74 KANSAS UNIVERSITY QUARTERLY. 
small portion near point F is used. (Fig. 12 shows the conditions 
for this case.) This portion is so nearly a straight 45°-line. per- 
pendicular to AF, that such a line may be used satisfactorily. This 
would mean an equal difference between the radii (or diameters) 
of the steps for a cone with three steps. 
ice 12) 
So it is only necessary to figure a pair of radu, R, and ry, of a 
, : R n 
suitable size and so that — ta) 
ice N 
Then Ki == also rs, 
i, —— alse Rey 
Reeves ip eres 
and oles 93 Rs amuless ia 
CROSSED BELTS. 
For a crossed belt any three step cone with speeds in regular 
progression may be figured thus, whether great or small in propor- 
tion to the distance between centers, for in the diagram for crossed 
belts a 45°-line replaces the circle arc. But only a three step cone 
can have a constant difference between the diameters of successive 
steps if the speeds are to be in geometrical progression. 
Any pair of cones for crossed belts may be figured arithmetically, 
but for any case except that above explained for a pair of three 
