( 93 ) 



II. Time determinations at Chiloango. Corrections an<t 

 rates of the chronometers. 



In 1903 before I left for Africa I added 10 my chronometer of 

 Hewitt another of Honwü. During my stay at Chiloango from May 

 1903 to July 1906 I have regularly controlled both by making at 

 proper intervals time determinations in the same way as before by 

 altitudes determined with my altazimuth. Moreover I have daily 

 intercompared the tw r o chronometers. 



With regard to the time determinations themselves I need only 

 add to what has been said before : 



1. that new determinations of the value of a level-part yielded 

 5". 4, exactly as before; 



2. that the flexure and the division errors of the instrument were 

 regularly taken into account according to the formulae in "Contri- 

 butions I". 



Here follow the results for the corrections and rates of the chrono- 

 meters. The rates, and also the temperatures added to them, refer to 

 the interval between the date on one line above and that on the 

 line itself. The temperatures for the periods of the two journeys 

 are wanting. To the "Rates Hewitt 20° C." I shall refer later. 



I have first investigated the rates of the chronometers with regard 

 to the temperature and to this end I have formed mean rates for 

 periods of about 2 months, in each summer and winter. 



Period 



Temp. Chron. Hewitt. 

 C. 



Chron. Hohvvii. 



For the chronometer of Hewitt I found a very distinct influence 

 of the temperature and, in so far as I could find then, no variation 

 with time. 



!) I have excluded the period of my journey from Dec. 20 to Jan. 3. 



