1912] BOVIE—PRECISION AUXANOMETER 5°09 
node did not elongate as much on the second day as it did on the 
first, hence the curve for this day is everywhere below the first one. 
Very interesting curves can be produced when several plants are 
compared, or when the increments of the various internodes of the 
same plant are recorded simultaneously. 
The writer is now working in cooperation with the L. E. Knott 
Apparatus Company on a new model, which involves a different 
mechanism for opening the circuit. This machine will be smaller, 
and it is hoped that it can be put on the market at a very low cost. 
HARVARD UNIVERSITY 
LABORATORY OF PLANT PHYSIOLOGY 
