282 
MINUTES OF PROCEEDINGS OF 
Phosphorus (amorphous) 8 parts mixed with 10 per cent, of calcined magnesia. 
Of the above mixture ... 8 parts. Shellac ,. 5 \ parts. 
Potash, chlorate of.16 „ Glass, ground. 6 „ 
the whole damped and made into a paste with about 30 minims of methy¬ 
lated spirits. 
The detonator rests upon a small india rubber washer,, and is protected 
on its upper side by a thin brass disc. 1 2 
The two Suspending Pins iii) are small pins of copper 3 by means of which 
the pellet is suspended in its position: they are screwed at one end 3 to fit the 
holes in the sides of the body. 
The four Washers, or discs, have been mentioned in the above description. 
The body of the fuze is lacquered externally. 4 
Action :—Before the fuze is fired the pellet is suspended by means of 
the two suspending screw pins, within about one-tenth of an inch of the 
needle point, about the same distance intervening between the bottom of 
the pellet and the bottom of the fuze. 
On the discharge of the gun the inertia of the pellet breaks the suspending 
pins, and the pellet rests during the flight of the projectile through the air 
on the bottom of the fuze. On the shell striking an object the pellet is 
thrown violently forward, the needle point being thus brought into contact 
with the brass disc, which it pierces, and so fires the detonating composition, 
the flame from which flashes through the pellet, blowing out the disc with 
which the fire-hole is closed, and communicating with the bursting charge of 
the shell. 
This fuze may be used with the four lower natures of segment shells,—with 
or without the brass time-fuze. 
It may be distinguished from Sir Wm. Armstrong's field service per¬ 
cussion-fuze C, by the presence of the two suspending pins and by the 
absence of a safety pin f also by the two small key-holes in the bottom; 
in other respects the appearance and dimensions of the two are almost 
identical. 
1 Brass plate *005 inch thick. The necessity for thus protecting the detonating composition requires 
a word of explanation. In Sir Wm. Armstrong’s first experimental brass percussion fuze the 
composition was not thus protected, and it was found in practice with the 9-pr. shell that explosions 
frequently occurred during the flight of the projectile through the air. This was explained by the 
fact that the 9-pr. shell being light it lost its velocity very rapidly, but the initial velocity having 
been communicated to the parts of the fuze, the pellet had a tendency to retain the higher velocity, 
or rather, to lose its velocity less rapidly than the shell, and thus had a tendency to work forward, 
whereby the detonating composition and needle point were brought into gradual contact, and 
premature explosions were the result. To obviate this defect the brass disc was added, its strength 
being sufficient to guard the fuze against premature explosions arising from this cause, but not 
sufficient to interfere with the action of the fuze on the shell striking an object. The disc is retained 
in the present fuze. 
2 The plain part of the pins is in diameter:—High, *11 inch; low, ’108 inch. The screwed part of 
pins is in diameter ‘125 inch.— Specification. 
3 With a right-handed screw 36 threads to the inch.— Ibid. 
4 With ordinary brass lacquer. 
8 Some of the first C percussion fuzes were issued without a safety pin; but even in this case 
there will be no difficulty in distinguishing the two fuzes. 
