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BRIEFER ARTICLES 
NEW NORMAL APPLIANCES FOR USE IN PLANT 
PHYSIOLOGY. V*. 
(WITH TWO FIGURES) 
In the preceding articles I have described some ten new pieces of 
apparatus designed for educational work in plant physiology; accounts 
of three more are given below, while others are to follow. They are called 
_ hormal appliances because they are intended to represent the optimum 
resultant, the harmonic optimum, as it were, between accuracy of results 
and convenience of use, while at the same time they can always be bought 
from the stock of a supply company. As in the case of the other pieces 
these are to be manufactured and sold by the Bausch & Lomb Optical 
Company of Rochester, N. Y¥ 
X. Space markers 
For some purposes, especially in the study of growth, it is necessary 
to mark off a structure into regular divisions, either areas as in the case of 
young leaves, or lengths as in roots, stems, or petioles. It is not difficult to 
improvise appliances for accomplishing these ends, but as yet no tools are 
available for effecting them quickly, accurately, and conveniently, while 
at the same time always ready for use. This need, I think, the two little 
instruments here described will supply. 
First, for marking lengthwise, the instrument is a wheel, the rim of 
which is a rubber stamp having raised cross-lines 2™™ apart. It revolves 
freely but evenly on an axle held in the end of a handle, and when suitably 
inked by the method described below, it may be run rapidly over long struc- 
tures such as roots, marking them with narrow black cross-lines equally 
spaced, precisely as shown at the bottom of jig. I. 
econd, for marking areas, the instrument is a disc, likewise @ rubber 
stamp, haying raised lines in the form of squares 2™™ on a side. It works 
by means of a scissors-frame against a cushion disc covered with soft felt 
and provided with a radial slot to admit the petiole of a peltate leaf. When 
the marking disc is inked and pressed firmly against a leaf held .on the 
Cushion disc, it marks a network of even fine black lines like the sample 
shown in jig. r. The marking disc is hinged to its supporting arm ms 
* Continued from Bor. GAzETTE 43:279. April 1907. 
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30r] Botanical Gazette, vol. 48 
