“146 BEATING EGGS. 
mingle the two parts of the egg, and to incor- 
porate air with it. 
For custards, etc., the first is all that is 
required. For cakes more beating is necessary 
to accomplish the latter. 
A variety of beaters are in the market, all 
doing the work in a more or less perfect way. 
But many of the best cooks, except for a large 
quantity of eggs, prefer a knife or fork or 
simple whip to the more elaborate machines. 
To gain the greatest possible amount of air, 
yolks and whites must be separated. 
The snowy appearance of the beaten white is 
caused by the mixture of air and probably also 
by a slight evaporation of water, since it be- 
comes frothy sooner in a draught of air. The 
oil, which the yolk contains, makes it lighter 
than the white, as is shown by its position in 
the shell, and when the two parts are beaten 
together it acts like oil on troubled waters, 
making it impossible for the air to get in or 
for any water to pass off. 
Cold eggs beat quicker than those that have 
been in a warm place. A little salt, or cream 
