344 Reflections on the Inadeqiiacy cf the principal Hypotheses 



alteration produced on the air. But the fact is far otherwises 

 the divergence, amounting to several inches, being instantaneous 

 when the wax touches the conductor from which the balls are 

 suspended. 



The imperfections of this j^art of the theory were not long 

 concealed from the penetration of its ingenious inventor. He 

 always mentioned his opinions -vith that heutation and modesty 

 •which so eminently characterize the operations of superior minds. 

 Cavallo, however, with a self-'^ecurity whicli is ever apt to excite 

 distrust, maintains*, that " by this hypothesis which is analogous 

 to the other phenomena of nature, the electrical appearances 

 are easily explained, and that there is not a single experiment 

 that seem^ to contradict it." He nevertheless was necessitated 

 to give a different view of negative repiilsion from Franklin's, and 

 whoever examines it will probably consider it far less probable : 

 he will find facts attemp.ted to be j)rovcd bv a-.umed principles 

 which may either l)e denied or allowed, which rest for proof on 

 the thing to be -jroved. 



\Vith regard to this long controverted speculative question, 

 whether the reccdence of negatively electrihed bodies be occa- 

 sioned by a mutual repulsion, or by the divellent attraction of 

 the electricity naturally contained in the siurounding media^ I 

 I have made an experiment which, notwithstanding its simpli- 

 city, seems strongly to countenance the former of these pro- 

 positions. 



A filament stript from a dov.'nv feather was suffered to float 

 in the air, and an excited stick of wax was approached. 

 The filament was immediately attracted but soon after flew off 

 to a great distance. By current of air the filament was carried 

 off several yards from its former situation. The wax being sud- 

 denly approached Avithin about 1.3 inches, the filament again 

 flew off; and by following it with the electric it might be driven 

 to any part. Upon this experiment we may reason as follows : 



After the contact of the filament and wax, both must have 

 been in tlie same state : the former flev\' oft' to where the fluid is 

 supposed to have existed in a denser state. When it was carried 

 to a distance of several yards, it must have entered a completely 

 neutral atmosphere. When the wax was suddenly approached, 

 it also must have passed into a neutral atmosphere 3 yet the fila- 

 ment instantly flew off. Must not tliis be a direct repulsion ? 

 It cannot reasonably be supposed, during the passage of the 

 wax to the filament, that the former had absorbed all the na- 

 tural fluid of the air : so quick an absorption from ah electric, 

 and by an electric could not take place ; and even were this 



* Complete Treatise, 107. 



possibis, 



