216 
THE SCIENCE OF FRONTIER DELIMITATION. 
two points about a mile apart to compute the distance between them 
and to chain it. A comparison of the results obtained by computation 
and measurement will serve to show what amount of accuracy can be 
expected from the triangles. 
Whilst the triangulation is going on, the topography must generally 
be filled in at the same time. If .possible, the topographer should be 
a day behind the triangulator, so as to get the benefit of his completed 
work, but in practise this is difficult to arrange. If -there are only two 
officers available, it is hardly possible for them to be separated. Their 
duties require that they should be constantly in communication with 
each other, and that they should meet daily to compute their triangles 
and observations. This difficulty may be partly modified by remaining 
two days in each camp, which will generally be necessary, in which 
case the topographer can work a day behind the tiiangulator. But he 
can always utilize the triangulatorks work by accompanying him to the 
observing stations and setting off on his plane table the angles as 
observed. He will at the same time have the benefit of all the points 
fixed beforehand. With these it is easy for him to sketch in the 
drainage, and to fix the position of any towns or features, on a scale 
of jopoo, which is probably the largest scale which would be used 
in the field, the trigonometrical points will be rarely more than an inch 
apart, and with a little practico the topographer can, under these con¬ 
ditions, fit in the work with great accuracy. He must be careful to 
indicate, as exactly as he can, the points where he cuts the routes of 
former travellers, or the position of places which have been previously 
fixed. This point is one of great importance on all work in little ex¬ 
plored countries, and it is the keystone of all compiled cartography. 
A route which runs between two places, the position of which is 
unknown, or from one known point into the air, is almost valueless, 
either as regards distances or direction, but the moment it is cut by 
another route, its value is enormously increased. If the route is more 
accurate than the boundary survey, it corrects the direction and 
distances of the survey, but if, as is more likely to be the case, the 
survey is more to be trusted, it fixes the route and gives a value to 
all the distances along it. 
In addition to the triangulation and topography, the commissioners 
have the work of delimitation to attend to. They must follow closely 
the boundary, and must select places for putting up beacons. Circum¬ 
stances will generally decide what places should be beaconed, and in 
what way the beacons should bo made. It is generally advisable to 
beacon every road and track, where they-cross the frontier, and every 
important river should also be marked. In a country where few roads 
or tracks exist, some other system must be adopted, but it should be 
borne in mind that there is little use in setting up beacons at places 
where no roads exist, unless roads bo made to them ; for if there are 
no roads the beacons will not be visited, and will soon be either 
destroyed or become overgrown with herbage and be lost sight of. 
The beacons should, if possible, be of permanent construction. If 
natural features cannot be adopted, piles of large stones in the shape 
