which water glass did they mean?

there is a chemical liquid--viscous, clear, and used as fireproofing.. some sort of silicon compound
Some one here with more chemistry will say exactly what what the compound is...

and there are waterglasses, a specific size/type glass that comes as part of a crystal set, and/or a specific glass made for water.--singular would be a waterglass.

i have the most exquisit italian glasses, in a cool translucent green, the glass is filled with very fine bubbles, so it looks effervenscent-- which are water glasses (and came as set with a pitcher.) there are one of the few family heirlooms i got.. from my great grandmother-- my great grand father brought them back from italy..in the 1870's. he was, as we like to say a stock broker, he traveled to the continent to buy the newest breeds of sheep, cattle and other stock!