Mr. Laming on the primary Forces of Electricity. 51 



quired by that ratio become less by certain decrements, in- 

 creasing for some distance nearly in arithmetical progres- 

 sion. 



53. That the comparative contiguity of the sides of the re- 

 ceiver really produced the apparent discrepancies, was verified 

 in two different manners ; first, by substituting for the balls 

 between which the discharges were taken others of smaller 

 size, by which the true ratio was extended to a greater di- 

 stance; and secondly, by replacing the receiver by others, 

 first of greater, and then of lesser dimensions, in which case 

 the extension of the true ratio became also greater and less 

 respectively. 



54«. It would appear from this that in the discharge of a Ley- 

 den jar through long tubes of glass filled with rarified air, al- 

 though the charge emanating from the ball connected with 

 the positive coating really enters the ball proceeding from 

 the negative coating, the free electricity is first attracted and 

 passed onward, by induction, by the more contiguous bodies; 

 and this view of the case not only explains the sensible passage 

 of electricity along the surface of the glass, as frequently ob- 

 served in experiments of this kind, but it makes clear also 

 certain other phasnomena of a similar nature which otherwise 

 would not be well understood. 



55. For example, a quantity of free electricity, which under 

 ordinary circumstances may be discharged through the sub- 

 stance of a conducting body, perhaps heating it to redness, 

 or even fusing it, will if the experiment be made in rarified 

 air pass only along its surface * ; a phaenomenon which we 

 may refer to the inadequate resistance by the minor force 

 in the conductor to the intensity of the major force acting 

 in the opposite direction, and now made very great by reason 

 of the reduced quantity of its contiguous compensating at- 

 mosphere. 



56. Let us in the next place examine our principles with 

 reference to the phsenomena which ensue when both the plus 

 and the compensating conductors are in a state of insulation. 

 Already it has been explained, that such bodies may compen- 

 sate free electricity, by becoming themselves positively elec- 

 trical (12.); and we have had abundant opportunity of con- 

 templating such an induced electrical condition as we find it 

 impressed on the insulating atmosphere in which experiments 

 for the most part are conducted : we shall do well to consider 

 also the same condition as it may be induced in insulated 

 solids. 



* PhU. Trans. 1834, p. 242, and Singer's Elements of Electricity, p. 63. 



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