iS ESSAYS AN-D OBSERVATIONS 



an intermediate diredtion, or produce irreo-u- 

 lar eddies. 



8. Here, by the bye, we may fee that the 

 ingenious fyftem of Bofcovich, the Ro?nan 

 ProfeiTor, concerning the elements of mat- 

 ter *, whatever may be laid for it from other 

 confiderations, gives us no affiftance in com- 

 prehending the mutual penetration of light; 

 for indivifible points, endued with an infu- 

 perable repulfive power, reaching to a finite 

 diftance, are as fubjed to interfere, as fohd 

 particles of a finite magnitude. 



SECT. It 



0?i the Heating of Bodies by Light. 



g. It appears, by Sir Ifaac Newton's expe- 

 riments on the inflexion of light, that bo- 

 dies fi(ft upon it at fome diftance ; and that 

 the fame power, varioufly exercifed in va- 

 rious circumftances, is the caufe, likeways, 

 of refrad;ion and reflexion. We know no 

 inftance of any kind of attra(5tion or repul- 

 fion in Nature which is not mutual ; we ob- 

 ferve likeways that bodies are heated by the 

 influence of the fun's rays : it is therefore na- 

 tural 



* See his Diflert. de lumine et de viribus vivis-. 



