we 
ee ee ee ee 
CARBON DIOXIDE UNDER SITTING HENS 161 
and B had good eggs and Hen C china eggs. The rubber 
tubes through which the air was drawn, were fixed permanent- 
ly in the box and passed into wooden nest eggs through which 
a hole was bored. This was kept near the center of the nest 
and the hen did not have to be disturbed when. the sample 
was drawn. 
_ The greatest trouble was the movement of the hen on the 
nest if the taking of the sample occupied a long period of 
time. Here again we see the increase of CO2 during the in- 
cubation period but not so markedly as in Table I. 
In the case of the hen with china eggs there is no increase 
of COz. During this period a few sample were drawn 
through potash bulbs with results as shown in Table 
III. The time occupied to draw 1,000 c.c. being about 3 hours. 
This method confirmed the results already given, but with 
higher readings in some cases. A sample from Hen C taken 
in this way gave 4.5 pts. This confirms the results already 
obtained for a hen without good eggs. 
TABLE III. 
(Hen A.) 
July 22, 133 pts. carbon dioxide in 10,000 of air 
6c ZY 96.3 ‘ 66 i ce ee (a9 ; 
eee 40.40 : 
ce 26, 74.0 66 ce se ee (a3 6é 
Table IV is typical of results obtained trom a number of 
tests with incubators. The samples were drawn with an 
aspirator from over the egg tray. Samples drawn from be- » 
neath the tray corresponded with those from above the tray. 
Incubator 11 was a Cyphers and Incubators 18 and 19 were 
the Prairie State. In No. 18 oats were sown in a pan contain- 
ing earth which is placed beneath the egg tray. The oats 
were sown to test the effect on the air of the incubator of the 
CO2 given off by sprouting seed. No noticeable difference 
was found in the air of the two incubators. | 
