557 
From the observations with this watch results for the difference 
of longitude have again been derived in different ways. 
1. From the separate journeys. 
a. Journeys Ji—Me.—Ji.; Jidda-time interpolated between the 
last time-determination before and the first after the journey. 
2nd journey 3rd journey 
+2 + 2m 
Febr. 24 35:08 March 11 36:39 
iy ae 0 a EB 2 00 
ite 33.89 Syl ae Ae ORO 
… Al, 3446 dre) 
Mean 42m 34559 „ 16. 3433 
Omitting Febr. 26 34.82 on <a t6 
Mean + 2m 35:93 
b. Journey Me—Ji—Me; discussed in the same manner. 
March 2 + 2m 32527 
et 53 5) 
eae 34.20 
eS 34.72 
Mean + 2m 33°58 
c. Journeys Ji—Me— Ji; all observations (including Febr. 26) 
represented by linear formulae 
2nd journey -+ 2m 35822 (+ 248) 
eo 5 36.46 (GE 1.05) 
As the formulae for the second journey to Mecca represent the 
observations unsatisfactorily, I adopt as the result of this journey 
that of the direct interpolation excluding Febr. 26; for the 3rd I 
adopt the mean of the results « and c, hence: 
2nd journey — 2m 34582 
3rd 36.20 
Mean + 2™ 35851 
Combining this result with equal weights with result 5 we obtain 
+ 2734554. 
2. From general solutions by means of quadratic formulae. 
Of such solutions based on the whole material four have been 
executed; I and II respectively excluding and including Febr. 26; 
III and IV as I and II but giving half weight to the six observations 
during the 3rd stay at Mecca, for the same reason as in the case of Dent. 
In this manner we found 
