Take a stone, or any heavy substance, and putting it in a large glass
with water, place it in the receiver. The air being exhausted, the
spring of that which is in the pores of the solid body, by expanding
the particles, will make them rise on its surface in numberless
globules, which resemble the pearly drops of dew on the tops of the
grass. The effect ceases when the air is let into the receiver.