1918] BAKKE—WILTING 103 
ratios between the day and night readings are respectively 0.95, 
0.63, 0.34, 1.83, 1.79, 1.19, 2.00. The ratio between the index 
of foliar transpiring power for the gth and 21st hours on July 21-22 
is 1.57. The ratio between the day maximum and the night mini- 
mum at that time is 2.11. 
Taking into consideration that the minimum for Id, during the 
march of foliar transpiring power on July 21-22 is 0.49, the maxi- 
mum values during the march of wilting are extremely low from the 
initial to the final point of wilting. On account of the drop in 
the maximum and the constant retentive character of the minimum, 
the index here is larger than recorded previously. The leaf was 
completely wilted on July 31. 
The day values for Ib, taken at the same time as before are 
Q.15, 0.20, 0.28, 0.13, 0.16, 0.14, 0.14, 0.21, 0.17, 0.15;. while 
the corresponding night values are 0.14, 0.21, 0.19, 0.20, 0.22, 
O.1I, 0.15, 0.10, 0.14, 0.12. The ratios between these two sets 
are, in order of their occurrence, 1.07, 0.95, 1.45, 0-65, 0.59, 1-45, 
0.93, I.40, 1.50, 1.42. The ratio between the readings for the 
goth hour and the readings of the 21st hour on July 21-22 for Helian- 
thus leat Ib, is 0.98:0.51, or 1.92. The ratio between the maxi- 
mum and the minimum is 2.23. In none of these cases can the 
proportion be regarded as normal. This plant from the beginning 
is evidently in a partially wilted state. 
In comparing the march of foliar transpiring power Gaus the 
Process of wilting for the two series Ia and Ib, there would natu- 
rally be some variation. The wilting of series Ia extends over a 
longer period (to August 7), while that of Ib reaches its permanent 
wilting point on August 3. In both cases the older leaf wilts long 
before the younger leaf. However, leaf Ia has a greater range 
of foliar transpiring power. Leaf Ia, wilts before Ia,; likewise Ib, 
before Ib,. 
The ratio between the morning and the night readings of each 
day gives in the majority of cases a value that is less than the 
normal. For Ia all the results are either near 1.00 or below it 
except for the first. As the maximum value is above that of the 
usual minimum the result cannot be anything but normal. With 
Ia the ratio on July 31 is extremely high, probably being due to the 
