Date of this Version
Bulletin of the Torrey Botanical Club (April 1881) 8(4): 41-42.
A dendrometer is constructed essentially as follows: A tube, t, about two inches in diameter, and nearly or quite a foot in length, is supported in a vertical position by two pins, pp, near its upper end; and these pins rest upon a ring, r forming a simple gimbal which allows the tube by its own weight to assume an exactly vertical position. In the lower end of the tube two mirrors, A and B, are placed side by side, each occupying one half of the section of the diameter of the tube. One of these mirrors (A) is inclined at an angle of 45° to the horizon when the tube is in a vertical position, and the other (B) has an inclination of 22.5°.