IIo EXPERIMENTS ON THE FROUDE. 
device. To set this pen at its zero it was sufficient to force the weighing 
lever down, out of contact with the indicator spring. The scale of the pen 
record was found by giving the indicator spring a measured deflection. 
Since only a fraction of the thrust was recorded by the thrust-pen fussy 
adjustments were unnecessary. 
This thrust mechanism was found to be sensitive and at the same time 
positive and worked without trouble, and almost without attention. 
