NEAR FORT ST. GEORGE. 



515 



The refraction due to 45° altitude, as established by 

 experiments, and very near the level of the sea is 

 50" = K".* 



The mean altitude of barometer at the time of observing 

 was 30.035 inches =: x. 



The general medium height of Mercury is 2Q.6 — ^. 



The mean altitude of thermometer at the time of ob- 

 servation was 71° =:/;. 



Tangt.Z = 0°9' i4''.3261og. 7-^'2g33lO 



3r zz 0.402 /^^--50Mog- I.60S97OO 



9.12S30]ON.N.O.]34 

 3 



3r — 0.402 

 Tangt. Z — 3r = o® 9' 13''.924 log. 7.42902291 

 R' = 50' log. 1 .6959700 



f__35^5 ]o 0.0062636 

 A 29 6 to 



4OOI02;. 2.60882S4 



> 



J.743OS49 



;^ + 350=:421 log. 2.6232S21 



Corrected Refract. R- o.\3\ N.N. 9.1 1 88028 



« - 30.035 log. 1.4775553 

 ^rr 29.6 log. 1.4712917 



log of-^ 0.0062636 



7^71- 



350 



^ +30 13 421 



* The quantity R', which represents the refraction due to 45o al- 

 titude (where Rud.n 1) is give i in Bradley's Tables := sy. But 

 fur obvious reasons I have preferred Le Gentil's quantity, as his 

 experiments at rondii,/urru ajipears to me unexceptionable 



LI 2 



