Here is a Par-Ex Beer Bubbler Sign from the Syracuse Brewing Company located in Syracuse, NY. This Par-Ex Beer Bubbler Sign dates from the 1930s era and is in excellent condition considering how old it is.
The sign was made by Biolite Inc. located in New York, NY. It is approximately 16″ by 7.5″ by 3″ and made of a metal body with a reverse-painted glass ad panel on the front; the glass letters are filled with a temperature-sensitive liquid what bubbles from the heat of the light bulb. Fun fact, Biolite Inc. signs will also bubble in cold weather too even when the light bulb is turned off.