Q. What is the cause of water when it is first drawn being just as white and thick as milk, but if you let a tumblerful of it stand for about one minute it will become as clear as you could wish? It leaves no sediment at the bottom, and you cannot by stirring or shaking, make it white again.

A. The milky appearance is probably due to air confined in the water under the pressure in the pipes, which escapes when the water runs from the faucet.