Some years ago, Dr. James Barr, medical officer at Kirkdale Gaol, published a letter in the _Times_ regarding what he considered the proper length of drop. He said that the length of drop ought to be such as to produce a momentum of 2600 lbs., meaning by "momentum," the convict's weight multiplied by the velocity of his descent at the end of the fall. Now, in estimating the convict's weight, I conceive that you ought to leave out the weight (as far as you can guess it) of his head, because the weight of his head is supported by the noose when the jerk takes place, and, therefore, cannot affect the amount of pull, or strain, on the neck. From what Dr. Barr says regarding the 2600 lbs. momentum, it is easy, by a little mathematics, to deduce the following rule. To find length of drop in feet, divide the number 412 by the square of the convict's weight of body in stones. By the above rule I constructed the following table:-- Weight of body without head. Length of drop. 15 stones 1 ft. 10 in. 14 " 2 " 2 " 13 " 2 " 6 " 12 " 2 " 11 " 11 " 3 " 5 " 10 " 4 " 2 " 9 " 5 " 1 " 8 " 6 " 6 " 7 " 8 " 5 " Convict Conway's weight, you are reported to have said, was 11 stones 2 lbs. Leaving 1 stone for the weight of his head, which is perhaps more than sufficient, his hanging weight would be 10 stones 2 lbs, so that a drop of 4 feet and a few inches[B] would have been, according to the doctor's rule, quite enough for him. Regarding the value of the rule, I am, of course, unable to speak; nor do I know, from what I remember of the doctor's letter, that he meant the 2600 lbs. momentum to apply in all cases. Much depends on the convict's build, strength of neck, etc. Yours truly, X. Y. (Second letter.) _August 25th, 1891._ _Re_ the Execution at Kirkdale. Sir,