTITUTION. 
173 
The detonator fits into the head of the fuze, which is shaped to receive it ; 
the top of the detonator being flush with the top of the fuze, and the 
bottom a short distance above the composition. 7 (See Fig. 1.) 
The presence of the detonator renders necessary some modifications in the 
construction of the head: in the first place, as the top of the fuze does not 
require (as in the case of the common fuze) to be opened before placing it 
in the gun it is not provided with a cap; but over the top is glued a collar 
of felt, which serves to reduce the jarring effect produced by fixing the fuzes 
into the shell. 
In the second place, the top being closed by the detonator, an escape is 
provided for the flame of the burning composition at the side of the head 
immediately below the detonator, by three “ escape ” or fire holes (fig. 1 , gg) 
being bored into the fuze with a downwards inclination; these holes are 
equidistant from one another, two of them being situated on that side of the 
fuze which is away from the side holes and powder channels, the third 
dividing the space between the rows of side holes. 8 The “ escape ” holes 
are countersunk, and are closed by means of a disc of fine sheet copper 9 
(Fig. 1, k), over which is a millboard disc (Fig. 1, k), and finally a broad strip 
of fine paper 10 is pasted over the outside of the holes, * 11 and painted black ; 
by this arrangement not only is moisture effectually excluded, but the fuz e 
is secured against accidental ignition. 13 
7 Immediately above the three fire holes, of which mention is made in the text (see p. 172). 
8 This distribution of the escape holes is thought to be conducive to the safety and efficiency of 
the fuze, by taking away the escape holes from the neighbourhood of the powder channels, and thus 
diminishing the liability of any communication between the two. 
9 Copper *012 in. thick. 
10 White fine paper. 
11 Immediately below the wire woolding (see text, p. 174). 
12 That this arrangement does secure the fuze from accidental ignition is proved by the following 
experiment instituted by Col. Boxer, and described by him in a Memo, for the Ordnance Select 
Committee of the 18th February, 1884. The experiments were made on 16th February, 1864. 
1st Trial. Four 40-pr. shells with fuzes fixed were placed as in the diagram, and the cartridge 
exploded. None of the fuzes were ignited. 
2nd Trial. 
3rd Trial. 
4th Trial. 
6th Trial. 
None ignited. 
None of the fuzes were blown out, or loosened in any way. 
Since then the experiment has been frequently repeated ; always with the same success. 
Same repeated, with four new fuzes: none ignited. 
do do none ignited. 
Same repeated, with the same fuzes as were used in the third trial. None ignited. 
Same repeated, with the same fuzes as were used in the second and third trials. 
