BRIEFER 2 UICEES. 
NEW PRECISION-APPLIANCES FOR USE IN PLANT 
PHYSIOLOGY. It 
(WITH FOUR FIGURES) 
IN the first of these articles I gave the reasons which have led to the 
development of some new pieces of apparatus for educational use in plant 
physiology, and I described two of these pieces. In brief, believing that 
improvised apparatus has been brought to its fullest practicable, if not to 
an actually harmful, degree of development, I am trying to devise for each 
of the leading physiological topics appropriate normal apparatus, viz., 
appliances which, manufactured expressly for the specific work, will yield 
accurate quantitative results, will be applicable to their work with economy 
of time and effort, and will be obtainable by purchase at any time from 
the stock of a supply company. In the foregoing article I described the 
new clinostat and the new portable clamp-stand; below are accounts of 
three additional appliances, and similar descriptions of other pieces in 
advanced preparation will follow later. They all are now, or soon will be, 
for sale by the Bausch & Lomb Optical Company, of Rochester, N. Y. 
III. AUTOGRAPHIC TRANSPIROMETER. 
A practicable and obtainable form of autographic (self-registering) 
transpirometer, suitable for use both in educational demonstration and also 
in certain lines of investigation, is one of the first desiderata of plant physi- 
ology. Several forms have been devised, of which the best known are 
the “évaporométre” of Richard Fréres, and the registering balances of 
Woods and of Anderson. The first of these, while obtainable, has serious 
limitations both in practice and in principle; while the two others, though 
admirable in their accuracy, must be made to order at large cost and with 
much delay, and they are somewhat elaborate withal. My new instru- 
ment, illustrated in the accompanying jig. I, is constructed as follows: 
A cylinder, shown in the upper part of the figure, contains on a spiral 
track between its outer and an inner wall some 2 50 spherical gram weights. 
These weights are steel bicycle balls of one-fourth inch diameter, the same as 
Anderson used in his balance; they weigh almost exactly one gram each. 
* Continued from 37:307. April 1904. 
1905] 145 
