1895.] Apparatus for Physiological Botany. 93 
at the base of the shaft is adjustable along a groove in the 
block m, which is screwed to the floor. It will be seen that 
a wedge extends the full length of the groove and by driving 
in a screw at each end of the wedge the iron cup may be 
clamped in any position along the groove. I find that ordi- 
Nary common twine makes an efficient belt. When the ends 
are tied the knot is so small as to be of no consequence. The 
slow motion for the clinostat is obtained by running a belt 
from the water motor to the large pulley on the centrifugal 
machine, and from the small pulley of the latter to the large 
pulley of the clinostat. The apparatus is shown harnessed 
in this way in plate IX. The zinc pan of the centrifugal 
machine may be put on the table of the clinostat as in plate 
IX, figure 2, and will there serve for imbedding the pots of 
the plants used in the experiments in moist sawdust to pre- 
vent rapid drying. 
A support for inverted plants is shown on the clinostat in 
plate IX, figure 1, and in detail plate X, figures z, 0, and p. 
The method of adjusting the height of the belt from the 
water motor is shown in plate IX, figure 6. The standard 
Carrying the pulleys is held at the desired height by means 
Of a screw pressing against a strip of spring brass set into 
the block f through which thestandard passes. See plate X, 
details g, 7, s, ¢, and u. The pulleys of figure 6 are shown 
Set at the proper angle for the large pulley of figure 5. When 
the belt runs over the small pulley of figure 5 the pulleys of 
figure 6 are unscrewed and set nearly parallel and closer to- 
gether. 
In the preceding pages the methods of making the shafts 
and pulleys and of inserting the metal cores have been given 
in detail. It is now necessary to describe only the parts and 
Manner of working of the following apparatus. 
VERTICAL CLINOSTAT.—Plate XI, figs. 1 and 2 show the 
Vertical clinostat set up for experiments with seedlings grow- 
ing in a moist atmosphere. The base plate a is clamped to 
the table in the manner described on page 91. To the 
Plate 4 are fastened the standards c, d, and the cross-plate e, 
to which the pulleys f g, are fixed. The whole apparatus is 
bolted to the plate a, and may be turned about this at any 
angle to the light. The wooden shaft % has a steel core in- 
Serted in one end which bears in the iron box z. A depres- 
Sion is turned into the shaft five and one half inches from the 
