On arriving they at once walked toward the entrance to the caverns of the nomes.
The Wizard carried a little black bag containing his tools of wizardry, while Dorothy carried over her arm a covered basket in which she had placed a dozen eggs, with which to conquer the nomes if she had any trouble with them.
Eggs may seem to you to be a queer weapon with which to fight, but the little girl well knew their value.

The nomes are immortal; that is, they do not perish, as mortals do, unless they happen to come in contact with an egg.

If an egg touches them--either the outer shell or the inside of the egg--the nomes lose their charm of perpetual life and thereafter are liable to die through accident or old age, just as all humans are.
For this reason the sight of an egg fills a nome with terror and he will do anything to prevent an egg from touching him, even for an instant.

So, when Dorothy took her basket of eggs with her, she knew that she was more powerfully armed than if she had a regiment of soldiers at her back..