( 212 )

and 4 • 87*X • 07956X30 = 56*6 cubic feet;only J- of a foot less than the former.

Rule 3 d .—Multiply the square of -J- of themean girth by twice the length.

5) 4 • 87 mean girth of the former tree.

•974

and * 974 1 XG0 = 5G • 92 cubic feet.

The quantity of water displaced by the totalimmersion of a piece of timber, is equal to itssolid content; and the difference between itsweight, and that of the fluid displaced, is theweight the tree will float.

The weight of a piece of timber of knowncontent, may be found by means of the follow-ing table of Specific Gravities,* which showsthe weight of a cubic foot of dry wood ofeach sort expressed in the table, in ounces avoir-

dupois.

Alder. 800 Campecliy wood . . 913

Apple Tree .... 793 Cedar, wild .... 596

Asli, the trunk . . . 845 -Palestine . . 613

Beech. 852 -Indian . . .flSl^

Box, French .... 912-American . . 561

-Dutch . . . .fl328 Citron.726

■-Brazilian red . ,fl031 Cocoa wood . . . .•f'1040

Bay tree. 822 Cherry tree .... 71^

* Taken from Dr. Gregory’s excellent treatise on M c "chanics.

f Will not float in water.