thickness. The nature of tension failure is apparently not
affected by the moisture condition of the specimen, at least not
so much so as the other strength values.[3]

[Footnote 3: See Brush, Warren D.: A microscopic study of the
mechanical failure of wood. Vol. II, Rev. F.S. Investigations,
Washington, D.C., 1912, p. 35.]

Tension at right angles to the grain is closely related to
cleavability. When wood fails in this manner the thin fibre
walls are torn in two lengthwise while the thick-walled fibres
are usually pulled apart along the primary wall.

|--------------------------------------------|
| TABLE III |
|--------------------------------------------|
| TENSILE STRENGTH AT RIGHT ANGLES TO THE |
| GRAIN OF SMALL CLEAR PIECES OF 25 WOODS IN |
| GREEN CONDITION |
| (Forest Service Cir. 213) |
|--------------------------------------------|
| | When | When |
| COMMON NAME | surface of | surface of |
| OF SPECIES | failure is | failure is |
| | radial | tangential |
|------------------+------------+------------|
| | Lbs. per | Lbs. per |
| | sq. inch | sq. inch |
| | | |
| Hardwoods | | |