Manufacturer and builder 3 / 1881
A mixture for writing on glass has lately been put on the market, under the name of "diamond ink," which is pronounced to be a very useful article for druggists and others for labelling bottles containing substances which would destroy ordinary labels. It has been examined, and found to consist of a mixture of ammonium fluoride, barium sulphate and sulphuric acid; the proportions for its manufacture being, barium sulphate, 3 parts; ammonium fluoride, 1 part; and sulphuric acid enough to decompose the fluoride and make a mixture of semi-fluid consistency. This mixture, when brought in contact with a glass surface on the parts it comes in contact with. The philosophy of the action is the decomposition of the ammonium fluoride by the acid, which disengages hydrofluoric acid, which attacks the glass; the barium sulphate is inert and is simply used to prevent the spreading of the markings. The mixture must be kept in bottles coated on the inside with paraffine or wax.