1895. | Apparatus for Physiological Botany. 95 
eral plants are needed in one experiment the pan shown in 
g. 5 is used. This is fourteen inches in diameter and six 
inches deep, and has a tube passing through the center which 
fits over the shaft 4. The pots are imbedded in moist saw- 
dust in a circle near the periphery and bound in as before. 
If however it is desired to place the pots so that the plants 
stand perpendicular to the axis of rotation the pan shown in 
fig. 4 is employed. This consists of two circular sides per- 
forated at their centers and connected by a tube which fits 
over the shaft 4, and by four partitions extending radially 
from the tube. When the plants are imbedded in moist saw- 
dust as above described they do not require watering for a 
week or more even in the dry atmosphere of the laboratory. 
UNIVERSAL CLINOSTAT. Plate XII.—The movement ina 
horizontal plane is obtained by a clinostat similar to the one 
described in the first paper, except that the shaft 4, fig. 3, 
Teaching to the floor, has a hole extending from end to end 
through the center, through which a three-eighths inch steel 
rod extends. To make this shaft, two strips the length of 
the shaft are cut two inches wide from one-inch stuff. Ex- 
tending to a distance of three inches from the lower end of 
the shaft a groove is cut longitudinally through the middle of 
each strip five-eighths inch broad and five-sixteenths inch 
deep. The strips are then glued together, with the grooves 
facing each other and forming an opening five-eighths inch 
Square in cross section. When the glue is dry, the upper end 
having been temporarily plugged, the shaft is put into the 
lathe and turned to one and one-half inches diameter. Then 
a three-fouths inch hole is bored two inches deep in the lower 
end of the shaft, and with a five-eighths inch bit this hole is 
Continued to meet the five-eighths inch opening through the 
center of the shaft. A steel core /, three-fourths inch in 
diameter and two and one-half inches long, with a one-half 
inch hole longitudinally through it is inserted in the lower 
end of the shaft, one-half inch of its length protruding. The 
iron bearing &, fig. 3, has a depression one-fourth inch deep 
to receive the core in the lower end of the shaft, and a three- 
eighths inch hole one-half inch deep into which fits and is 
Made fast by a screw the steel rod extending through the 
Shaft. It will be seen that the steel rod remains stationary 
while the horizontal clinostat revolves about it. The upper 
end of the rod is made square and the three wooden pulleys 
