254 
POPULAR SCIENCE REVIEW. 
Gun Cotton. — 3Ir. Scott Eiissell read to the British Association the report 
of the Committee on gun-cotton. It stated that General Hay had constructed 
a form of cartridge suited to the Whitworth Eifle ; that he found the use of 
gun-cotton was clean, and did not foul the gun ; that it had? much less recoil 
for the same effect ; that one-third is the equivalent weight of charge, and 
that it does not heat the gun. For drhdng shafts and tunnels it had been 
applied in many instances. At Wingeworth CoUier}^ one-thirteenth the 
weight of gun-cotton, as compared with gunpowder, produced the same effect. 
At the slate quarries of Llanberis and at Allenheads one-seventh was 
required. The air was uncontaminated by smoke, and the work could be 
carried on more rapidly. It had been tried in detaching large masses of rock 
at Festuiiog and Holyhead, and it -was found that lib. of gun-cotton was able 
to detach 50 to 60 tons of rock. 
On the other hand, MM. Pelouze and oMaurey have communicated a 
memoir to the Academy of Sciences at Paris, chiefly on the chemistry of the 
subject, but leading to conclusions adA^erse to its employment. They sum 
up their results as follows : the question of the employment of gun-cotton in 
firearms “ remains pretty much in the state in which it was left by the 
French Commission of 1846. JSTothing, in fact, justifies our thinkmg it pos- 
sible in the present state of oiw knoAvledge, either to preA^ent the spontaneous 
explosion of gun-cotton, or to correct practically its bursting properties, still 
retaining the ordnance in use for ordinar}" poAvder. 
Tvl. Seguier, however, has employed mixtures of gun-cotton, and coarse 
gunpowder, managing the point of infla,mmation so that the poAvder shall be 
first fired. The projectile, Ke says, is thus gradually urged oiiAAnrds in its 
movement, and its inertia no longer presents a resistance capable of causmg 
the rupture of the barrel by the instantaneous detonation of the cotton. — See 
Reader, Nov. 26, 1864. 
Superheated Steam and Feathering Paddles. — ]\Ir. Beardmore has com- 
municated to the Institution of Engineers in Scotland the results of a large 
number of trials of steamships, before and after the application of superheat- 
ing apparatus, and in certain cases Avith the substitution of feathering for 
ordinary paddles. We have condensed into a tabular form the average 
results of these trials : — 
[ 
Steamship. 
Without Superheating. ' 
With Superheating. 
Percentage of 
Coal saved. 
Time on 
Voyage. 
Hours. 
Coals. 
Tons. 
Time on 
Voyage. 
Hours. 
Coals. 
Tons. 
Metropolitan 
51-33 
46-16 
51-16 
35 
23 
Berlin 
39‘3 
96-6 
40-6* 
62-1* 
35 
Concordia 
21-7 
20-9 
19-5* 
12-2* 
41 
Seine 
97* 
7’4* 
9-S* 
5-4* 
27 
The figures given above are the aA^erage of from 6 to 10 trials each. Those 
o o o 
marked Avith an asterisk give the result of trials in Avhich feathering paddles 
Avere employed. 
Hydraulic Press. — In the ordinaiy hydraulic press the adA^ance of the 
piston is effected by fluid pumped in. ISIIM. Desgoffe and Ollivier liaA^'e con- 
