BOTANICAL GAZETTE 
APRIL 1802, 
A simple self-registering auxanometer. 
GEO, E. STONE. 
(WITH PLATE y.) 
The various forms of self-registering auxanometers used 
in botanical laboratories are more or less complicated and 
Costly instruments. Such instruments as are used by Sachs, 
Wiesner, Baranetzky, Pfeffer, and others, vary consider- 
ably in their construction and utility. One of the best aux- 
anometers for general purposes that has been devised is that 
of Baranetzky. A modified form of this apparatus is used by 
Pfeffer, a figure and description of which is given in his Pflan- 
zenphysiologie, ! 
The multiplying apparatus, which, however, is the most im- 
Portant part of an auxanometer, consists of two grooved 
Wheels of different radii that are fixed to a horizontal axis 
Which revolves on delicate bearings. The large wheel has a 
mm., and the small one of usually about 12.5 
mm., thus giving an enlargement of eight times; over the small 
eer passes a thread, one end of which is connected 
With t F 
ea 
anometer 
ny one 
Such as is 
follows: oO 
Ti sae 
—" though rigid straw, to the free end of the straw there is 
ened, by means of sealing wax, a fine pin of spring brass 
1 
See also Goodale’s Physiological Botany, p. 383. 
4. 
Vol. XVII._No 
