28 BULLETIN 1775, U. S. DEPARTMENT OF AGRICULTURE. 
Table 11 and figure 8 give the average percentage relative humidi- 
ties! by weeks in Room 3. The humidity from the beginning of the 
season up to September varied from 72 to 77 per cent, and from that 
time until the end of the season gradually increased to a maximum 
of 91 per cent. The cause of the rise in relative humidity in this 
room may be attributed to several factors: (1) Beginning with Sep- 
tember the doors were opened frequently on account of the removal 
_of eggs from cold storage, thus allowing an inrush of air frequently 
jaden with moisture; (2) during the early fall months the cases and 
fillers had become saturated with moisture for the temperatures at 
which they were held, so that they did not continue to assist ma- 
terially in the removal of moisture from the air; (3) by this time the 
brine pipes had become heavily frosted because of the condensation 
of moisture from the air, which rendered them less efficient both as 
absorbers of heat and as condensers of moisture; (4) after the warm 
weather of the summer had passed, less brine was circulated through 
the pipes, thereby reducing their efficiency as condensation agents; 
(5) with the advance of the season the number of cases decreased, so 
that there was more air in the room to carry moisture and less surface 
exposed for condensation and absorption. In this room, as well as 
in the other two rooms in which observations were made on the 
shrinkage of eggs, calcium chlorid was used as a drying agent. All 
three rooms were chilled by brine pipes on the walls. 
PHYSICAL AND CHEMICAL CHANGES IN EGGS DURING STORAGE. 
During the commercial holding of eggs in cold storage the air 
Space increases in size because of the evaporation of moisture; the 
white becomes thinner and eventually loses its opalescence. After 
six or seven months the white usually develops a yellow tinge, which 
deepens with the length of the storage period. The clouded appear- 
ance of the white is especially noticeable when eggs are separated 
in large quantities, as is done in a commercial egg-breaking room. 
The slightly yellow color does not destroy the beating quality of the 
white nor the porcelain white color of the resulting froth. The yolk 
membrane weakens slowly, but, if the eggs are fresh on storing, most 
of them can be separated, even after storage for 11 months. The 
. . Ud . *. 
separation, however, is usually not as easy as in the earlier part of 
1 The determinations of relative humidities were made according to a sulphuric acid vapor pressure 
method by N. Hendrickson and H. C. Woodward, which, in brief, was as follows: Two gram samples of 
sulphuric acid of concentrations varying from 15 to 35 per cent were allowed to come to equilibrium in the 
storage rooms in low, wide-mouth weighing bottles. The bottles were then covered, allowed to come to 
room temperature, and then weighed. The percentage of the sulphuric acid in equilibrium was calculated 
from the original concentration. The vapor pressure corresponding to the concentration of the sulphuric 
acid in equilibrium divided by the vapor pressure of saturated water vapor at 32° F. equals the percentage 
of the relative humidity of the air of the cold-storage room. The usual method of determining the relative 
humidity by a sling pschychrometer was not used, as it is not accurate at 32° F. and below, because of 
the freezing of the water on the wet bulb. 
