68 GALTON ON THE EXPLORATION OF ARID COUNTRIES, [Dec, 14, 1857, 
A traveller, wishing to make use of Table 4, must first ascer- 
tain the number of day- rations that each member of bis party can 
transport, and then be must extract from tbe Table every case that 
corresponds with this number ; out of these he will have to select 
the one that best meets his particular wants. To take an example, 
we will suppose that each of his men can carry between 2 and 3 
day-rations ; he will then have to copy out, as is done below, every 
entry in the body of the Table 4 that falls between 2 and 3. In 
order to compare each of these with the rest, he should roughly 
determine upon the distance to which he wishes to transport his 
exploring party — we have supposed it to be 2 days’ journey out from 
camp. He will then write out, by the side of each of his previous 
entries, — 1st, the number of men (including the explorers them- 
selves) that would be required at starting in order to accomplish 
this journey ; 2ndly, the exact distance to which the explorers will 
be conveyed and provisioned by the supporting party ; and 3rdly, 
the number of stages, or, what comes to the same thing, of sections, 
that must be employed. In cases where the number of the exploring 
party, as shown in the headings to the columns of Table 4, is other 
than 1, the only easy way of making a comparison between the 
number of men required in them and in the rest is to enter them 
under a fractional form as 2 T ° = 5 men. Having done this, the 
cases that are obviously of little use must be scored out — I have 
marked them with an asterisk (*) — and then a careful comparison of 
the rest will show the one that is the most suitable for the special 
requirements of the particular case. Thus the question of weight 
may or may not be more important than that of numbers ; a single 
meal per day may not be objectionable, or else the heat and drought 
may be such that men will not work well with less than three 
meals; it may be essential, as a point of discipline, to keep the 
rations of water separate ; there may not be enough trustworthy 
men to allow of a subdivision of the supporting party into many 
sections?; — and so forth. 
Principle of 11 Repetition.” — Diagram Ho. 6 (p. 69) offers an illustra- 
tion of a supporting party composed of three sections, whose numbers 
are respectively e , 2 e, and 4 e ; the dark lines represent the outward 
routes, and the dotted lines the homeward ones ; but by it we may 
also see that precisely the same effect is producible by “ repetition” 
as by numbers. It is clearly a matter of indifference whether two 
men, whom we will call M and -ZV”, start from camp simultaneously, 
M turning back at the end of a stage and N going on, or whether a 
single man perform the duties of M and N consecutively, and it is 
quite possible that a single man might go through the whole scheme 
