Brunnquell prepares crayons for writing on glass, so as to enable the contents of glass vessels to be described immediately upon them in the following manner:—Take four parts of spermaceti (or stearine) three parts of tallow, and two parts of wax are iused in a cup; six parts of minium and one part of potash are then stirred into it, the mass may be screwed up and down in the tube, and cut to the finest point with a knife. A crayon is thus obtained which will readily wiite upon clean dry glass.