1874.] British Artillery Matériel. 47 
VII. Complaints, it appears, are frequently made with 
regard to the irregularities in burning of Boxer wood time- 
fuzes, especially in mountain batteries, under varying 
atmospheric pressure above the sea-level. 
The whole subject of the influence of local altitude on 
the burning of time-fuzes has been carefully investigated 
both practically and theoretically,— 
Practically by Quartermaster Mitchell, in India, in 1849, 
at different altitudes, viz.: 
St. Thomas’s Mount . . . Sea level. 
Bangalore . .. s+ <- » = ooofeet: 
omeiteny 9.) 2. 255. 16500.",, 
Cctacamund 4) 4i.s “2. + +7300 
99 
Theoretically by Professor Frankland, in 1860, and subse- 
quently, practically, by the French Academy of Science, at 
altitudes, viz. :— 
Oonishi as as ets eso feet: 
eIMCEEO 2 Fs on. oe ss SOO). ,, 
@henallettis: = ours ee ORT | 
The agreement in these different and distinct observations 
was most remarkable, and from them was deduced the fol- 
lowing practical rule :— 
That the time of burning of a fuze increases in the ratio 
of ovoort of its value for each diminution of 0°0394 inch of 
barometrical pressure; or, in other words, of about 0°03 of 
its value for each variation of 1 inch pressure. Atmospheric 
pressure diminishes almost uniformly at the rate of 1 inch 
for every 1000 feet of altitude; hence the time of burning of 
a time-fuze increases 0'03 of its value for each increase of 
1000 feet of altitude, or 0°003 of its value for each variation 
of roo feet of altitude. 
Thus if a g-seconds fuze burns exactly g seconds at the 
sea level, it will burn 11°16 seconds at an altitude of 8000 feet 
above the sea. The times of burning of the fuzes at the 
sea level will, in future, be placed in the cylinders, together 
with a notification that ‘“‘ The time of burning increases 
nearly 3 per cent for every 1000 feet of altitude.” 
IX. It is most important that an efficient gas-check 
should be provided in order to prevent the erosion in the 
bores of muzzle-loading rifled guns which is caused by the 
scoring rush of gas over the top of the shot, more especially 
when firing with pebble-powders. Various tin cups and 
cow-hide wads, &c., have been tried, at present without 
success, and the service wad is discontinued as useless. 
X. Colonel Inglis’s muzzle derrick will be adopted for 
