308 LOGGING 
A greenish color on the cartridges is an indication of chemical 
decomposition, and handling dynamite in such condition is always 
dangerous. 
Nitro-glycerine from the cartridge may be absorbed through 
the hands, and men who handle dynamite are subject to severe 
headaches. This may be obviated partially by wearing gloves 
which should be thrown away as soon as they become saturated. 
Loading Holes. — The charge should completely fill the bore 
hole because explosives exert the greatest disruptive force when 
there are no air spaces below the tamping. 
In loading dry holes the cartridge case is cut on one side, and 
the cartridge lowered into the hole and gently pressed until it 
completely fills the bore. This is repeated until a sufficient 
amount of explosive has been placed. When the hole is wet the 
cartridge case should not be cut. 
The hole is now ready for the primer and for tamping. 
Primers and Priming. — Most forms of dynamite are exploded 
by the use of a fulminate detonator or cap, which is ignited either 
by a safety fuse or an electric fuse. The former is used for 
individual charges and the latter where many are to be fired 
simultaneously. 
Safety Fuse and Caps. — There are several grades of safety 
fuse offered on the market, some of which are waterproofed for 
submarine work. The fuse used for blasting burns at the rate 
of 2 or 3 feet per minute, and is marketed in packages containing 
two coils, each 50 feet long. 
The cap is a hollow copper cylinder j by 1| inches in size 
which is closed at one end. It is partly filled with from five 
to thirty-one grains of fulminate of mercury. The open end is 
sealed with shellac, collodion, thin copper foil, or paper. Caps 
deteriorate very rapidly when exposed to moisture. Several 
grades are made but for general use a No. 6^ is preferred. 
In making the primer for an ordinary blast a piece of safety 
fuse of the required length is cut off and one end inserted into 
the cap until it comes in contact with the filling. The fuse is 
held in place by crimping the cap |-inch from the open end. 
The fuse and cap are then ready for insertion in the primer, 
which is a cartridge of dynamite of the same size and quality 
as that used in the charge. 
' A No. 6 cap contains 15.4 grains of mercury fulminate. 
