8 A MANUAL OF TOPOGRAPHIC METHODS. 



boundary lines in such way that their position may be recognized upon the 

 ground. On the other hand, the scales are not so large as to prevent the 

 representation upon a single sheet of a considerable area, so that the rela- 

 tions between different regions can be seen at a glance. 



A map on a larger scale than this would require a greater time for its 

 completion and a greater expense, and when one considers the fact that the 

 map upon these scales of the entire United States, even excluding Alaska, 

 will, at best, cost in the neighborhood of twenty million dollars and at the 

 present rate of progress require fifty years for its completion, one scarcely 

 feels inclined to increase the labor and expense without an excellent 

 reason for so doing. There is yet another objection to increasing the scale 

 beyond that absolutely necessary. To be of value, such a map must undergo 

 revision at frequent intervals, in order to incorporate an}' changes in culture 

 and possibly in natural features due to natural or artificial agencies. The 

 larger the scale the more frequently such revision should be made, and 

 hence the labor and expense of keeping a map up to date would be greatly 

 increased. 



In this matter the experience of the civilized nations of Europe, all of 

 which have prepared topographic maps of more or less of their areas, while 

 certain of them have mapped their entire areas several times, is of great 

 service and points unmistakably in the direction of the adopted scales. The 

 history of these nations in this matter presents a singular degree of uni- 

 formity. Their first maps were upon large scales, and upon them they 

 attempted to represent all details of natural and artificial topography, even 

 property lines, so that one set of maps would answer for all purposes. Ex- 

 perience of the difficulty and expense of keeping up such maps (without 

 counting their original cost) has taught them that economy consists in the 

 production of, not a single map, but a series of maps, each designed to serve 

 a special purpose; one as a cadastral map, another as a military map, and 

 another, and this the most important, as a general topographic map. It 

 further taught that this topographic map should be on a comparatively small 

 scale, and accordingly, as a ride, the maps of foreign countries are upon 

 scales approximating one mile to an inch, a scale which is sufficient to show 

 all topographic details of a general character, and serves all ordinary pur- 



