ASCENT IN ROADS. 89 



red dollars yearly per mile, and one hundred teams 

 pass over it daily, at a cost for traveling of four' cents 

 each per mile, being four dollars daily, or twelve hund- 

 red dollars per annum, then the cost of making and re- 

 pair would be one quarter of the expense of travelmg 

 over it. Therefore the mile should be diminished one 

 quarter in length to make these two sources of expense 

 counterbalance each other. Hence a road with this 

 amount of travel should, with a reference to public ac- 

 commodation, be made three fourths of a mile longer 

 to avoid a hill of one hundred and five feet. This es- 

 timate applies to loaded teams only. For light car- 

 riages the advantages of the level road would not be 

 so great. One half to five eighths of a mile would, 

 therefore, be a fair estimate for all kinds of travehng 

 taken together. 



The following table shows the rise in a mile of road 

 for different ascents : 



For a rise of 1 foot in 10, the road ascends 528 feet per mile. 



The same kind of reasoning applied to a common 

 good road will show that it will be profitable for the 

 public to travel about half that distance to avoid a hill 

 of one hundred and five feet. In this case the whole 



