” 
64 TESTS OF THE FRESHNESS OF EGGS. 
TESTS OF THE FRESHNESS OF EGGS. 
HE perishable nature of eggs is their 
og : 
KR greatest disadvantage. 
& £7 Though many experiments have 
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been tried, as yet no practical method 
has been discovered for keeping eggs in their 
original freshness for any great length of time. 
An “egg tester” is a little instrument for 
holding an egg directly before a strong light, 
which is obtained by an arrangement of mirrors ; 
this is convenient, but not essential. 
Fresh eggs are transparent throughout; old 
ones only at the top, and dark spots appear in 
the center. If held before a bright light these 
spots appear; therefore this process is called 
“ candling” by egg-dealers. 
The specific gravity of the fresh egg is 
greater than that of water. (Hence is used as 
a test of solutions.) 
As the egg grows older it loses water by 
