MOISTURE OF THE ATMOSPHERE.
Moisture is always present in the air, even when it is driest. To prove this, press a piece of sheet copper into the form of a cup; place on it a piece of phosphorus, thoroughly dried between blotting-paper; put the cup on a dry plate, and beside it a small piece of quick-lime; turn over it a glass tumbler, and leave it for ten minutes, that the lime may remove all moisture from the included air; take off the tumbler, touch the phosphorus with a hot wire, and instantly replace the glass; when a dry solid will be formed, resembling snow. As soon as the flame is extinct, examine the plate; when the solid will, in a very short time, attract so much water from the air, that it will pass into small drops of liquid.