740 PROCEEDINGS OF SECTION J. 
good results, being cheaper than bluestone, more elastic, and 
quite strong enough as a bearing surface. Occasionally pitching 
is necessary where, with heavy traftic, the bed is too soft to bear 
broken metal, but, if resorted to, should be proper Telford pitching, 
wedge-shaped stones on edge, with the narrow edge uppermost, 
laid in regular courses across the ro oad, breaking bond, and care- 
fully hammer-packed with spalls. Rough-pitching is a good deal 
used, but I cannot reconcile it with my notions of good road- 
making. 
The surface-metal should be of a hard and durable material, 
and requires renewal from time to time as it is worn away by the 
trafic. How to reduce this wear to a minimum is one of the 
important problems of road-making, and can best be studied by 
observing the chief causes of wear, especially those due to faulty 
construction or insufficient care in maintenance. Until a road 
is consolidated, the metal below the surface, as it is disturbed 
by traffic, is being crushed and injured; after consolidation this 
wear ceases as long as the upper surface or skin of the road 
remains unbroken. Any loose stones, sand, mud, or water, lying 
on the surface increase wear, and should not be allowed to 
remain. Loose stones, projections and hollows also cause con- 
cussion from wheels passing over them, and tend to wear and 
break the surface. 
The surface-metal should be broken to a small guage, 2-inch, or 
at the most, 24-inch. Opinions differ as to the relative 
advantages of machine-broken and hand-broken metal; the 
oO 
advantage of the former is that it costs less and consolidates more 
rapidly i on the other hand, it is claimed that it is not so cubical 
or durable as the latter, being injured by crushing in being 
broken by machine. The hand-broken metal has to be crushed 
by traflic or roller before it consolidates, and I doubt if it is then 
any more durable. 
The surface-metal should be spread and raked to its proper sec- 
tion, the same transverse slope being given as to the bed; large stones 
should be broken down with the hammer; the road should then be 
rolled until consolidated, all hollows must be filled up as they appear, 
and after partial consolidation, blinding added in sufficient quantity 
to fill all interstices in the surface ; but care should be taken in the 
selection of blinding-material. Screenings from the stone crusher 
answer the purpose well, and so do some loams and marls; but 
one often sees most objectionable material used, such as sand, 
clay, or even the sweepings of gutters. During rolling in dry 
weather it is often necessary to water. Want of sufficient rolling 
is the cause of many of our bad roads; a steam-roller is much 
more rapid and effectual than a horse-roller, and is an economical 
investment for any municipality spending much money upon 
metalled roads, if the bridges and roads are good enough for it to 
travel upon. 
