METHODS OF MAP MAKING 
129 
D. Western Topography. Use of the Clinometer. 
The above described methods grew up in the East among 
varied conditions of topography and value. Brush that 
interferes with sighting is widely prevalent, and another 
determining factor is the general employment of horse 
logging, a style of operation for which close regulation of 
grades is not essential. Conditions in the West are fre¬ 
quently different from the above, in respect to one or 
more particulars. 
The aneroid barometer has not on that account yielded 
its place entirely. Particularly in Western Washington 
and Oregon does it still hold the field, because of the dense 
brush widely encountered, which makes almost impossible 
the clear sighting necessary for the employment of any 
other height-determining instrument. On the contrary, 
the temptation is to rely on the aneroid for work that it 
should not be called upon to do. Where, as is the case 
here, railroads are employed for nearly all main transpor¬ 
tation, heights with a reliable basis are essential if a 
map is to be widely serviceable. Frequently the ground 
lies in such a way that the routes of future railroad de¬ 
velopment are evident. Levels run along these routes, 
with aneroid work for the rest, is then the natural treat¬ 
ment. Just this method has been employed in numerous 
cases. 
Such logical and adequate treatment is not always 
possible, however, nor is it always permissible under the 
restrictions of the work in hand. A variety of methods is 
in fact employed, especially for the control work. As 
for the detail, the fact remains that when points in eleva¬ 
tion have been reliably determined at distances not more 
than from one to two miles apart, good aneroids intelli¬ 
gently used will give topography sufficiently accurate for 
general purposes, while here as elsewhere their use saves 
expense by permitting the topographic and estimating 
work to be done together. Complaints of the results of 
aneroid work frequently arise from unskilled use and from 
employment of instruments of inferior character. The 
quality of instruments obtainable at moderate cost has 
within a very few years greatly improved. It is not to be 
