What glass company embossed its bottles on the bottom with circle around a triangle and a W over a T?

Question

Base of a small rectangular clear glass bottle- broken off- 1 ¾” wide- embossed on base: inside a circle is a triangle and inside a triangle are the letters W over the letter T. There are also three or four dots around the triangle and under it is: USA. This is a glass company, they made the bottle not what went in the bottle.

Answer 1

Could be Whitall Tatum?  I found that they made glass insulators also.  Found at the following source.