17G All Aliempt to explain the Phcenomenon 



fall : as the eye is deceived in this case, so I presume tlie ear is in 

 the other. 



I may here remark that, independent of every other argument, 

 the failure of ail attempts to ascertain the height of the illumined 

 arches, or of the aurora iGrenlis, at any time, completely over- 

 turns the common hypothesis, and estnhlishes mine. If those 

 phenomena were masses of the electric fluid, or the combustion 

 of anykind of matter, while thev remained stationary, their height 

 inioht be found as readily as that of any other object: but this 

 has never been done; and, according to my account, cannot by 

 the common metliod, because, as in the case of the rainbow, 

 every spectator sees a different section of the beam of light by 

 which thev are produced. 



I will take this opportunity of stating an opinion I have also 

 long held, and which is indirectly connected with the present 

 subject. It is, that a sphere of light is not formed around the 

 sun, or any luminous body, by the particles of light being projected 

 in every direction to that distance which they are known to 

 reach. This v/ould be an expense of light millions of times be- 

 yond what is necessary, and utterly at variance with the si,mplicity 

 and oeconomy invariably observed in all the works of creation of 

 which man has attained any knowledge. The positive part tiien 

 of my opinion is, that as light is known to be attractible as well 

 other matter, every planetary or other body nill attract its due 

 quantity of light according to its size and distance from the 

 source whence it is supplied. Hence a large planet, such as 

 Saturn, notwithstanding his distance from the sun, may be more 

 bountifully supplied with light than has hitherto been supposed : 

 and it is observable that the planets most remote from the sun 

 are, generally speaking, the largest. That particles so incon- 

 ceivably minute should be projected from the sun in every di- 

 rection, to the utmost verge of the system he enlightens, is au 

 operation scarcely conceivable; and considering that this enor- 

 mous expenditure of light and power would be to no purpose, 

 except the comparatively minute portion falling on a' few wan- 

 dering specks in this immense space, is too absurd to be imagined, 

 since it is so easy to conceive how the process of enlightening 

 may be carried on by the mutual action of the two bodies con- 

 cerned, without a particle of light being lost. The principles of 

 attraction and repulsion may be the agents employed in this 

 case, as thev are known to be in others. What is advanced in 

 the annexed Essay is independent of the result of this incjuiry, 

 as the reflection and refraction of light are not thereby necessarily 

 affected. Much might be said on this subject ; but having 

 shortly stated my opinion and reasons for adopting it, I leave it 



for 



