OUR COMMON ROADS—MURPHY. 439 
tough basalts are much more valuable for road covering than 
soft schist ; and (3) that for roads of large trattic, the system of 
maintenance by periodical reconstruction, accompanied by such 
intermediate repairs, more or less constantly, as will secure hard- 
ness, and smoothness of surface and uniformly diminishing 
thickness, is superior to the one on minute and constant repair 
exclusively. It is now generally admitted in France that this 
last-named system is not advantageously applicable to roads on 
which the daily tonnage exceeds 600 tons. The same principles 
will apply to the repairs and maintenance of road coverings 
composed of gravel or a mixture of gravel and broken stone 
(Gilmore.) 
COST OF ROAD MAINTENANCE. 
The whole cost of the macadamized national roads of France 
taking an average year, was: 
Ma berIaIS fan wate s «ess $ 89 06 per mile. 
Manual labor. cs o.: « PRaode 
$160 60 per mile. 
The average quantity of materials was 78 cubic yards per mile, 
the mean rate of wages was $0. 45 per day. and the labor per 
cubic yard of material $0.91, of which 4 day’s work per cubic 
yard was for the maintenance of the surface of the road. 
The cost of maintenance of course varied a good deal in diff- 
erent departments, the average in some being as low as $73.00 
or $77.86 per mile, but in the majority the cost was not very far 
removed from the average. 
The cost of repairs for four roads in the county of Edinburgh 
is given as follows, and may be taken asa fair average of the 
annual expenditure : 
Lasswade and Wright’s Houses, 1864 miles ...... $109 98 
Dalkeith and Post Road, 85? miles ............. 237 74 
Cramonds 29 Lamiles ccc idan! stin'a thao anew acim 315 85 
Calder Slateford and Costerphine, 139 miles..... 137 96 
In each district the roads extend from Edinburgh to the 
