458 OUR COMMON ROADS—MURPHY. 
No. 3—Is a clay road with a six inch gravel covering 8 to 10 
feet in width, with a centre drain of stones. 
No. 4—Is a clay road with a centre drain of poles where stone 
cannot be had. 
No. 5—Is a cross-section of road made over bog or marsh. 
No. 6—Is a section of road to be made over a peat bog. 
No. 7—Is a section of road to be made on hill side ground. 
No. 8—Similar to No.7, but with embankment retained by 
erib-work or a stone wall. 
No. 9—Similar to No. 8, but both plank and cutting are 
retained by crib-work. 
Nos. 10 and 11 are sections that could be adopted to rock side- 
hill. 
In locating a line of road departures from a straight line are 
determined by many considerations. In crossing a dividing 
ridge between two valleys the lowest depression in the summit 
is generally taken. A continuous hill side without serrated 
ravines or secondary water courses is also sought for. Next find 
by an aneroid barometer the height to be overcome and the 
distance along the side hill which it is practical to climb to 
or descend from the summit. If the height is divided into the 
distance it will give the rate of incline or the gradient obtainable, 
and if with a level the engineer or surveyor commence above 
and descend with that rate of grade following an inclining con- 
tour, he must obtain the best location available. It may be 
necessary to diverge from such an ideal line to avoid bridging 
ravines, crossing expensive rock ledges, avoiding swamps and 
many other causes, all of which, and many others, may have to 
be considered, but are seldom taken into account in Nova Scotia. 
If any thoroughly practical system of road making is adopted in 
this country it will be necessary to alter many of our present 
great roads so as to obtain easier traction and better surface. 
“Tn selecting among the different lines of survey the one most: 
suitable for a common road, the engineer is less restricted, from 
the nature of the conveyance used, than in any other kind of 
communication. The main points to which he should confine his 
attention are, (1) to connect the points of arrival and departure 
