42 
MINUTES OF PROCEEDINGS OF 
the mouth of the canister, had become damp; and in the fourth, the powder 
was caked together and injured by the penetration of moisture, to the extent of 
about one-third of the entire quantity. 
3. Open keg containing 5 lbs. of loose powder. The surface of the powder had 
become coated with a crust, consisting of agglutinated grains, which had become 
friable; the crust was browner in appearance than the remainder of the powder. 
The portions of powder which were in contact with the sides of the keg had 
become similarly agglutinated. Upon removal of the crust and careful separation 
of the grains which adhered loosely to it and to each other for some little distance 
beneath, the agglutinated portions were found to be from -^th to -g-thin. in thickness. 
The grains immediately beneath were found to be unaltered in composition, but 
the crust itself had sustained a slight loss of sulphur, as the following analytical 
results show 
Composition of unaltered Composition of 
powder grains. ' the crust. 
Per cent. Per cent. 
Saltpetre . 75-63 75-79 
Sulphur. 9-95 9-48 
Charcoal . 14-42 14-73 
Water . 1*32 1-29 
It is probable that in the first instance a slight absorption of moisture took place 
by the portions of powder to which the aqueous vapour would have more immediate 
access, but that the temperature of the external portions becoming in time raised 
somewhat above 212° (the thermometer had registered 250°), the sulphur had even¬ 
tually commenced to volatilise very slowly. 
The appearance of the crust did not indicate that the grains had been to any 
considerable extent penetrated by moisture. 
The agglutination of the grains was no doubt partly due to the action of the heat 
upon the sulphur, and to some extent also to the slight impregnation with, and 
the subsequent expulsion of moisture. 
(Signed) P. A. ABEL. , 
October 19, 1872. 
