257 
and curves of the form 
x2 = aos (Ft+a) —beos (Frt+2), 
AN T. 
1 
y =a sin (Feta) —bsin (F++8), 
7, T, 
when « and 8 are constants, or 4~B a fraction of t+ 
a constant. By J. C. W. ELLIS, M.A. 
DrivingWheel 
A 
A driving wheel (A) drives by means of a band a disk B,. 
B., C,, C, are three other disks equal to B,. A, B, B,, Cs, 
are all in a vertical plane. The centres of B,, B, are fixed in 
the same horizontal line at a distance of about four times the 
diameter of the disks. The centres of C,, C, are similarly 
placed in a vertical line. B,, B, are so connected by rods or 
otherwise so as to revolve simultaneously. So are C,, C, The 
axis of B, is also the axis of a cone with the vertex pointing 
from B, and revolving with B,. This cone drives by means of 
a band (b) the disk C,, which is attached to a similar cone with 
its vertex pointing towards C,. In the disks are bored a 
number of equidistant holes along the diameters, into which 
20 
