256 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1914. 
ease of handling. The charge for one round for a 16-inch gun is 
shown in plate 2. It weighs approximately 666 pounds, and is sub- 
divided into six sections of about 111 pounds each, for ease of 
handling. 
To improve the speed and uniformity of ignition, a small charge of 
black powder is fastened to one or both ends of each section of the 
charge. Ono of these is ignited by the flame from a primer inserted 
in the breech of the gun and serves to facilitate the ignition of the 
smokeless powder charge. 
Life of smokeless powder.—The life of smokeless powder varies 
ereatly with the conditions under which it is stored. If stored in a 
cool, dry climate it will remain in good condition indefinitely, but if 
eM 
Fra. 1.—Powder grain for 14-inch gun. 
exposed to high temperatures, especially if moisture be present, the 
stability life will be greatly reduced. In the manufacture of the 
United States Government smokeless powder there was used for a 
number of years a small percentage of a material called rosaniline, 
which gave the powder a strongly pinkish color, which gradually 
faded as the powder lost its chemical stability. This material did 
not retard the change, but merely served as an indicator that the 
powder was becoming dangerous. 
About five years ago there was adopted as one of the constituents 
of the powder used by the United States Army and Navy a material 
called diphenylamine, which by combining with the products of 
decomposition of the smokeless powder, serves to retard the progress 
of decomposition, and thus greatly lengthens the stability life of the 
