1 8 2 Waf.e of Light from the Sun's Body. [ Book III. 



one twelve hundred millioneth part of a grain. But 

 the denlVy of the rays of light at the furface of the 

 fun is greater than at the earth in the proportion of 

 45,000 to i. There ought therefore to ifiue from 

 one fquare foot of the fun's furface in one fecond 

 T^-s-e-s- part of a grain of matter to fupply the coh- 

 fumption of light j that is at the rate of a little more 

 than two grains a day, or about 4,752,000 grains, or 

 670 pounds in 6,000 years, which would have fhort- 

 ened the fun's diameter about ten feet, if it was form- 

 ed of matter of the denfity of water only *. 



Thus we fee there are little grounds for any rea- 

 fcnable apprehenfions concerning the body of the fun 

 becoming exhavifted by the confumption or wafte of 

 the matter of light, if the immenfity of his diameter 

 (878,808 nglifh miles) is confidered. It is, how- 

 *ever, not impoffible that there are means by which the 

 fun jnay be enabled to receive back again a part of 

 that Jight or fire which he is continually emitting ; it 

 is not impoitible that this world, a/id the other planets, 

 may have a power of reflecting back a certain portion 

 of their light within the fphere of the fun's attraction, 

 or ihat the fixed ftars or funs may have fome power 

 of replenishing one another. After all, we have no 

 right to fuppofe our world, or the fyftem of which it 

 makes a part, defigned for an eternal duration ; its 

 exiftence is doubtlefs proportioned to the ends which 

 were intended to be accompiifhed in it ; but with 

 refpect to the period of it: termination, there is no 

 chain, of moral or phyfical reafoning which appears to 

 conduct to any fatisfactory conclusion. 



Notwithftanding the minutenefs of the particles of 

 light, and the amazing velocity with which they are 



* PriefUey's Optics, p'. 389. 



projected, 



