a Mechanical and Physiological point of view. 33 



2240, the value of P (the weight required) will be negative; 

 but Qh denotes the work produced by the criminal Q falling 

 through the height h. 



Let h therefore denote the "long drop" found by Rule I., and 

 the following consequences may be inferred from (18). 



1st. In the American mode of hanging, if the weight be let 

 fall through the height h, sufficient to cause death instanta- 

 neously by the "long drop," it would require an infinite weight 

 to cause immediate death ; for in this case 

 Qh- 2240 = 0, 



and therefore P is infinite. 



2nd. In the American mode of hanging, if the weight be let 

 fall through twice the height of the "long drop," a weight equal 

 to that of the criminal will be sufficient to cause immediate death; 

 for in this case 



Qh- 2240 = 2240, 

 and therefore, by equation (18), 



P = Q. 



For all heights intermediate between h and 2h, the weight P 

 must be found from equation (18), and it will always lie between 

 Q and infinity. 



In practice, twice the height of the " long drop " would always 

 be found convenient ; and therefore the following Rule for pro- 

 ducing instantaneous death by the American method is confi- 

 dently recommended. 



Rale II. " Having found from Rule I. the height of the 

 Irish long drop, use twice this height, and a weight equal to 

 that of the criminal, in the American method. 



Note. — I have searched in vain for well-authenticated instances 

 of fracture of the cervical vertebra? produced by the usual me- 

 thod of hanging. Among the longest drops that I can find 

 recorded, are two observed by Dr. Charles Croker King, when 

 Professor of Anatomy in the Queen's College, Galway. 



Case I.* A young man, named Hurley, was executed in Gal- 

 way, at 6.25 p.m. on the 27th of August, 1853, for the murder 

 of a young woman in Dunsandle Wood. The rope used was 

 10 lines in diameter; the knot was large, formed of three turns 

 of the rope, and, on the noose being tightened by the execu- 

 tioner, corresponded to the occipital protuberance. His weight 

 was 10J stone, and he was allowed a drop of 1\ feet. These 

 data give us as follows : — 



15 

 work done =147 x -^- =1102 foot-pounds. 



* Dublin Quarterly Journal of Medical Science, vol. xviii. (1854) p. 86 

 et seq. 



Phil. Mag. S. 4. Vol. 32. No. 213. July 1866. D 



