158 Experiments to detei'mine 



guished, and the remains of the grain will fall to the 

 ground, unchanged, and as inflammable as before. 



This extraordinary fact was ascertained beyond all 

 possibility of doubt by the following experiments. 

 Having procured from a powder-mill in the neighbour- 

 hood of the city of Munich a quantity of gunpowder, 

 all of the same mass, but formed into grains of very 

 different sizes, some as small as the grains of the finest 

 Battel powder, and the largest of them nearly as big as 

 large pease, I placed a number of vertical screens of 

 very thin paper, one behind another, at the distance of 

 \i inches from each other ; and loading a common mus- 

 ket repeatedly with this powder, sometimes without, and 

 sometimes with a wad, I fired it against the foremost 

 screen and observed the quantity and effects of the uncon- 

 sumed grains of powder which impinged against it. 



The screens were so contrived, by means of double 

 frames united by hinges, that the paper could be changed 

 with very little trouble, and it was actually changed after 

 every experiment. 



The distance from the muzzle of the gun to the first 

 screen was not always the same ; in some of the experi- 

 ments it was only 8 feet, in others it was 10, and in 

 some 12 feet. 



The charge of powder was varied in a great number 

 of different ways, but the most interesting experiments 

 were made with one single large grain of powder, pro- 

 pelled sometimes by smaller and sometimes by larger 

 charges of very fine-grained powder. 



These large grains never failed to reach the screen ; 

 and though they sometimes appeared to have been 

 broken into several pieces, by the force of the explosion, 

 yet they frequently reached the first screen entire ; and 



