542 
Journal of Agricultural Research 
Vol. VII, No. ta 
A comparison of the ratio values in Table IV shows very clearly the 
accelerating influence of a film of Bordeaux mixture on the rates of 
transpiration of pepper plants. If each of the three ratio values for the 
period before spraying is made equal to i.oo, the corresponding ratio 
values for the period after spraying are, in every case, i .29—that is, 29 
per cent higher than the values for the standardization period. 
SOY-BI$AN PLANTS 
The soy-bean plants here employed were about 20 cm. tall when the 
experiment was begun. Soy-bean seedlings were transplanted directly 
into the containers when they were about 5 cm. tall. Three seedlings 
constituted a culture. Four series of cultures were employed, each series 
comprising six cultures and a total of 18 plants. The four series will be 
designated series A, series B, series C, and series D, respectively, for the 
standardization period. Series D is here considered the control series and 
remained untreated throughout the experiment. The plants of the first 
three series were treated at the end of the standardization period and are 
designated “series A',” “series B',” and “series C',” in the order given, 
for the period after treatment. As in all the experiments here reported, 
the leaves of the plants of series A' were covered with a film of Bordeaux 
mixture. The leaves of series B' were sprayed with a suspension of 
barium sulphate in water. The mixture consisted of 28 gm. of barium 
sulphate in 1 liter of water. This was applied by means of an atomizer 
in precisely the same manner in which the Bordeaux mixture was applied. 
The leaves of series C' were treated with dry copper sulphate in the form 
of a fine powder. The copper sulphate was prepared by gently heating 
the crystals in a porcelain crucible until all the water of crystallization had 
been driven off. After the salt had thus been dried to constant weight, it 
was ground to a fine powder in a mortar and kept in a desiccator until 
used. This powder was dusted on the upper surfaces of the leaves until 
a thin but fairly uniform covering was obtained. During the time period 
of the experiment the copper sulphate produced no injurious effects upon 
the leaves, though during this period care was taken to keep the green¬ 
house room as dry as possible. 
For the sake of convenience in presenting the data for this experiment, 
the transpiration quantities for series A, series B, series C, and series D 
are denoted by “A,” “B,” “C,” and “D,” respectively, for the stand¬ 
ardization period; the transpiration quantities for the corresponding 
series for the period after spraying are denoted by “A',” “B' f ” “O',” 
and “D,” respectively. 
The period of standardization extended from February 29 to March 4; 
the period after treatment continued from March 4 to Match 11. The 
data for this experiment are presented in Table V. 
