travellers must content themselves with less. Thus Captain Speke, who
started on his great journey amply equipped with log-books and
calculation-books, such as I have described, found them too great an
incumbrance, and was compelled to abandon them. The result was, that
though he brought back a very large number of laborious observations,
there was a want of method in them, which made a considerable part of his
work of little or no use, while the rest required very careful treatment,
in order to give results commensurate with their high intrinsic value.



MEASUREMENTS.


Distance.--To measure the Length of a Journey by Time.--The pace of a
caravan across average country is 2 1/2 statute, or 2 geographical, miles
per hour, as measured with compasses from point to point, and not
following the sinuosities of each day's course; but in making this
estimate, every minute lost in stoppages by the way is supposed to be
subtracted from the whole time spent on the road. A careful traveller
will be surprised at the accuracy of the geographical results, obtainable
by noting the time he has employed in actual travel. Experience shows
that 10 English miles per day, measured along the road--or, what is much
the same thing, 7 geographical miles, measured with a pair of compasses
from point to point--is, taking one day with another, and including all
stoppages of every kind, whatever be their cause,--very fast travelling
for a caravan. In estimating the probable duration of a journey in an
unknown country, or in arranging an outfit for an exploring expedition,
not more than half that speed should be reckoned upon. Indeed, it would
be creditable to an explorer to have conducted the same caravan for a