Heat one-fourth of a glass of water in a pan. Stir in three or four teaspoonfuls of Epsom salts (magnesium sulfate) until no more will dissolve. Remove pan from fire and add a drop or two of liquid glue; stir until the glue has dissolved.
Using a wad of cotton, spread some of the mixture evenly on a piece of glass. In a few minutes, needle-like crystals will begin to appear, and soon the glass will be covered with frosty crystal patterns. When the water dries, you will have a good sample of magnesium sulfate crystals.