Degrees of pulling: from dragging to wheeled carts
Simple pull versus compound pull in the first, second and third degree
Four sketches classify modes of traction by degree. A man dragging a pole with a hanging basket is labelled compound pulling in the first degree, while a ball drawn by a cord is simple pulling. A two-wheeled cart is compound pulling in the second degree and a four-wheeled cart in the third. The series grades the effort of hauling as resistance is progressively altered by wheels.
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Simple pulling: a ball drawn by a cord
A ball hauled by a single cord along the ground is named simple pulling. It serves as the baseline case against which the compound modes are graded.
Compound pulling in the first degree
A man leaning into a pole from which a basket hangs is called compound pulling in the first degree. The load rides on the dragged pole rather than on wheels.
Compound pulling graded by wheels
A two-wheeled cart is compound pulling in the second degree and a four-wheeled cart compound pulling in the third degree. The wheels progressively change the character of the resistance to be overcome.