In 1863, Prussian artillery captain Johann F. E. Schultze patented a small-arms propellent of nitrated hardwood impregnated with saltpeter or barium nitrate. Prentice received an 1866 patent for a sporting powder of nitrated paper manufactured at Stowmarket, but ballistic uniformity suffered as the paper absorbed atmospheric moisture. In 1871, Frederick Volkmann received an Austrian patent for a colloided version of Schultze powder called "Collodin", which he manufactured near Vienna for use in sporting firearms. Austrian patents were not published at the time, and the Austrian Empire considered the operation a violation of the government monopoly on explosives manufacture and closed the Volkmann factory in 1875.