The posts above pretty well cover the subject.
Old style scuttles with the itty bitty bowl on top and the water well for the brush in the bottom were a way to get hot water from the range to the shave stand.
If you find one of these, they were really more for face lathering with a shave stick or rubbing the wet face with a soap. The brush was to work up a lather on the face and it would set onto the scuttle out of the way and could get more water if needed.
I find the old style scuttles fun. I can rub or smear a small amount of a softer soap into the bowl and lather there. Then put the loaded brush to my face for fuller penetration of the stubble. a bit more hot water in a minute makes the lather complete.
The new style scuttles are a winner and the same soft soap or cream smeared into the bottom makes a great lather and...stays warm.
YMMV of course as with any other shaving info.
~Richard