DECEMBER 20, 1906 | 
NATURE 175 
mental vessel had been employed. Sir Andrew Noble 
and his colleagues fully appreciated the necessity 
of examining the products when the powder was fired 
as nearly as possible under like conditions to those 
existing in the gun, and it was not until they suc- 
ceeded in retaining all the products when the charge 
was fired in a space which it completely filled that 
knowledge on the changes commenced to have any 
claim to scientific accuracy. Charges so large as 
23 lb. of gunpowder and 5 lb. of guncotton have been 
fired in the author’s explosion vessels, illustrations of 
which we reproduce. 
We have become familiar with combustions under 
these conditions, but it is not difficult to appreciate 
the risks and troubles incidental to such work, and 
the patience required by the pioneers to overcome these 
difficulties. Interesting references will be found to 
some of these troubles in more than one paper. An 
account of one singular accident may be quoted :— 
‘““The end of the vessel was placed against a 
wrought-iron beam. The screw—a half-inch pitch 
being a very good fit, was screwed into its place with | 
much difficulty, and with the use of a good deal of 
oil. On firing, the screw unscrewed . . . until the 
last two threads were reached. These were sheared. 
Owing to the wrought-iron beam . . . there was no 
EXPLOSION VESSEL. 
VM 
| With Service gunpowder the author concluded the 
temperature to be about 2200° C., and regarded the 
signs of fusion of pieces of platinum in the charge 
as confirming this, Deville’s value of ‘nearly 
2000° C.”’ being taken as the melting point of plati- 
num. Holborn and Wein have more recently shown 
the melting point to be close to 1780° C., so that 
possibly the temperatures for gunpowder are some- 
what high. 
It may be noted that as a direct result of the re- 
searches on gunpowder, guns were constructed which 
advanced the velocities from 1600 to 2100 feet per 
second. 
Although gunpowder held its own for centuries 
with but slight modification, it has now become a 
thing of the past as a military propellant explosive. 
The advantages of a smokeless powder are so great 
that as soon as the difficulty of ‘taming ’’ gun- 
| cotton had been overcome, its adoption, either 
gelatinised alone or mixed with nitroglycerin, 
| quickly followed. Again Noble and Abel were 
pioneers in our knowledge of the conditions attend- 
| ing the use of smokeless powders. Naturally the 
| very full and lucid accounts of the large number of 
| experiments made by Sir Andrew Noble and his 
colleagues will prove of even greater interest than 
the earlier work on gun- 
powder. Throughout they 
enjoyed enviable facilities 
for actual trials in large 
Ye 
8 
Cellllétde 
a 
experimental guns with 
full charges, and so were 
enabled to correlate the 
values in practice with 
laboratory experiments. 
The changes involved 
during the combustion of 
smokeless explosives are 
less complicated than 
with gunpowder. Con- 
ditions, however, greatly 
az 
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Vill ddiidde 
Se EEE ner REE EE Ter Z 
LLL RL Y modify the proportions in 
(Saree See 
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Fic. 2.—Vessel employed for heavy charges. 
motion of translation, but the motion of rotation was 
so high, that the screw first striking the ground and 
then an iron plate at an angle of 45°, went vertically 
into the air with a singular humming noise, de- 
scending in about 30 seconds a few feet from the 
place whence it rose.”’ 
Only two points néed be mentioned in connection 
with the researches on gunpowder. 
adopting and relying on Bunsen and Schischkoff’s 
method for estimating hyposulphites in the residues, 
regarded potassium hyposulphite as being formed as 
a primary product during combustion, a conclusion 
questioned by Berthelot, who regarded it “entirely | 
as a product formed during the collection and ana- 
lytical treatment of the solid residue.’”? In a con- 
troversy which followed, Noble made out a good case 
for supposing no change to have been possible during 
the preparation of the material, but appears not to 
have considered the other possibility, faulty analytical | 
methods. Later Debus showed that this was the 
case, and that actually the treatment produced hypo- 
sulphite, which necessitated a re-calculation of the 
composition of the residues. Attention might have 
been directed to this earlier in the book. 
Na practical method is available for determining 
the actual temperature of explosion, but making 
certain justifiable assumptions, calculated tempera- 
tures of approximate accuracy may be obtained. 
NO. 1938, VOL 75] 
Crusher gauge is shown at , the firing plug being situated at the 
opposite end. The shell proper was strengthened by being wound with steel tape. 
The author, | 
a which the various per- 
ZZ, manent gases are found, 
hence the total gas 
volume is also affected. 
| The influence of increasing amounts of nitroglycerin 
to nitrocellulose in cordites was first fully worked out 
by Noble, and has proved of the greatest practical 
value, since it has a close connection with the im- 
portant question of erosion. With the introduction of 
the old form of cordite for large guns, the loss of 
accuracy and short life of the gun became serious 
matters for consideration. Noble showed erosion to 
be due to two causes, (a) high temperature of the 
products, (b) the motion of these hot gases. Further, 
a series of elaborate experiments with specially pre- 
pared cordites containing increasing percentages of 
nitroglycerin showed that increase of temperature 
went hand in hand with increase of nitroglycerin, and 
consequently also the erosion. 
The logical step, therefore, was to reduce the per- 
centage of nitroglycerin, and, as is now common 
| knowledge, the new M.D. cordite contains only 30 
| per cent. of nitroglycerin instead of 58 per cent. as 
| in the earlier form. Powder of this composition will, 
| for the same charge and size of cord, give less energy 
in the gun, but this may be overcome by suitable 
modification of the charge and size of cord. These 
| points are all made beautifully clear by some excel- 
lent coloured plates in the last paper, which was de- 
livered in 1900 at the Royal Institution. Other 
instructive plates in the same paper are those dealing 
with velocities and pressures derived from them, in 
