MANAGEMENT IN TRACTION PLOWING 245 



goes on in this country at a prodigious rate. We Americans 

 use the scrap heap oftener than any other nation, but we never 

 yet used it quickly enough." 



If an engine costing $2750 has a life of 1000 working days, 

 which are spent during the course of five years, the charges 

 for interest, depreciation and repairs may be figured at $3.52 

 per day. This is figuring the annual repairs at 2 per cent, of 

 the first cost and interest at 6 per cent, on the average invest- 

 ment. If the same amount of work is spread out over eight 

 years, the cost per working day would be $3.77; if over fifteen 

 years, $4.35. These costs assume that the repairs will be the 

 same in the life of the outfit, whether it lasts five or fifteen years. 

 As a matter of fact, the longer the life, the greater the depre- 

 ciation during idleness, and the greater the repair bill necessary 

 to accomplish the same volume of work. Interest is based 

 on the average inventory value, since depreciation is written 

 off each year. This reduces the interest to a little over one 

 half what it would be if based on the first cost, and the method 

 is only fair, since depreciation and repairs are also charged. 

 The longer the life in years for the same volume of work, the 

 heavier the interest charge each day. It is therefore false 

 economy to refrain from using an engine for any good purpose, 

 simply to prolong its life, although every care should be taken 

 to prevent unnecessary depreciation, especially during idleness. 

 Nor can this paragraph be construed as an argument in favor 

 of buying a short-lived engine to save interest, since depre- 

 ciation is a much larger item. 



In the case of the farm owner, the labor during rush seasons 

 may be greatly reduced and much time saved, if fuel and other 

 materials which are known to be necessary are purchased in 

 quantity and hauled to the farm for storage, during seasons 

 when no other work is possible. Operators will save much 

 expense and loss of time, if the equipment is thoroughly over- 

 hauled prior to the beginning of the season, and worn parts 

 replaced. A supply of the extras which are most frequently 



