COMPARATIVE MERITS OF PAVEMENTS. 7 
regard to stone, there is a vast difference in the endurance of hard and tough ba- 
salt and trap, and the average granite and gneiss. 
In economy of maintenance per year during the lifetime of a pavement, in- 
cluding its first cost, the hard basaltic trap rocks should be placed first, asphalt 
second and wood third, except in localities where wood is very cheap and suita- 
ble stone cannot be procured, or is subject to heavy charge for transportation. 
Under such circumstances stone would take the third place and wood would rise 
to the first. Where wood and stone are both expensive, or the latter is not of the 
best quality with respect to toughness, asphalt would take the first position. 
Both mud and dust adhere with more. tenacity to wood than to asphalt or 
stone, more especially after the fibers of the former begin to crush and abrade, 
and the order of merit in respect of facility of cleansing, will be first, asphalt, sec- 
ond, stone, and third, wood, whether the cleansing be done by sweeping or by 
washing. It stands to reason that a smooth, even surface can be cleansed more 
rapidly than one cut up with numerous joints. 
Mr. William Haywood, C. E., of London, in his report ‘‘ as to the relative 
advantages of wood and asphalt for paving purposes,” made to the Commissioners 
of sewers of the city of London, March 17th, 1874, says that ‘‘asphalt is the 
smoothest, dryest, cleanest, most pleasing to the eye, and most agreeable for gen- 
eral purposes, but wood is the most quiet.” It might perhaps be better to say 
that the noise produced by wood is of a different kind, which may be more disa- 
greeable to some persons and less so to others. Stone is the noisiest of all pave- 
ments. : 
The noise produced by wood is a constant rumble, that by asphalt an inces- 
sant clicking of the horses’ feet upon the street surface, with scarcely any noise 
from the carriage wheels, while stone gives out a deafening din and rattle from 
feet and vehicle combined. 
On the supposition that the surface is kept clean by either sweeping or wash- 
ing, the difference in slipperiness between wood, stone that does not polish under 
wear, and asphalt, is not great, although enough, perhaps to place asphalt last ; 
while a horse not only falls more frequently, but recovers himself less often and less 
easily upon it than upon the others, by reason of the joints in the latter, which give 
a foothold. When the surface is covered with mud, asphalt is the most slippery of 
the three, and very little mud makes it slippery. It cannot be said to be slip- 
pery when very dry, or, if free from mud, when very wet. 
In times of snow there appears to be little if any difference in this respect be- 
tween wood, asphalt and stone, but under a sharp dry frost, asphalt and stone 
are generally quite dry and safe, while wood retains moisture and is very slippery. 
In the condition in which they are usually maintained, a slight rain adds to 
the slipperiness of each of these pavements, with this difference, that on asphalt 
and stone this state begins with the rain or very soon thereafter, while the worst 
condition of wood ensues later. It however lasts longer than upon the others on 
account of its absorbent nature. With regard, therefore, to the convenience and 
comfort of those using the street, as well as those living adjacent thereto, the 
