'All "Bodies tvbxt mud} healed firne. [Book 111=? 



its particles to be emitted with a rapid projectile force, 

 and will produce the effects of light *. The light of 

 the fun is conlidered as " the fame matter propelled 

 by the fame powers, in greater quantity and with 

 greater vigour -J-." The atmofphcre through which 

 light has to pafs in proceeding from the fun to us is in 

 ail probability of infinitely greater purity than ours, 

 and confequently, according to the laws of motion, 

 the projectile force of the rays of light is very little 

 diminifried in their pailage from the great fource of 



light and fire. 



The theory which is here advanced appears to reft 

 chiefly on the great fact of the fun's rays, when con- 

 centrated by a burning glafs, producing all the pheno- 

 mena and effects of elementary nre. There are, how- 

 ever, other facts which countenance the opinion. Sir 

 Ifaac Newton obferves, that all bodies, when heated 

 beyond a certain degree, emit light, and mine. Light 

 alfo accompanies the electric fire, whenever it exifts 

 in a difengaged or projectile ftate. The abfbrption ot" 



* When we confider that the elafticity of aeriform fluids is 

 owing to the matter of fire; that a cannon ball is propelled only 

 by the excefs of the repellant powers of parts of this matter, above 

 the forces with which they are attracted by the grofs parts of gun- 

 - powder, or of the airs emitted during the deflagration of it; that 

 the velocity of the ball is incomparably lefs than it would be if" it 

 were mot through an unreiiiling medium; and that even this lat- 

 ter velocity would be an inadequate reprefentation of that, with 

 \vhich the parts of the fiery matter are fhot forth, in the firft in- 

 flant cf their liberation from the combufable body which held 

 them clofely approximated ; we find the natural powers already de- 

 fcribed, fufficicnt in themfelves, for the projection of thefe parts/ 

 with all the velocity experienced in the light of flaming bodies on 

 earth, and to every diftance at which it has been perceived.' 



Higgini 1 ! Experiments and Obfer -vat ions, p. 338. 



j- Higgins's Experiments and Obfervations, p. 339. 



light 



