318 REMARKS ON TRAVELS 
In a memoir inserted in the eighty-first volume of 
the Philosophical Transactions, Major Rennell has fixed 
the day's journey of a caravan heavily laden at sixteen 
geographical miles (or minutes of a degree) and one sixth; 
and that of a light caravan^ at seventeen miles and one 
third. It appears to me^ that the second of these results 
is too small, and especially that an intermediate term 
should have been established, between the light and the 
heavy caravans, for there is a vast difference between the 
two extremes. The former certainly advance more than 
twenty geographical miles a day, especially, as they are 
able to continue their journey longer, that is to say, for a 
greater number of hours each day. Then, again, it would 
be convenient to fix an intermediate valuation between 
sixteen and twenty miles, that is to say, the day's journey 
of the medium caravans, if they may be so called. I find 
Major Rennell's appreciation of the first denomination of 
days' journeys confirmed by the experience of the engi- 
neers attached to the French expedition, in crossing the 
deserts near Egypt. We estimated the hour's march at 
nineteen hundred toises ; eight hours would amount to 
fifteen miles two hundred toises, or very nearly sixteen 
geographical miles ; the hour's march would thus be esta- 
blished at two miles, or thirty hours to the degree. In 
consequence of several calculations much too long to be 
reported here, I consider the day's journey of the medium 
caravan to be eighteen geographical miles and four tenths, 
the hour being between two miles and two miles and one 
tenth. I shall not here take the light caravans into ac- 
