TO CAILLIE^S TRAVELS. 2(U 
work which results from them a greater value than apper- 
tains to the materials ; these again have no other than 
what they derive, whether from the instruments and 
methods which the traveller has employed, or from the 
manner in which he has collected the observations and 
information which form the basis of his description. M. 
Cailli^ was not provided with any astronomical instru- 
ments ; he had no watch, and measured the hour only by 
the height of the sun ; but he possessed two compasses 
which were of great assistance to him. All his bearings 
were carefully noted by this instrument during the day, 
and by the stars at night. With regard to distances they 
were estimated according to several experiments made by 
himself at Sierra- Leone while preparing for his enterprise. 
He made a practice of walking over a certain space mea- 
sured exactly in P^nglish miles and of observing the time 
he spent upon the road. It is thus that he calculated the 
number of miles in each of his marches from Kakondy to 
Djenne at three English miles an hour, or two geographi- 
cal miles and six- tenths : as far as Timbo, however, that 
is to say during the first days of the journey, this number 
must be a little increased ; this results from the situation 
of Timbo, as determined by Major Laing ; and en passant 
we may observe that this part of M. Caillie's journey proves 
that the ancient position of Timbo, according to Watt and 
Winterbottom, is totally inadmissible. This rate of two 
geographical miles six-tenths an hour, or more exactly 
from two miles four- tenths to two miles six-tenths, can in 
general only be ascribed to isolated marches, and to cara- 
