( 14J ) 
tipper Parts, under which the Colours have appear’d. I 
have taken notice of this fo very often, that I can hard- 
ly look upon it to be accidental, and if it Ihould prove 
true in general, it will bring the difquifition into a nar- 
row compals ; for it will Ihew that this Effed: depends 
upon fome Property, which the Drops retain, whilfl: 
they are in the upper part of the Air, but lofe as they 
come lower, and are more mix’d with one another. 
Tetworthy 1 3 . 
lyxx. 
V. A Letter to Dr.Jurin, Coll, Med, Lond. Soc. 
<2^ Seer, ^ S, concerning the ahoVementioned Ap^ 
pearance in the (p(ainboWj with fome other (^fle- 
Elions on the fame SubjeEl* !By Henry Pem- 
berton, Mil>» 
SIR, 
U PON your communicating to me the curious 
Oblervations, your Friend Dr. Langwith had 
made on the Rainbow, I inform’d you thofe Appear- 
ances might, I thought, be explain’d by the Dilco- 
veries, the Great Sir Ifaac Newton had made in 
the Subject of Light and Colours, in his wonderful 
Treadle of Optics. As you leerned not dilplealed 
with what I mentioned to you in relation to this Mat- 
ter by word of mouth, you defired that I would let 
down in writing my Thoughts thereupon, which 1 
have here accordingly done in the following manner. 
R 
Let 
