What are these upside-down glass egg-shaped containers for?
This is called an inverted specimen jar, sometimes called a sample jar, for obvious reasons intentionally designed to stand on the stopper (it is not a standard one to close the other jars in the lab).  Their use was something more popular around 1900's, when showcasing dyes and other visual appealing chemicals, especially towards the general public. Your example invites to look at the granular character of the product.

A more traditional design is this one, more conveniently used in collections / museums.


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