80 WOODY PLANTS OF MASSACHUSETTS. 
in diameter at the ground, that is, somewhat less than half 
an incha year. The largest of these measured five feet and 
three inches, the smallest, two feet and nine inches in circum- 
ference. 
The timber of the hemlock is wanting in strength, in conse- 
quence of having the circles of growth separated at intervals, 
or, to use the language of the dealers in timber, being “ shaky.” 
This defect Michaux * supposes to be produced by the winds, 
acting with great force upon a broad compact summit rising 
above the heads of the surrounding trees. Its firmness is great, 
and it is very durable when not exposed to the atmosphere, but 
as it has little resin, it ill bears the alternations of moisture and 
dryness. It is therefore employed, together with spruce, in 
every part of New England, as a substitute for white pine, 
where the latter has grown scarce, for the frames of all kinds 
of buildings which are to be covered, for the board covering of 
wooden houses which are to be clap-boarded, and particularly, 
on account of its hardness, for the threshing floors of barns. It 
is preferred to other woods for the material of lathes, and for 
any purpose where stiffness is wanted without the property of 
yielding, or elasticity. It is much used in the large Atlantic 
cities, as a substitute for stone in the pavement of streets, for 
which purpose it is sawn into hexagonal blocks of eight inches 
in thickness, and eight, ten, or eighteen inches in breadth. 
For fuel, it has not great value, as it burns with a great 
crackling and snapping. It is, however, used in close stoves. 
Many cords of the bark are annually consumed as fuel. But the 
most important use to which this bark is apphed, and for which 
it is imported from Maine is, as a substitute for oak bark in the 
preparation of leather. It contains a great quantity of tannin, 
combined with a coloring matter which gives a red color to the 
leather, apt to be communicated to articles kept long in contact 
with it. On which account, this bark is not commonly used for 
the best kinds of leather, by itself, but mixed with oak bark; 
and the compound is said to be superior to either alone. 
* Sylva, III, 188. 
