SCIENTIFIC AND TECHNICAL LABOURS TO 1860. 235 



obtained at first but little credit in scientific circles; 

 even William Weber trying to explain the disturbances 

 occurring in the Prussian underground conductors by 

 self-induction. Faraday's ingenious theory likewise, 

 according to which the electro -static induction is not 

 effected by direct electric action at a distance, but by 

 the induction proceeding from molecule to molecule of 

 the dielectric, was unable to obtain acceptance with 

 most physicists of the old school. The actual influence 

 of the matter between two conductors on the extent 

 of the electric charge was explained by a more or 

 less profound penetration of the electricity into the 

 insulator and the diminution of the distance thereby 

 caused between the effective quantities of electricity 

 in the two conductors. I determined therefore to 

 carry out an experimental investigation, in order to 

 establish the actual state of things without connecting 

 it with any of the existing theories. My investigation, 

 which was made considerably more difficult by the 

 then very imperfect development of the means and 

 methods of investigation, led to a complete confirma- 

 tion of Faraday's molecular distribution theory. The 

 result arrived at was, that the laws of the motion of 

 heat and electricity in conductors also applied to elec- 

 tro-static induction, and that consequently the form of 

 Ohm's law for the electric current is applicable to it 

 likewise. I obtained in this way with the help of 

 Faraday's theory Poisson's formulae for the density 

 of electricity at the surface of bodies, and was able 

 to furnish an experimental proof that in all cases the 



