64 CONSTANT-VOLTAGE TRANSMISSION 



that the right-of-way may vary in cost from $25 per acre 

 for barren land to $250 per acre for good farm land and 

 to $2,000 or $3,000 per acre for land near a large city, and 

 that the total cost of the right-of-way is a large item and 

 may be as high as 25 to 40 per cent of the total cost of 

 the construction. It may be mentioned that the usual 

 practice is to purchase a complete strip of land for the 

 transmission line, and not to purchase rights for merely 

 the land on which the towers rest, as has been done in 

 some instances. Since the constant-voltage system uses 

 fewer lines for a given block of power, and often at lower 

 voltage, it requires much less land, and accordingly its 

 economies will show very much larger when the cost of 

 land is included in the estimate. 



Another item which is not directly represented in the 

 comparisons of first costs is that of maintenance and 

 attendance. This item is fairly omitted in a first esti- 

 mate, because it occurs on both sides of the comparison. 

 Thus, suppose that the limit has been reached for the 

 load of a line, and it is to be decided whether to build a 

 duplicate line, possibly along a new route, or to install 

 synchronous motors to double the rating of the old line. 

 In either case, the runnuig expenses would be increased, 

 for the new line would require repair men and patrols, 

 and the machines would require attendants. Therefore, 

 except where precise results are being figured for a par- 

 ticular case, it is not necessary to estimate the difference 

 in running expenses of the two methods nor the differ- 

 ence in depreciation. 



Since one method involves greater power losses than 

 the other, the best way to account for this in the com- 

 parisons is to estimate the first cost of the power-plant 



