Place into a change can mixer, 19 pounds rosin oil (first run will do), 3 pounds pine tar (free of water), 30 pounds cheap Venetian red, 24 pounds ground slate (slate flour) and 24 pounds common whiting; mix well, adding a few ounces finely chopped fibre or cow's hair. Put up in paste form and sold by weight. Pressed into leaks with flexible putty knives.
In a portable iron kettle, of 100 gallons capacity, melt 150 pounds black rosin and 150 lbs. tar pitch together, then add 15 gallons of tar oil (heavy naphtha) and when this is well in, take kettle from fire (or if kettle is not portable, draw fire) and add 25 gallons of thin benzine asphaltum varnish, stirring the mixture well, while kettle is still hot. If on cooling, the black paint is too stout to spread readily under the brush, thin with benzine or still better, with solvent naphtha. The formula, as above given, should produce not less than 67 gallons of paint, making allowance for waste.