all over the country, and impossible to correlate. A series should
consist of six sets, each set including three simple distances. Three of
these sets should be to a star or stars E. of moon, and three to a star
or stars W. of moon. Lunars not taken on the E. and W. plan are almost
worthless, no matter how numerous they may be, for the sextant, etc.,
might be inaccurate to any amount, and yet no error be manifest in their
results. But the E. and W. plan exposes errors mercilessly, and also
eliminates them. One of the best authorities on the requirements of
sextant observations in rude land travel, the Astronomer Royal of Cape
Town, says to this effect:--"Do not observe the altitude of the star in
taking lunars, but compute it. The labour requisite for that observation
is better bestowed in taking a large 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,