SKILL IN TARGET-SHOOTING. S07 



pressed numerically by such a multiple of this integral, so taken, as 

 to give I for its value when r is infinite : which gives 



H= I E{kr'^) ; and therefore M = E {kr^). 



Now, when r = a, the radius of that circle within which just half 

 the total number of arrows strike ; the probabilities of hitting and 

 missing that circle are equal : so that H and M are in that case 

 each = ^. We have, consequently, 



E {-ka') = I, 



and eliminating ^, we obtain 



Log. y1/ = -2-, log. (^); 





= (i) 



COLLINGWOOD, Jiwe 8, 1866, 



THE END. 



