Westinghouse 300w Daylight Incandescent

Local Kijiji find, I've always thought these daylight blue incandescent lamps were pretty neat. I'm guessing this was probably WWII era surplus as it still had the Mazda trademark on the etch and there's a second stamp on the side that says "GOVT OF CANADA". Interesting collection piece for sure. I have it shown here lit at reduced power (~40v, 55W) on a variac.

A similar lamp appears in the 1938 Westinghouse Mazda Lamp Catalog. In that catalog, the daylight bulb lamps were promoted for use in industrial facilities, and for blending daylight and artificial lighting in places such as offices and stores.