i8 



THE CANADIAN HORTICULTURIST. 



the roiul h\- frost will be as little as o\\ foun- 

 dations of other material. 



The thickness oi the road material de- 

 pends entirely upon the traffic to which the 

 road is to be subjected. The lig-htest oi all 

 roads in parks, some little turn outs to hitch- 

 in<4- places or the like, miy^ht be five inches 

 in thickness if resting^ on confined sand and 

 constructed of sound stone or j^^ood gravel. 

 This thickness should never be less than 

 seven inches on clay. The road material in 

 the ordinary park road shonld not be less 

 than nine inches in thickness after rolling-. 

 Not because that much material is required 

 to hold up the traffic, but because the sur- 

 face will probably be worn down at least 

 two or three inches before it is resurfaced. 

 At its thinnest it should be capable of hold- 

 ing up heavy sprinkling wagons and coaches 

 or any vehicles which may come upon it. 



A well built nine-inch road of good 

 material is amply heavy for ordinary park 

 uses. For boulevard roads the material 

 should be somewhat thicker. If properly 

 cared for in any boulevard twelve inches is 

 ample. In some of the outer boulevards 

 nine inches will be sufficient. The question 

 might be asked why if a nine-inch road will 

 hold up a traffic in the parks when frequently 

 very heavy vehicles pass over it, is it neces- 

 sary to have a heavier road in a boulevard ? 

 It is the matter of wear again. Take a busy 

 avenue, for instance, in the busiest part, 

 where it, coo vehicles have frequently passed 

 over the road in 24 hours and the traffic is 

 always very heavy even in wet weather. 

 The wear is, of course, great. Suppose 

 the road to have gone two years without 

 surfacing ; nearly three inches is worn oflf the 

 surface. Suppose the following winter to 

 be a severe one on roads, that is to say a 

 wet one, then if the road was nine inches 

 thick to start with there would be perhaps 

 only five or six inches of material remaining 

 with its bond broken, utterly incapable of 

 holding up the traffic. With a twenty-inch 



road there would still be eight or nine inches 

 of material, which would be sufficient. 



The kind of material to use ? There are 

 several things to consider in determining 

 this. Principally it must be durable and of 

 two grades. The upper three inches should 

 be material that will best resist abrasion, 

 which means a hard, tough uniform granite 

 or trap rock. The under six or nine inches 

 as required may be any hard stone that will 

 preserve its integrity when subjected to frost. 

 The upper three inches should be stone bro- 

 ken into pieces closely approximating one 

 and one-quarter inches in their largest di- 

 mensions, as nearly cubical as possibie ; the 

 luider layer into two and one-halt inch pieces. 

 The granite or trap rock as was said should 

 be used for the upper three inches. For the 

 much used boulevard drives this is almost 

 imperative, but for the outer boulevards and 

 the park roads a softer and less expensive 

 material may be economically and satisfact- 

 orily substituted, limestone or good bank 

 gravel. 



For the roads in the park color of surface 

 is a consideration. The glaring white sur- 

 face of a limestone road is very painful dur- 

 ing the bright days and at all times its great 

 contrast with the surrounding dark greens 

 is anything but pleasant or desirable. The 

 sienna of the bank gravel is much better, 

 but the gravel road is more difficult to keep 

 clean and is much more liable to be muddy 

 after the summer shower or if as frequently 

 happens, the sprinkling is too heavy. The 

 determination of this matter must be largely 

 affected by the local conditions in each case 

 as to the cost and materials found at hand. 

 To darken the surface of limestone roads a 

 dressing of crushed granite or trap rock, say 

 one-half an inch thick, has been applied, but 

 it is expensive because of the frequent renew- 

 al necessary to keep the color at all even. 

 If it is thought necessary to darken the sur- 

 face it would be economy in the end to make 

 the upper three inches of the road of the 



