Page:Popular Science Monthly Volume 56.djvu/548

532 the surface is covered with half an inch of clean coarse sand or granite screenings.

Improved wood pavements are a luxury. They have many points of superiority over asphalt. They are so considered in London, where their use is continued, although they require renewal



oftener than asphalt, and much more often than granite. They will undoubtedly be used more frequently in this country when the people are willing to pay the additional cost for the quiet and freedom from dust and from the somewhat disagreeable glare of asphalt.

For a dozen years or more brick has been used for street pavements in the cities of the middle West, The use of this material is by no means new. It began in Holland in the thirteenth century, and in the seventeenth century the highway from The Hague to Scheveningen was paved with brick. In Amsterdam such pavements are said to last from ten to twenty years, or an average of fourteen years. After about ten years they are commonly turned over and relaid, after which they will last about four years more. The size in common use is about the same as that made in this country.

A good paving brick should be tough enough to withstand the wear to which a street surface is subjected without chipping or cracking, and should not absorb more than from two to four per cent of its weight of water after submersion for forty-eight hours. It has not the wearing qualities of granite, although there is one block on Ninth Avenue, in the Borough of Manhattan, which has been subjected to very heavy traffic for eight years, has had