The very best composition for this purpose so far designed is one that is based on an alcoholic solution of shellac and pine tar oil for vehicle, and finely ground ferric oxide of iron as pigment, with red oxide of mercury as the insecticide. The mixing formula is as follows: Dissolve 25 lbs. gum shellac T. V. or V. S. O. in 14 gallons alcohol 95% (denatured will do). Grind 25 lbs. zinc oxide American process and 25 lbs. dark Indian red (96% Fe2O3) fine as possible in 15 lbs. each pine tar oil and Venice turpentine, adding 10 lbs. mercuric red oxide on the last run, and add this to the shellac solution, mixing the ingredients thoroughly and straining through a fine sieve. This will produce 19 gallons of paint. However, under existing conditions, it will not be a paying venture for paint manufacturers to introduce anti-fouling compositions upon the market in this country at least, as naval authorities are very skeptical as to the merits of this line.