Appendix B. 



Fort Portal. — 22nd July, 19'' SB"" 



22iul „ 19 5.5 



23rd „ 20 6 



23rd „ 20 8 



Of this the mean for the double .series required by the al)ove-mentioned 

 inversion of the ghiss roof of the artificial horizon is : 



21. St July, -IMS'" ... K,= +3''15"' 16^-0 



21st „ 19 54 „ = + 17-0 



22nd „ 19 54 „ = + 19-5 



23rd „ 20 7 „ = + 22-4 



Referring these values to the date coinciding with the first of them, and 

 noting the hour indicated l)y the chronometer, we get : 



21st July (civil)— (p.m.) : /, = 10'' 57"' 49^..Kl = 3l' 15'" 15'-8 



as the mean on Greenwich mean time. 



From the determinations of the time at Bujongolo on the 10th, 11th, 

 and 12th July (astronomic dates), the results of which have been given at 

 p. 312, we obtain the absolute correction of No. 1 chronometer. Eefening all 

 the values to the date of the last, and passing from the absolute correction 

 of the chronometer to the absolute correction on Greenwich, we get : 



13th July (civil)— (a.m.) : ^, = 2'' 51'" 6^..K, = 3l■ l-S"' 28*-4 



from which in the interval lietween the 13th and 21st July the daily correction 



of the chronometer is found to be : 



Kj = - 1-521. 



As already stated at p. 315, on the return journey the chronometers at 

 Fort Portal varied consideralily through lack of control, .so that, before leaving 

 this place, we proceeded to the determination of their correction by means of 

 six series of altitudes, the results being : 



Ki = + 3" 32"' 57"- 6 

 51-0 

 59-5 



„ = 59-9 



64-8 

 64-7 



The disagreement of the second series induced us to abandon it, the 

 influence of some error in the observations being obvious. 



316 



