W. Neilson Jones. 
35 ^ 
short duration the turning can he performed, without great 
inconvenience, by hand. For longer experiments an automatic 
turning device is desirable. The simple mechanism illustrated in 
Figs. 4 and 5, in connection with an intermittent klinostat, has been 
found to serve the purpose well. 
In Fig. 5, h is the driving axis of the intermittent klinostat 
timed to revolve through 180° once every hour. To this axis is 
affixed an arm aa' carrying a small pulley wheel p at its outer end. 
A cord, attached by a loop to this pulley wheel, runs from it to a 
point p' on a drum d. Another cord is attached to the drum d at a 
point q and after passing once completely round the drum, is fixed 
to a weight W. The effect of this cord and weight is to keep the 
cord pp' always tightly stretched. 
Thus, as the axis h turns successively through 180°—always 
turning in the same direction—the drum d also turns through 
7T 
positions 180" from one another (if the length of aa' = n X radius 
