As noted in National's 1920's Catalog:
* Article -- Radiator Water Cup
* Price -- unpainted for 50 cents or
electroplated with brass, copper, or nickel for $1.80
They also sold paint kits or their doorstops painted.
Note 2: -- Way Device Works
This was a cast iron device that sat on top of a room's radiator in the winter.
Water was poured in its tray portion.
When the radiator got hot, the water would evaporate and
put moisture in the air of the room for comfort.
Cast Iron Device consists of 2 pieces
Open tray area measures (9"X 2 1/2"X 1 1/2"),
Weighs almost 4 lbs.
Device has 4 feet with a groove in each
The grooves fit on top the ridges of the radiator fins for stability.
There is a very similar cast iron piece that is a Doorstop
that may be seen under the icon, "WOMEN"
on the Home page.