What is the purpose of this glassware?
It is an apparatus for taking a sample of a liquid from a big container. Let's suppose you have at your disposal a big bottle (at least one liter) which has two holes on a level with one another at middle height. Now imagine that a flow of a small river is entering the bottle from the upper neck, at such a rate that the level of the water inside is always on a level with the holes. The water gets out through the lateral holes. Now you put a punched rubber stopper in one of these holes. And the long thin pipe of your glassware is horizontally inserted into the stopper hole. Your glassware can then be turned and placed in such a way that the broader tube is vertical with its neck above. With this equipment, the broad tube is all the time half-filled with water. If the composition of the water slowly changes, a sample of its composition may be taken by turning the broad tube so as to empty it upside down, then putting it vertically again.