parts, and amoiigft thefe the particles of light in ^m* 

 cular ? 



IIL JNIuft not this feparatron of pn;rts be great m propartloi^ 

 to the cjuaatlty of extraneous particles which are added to the 

 body ? Or (agreeable to the 4th obfervation) mud not the 

 fpark be more fplendid and brilliant, the more the eledrical 

 fluid is concentered in any given fpace ^ 



IV. In the diminution or alteration of that attrai5live force od 

 which depends the conftitutio-n of bodies, may there not be a 

 gradation which, in the prefent cafe, as well as in that of 

 burning bodies, will caufe the efcape of fome rays fooncr thaa 

 others I 



Otfervations on phojphork ligBL 



It is obvious, from Mr. B. Wilson*s experiments, that 

 there are many curious diverfities in the appearances of phof- 

 phori. Some iliells, prepared agreeably to his diredions, after 

 expofure to the fun or to the flafh of a battery, emit a purple, 

 others a green, and others a reddifh light. If wdth Mr, Wil- 

 son we fuppofe, that thefe ihells are in a ftate of flow com- 

 budion., may we not conclude, that fome are jufl beginning to 

 burn, and therefore, agreeably to what I have obferved on com- 

 buflible bodies, emitting the maft refrangible rays; wbilft others ^ 

 are in a more advanced flate of combuflion, and therefore 

 emitting the lead refrangiible. If this conclufion be right, 

 the ihells which are emitting the purple, or the green, muflr 

 Bill retain the yellow, the orange, and the red, which will 

 ^Ifo make their appearance as foon as the combuftiou is fuffi* 

 cieutly increafed. 



