In the third quarter of a turn, the dial A1, fig. 3, will remain unmoved, since 0 is at the index below it; the dial B1 will be moved forward through three divisions; C1 through nine divisions, and so on; and in like manner the dials of the row D3 will be moved forward through the number of divisions expressed at the indices in the row D4. This change will convert the arrangement into that expressed in fig. 4, the dials to which a carriage is due, being distinguished as before by (*).