WHITE PINE. 
121 
way sixteen feet wide and four feet deep, having a towing- 
path on each side. The whole structure is roofed and 
feather-boarded, it is thirty feet wide, and built of pine 
brought down the Alleghany river. The entire cost of the 
aqueduct, including the heavy masonry of the abutments 
and piers, was about $110,000. 
“ I have lately erected several very large bridges with 
wooden superstructures of White Pine ; the piers being 
built of stone ; but one of them, put up in a peculiar place, 
has two piers, the foundations of which are of stone, on 
which are erected piers of timber , framed with half-lap 
splices and lock-joinings secured by screw-bolts, so that 
any stick may be replaced. The sills are of white oak ; 
the posts, standing in cast-iron shoes, are of white-pine, 
and so are the braces. The w r ooden portion of each pier 
is one hundred feet in height, and each span of the bridge 
127 feet.” S. W. Roberts. 
Mr. Roberts remarks, that the Yellow Pine (P. varia- 
bilis,) which grows on the hills bordering the Susquehanna 
in Columbia County, (Pennsylvania), is a fine, sound cohe- 
sive timber; but that the kind called Norway Pine, (P. 
resinosa ? Ait. P. rubra , Mich. t. 134,) from Steuben 
County, New York, is inferior to the Yellow Pine, as the 
layers of the wood are more easily separated. He also 
adds, it is well known that the quality of timber depends 
very much upon the age of the tree, the soil in which it 
grows, and in some cases the influence of the sea-air. 
Generally speaking, in Pennsylvania, the timber grown in 
the river valleys, and still more that grown in the moun- 
tains from 1500 to 2400 above tide, is inferior to that from 
the hills at intermediate heights. 
