Numb. 493. 
PHILOSOPHICAL 
TRANSACTIONS. 
For the Months of Oftob. Nov. and ‘Dec . 1749. 
I. A Defer iptmi of an extraordinary Rain- 
bow obferved July 15, 1748. by Peter 
Daval, Ejq\ Secret. R. S. p. 1 93 
II. A Letter from Mr. Henry Baker, F. R. S. 
to the Pr eli dent, containing an ExtraSl of 
a Letter from Mr. William Arderon, 
F. R. S. to Mr. Baker, giving an Ac- 
count of the prefent Condition of, the Ro- 
man Camp at Caftor in Norfolk, with a 
Flan of it \ and alfo a Reprefentation of 
an Halo or Mock-Sun obferved by the 
fame Gentleman July 11, 1749. p. 196 
III. Fart of a Letter from Leonard Euler, 
Frof. Math, at Berlin, and F. R. S. To 
the Rev. Mr. Cafpar Wetftein, Chaplain to 
his Royal Highnefs the Prince <?/Wa]es, con- 
cerning the gradual Approach of the Earth 
to the Sun. Tranflated from ^French, by 
T S. M.D. F. R. S. p. 203 
IV. 
