OUR COMMON ROADS—MURPHY, 449 
there may be an abundance of stone, such as sandstone and the 
softer varieties of slate and limestone, which would be suitable 
for the Telford bottoming but would not possess the requisite 
hardness and toughness for the top covering of broken stone. 
In some cases, after the bottoming is set, the road may be finished 
with three to four inches of good gravel in the rnanner described. 
for gravel roads. We would prefer having all the pavement 
stones of equal depth, and obtaining the requisite transverse 
convexity by forming the sub-strata to the desirable degree of 
curvature to receive them. A better drainage of the road-bed 
would doubtless be secured by forming the bed of the road 
parallel to the finished road surface. 
The advantages and disadvantages of the sub-pavement or 
“bottoming ” which forms the characteristic difference between 
the Telford and McAdam roads, have been the subject of lengthy 
discussion ; both systems have their respective advocates, and 
both can claim respective merits; the materials at hand, the 
facilities for thorough drainage, and the extent and nature of the 
traffic, as well as the liability of displacement by freezing must 
all be considered. From the experience of the writer in Nova 
Scotia, now extending over a period of 20 years, if either is adopted 
he would prefer the Telford system of road-making, for the follow- 
ing reasons: 
1. A foundation of this kind is believed to be as firm and 
durable as one of the same thickness composed entirely of broken 
stone, while it consists of considerably less. 
2. A carefully-laid Telford pavement, covered with screened 
gravel, may answer all the purposes of our present country trafic, 
and can be constructed without the aid of expensive machinery. 
3. It adapts itself more generally to the materials at hand, 
comes more within the scope of our resources, whilst the possibili- 
ties of success are nore promising. 
We might fairly assume that the cost of drainage and forming 
of road will be necessarily the same to receive a covering of 
either system. The cost of the Telford sub-pavement of 8 feet 
wide (same as the McAdam) 7 inches in depth, with a covering 
of 2 inches of screened gravel and a blinding of 1 inch of finer 
