1895.] Apparatus for Physiological Botany. gt 
The circle is now sawed out as accurately as possible on the 
scroll saw, and then trimmed if necessary with a spoke shave. 
A V-shaped groove for the belt may be cut on a former 
machine or with a hand beader. The pulley is now slipped 
on the shaft, crowded firmly against the small pulley and 
screwed to it. Ifthe work has been carefully done it will be 
found when the shaft is adjusted in the frame that the appar- 
atus revolves with perfect ease and accuracy. 
A circular zinc pan is made of the diameter of the large 
pulley and six inches deep, with a tubular opening in the 
center one and one-half inches in diameter to fit over the pul- 
ley shaft. This can be seen in section in plate X, figures 2 
and 2’, and in position on the clinostat table, to be described 
further on, in plate IX, figure 2. 
To clamp the apparatus to the table it is placed with its 
base across the table with the ends of the base projecting on 
either side. A piece of the same size as the base of the 
frame, namely 3 x 22 inches, is passed under the table and the 
table is clamped between these two pieces by bolt and thumb- 
Screw at either end as shown in plate X, figure I. 
To use the apparatus as a centrifugal machine for germi- 
nating seeds, the zinc pan is placed over the shaft so that it 
rests on the large pulley. It will be noticed that the shaft 
and pulleys can be removed for this purpose by simply un- 
screwing the large screw (e) fitting the upper end of the shaft. 
Fine white pine sawdust is put into the pan to the depth of 
four inches, and seeds of beans, peas, corn, etc., planted toa 
depth of two inches, about five inches from the center. The 
sawdust is thoroughly moistened and pressed firmly over the 
Seeds; mosquito bar is then spread over the saw dust, and 
Over this is placed wire netting with one inch meshes, so cut 
as to press snugly against the central zinc tube and the outer 
wall of the pan. This keeps the sawdust from heaping up 
against the sides of the pan while revolving rapidly, but does 
not press too hard against the seedlings, for the whole mass 
of Sawdust loosens up to a considerable extent after the pan 
1S set in motion. If any of the seedlings grow to the surface 
it is an easy matter to cut away tHe mosquito bar or even to 
Separate the wire of the netting if this should happen to be in 
the way. A rubber tube connected with a siphon from a jar 
of water standing ona shelf above the apparatus is so clamped 
between two sticks screwed together as to allow a slow drip- 
