. . . . "Examples of such bases are alkali metal hydroxides, such as sodium hydroxide and potassium hydroxide, alkali metal siliconates, such a sodium siliconate and potassium siliconate, amines, for example methylamine, dimethylamine, ethylamine, diethylamine, triethylamine and n-butylamine, ammnoium compounds, for instance tetramethylammonium hydroxide and tetra-n-butylammonium hydroxide, with preference" .