An auxanometer for the registration of growth of stems 
in thickness. 
KATHERINE E. GOLDEN. 
WITH PLATES XII AND XIII, 
Description of the instrument. 
The main feature of this auxanometer for measuring growth 
in thickness (see plate XII) is a balanced glass arm supported 
hear one end, acting as a multiplying lever. The longer part 
of the arm has a bristle fastened at the end that registers the 
lateral movement upon one or more blackened glass rods car- 
oe on a brass spool, the spool being revolved by a 
clock, 
The glass arm passes through a short brass tube held be- 
tween two hardened steel points. The position of the arm is 
varied by changing the brass Y, holding the points, which is 
kept in place by aset screw. The longer arm is counterbal- 
anced bya weight suspended from the shorter arm. Close 
behind the steel points is a small fork; this fork presses the 
is : be measured upon one side, and the glass arm upon 
sink _ The fork is made at the end of a screw thread, to 
bese oe era backward and forward, to accommodate 
fine aan stems. To keep the long glass tube straight a 
an ae apes from one end to the other, passing over 
na aa yt ‘9 forming a truss. These pieces of mechanism 
esi A ace by a long wooden beam, supported on three 
levelling oo ling one end, one of which is provided with a 
height cv to admit of adjustment for plants of varying 
tended at € spool is made to revolve by having the axis ex- 
ar one end beyond its supports to carry a grooved 
pull eas t pO 
Suclicg ae ‘S connected with a similar grooved pulley, at- 
tween is u 
fect me fixed fork and the short arm of the glass rod. Per- 
Maintained hy the glass arm and the stem of the plant is 
t Y Means of a very light wire spring fastened be- 
oe * . 
tration)" Peam and the glass arm (not shown in the illus- 
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