54 
much to be regretted that the congas of Dr. Allen’s 
which he has already advanced so far in the direction of com- 
pleteness. 
Marsuacyi A. Howe, 
MEASUREMENT OF GROWTH. 
The growth of a stem or leaf, as indicated by its elongation, 
perature and other factors upon the process ma 
only by some apparatus, which will keep a pootons recon of 
the amount of growth for several days at a 
The best method of nines of - rate a growth of a 
stem consists in the attachment of the short arm of a thin lever 
to the tip of the stem to be tested, by means of a thread, and 
allow the other end of the lever carrying a pen to trace a line on 
e two arms of the 
instrument consists of a compoun 
pinwheel bearings. The long arm of a 
e short arm of another lever, the free end of which may be 
