A Home-Made Barometer
Take 1/4 oz. of pulverized camphor, 62 gr. of pulverized nitrate of potassium, 31 gr. nitrate of ammonia and dissolve in 2 oz. alcohol. Put the solution in a long, slender bottle, closed at the top with a piece of bladder' containing a pinhole to admit air, says Metal Worker. When rain is coming the solid particles will tend gradually to mount, little crystals forming in the liquid, which otherwise remains clear; if high winds are approaching the liquid will become as if fermenting, while a film of solid particles forms on the surface; during fair weather the liquid will remain clear and the solid particles will rest at the bottom.