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Astronomy. — "Contributions to the determination of geographical 

 positions on the West-coast of Africa. III. Appendix" By 

 C. Sanders. (Communicated by E. F. van de Sande Bakhuyzen). 



6. Modified computation of the determinations of longitude in 1904. 



For the computation of the correct ions of my chronometers to the 

 M. T. of Chiloango during my journey of June 11)04 I have supposed 

 that the chronometer of Hewitt had not been influenced by the 

 perturbation on June 3 and that the one of Houwü had advanced 

 2 sees. 



1 had adopted the value of 2 sees, chietly in order not to 

 exaggerate. But the result of the time determination on June 5 at 

 N'Kutu, taking into account the modification of the rate involved 

 in the supposition of a jump of a given amount, as well as the com- 

 parisons on June 3 render it more probable that Hohwü advanced 3 sees. 



I shall therefore give here the results which we obtain on the 

 latter supposition, assuming a daily rate for Hohwü of -4- s . 95. 

 I shall also show to what results we should arrive if we adopted 

 the extreme supposition in the opposite sense, namely that Hohwü 

 was not perturbed and that Hewitt had omitted 6 beats = 3 sees, and 

 if we again assumed daily rates of both in accordance with the last 

 supposition. This supposition is not very probable but neither quite 

 impossible, and in this way we may at least form some idea of the 

 still remaining uncertainty. For the rest I still hold the supposition 

 that the rate of Hewitt has varied during the journey owing 

 to the fall of temperature. Here follow the values obtained for the 

 difference of longitude between the 4 stations and Chiloango : 



a on the previous supposition ; 



b adopting for Hohwü a jump of 3 sees. ; 



c adopting a jump of 3 sees, in the opposite sense for Hewitt. 



Hohwü Hewitt Mean 



Mayili a— 1™21 S 56 19*31 — 1™ 20*44 



