282 
Journal of Agricultural Research 
Vot. XIV, No. 7 
EXPERIMENT UNDER A PRESSURE OP LESS THAN ONE ATMOSPHERE 
A single experiment was carried out in which the sweet potatoes were 
stored in a vacuum chamber which was kept in a water bath at 30° C. 
For this purpose the gas cylinder described above was used. The air 
was exhausted to a pressure of 4 mm. A dish of moist soda-lime was 
placed on the bottom of the chamber to absorb the carbon dioxid. The 
potatoes were kept in the chamber for five days. Owing to the absorp¬ 
tion of water by the soda-lime the interior of the chamber was very dry 
and the potatoes were much wilted, but otherwise uninjured. The 
results of this experiment are given in Table V. 
Table V.— Changes in composition of sweet potatoes stored for 5 days at,jo° C. and at 
a pressure of 4 mm . 
Sweet potato 
No. 
On the basis of fresh material. 
On the basis of dry matter. 
Moisture. 
Starch. 
Reducing 
sugar as 
glucose. 
Cane 
sugar. 
Starch. 
Reducing 
sugar as 
glucose. 
Cane 
sugar. 
Per cent. 
Per cent . 
Per cent . 
Per cent. 
Per cent. 
Per cent. 
Per cent. 
63a. 
76.74 
15*51 
o -35 
2. 27 
66.68 
i- 54 
9.76 
63b. 
76.78 
IO. 29 
•55 
6/06 
44-32 
2 - 37 
26. IO 
64a. 
76. 88 
15 * 27 
•32 
2. 30 
66. 05 
1. 38 
9-95 
64b. 
76. 80 
IO. 61 
•47 
5-87 
45-73 
2.03 
25 * 30 
65a.. 
78.19 
13 * 97 
• 5 ° 
2. 22 
64.05 
2: 29 
10.18 
65b. 
76. 29 
10.18 
.91 
6. II 
42.94 
3-84 
25*77 
66a. 
77 - 59 
x 4 * 59 
•29 
2 .45 
65. IO 
1.29 
10.93 
66b.. 
70.87 
14.83 
• 3 i 
6-45 
50.91 
1.06 
22.14 
67a. 
75- 01 
16.87 
.24 
2. 29 
67.51 
.96 
9.16 
67b. 
73- 86 
12.09 
•38 
6.44 
46.25 
45 
24.64 
68a. 
77.66 
14.40 
•43 
2. 33 
64. 46 
1.92 
10.43 
68b. 
77-94 
10.15 
. 61 
5.43 
46. 01 
2 .77 
24.61 
It is very probable that the available oxygen within the cylinder was 
soon removed by the potatoes and that thereafter they were in an atmos¬ 
phere free from oxygen. The behavior of the potatoes under these 
conditions is like that of the potatoes stored in hydrogen at the same 
temperature. There is a marked accumulation of cane sugar but scarcely 
any increase in reducing sugar. 
DISCUSSION OF RESULTS 
In the experiments of Cruickshank the lack of sweet taste in the soaked 
barley kept in an atmosphere free from oxygen may be taken to indicate 
the absence not only of cane sugar, which, according to O'Sullivan, 1 may 
constitute as much as 4.5 per cent of the dry weight of the germinated grain, 
but also of the other sugars occurring in malt. It is therefore reasonably 
sure that under the conditions of the experiments no cane sugar was 
formed. In like manner the experiments of Boysen-Jensen show that in 
1 O’StTLUVAN, C. ON THE SUGARS OF SOME OF THE CEREALS AND OF GERMINATED GRAIN. (Abstract.) 
In Chem. News, v. 52, no. 1359, P- 293. 1885. 
