250 BOTANICAL GAZETTE [MARCH 
used; one of these projects vertically upward from near the center of the 
base of the framework (see fig. 1) to a level somewhat less than half- 
way to the top; the other projects downward from the top of the frame- 
work, in line with the first, to a level somewhat less than halfway to the 
bottom; the distance between the two contiguous ends of these uprights 
should be slightly greater than the length of the wheel hub; both uprights 
should be firmly braced. The wheel is held in position between the two 
uprights by means of two iron “corner-braces”’ (which can be secured 
at any hardware store), in each of which one of the four screw holes has 
been bored large enough to fit the axle of the wheel. In adjusting the 
FIG. 1 
wheel to position a corner-brace is first screwed vertically to the upper 
end of the lower upright; the wheel is set in this and then firmly fixed 
in place by means of the second corner-brace which is screwed to the 
lower end of the upper upright; any slight divergence of the wheel from 
the horizontal plane can be corrected later by tilting the entire frame- 
work. For vanes 8 pieces of light wood about 8X ro inches are used; 
these are attached to the spokes by means of screw-hooks, being hung 
at a slight angle to the radii of the wheel; they are tied to the rim at 
their upper edges and are further held in position by means of wooden 
strips tacked to their lower edges. This table will accommodate 20 or 
more atmometers. As a precaution against the possibly disastrous 
