A gentleman of this city has sent us the accompanying diagram of an improved hoisting pulley, for which he say she would be willing to pay any reasonable price provided he knew where to obtain it--the wheel, not the price. It is a pulley within a pulley, the friction of the outer one upon the inner one--the latter being held by a ratchet and pawl-acting as a brake in lowering weights, while both would turn together in elevating weights. The idea is rather an ingenious one, but we are confident our inventors can attain a like object by simpler means.