ge number of distances." So much
delicacy of hand and of eyesight is requisite in taking lunars that shall
give results reliable to seven or eight miles, and so small an exertion
or flurry spoils that delicacy, that economy of labour and fidget is a
matter to be carefully studied.

These things being premised, it will be readily understood that outline
forms sufficient for an entire series of lunars will extend over many
pages--they will, in fact, require eighteen pages. There are four sets of
observations for time:--one E. and one W., both at beginning and close of
the whole; one for latitudes N. and S.; six for six sets of lunars, as
described above; six for the corresponding altitudes of the stars, which
have to be computed; and, finally, one page for taking means, and
recording the observations for adjustment, etc. Each double observation
for latitude would take one page; each single time observation one page;
and each single compass variation one page. An occulation would require
three pages in all; one of which would be for time. At this rate, and
taking the observations mentioned above, a book of 500 pages would last
half a year. Of course where the means of transport is limited,
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, m