4-2 Experwieiits tipon Gimpowder, 



ence of those velocities with all the charges except the 

 first, thus : — 



Sum of the Velocities — 1764. 

 Computed. Actual. Difference. No. of Exp. 



9S64 9854 10 23 



So that it appears that the difference or the actual 

 velocity was smaller than the computed by -^\^ part 

 only, at a mean of 23 experiments. 



But as by far the greater number of the experiments 

 were made with the following charges, v'vz., -90, 218, 

 208, 165, and 145 grains of powder, let us take the 

 sum and difference of the computed and actual velocities 

 of those charges, thus : — 



Sum of the Velocities. 

 Computed. Actual. Difference. No. of Exp. 



59S5 6044 -f 59 18 



Here the agreement of the theory with the experi- 

 ments is so very remarkable that we must suppose it 

 was in some measure accidental ; for the difference of the 

 velocities in repeating the same experiment is, in gen- 

 eral, much greater than the difference of the computed 

 and actual velocities in this instance; but I think we 

 may fairly conclude, from the result of all these trials, 

 that the velocities of like musket-hwW.o.t'S,^ when they are 

 discharged from the same piece by different quantities 

 of the same kind of powder, are very nearly in the 

 sub-duplicate ratio of the weights of the charges. 

 Whether this law will hold good when applied to 

 cannon-balls, and bomb-shells of large dimensions, I dare 

 not at present take upon me to decide ; but for several 

 reasons that might be mentioned, I am rather of opin- 

 ion that it will not ; at least not with that degree of 

 accuracy which obtained in these experiments. 



