1918] 
DUGGAR AND BONNS—RATE OF TRANSPIRATION 161 
lower ratio during the night intervals. Since the conditions 
are the same for all the plants, this variation is unexplained. 
Leaving individual variation out of consideration, it will be 
seen that for the whole period of the observations the water 
loss is again higher for the plants sprayed with Bordeaux 
and lime Bordeaux than for the control. More interesting, 
however, are certain comparisons between single intervals be- 
fore and after standardization. Assuming that the plants in 
the different lots before and after standardization are more 
nearly comparable in intervals which are relatively close to- 
gether, we may compare the first interval after spraying, XV, 
which in other eases has shown marked increase as a result 
of the Bordeaux applieation, with interval XII before stan- 
dardization, these two being night intervals of approximately 
equallength. Again, we find that the effect of the Bordeaux 
film during the first interval after spraying is very consider- 
able, giving a percentage increase of 310, and that the Bor- 
deaux lime preparation shows an increase of 479 per cent. 
On the other hand, if we compare the second interval after 
spraying under conditions of sunshine, XVI, with the last in- 
terval before spraying, XIV, we find a slightly diminished 
transpiration in the sprayed plants. 'The ratios of all sub- 
sequent intervals except one after spraying, XVII-XX, are 
nearly constant and approach the normal or average before 
standardization,—the exception being interval XVIII. The 
exceptional interval is a night period where again the ratio 
for sprayed plants is high. It seems well here to emphasize 
the fact that environmental conditions are obviously in some 
way important in determining the increased transpiration due 
to surface films. 
The data given for series C in table m is noteworthy for 
several reasons. In the first place, it will be seen that in the 
several intervals of standardization the L group of plants ex- 
hibits a relative falling off in the rate of transpiration. There 
was no apparent cause for this, as the soil conditions were as 
moist as in the other pots, and evidence of flagging was en- 
tirely lacking. In the second place, after spraying the water 
loss of the B’ and BC’ plants is very great during interval 
