330 



TABLE III. Experiments of December 13, 1859, and January 17. 

 1860, compared. 



The close agreement with one another of the numbers in Col. 4, 

 derived from series differing so much as those in Cols. 2 and 3, 

 and obtained by means of electrometers differing so much in con- 

 struction, constitutes a very thorough confirmation of the remarkable 

 result inferred above from the experiments of the first series, and 

 shows that the law of variation of the electrostatic force in the air 

 required to produce sparks of the different lengths, must be repre- 

 sented with some degree of accuracy by the numbers shown in the 

 last column of either Table I. or Table III. 



The following additional series of experiments were made on pre- 

 cisely the same plan as those of Table II. 



