< ^ 4 ' > 
IV. ExtraSis of feVeral Letters to the TuhliJherj 
from the (^Verend Dr, Langwith, (I(eBor of Pet- 
worth in Suflex, concerning the Appearance of 
federal Arches of Colours contiguous to the inner^ 
Edge of the common ^inhow, 
t 
W HEN the Primary Rainbow has been very vi- 
vid, I have obferv’d in it, more than once, 
a fecond Series of Colours within, contiguous to the 
firft, but far weaker, and foinetimes a faint Ap- 
pearance even of a thiri Thefe increafe the Rainbow 
to a Breadth much exceeding what has hitherto been 
determin’d by Calculation. I remember, I had once an 
Opportunity of making an ingenious t fiend take no- 
tice of this Appearance, who was much furpriz’d at it, 
as thinking it not to be reconciled with the Theory. 
Tetworth.Jan.iz, . 
S ince my laft I have obferv’d fomething of the fame 
Nature, though not in the fame Degree of Perfe- 
dion, with what I fent you an Account of before. On 
Saturday lafl, a little before fix in the Evening, Wind 
at N. W. by W. we had here a lively, diflind, primary 
Rainbow, the inner and purple Colour of which had a 
far greater Mixture of red in it, than I could ever ob- 
ferve 
