The effect of water on egg shell strength including a study of the translucent areas of the shell

Abstract

A series of measurements of egg shell strength was carried out, using a needle to pierce the egg at a number of points at the waist up to a maximum of eight. It was found that water weakens the egg shell whether it gets in from the outside of a normal egg or from the inside of an emptied egg. This weakening caused by water is not permanent and the shell recovers its strength on drying in air. Absolute alcohol strengthens the empty shell even more than air‐drying, but not to the same extent as oven‐drying. Shell strength slowly increases when a normal egg is allowed to stand in the air for a month. Translucent areas of the shell are weaker than opaque areas and this difference is more marked at a week old than in a newly laid egg. Soaking the shell in water weakens it but also eliminates the difference between the two types of area, while oven‐drying strengthens the shell but also eliminates the difference. The possible relationship of these points to the more practical aspects of shell strength and to the accurate measurement of shell strength is mentioned.