XXXll 
APPENDIX. 
ing has been to the northward of the observations ; and that, by about 
te7i degrees on the whole traverse, when 17 degrees of variation have been 
allowed. It will hardly be supposed that the difference arises from allowing 
too much variation byteti degrees; but it is singular, that the eiror should, 
in all cases but one, lie the same way. I do not by any means regard the 
error as considerable, circumstances considered:* nor is it of any conse- 
quence in the parts where the observations of latitude serve to correct it : 
as between Pisania and Jarra. 
Mr. Park was plundered of his sextant at Jarra, which accident of course 
put an end to his observations of latitude ; and thus, unfortunately, left the 
remaining half (very nearly) of his geography in a state of uncertainty, as 
to parallel. This point, therefore, must be regarded as the most advanced 
geographical station, that rests on any certa'm basis of parallel. However, 
the remaining part of the route will not appear to be much out, when it is 
seen how nearly the bearing of Sego, as determined by Mr. Park, agreed 
with the line of direction pointed out from Jarra. 
It is, no doubt, a favourable circumstance, that the instrument was not 
lost at an earlier period, and before the commencement of the intricate 
route between the pass of the Senegal river and Jarra; to which may be 
added, the advantage of a known parallel, from whence to set off the very 
important bearing of Tombuctoo. In elFect, the bearing wa-s pointed out 
from Benowm, but this place being nearly east from Jarra, and the bearing 
An question E |- N, no error of any magnitude can be looked for. 
Jarra (called ^Iso Yarra), has already appeared in the :Maps drawn for 
'-the Association, and was originally taken from M. Delisle's Map; but was 
Jieglected, or overlooked, by M. D' Anville. In the former Map it was placed 
somewhat more to the west, and in a higher parallel by about :|- of a degree. 
Between Jarra and Wassiboo, Mr. Park's reckoning, as it appears 
^wrought up in his table of day's works, gives 41 min. difF. of 'latitude N, and 
f Mr. Carmichael cime within 6 or 7 degrees in the bearing between Aleppo and 
Bussorah, on a distance of 720 British miles. But the advantages were prodigiously ia 
his favour ; the road being straight, the country open, and the camel walking an equable 
jia^e. (See Phil. Trans, for 1791 ■) 
