This float is stamped with maker's mark WP #49; which is the symbol 'Go' 合. 

It's also sometimes referred to as a "TID" mark by beachcombers which is WP #20.  According to Walt Pich in his definitive book 'Glass Ball Marks', these TID floats are partial or mis-stamps of the WP #49 sealing iron.

Another interesting aspect of this mark is that the roof is a 'Flying Roof'.  By that, I mean there's an extension that goes up to the left beyond the peak of the roof.

This example also has great provenance having come from the ex-Rich Richardson collection.