I. — Astronomic Observations. 



Here Nos. 2 and 3 point to irregularities in their movement. For this reason, 

 and also because the daily comparisons were occasionally omitted, it was 

 considered desirable to make use only of the indications of the No. 1 

 chronometer, which was in fact the one generally employed for the observations. 



With the view of fixing, if only approximately, the daily correction of the 

 No. 1 chronometer for the period of the journey, the calculation of the 

 astronomic elements of Bujongolo was taken in hand, and here were recorded 

 determinations of time between 11th and 28th June, taking the latitude at 

 9) = 0° 20' 16" N., roughly obtained from the already determined elements. 

 The corrections of the No. 1 chronometer on the mean local time were for 

 Bujongolo : 



11th June, 3»» 40™* ... 01 )s. No. 32 

 3 43 



26th 



27th 



28th 



3 



3 

 19 

 19 

 19 

 19 

 20 

 20 



48 

 49 

 19 

 23 

 38 

 43 

 23 

 27 



From the mean of the results for 11th and 28th June respectivelv, we 

 get, omitting the intermediate observations : 



11th June, 3'' 45™ C„„ = + 5'> 15'" 37^-1 

 28th „ 20 25 „ = + 5 15 28 -1 



Interval 17'"'>'^ 16^ 40™ Difference 9^-0 



Hence : B = - 0^-509. 

 The change occurring in the mean daily correction of this chronometer is 

 seen to be considerable, if the value just found l>e compared with that previouslv 

 obtained at Entebbe ( - 2^-762). But now we merely require an approximate 

 value of the longitude of Bujongolo for the calculation of the emersion of 

 B A C 81, and this will give us the absolute longitude of that same point. 

 Hence we take the by no means arbitrary course of adopting, as mean dailv 

 correction of the No. 1 chronometer during the journey, the mean of the two 

 daily corrections ol)tained at Entebbe and at Bujongolo, that is to say : 



* Tlie date is astronomic, and the hour is referred to the mean local time 



311 



