522 TRANSACTIONS OF SECTION KE. 
plane table; but it should be remembered that it is the truest economy to 
make the best triangulation which funds admit of. In forests or in wooded 
and rather flat country, where triangulation would be very expensive, lines 
of traverse made with every possible accuracy, and starting and closing on 
trigonometrical points, may be used instead of minor triangulation. 
Detail Survey. 
Provided the detail survey is based on triangulation, it may be made 
by any recognised method. Plane tabling is now almost universally resorted 
to, and is probably as cheap and convenient as any other method. The 
vertical heights of the trigonometrical points will have been fixed by vertical 
angles with reference to some datum. The height of intermediate points can 
be fixed by clinometer lines, especially down spurs and valleys, and even by 
aneroid, and from these heights the contour lines can be sketched in. 
Altitudes can be more accurately fixed by spirit-levelling, but this is an 
expensive method not likely to be much used in the case of topographical 
surveys. It is possible that in exceptional cases photographic surveying 
may be resorted to with advantage, and undoubtedly photographic methods 
sometimes enable work to be done which would not otherwise be feasible. 
The photographic method suggested by Captain F. V. Thompson, R.E., is 
an advance on previous methods. In Canada, I understand that a good 
deal of photographic surveying has been done, and presumably the condi- 
tions in Canada have heen found suitable for this method. It has been 
little used elsewhere. 
Scale of Map. 
The next point for consideration is the scale on which the map is to be 
published, and itis animportant one. Speaking generally, the cost increases 
with the scale, and cost is therefore one of the main determining considera- 
tions. The physical and artificial character of the country, the amount of 
detail it may be decided to show on the map, the method adopted for repre- 
senting hills and other detail, and the method of reproduction to be used, 
all affect the question. 
Clearness and legibility are among the first essentials of a good map, 
and it is desirable that the scale should be such that all detail it may 
be decided to show on the map can be inserted without overcrowding, or 
conversely, if the scale is fixed, the amount of detail and method of showing 
it should be such as to avoid the common fault of overcrowding the map. 
In populous countries, such as Belgium, France, and Germany, where ~ 
buildings, roads, railways, &c., are numerous, a larger scale is, ceteris 
paribus, desirable, than in less populous countries. 
All important detail such as roads, railways, canals, forests, woods, etc., 
should appear on the map, as should the more important names, but it 
is a matter for consideration how far minor detail such as orchards, marshes, 
rough pasture, state of cultivation, &c., should be inserted on the map, 
and to what extent the less important names should be omitted. 
In hilly country hachures and contours, especially if in black, tend to 
obscure the detail and names, and the smaller the scale the greater this 
tendency. 
Methods of reproduction will be dealt with later, but I may here say 
that more detail and names can be shown clearly on a given scale if the map 
is engraved on copper than if reproduced in any other way. The scales 
adopted by different countries vary very much—I give below the scales 
adopted by some of the principal surveys. 
nreos scale—Switzerland (the more populous parts), Prussia, Baden, 
Saxony, Bavaria, and Wirtemberg (these German maps, although called 
maps of position, are practically topographical), 
Z0007 scale—Belgium and Denmark, 
