46 STATE BOARD OF AGRICULTURE. 



Neither sand on clay nor clay on sand should be applied till the bed 

 has been properly graded and shaped for a permanent road. 



Repairs. — Repairs to this class of roads will consist in maiutaii^ing the 

 drains and culverts in good condition and applying such material to th«» 

 surface as was originally used to build the road. Care should be taken 

 in applying this new material when filling ruts to see that it is prop- 

 erly leveled. If very much new material is added it is better to h'arrow 

 again and re-roll. 



GRAVEL ROADS, 



Grade, shape and drain as above specified for the various kinds of 

 earth roads. Then, by use of the grader, push enough of the earth from 

 the center of the road to each side to form shoulders and at the same 

 time make a properly shaped bed of suitable width to receive the gravel. 

 This bed should be crowned parallel with the finished road and rolled 

 until firm and hard before the gravel is applied. 



Selecting gravel. — The pebbles composing suitable road gravel should 

 range in size between that of grains of wheat and hickory nuts. Analy- 

 sis of some of the best road building gravels of New Jersey shows them 

 to contain: pebbles 50 per cent; sand 30 per, cent; and clay 20 per cent. 

 Gravel that has no cementing qualities is of little value for roads, espe- 

 cially for sand roads, while those kinds which contain too much clay are 

 equally objectionable, particularly for clay roads. All gravels, how- 

 ever, have more or less value, according to the kind of soil composing 

 the road bed on which they are to be placed. It is plain therefore, 

 that to secure the best results a gravel should be selected especially 

 adapted to the kind of road on which it is to be used. 



A good gravel will always stand in vertical walls when the pit is 

 opened. 



After the road bed has been prepared the gravel should be applied 

 in layers of not more than four inches in depth. Level the gravel well 

 by hand or with a road machine, harrow till uniformly spread, sprinkle 

 with a horse sprinkler and roll thoroughly. 



Proceed in the same manner with each of the other courses till the 

 required depth of gravel has been placed upon the road. This method 

 will very much hasten final consolidation and make a homogeneous mass 

 of hardened gravel and not a thin crust over several inches of loose 

 gravel. It cannot be expected however, that gravel will pack under 

 the roller to such an extent as will crushed stone. When the final 

 layer has been applied the shoulders should be smoothed down and the 

 whole surface of the road thoroughly rolled from gutter to gutter. 



Repairs. — Repairs to gravel roads should begin as soon as the road is 

 finished and be kept up in so thorough a manner as never to allow large 

 ruts to form. A well kept gravel road will never require extensive re- 

 pairs until it becomes nec^essary to re-surface the road by adding an- 

 other layer of gravel. 



MACADAM ROADS. 



Grade, shape, drain, prepare the shoulders and roll the bed as already 

 specified for gravel. 

 For single track country roads nine feet is an economical width and 



