20 S Mi'\ MogGAN*s QS/erva^ms and Experiments an 



parts, and amongft thefe the paiticlea of light in parti* 

 cilia r ? 



III. Mufl; not this feparation of parts be great ia proportion 

 to the quantity of extraneous particles which are added to the 

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

 fpark be more fplendid and brilliant, the more the ele6;rical 

 fluid is concentered in any given fpace ? 



IV. In the diminution or alteration of that attradive force ors 

 which depends the conftitution 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 than 

 others ? 



Ohfervations on pJoofphoj-ic light. 



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

 there are many curious diverfities in the appearances of phof- 

 phori. Some (hells, prepared ngrccably to his diredlons, after 

 expbfure 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 fliells are in a ftate of flow com- 

 buflion, may we not conclude, that fome arejull; beginning to 

 burn, and therefore, agreeably to what I haveobferved on com- 

 buftlble bodies, emitting the mod: refrangible rays; whilft others 

 are in a more advanced flate of combuftion, and therefore 

 emitting the leaft refrangiible. If this conclufion be right, 

 the fhells which are emitting the purple, or the green, mufl 

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

 alfo make their appearance as foon as the combuftion is fuffi- 

 dently increafed. 



EXP. 



