324 
CHARLES A. SHULL AND S. P. SHULL 
data which had been running so regularly during the preceding 500 hours 
would suddenly rise above the curve, and then drop back again to the 
curve 168 hours later. If the error involved accidental addition of the 
water to the gelatin, it should show in the last reading also. If an error 
was made it was most likely an error in counting the weights, as a reduction 
of 10 milligrams in the weight would bring the data to 162.46, which would 
bring fair agreement with the calculated value. But even as the figures 
stand the agreement is very striking, and shows that water intake goes 
steadily forward at a rate determined by the conditions of the experiment. 
Table 5. Agreement of Calculated and Observed Intake by Gelatin from Saturated 
Atmosphere 
Time 
Data Low 
Calculated Intake 
Data High 
6.5 hrs 
15-27 
18.08 
16.5 hrs 
27.61 
27.62 
24 
hrs 
33-53 
34.28 
48 
hrs 
48.16 
48.23 
72 
58.43 
58.89 
96 
67.37 
67.75 
121 
hrs 
74.64 
74.76 
144 
hrs 
79.54 
80.35 
192 
90.17 
90.20 
Break in curve 
240 
hrs 
98.17 
98.52 
288 
hrs 
105,22 
106.17 
336 
hrs 
110.97 
III. 54 
432 
hrs 
122.52 
122.54 
528 
131.81 
131.82 
624 
hrs 
139-50 
139-93 
720 
hrs 
147.08 
147.42 
840 
hrs 
154-98 
155.13 
960 
hrs 
161.99 
163.73 
1,128 
hrs 
170.59 
170.62 
The actual rate of intake has been measured at several points by measur- 
ing the tangents to the calculated curve, and we give the rate of intake in 
grams per minute. 
When y = 2^ percent, velocity of intake is .015101. 
When 3^ = 30 percent, velocity of intake is .013348. 
When 3^ = 35 percent, velocity of intake is .011672. 
At the break, y = 93 percent, velocity of intake is .002808. 
The rate at the time the break occurred was approximately one fifth of the 
rate when 25 percent had been absorbed. The steady fall in the rate of 
intake should be noted. These rates are very much lower, of course, than 
when gelatin is immersed in water, and must depend partly at least on the 
surface-volume relation of the particular pieces of gelatin used. One would 
expect a thin, flat piece of gelatin to absorb more rapidly than an equal 
mass in spherical form. 
