507. Another form of epicyclic train designed for producing a very slow motion. m is a fixed shaft upon which is loosely fitted a long sleeve, to the lower end of which is fixed a wheel, D, and to the upper end a wheel, E. Upon this long sleeve there is fitted a shorter one which carries at its extremities the wheels, A and H. A wheel, C, gears with both D and A, and a train-bearing arm, m, n, which revolves freely upon the shaft, m, p, carries upon a stud at n the united wheels, F and G. If A have 10 teeth, C 100, D 10, E 61, F 49, G 41, and H 51, there will be 25,000 revolutions of the train-bearing arm, m, n, for one the wheel, C.