Knight's American mechanical dictionary : a description of tools, instruments, machines, processes and engineering, history of inventions, general technological vocabulary ; and digest of mechanical appliances in science and the arts . ng of form has alternate short blocks, the spaces filled withgravel. Numerous varieties of wooden pavement have beenpatented in the United States, and some of tliemare very used. Plate XXXVIII. showsforty vaiieties of patented pavement. The ditterencebetween them lies in tlie form of blocks, method oflaying, foundation, and chemical trea
Knight's American mechanical dictionary : a description of tools, instruments, machines, processes and engineering, history of inventions, general technological vocabulary ; and digest of mechanical appliances in science and the arts . ng of form has alternate short blocks, the spaces filled withgravel. Numerous varieties of wooden pavement have beenpatented in the United States, and some of tliemare very used. Plate XXXVIII. showsforty vaiieties of patented pavement. The ditterencebetween them lies in tlie form of blocks, method oflaying, foundation, and chemical treatment or other-wise of the wood. The greatest enemy to wooden pavements has beendry-rot from below. The surface of a well-laid pave-ment soon becomes water-proof from dust beateninto the pores of the wood, and if sufficient inclineis given to the surface rain will flow otf as from aroof. Dampness from below is drawn into the blocksby capillary attraction, and the lower part of theblocks crumbles into clust while the shell on top re-mains perfect. To prevent this decay, compound pavements, which exclude the absorption of theI moisture of the soil by means of a layer of asphalt,1 would seem to offer more chances for duration than. Concrete Pavements. PAVILION. 1642 PAWL. any otlier system, especiallj- if the wood has beenchemically treated. Of these eonipoimd systems used, two forms areshown in Fig. 3576, one employing sijuare blocks Fig 3576.
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Keywords: ., bookcentury1800, booksubjectin, booksubjectmechanicalengineering
