10 EXPERIMENTS OX 



EXAMPLE II. 



At the same hour, the top of the flag-staff was 

 observed 4' 37." 32 ; which, corrected for the height 

 of the instrument, as above, gives the depression 

 4' 07" 9S=^D. Again, the length of the flag-staff 

 being M feet, this subtracted from 59. 7, leaves the 

 perpendicular depression below the line of the level 

 15. 7 feet; and the angle which it subtends^:!' 21' 

 36=a. 



Hence we have, 



+ a-\ 21 3G 



4 38 70 

 — D=:4 7 9^ 



r=0 30 77 



The refraction entered in the tables. 



EXAMPLE HI. 



1st. The distance from the N. extremity of the line 

 (Banswary) to the Mimtapum is 26327- 3, which, con- 

 verted into an arc of a great circle, is 4' 18" 7=A. 



2d. Again, the elevation of the Mimtapum was 

 taken at Bamwary (on the same day 8'" 17" A. M.) 

 5' 21" 84, and this corrected for the height of the 

 instrument (by adding 44" 43), makes the elevation 

 10'-6''27=i^. 



3d. Lastly, in the beginning of August, during the 

 afternoon, being at the Muntapum, the depression of 

 N. end of line was observed, on a mean of four obser- 



