English: It shows a so-called aliquot charge of propellant for the 12-inch coast defense mortar, which was composed of a variable number of 6.3 lb. bags of powder, up to a total of ten bags (or 63 lbs.) of powder. Although the image is very over-contrasty, the binding straps that were used to tie the separate powder bags together can be seen, as well as the point (at the right-hand edge of the stack) where the straps are tied together to complete the "stack." The charge shown in this image is the maximum charge allowed for the M1890 mortar (ten separate 6.3 lb. bags of powder strapped together), and is just over 20 in. long. There was also a minimum powder charge, which was likely five of the smaller bags strapped together. A small igniter of black powder was part of the base bag, to the left in this image. The base bag was often dyed red, to insure that the propellant "stack" was inserted into the breech correctly, with the red end toward the breech block. A detonator was then inserted through the breech block so that it touched the igniter, and was set off by an electric current or by friction (via a lanyard pull) at the command, "Fire!"