I. 3. THE BALSAM FIR. 85 
when it can be had, for the lighter spars of vessels, on account 
of the smoothness and beauty with which it works. It is found 
farther north than any other tree of America, and in latitude 
673° attains the height of twenty feet or more.* 
This tree has considerable rapidity of growth. Seven trees 
in the Botanic Garden, Cambridge, which had been planted 
thirty-one or thirty-two years, measured, one, two feet ten 
inches; one, two feet nine inches; three, two feet five inches 
each; one, two feet four inches; and one, two feet three inches ; 
giving, on an average, a diameter of ten inches in thirty-one 
years, or a growth of somewhat less than one-third of an inch 
annually. 
1. 3. Tee Fir. Picea. Link. 
The firs are lofty trees, social inhabitants of the colder regions 
of both hemispheres, and often forming vast woods. They are 
remarkable for the regularity and symmetry of their pyramidal 
heads. ‘The leaves are solitary, needle-shaped, rigid, semper- 
virent, supposed by botanists to be formed of two, grown to- 
gether. They are distinguished from the other pines by the 
smoothness of their barx, in which are formed cavities or crypts 
containing their peculiar balsam, by the silvery whiteness of 
the under surface of the seemingly two-rowed leaves, and by 
their long erect cones, formed of woody, deciduous scales, with 
a smooth, thin edge. 
Sp. 1. Tse Batsam Fir. Picea balsamifera. Michaux. 
Figured in Lambert’s Pinus; Plate 41. 
Michaux ; Sylva, TI, Plate 150. 
Loudon; Arboretum, VIII, Plate 334. 
This beautiful evergreen resembles the spruce in its regular 
pyramidal form. It differs from it in its bark, which is smooth 
when young, and continues so until the tree has attained con- 
siderable age; in its leaves, which are nearly flat, and of a beau- 
tiful silvery color beneath, and in having large, upright cones. 
* Hooker’s Fl. Bor. Am. II, 163. 
