Phenix Gazette

Power of Muscles.—One of the most wonderful properties of the muscles is the extraordinary force they exert, although they are composed of such slender threads and fibres. The following facts in relation to this point, are demonstrated by the celebrated Borelli, in his De Motu Animalium. When a man lifts with his teeth, a weight of two hundred pounds, with a rope fastened to the jaw teeth, the muscles named Temporalis and Masseter, with which people chew, and which perform this work, exert a force of above fifty thousand pounds weight. If any one, hanging his arm directly downwards lifts a weight of twenty pounds with the third or last joint of his thumb, the muscles which bends the thumb, and bends that weight, exerts a force of about three thousand pounds. When a man, standing upon his feet, leaps or springs forward to the height of two feet, if the weight of such a man be one hundred and fifty pounds, the muscles employed in that action will exert a force two thousand times greater; that is to say, a force of about three hundred thousand pounds. The heart, at each pulse or contraction, by which it protrudes the blood out of the arteries into the veins exerts a force of above a hundred thousand pounds.
Dick's Christian Philosopher.