Your best bet would be to post your query over on the Large Format Forum http://www.largeformatphotography.info/forum/ in the "lens and lens accessories" section.
Baush and Lomb probably was the largest manufacturer of lenses in the U.S. in those days. An 8" focal length certainly would cover a 4x5" negative, probably would cover a 5x7" negative stopped down. I'm guessing, but it probably is a rapid rectilinear, the characteristic of which is to be sharp over most of the circle of illumination but soft toward the edges. My 8" RR from 1905 covers 5x7 easily, but the corners of the negs tend to be soft. What kind of camera your lens came from would be hard to say, there were so many different types and manufacturers back then. Yours looks to be in great shape! Those old beauties are a lot of fun to use.