Microscopical Essays. 



Many and important are the inferences which may be deduced 

 from the foregoing experiment, among which are the following : 



1. That light flows in a right line. 



2. That a luminous point may be feen from all thole places to 

 which a ftrait line can be drawn from the point, without meeting 

 with any obilacle ; and confequently 



3. That a luminous point, by fome unknown power, fends 

 forth rays of light in all directions, and is the center of a fphere 

 of light, which extends indefinitely on all fides ; and if we con- 

 ceive fome of thefe rays to be intercepted by a plane, then is the 

 luminous point the fummit of a pyramid, whole body is formed 

 by the rays, and it's bafe by the intercepting plane.' — -The 

 image of the furface of an object, which is painted on the wall, is 

 alfo the bafe of a pyramid of light, the apex of which is the 

 hole ; the rays which form this pyramid, by croffrng at the hole, 

 form another, fimilar and oppofite to this, of which the hole is 

 alfo the fummit, and the furface of the objecl; the bafe. 



4. That an objecl: is vifible, becaufe all it's points are radiant 

 points. 



5. That the particles of light are indefinitely fmall ; for the 

 rays, which proceed from the points of all the objecls oppofite to 

 the hole, pafs through it, though extremely fmall, without em- 

 barraffmg or confounding each other* 



6. That 



