The force necessary to break or tear out a half-inch iron pin, applied in the manner of a pin to a tenon in the mortice, has likewise obtained the attention of the same celebrated experimentalist. The thickness of the board was 0.87 inch, and the distance of the centre of the hole from the end of the board, 1.05 inch. The force required was 976 lbs. As the strength of a tenon from the pin-hole may be considered to be in proportion to the distance from the end, and also as the thickness, we may, for this species of wood, obtain the breaking force in pounds nearly, by multiplying together one thousand times the distance of the hole from the end, by the thickness of the tenon in inches.