Could he have siphoned the water from one reservoir to the other?
The clear water is then siphoned or poured off and the glaze is ready for use.
The whole is well stirred from time to time for 48 hours, and the clear liquor is siphoned off from the precipitate.
Every few days some of the water was siphoned off through a piece of hose and fresh water run in.
When the other tank, which is below the level and to one side, gets full of water, the fluid is siphoned out.
The clear water on top is siphoned off and the paste dried sufficiently to handle.
Its weight may be inferred from the fact that it can be siphoned, or poured like water, from one vessel downward into another.