44 British Artillery Matériel. (January, 
Samples have been exposed for several days successively 
to 212° Fahrenheit without sustaining any change. 
Samples have also been heated for several hours daily, 
during several days, to a temperature ranging from 300 to 
320 Fahrenheit. The picrate of ammonia was slowly 
volatilised from the powder by this treatment, just as the 
sulphur would be from gunpowder. In other respects the 
powder was unchanged. 
A sample of picric powder, which had not been submitted 
to pressure, was exposed in an atmosphere saturated with 
moisture for 18 days, when it had absorbed 14 per cent of 
water; it was then exposed to the open air at the ordinary 
temperature (September, 1870), and was found to have 
parted with the whole of the water absorbed. 
At the end of 20 days another sample was exposed to the 
damp atmosphere until it had absorbed 5 per cent of water 
in 6 days; upon subsequent exposure day and night to the 
air it returned to its original weight in 8 days. Its exposure 
to the open air day and night was afterwards continued for 
40 days, in the months of September and October, and its 
weight ascertained early each morning. The maximum 
increase in weight during the experiment was 6 per cent. 
On the 4oth day, as on several other days during the experi- 
ment, it had returned to its original weight, and its pro- 
perties were unchanged. 
Not the slightest indication has been obtained, in very 
searching experiments, that picric powder is in any respect 
more prone to change than gunpowder. 
Further trial of picric powder will be combined with the 
trial of gun-cotton pulp as a bursting charge for shells. 
In the opinion of the Dire¢tor of Artillery, picric powder 
has the disadvantages of gunpowder as regards danger, and, 
on the other hand, is not equal to gun-cotton as to power or 
safety. 
The quantities of picric powder already tried have been 
small, and it has not as yet developed qualities to lead 
to the conclusion that it will either supersede gunpowder or 
gun-cotton. 
Considering, therefore, that as the qualities of gunpowder 
are known, and those of gun-cotton are being developed, he 
thinks it would be premature to introduce picric powder 
into the service at present, but that it had better remain in 
an experimental stage until its actual properties and com- 
parative safety are more fully known. 
But the Director of Naval Ordnance considers it desirable 
that further experiments should be carried out with picric 
EEE 
