FAKMEES' INSTITUTES. 



113 



and the broken stone or macadamized road ; the stone pavement in its various 

 modifications is far too costly for any extensive use as yet. The following table of 

 resistances, taken in part from Gillespie's Eoads and Eailroads, shows verv clearly 

 the comparative value of dilferent materials as road covering for level roads. 

 The table also shows the amount a single horse should draw, deduced as fol- 

 lows : From repeated experiments it has been found that an ordinary horse can 

 exert for 10 hours in a day a steady pull of about 120 pounds : consequentl}-, if 

 the proportional resistance of the draught to the load is known, the load can be 

 found by multiplying the reciprocal of the resistance by 120 : 



KIND OF SUHFACE. 



Stone pavement 



Broken stone on stone pavement 



Broken stone on flints 



Broken stone on soil 



Gravel road 



Soft sand and gravelly road (ordinary dirt) 



Load one 



horse 



sho'd draw, 



tons. 



1-29 

 9-11 

 8-9 

 2-5 



By referring to the last column it is seen that the power of a horse is 10 

 times as effective on a stone pavement as on an ordinary dirt road ; and on a 

 gravel road 2 2-9 times as effective as on our ordinary roads. 



The most important consideration with all these roads is the preparation of a 

 thoroughly drained road-bed. Xo amount of work or expenditure of money in 

 another direction can compensate any deficiency in this. No matter how costly 

 be your road covering, if it is constantly saturated with water your road will be 

 a failure. 



Draining may be accomplished by a sufficient number of open ditches, or in 

 a more thorough and permanent manner by covered sewers at the side of the 

 road, fed by diagonal under-drains running under the road-bed proper. 



Flank lioacls. 



Plank roads are suited only for a heavily timbered country ; at the best they 

 are but temporary affairs, and are the worst roads possible if not kept in the 

 lest of repair. As our country grows older they must of necessity be replaced 

 by roads of more permanent character. 



Gravel lloads. 



There is, perhaps, no road covering so well adapted to the wants of the 

 community in general as our coarse, sharp gravel. K^early every neighborhood 

 has a bank of excellent road gravel, and the cost of their road covering need 

 be little more than the expense of hauling, thereby forming aji excellent road at 

 small e.xj^ense. 



Broken Stone Koad. 



The best road Ave can command is the broken stone or macadamized road. 

 The method of making in its earlier stages is very similar to that of the gravel 

 road, viz. : by preparing a well drained and neatly graded road bed slightly 

 convex at the center ; to this apply the road metal (which, in this case, consists 

 of angular fragments of stone, not over 1^ inches on any side), in layers of a 



15 



