The boiling process being now finished, the whole may stand twelve or fourteen hours, and if the quan tity be two or three tons, it will be the better of stand When one-third of the ley, or 133 gallons, is put -into the boiler, add the tallow, and after it is melted, put in the olive oil. Let the fire be now drawn a lit tle, and the whole stand two hours. When the fire is again lighted, put in twenty gallons additional ley. As the whole boils, add occasionally a little more ley to pi event the soap from boiling over, until the soap is considered to be hall' boiled, when it will be time to ascertain whether the soap has got too much or too little ley. This operation, called proving, and which is requisite frequently, is thus performed: With a knife take up a piece of the soap, and if it turns white upon the knife, and falls from it in short pieces. too touch Icy has been put in, and consequently a little more olive oil must be added. But if it fall front the knife in long ropy pieces, an additional quantity of ley must he added. If, on the other hand, it is neither too white nor too ropy, but transparent, it neither needs oil nor ley. When it arrives at this state it may be put into the barrels or other vessels destined to hold it. After the second lighting of the fire, the boiling should be briskly kept up, and when the soap is nearly ready, it should boil slowly till it is put into the barrels.
2. Second crown soft soap. For this soap take, ing double that time, keeping it however close and warm in the boiler. If any blueness remains, the washing must be repeated.
The frames into which it is now to be cast should have a bottom. and be lined with coarse cloth. If a perfume is wished for, a little of the essential oil of Caraway seeds, mixed with a small portion of alcohol, may be incorporated with the soap in putting it into the frames, stirring in a little of it at a time to diffuse it through the mass.
When it is cast into the frames, the whole should be covered up with old sheets, mats, ice. and allowed to cool gradually for three or four days, when it may be taken out, and cut into pieces of the required size.
2. Process for making hard, brown, or yellow soap.
In order to charge a pan for hard yellow soap, pour in 150 or 200 gallons of ley. and add 10 cwt. of tallow, and 93 cwt. of rosin broken into small lumps. The whole is now to be boiled and stirred, taking care al ways to damp tlk fire when the materials swell up. After two or three hours boiling, withdraw the fire, and allow the whole to stand four or six hours, when the weak Icy is to be pumped off and fresh ley added. If it is wished to pump off sooner, a few parts of cold ley must be thrown in a short time after the fire is drawn. The whole is now to be boiled a second time for two or three hour‘ and the boilings continued (lay after day till the soap squeezes into a scale be tween the finger and thumb, as described in the pre ceding process. When this is effected, the pan is to be
treated in the same way as in the process for white soap, si:e or eight parts of water being in this case put in, in place of eight or ten in the white soap. If we wish to give a beautiful colour to the soap by means of palm oil, put 20Ibs. of the oil into the boiler, when the soap is considered to be finished, then after boiling for half an hour draw the fire, and allow the whole to stand for 43 hours, when it may be cast into the frames. If the frames arc 30 inches deep, the soap may be cut in bars in about three days.
The following table has been given as showing the average proportions of the materials for yellow soap.
Process for making blitrk or green soft soap.
The difference between hard and soft soap is, that in the former the whole of the ley is extracted, while in the latter the whole is retained, forming a compound body with the other materials. This soap is of two kinds. viz. first Croon soap, made of tallow, hogs' lord, and olive Oil: and second crown soap, made with tallow and whale oil.
1. First er9wn snap. For a charge of eighteen bar rels take When 100 gallons of the ley are put into the boiler, add the tallow, and when it is melted, put in the whale oil and draw the fire. When the whole has stood two hours, light the fire and add twenty gallons of ley. Continue to boil briskly till the soap is considered to be half finished, and then put in ten gallons of addi tional ley. Add the other ten gallons during the rest of the boiling, and finish the soap as in the last process.
Hard soap in a proper state for the market, should contain thirty per cent. of water; but by fraudulent practices it may be made to contain sixty per cent.
The simplest and the most beautiful soap, is the fine white soap made of olive oil and soda obtained from the best barilla. A more expensive kind is made of soda and oil of sweet almonds. The former kind, which is made at Marseilles, Naples, and several parts of Italy, is sometimes streaked throughout with I ell and blue veins. This is effected by a solution of sul phate of iron, and by the brown red oxide of iron.
4. Method of improving Pope of Lom bard Street, has given the following method of im proving soap. Take one cwt, of good soap, slice it into thin pieces, and mix with it seven lbs. of marl of the purest kind, and a sufficient quantity of water, to reduce the whole into a fluid state. When the whole arc stirred together till they are of the consistency of cream, they are boiled, and then poured out into suit able moulds fur making them into cakes. By this process, the soap is rendered smooth and soft, and the action of the caustic alkali upon the skin is destroyed. See Dr. Brewster's Journal of Science, No. xiv. p. 361.