The soap is now ready for finishing and is first boiled through and tried for strength. A drop of phenolphthalein (1 per cent. phenolphthalein in 98 per cent. alcohol) is allowed to drop on the molten soap taken up on a trowel. The red color should be instantly produced and develop to a full deep crimson in a few seconds, or more lye must be added until this condition is realized. Should it flash a deep crimson immediately it is on the strong side. This cannot be conveniently remedied; it can only serve as a guide for the next boil, but in any case it is not of any serious consequence, unless it is too strong. With the steam on, the soap is now examined with a trowel which must be thoroughly heated by working it about under the surface of the hot soap. The appearance of the soap as it runs from the face of the trowel indicates its condition. It is not possible to absolutely describe the effect, which can only be properly judged by practice, yet the following points may serve as a guide. The indications to be noticed are the shape and size of the flakes of soap as the sample on the trowel breaks up and runs from the hot iron surface, when the latter is turned in a vertical position, as well as the condition of the iron surface from which the soap flakes have fallen. A closed soap will run slowly into a homogeneous sheet, leaving the trowel's surface covered with a thin layer of transparent soap; a grained mass will run rapidly down in tiny grains, about one-half an inch in diameter or less, leaving the hot trowel absolutely dry. The object of the finish is to separate the soaps of the lower fatty acids from those of the higher, and both from excess of liquid. A point midway between "open" and "closed" is required to arrive at this point. Having arrived at the above condition, the soap is allowed to settle anywhere from one to three days and then run off through the skimmer pipes to the nigre and framed or pumped to the tank feeding the drying machine. The stock thus obtained should be fairly white, depending upon the grade of tallow used and slightly alkaline to an alcoholic phenolphthalein solution. If removed at exactly the neutral point or with a content of free fat the soap will sooner or later develop rancidity. The soap thus obtained is an ordinary tallow base, and the one by far greatest used in the manufacture of toilet soaps. The percentage of cocoanut oil indicated is not fixed and may readily be varied, while in fine toilet soap the rosin is usually eliminated. In the manufacture of full boiled soda soaps in which no glycerine is obtained as a by-product, it being retained in the soap itself, the soap formed is known as a "run" soap. The process is used most extensively in the manufacture of marine soaps by which the method may be best illustrated. This soap is known as marine soap because of its property of readily forming a lather with salt water and is mostly consumed aboard vessels.