Cant say much without seeing them, but the blue tinted lamps were made to simulate daylight, and thereby allow colour critical work to undertaken in dull weather.
An incandescent filament emits emits the full spectrum of light, but with a bias towards the orange/red.
The blue tinted glass blocks some of the red/orange and therefore gives a close approximation to natural daylight.
A common use was the grading and pricing of tobaco, hops and other produce.
Small lamps with light blue glass are still made today, the larger ones have been replaced by color matching flourescent lamps.
