Answer:

Germans have a process by which they claim to be able to determine the age of an egg to the day.

The egg is dropped in a solution of salt containing eight ounces to the pint. If the egg is only one day old it sinks immediately to the bottom; if three days old it sinks just below the surface only, and from five days upward it floats.

It is well known that the air cavity at the blunt end of an egg enlarges as the age of the egg increases. When the egg is placed in the salt solution it will have a tendency to float with the long axis vertical.

A scale of angles is placed at the back of the vessel, and from the inclination of the egg to the horizontal, it is said, the age can be gauged almost to the day.

A new laid egg lies horizontally on the bottom of the vessel. When three to five days old it raises itself so that its long axis makes an angle of about 20 degrees with the horizontal.

At eight days the angle increases to about 45 degrees; at 14 days it is 60 degrees; at about three weeks it is about 75 degrees, while after four weeks it stands upright on the pointed end.