Verification of theory of spreading of charge 

 324] Plates with circular coatings. 



325] The same plates with other coatings. 



By the observed charge in the foregoing table, I mean only the pro- 

 portion which the observed charges bore to each other, not the real 

 observed charges. [See Art. 671.] 



326] From the circumstance of the light mentioned in [Art. 307], it 

 appears plainly that the electricity does actually spread instantaneously 

 to a small distance on the surface, and from the rings of dirt taken notice 

 of in Art. 308 it seems likely that the distance to which it spreads is not 

 very different from what we have here supposed ; moreover, if the distance 

 to which the electricity spreads is such as we have supposed, the charges 

 of all these plates bear very exactly the same proportion to each other 

 that they ought to do by theory, whereas if the distance to which the 

 electricity spreads is different from that here assigned, and consequently 

 the proportion of the charges of different plates to each other different 

 from that furnished by theory, it seems very strange that their charges 

 should all have happened to agree with computation, notwithstanding 

 that their thickness and the size and shape of their coatings are so very 

 different. I think therefore that we may fairly infer both that the distance 

 here assigned to the spreading of the electricity is right, and that, if it 

 was not for this spreading of the electricity, the charge of any plate of 



