300 



FARM DEVELOPMENT 



The road engineer, or person who has charge of public 

 highways, must have a sense of careful discrimination 

 that he may not make a plan so expensive that the peo- 

 ple will never carry it out. But, taking all things into 

 consideration, he should make a plan, which, when fol- 

 lowed out, will give the most permanent road which it 

 is practical under all the circumstances to build and 

 pay for. 



Bridges and culverts. It is outside the scope of this 

 book to discuss the intricate problems of general bridge 



engineering. The effort 

 is rather to educate farm- 

 ers in the lines which 

 they often must manage 

 unaided, leaving the 

 planning and construction 

 of expensive steel, stone, 

 cement and complicated 

 wooden bridges to bridge 

 engineers and to bridge- 

 companies. 

 Extensive observation 



and experience warrant some general advice to those 

 made responsible for the giving of contracts for public 

 bridges. County commissioners sometimes make the 

 mistake of deciding upon the size of a bridge needed 

 over a given stream without having first secured all the 

 facts. Thus numerous bridges have been built too low 

 and with insufficient room allowed between the abut- 

 ments, or the abutments have not been sufficiently well 

 built to withstand the strain of the occasional excessive 

 flood. It pays the board which is responsible for the 

 bridge to employ a competent engineer who knows how 

 to secure the facts as to the probable height and force 

 of flood water and how to estimate the height, width 

 and strength of the structure necessary to meet the con- 



Figure 175. Pioneer wooden culverts are 

 being rapidly supplanted by stone and cement. Constructing 



