848 SOAP 



' Two kinds of soda-ash are used in Marseilles the soft soda (soude donee) and the 

 salted soda (soude salee), which contains a large quantity of common salt. 



' To prepare the lye, the soft soda previously reduced into small lumps is mixed 

 with 12 per cent, of slaked lime, and shovelled up into tanks of masonry of about 

 2 cubic yards' capacity, called barquieux, and the exhaustion of the mass with water 

 gives lyes of various degrees of strength. 



' The lye marking 12 is used for the first treatment, orempatage of the oil which is 

 then submitted to a second and third treatment with a lye marking 15 or 20, the 

 object of which is to close the grains of the emulsive mass in process of saponification 

 (serrer I'empatage). The operation requires about twenty-four hours. During all the 

 time of that operation a workman is constantly agitating the boiling mixture of the 

 oil and lye by means of a long rake or crutch, called rdble. The empatage is gene- 

 rally practised in large conical tanks of masonry terminated at bottom by a copper- 

 pan, and capable of containing 12 or 13 tons of made soap, and the operation proceeds 

 so much the more rapidly, as the soda- lye employed contains less common salt, where- 

 fore soft soda-lye (soude douce) must be used at the beginning, as we said. 



' The next operation is that called relargage, the object of which is to separate the 

 large quantity of water which has been used to facilitate the empatage. This separa- 

 tion of the water, or relargage, is effected by means of salted soda (that is to say, of 

 soda-ash, containing a good deal of common salt), of which as nmch is dissolved 

 in water as will make a lye marking 20 or 25. This salted lye is then gradually 

 poured by a workman on the surface of the saponifying goods in the copper, while 

 another workman is diffusing it in the mass by stirring the whole with a rake or 

 crutch. 



' The immediate effect of the salt thus added is to separate from the soapy mass the 

 water in which it was dissolved, and which gave it a homogeneous and syrupy 

 appearance, and to coagulate it, the soap being thereby cured or coagulated, and 

 converted into a multitude of granules floating among the excess of water in which 

 they were dissolved, and which the salt has separated. The whole being then left at 

 rest for two or three hours, in order to give the grains of soap time to rise and agglome- 

 rate at the surface, a workman proceeds to the epinage, an operation which consists in 

 withdrawing the liquid portion by removing a wooden plug placed at the lower part 

 of the boiler.' 



In this country the epinage is generally performed by means of an iron pump 

 plunging through the soap down to the pan at the bottom of the copper. 



This spent lye, in well-conducted factories, retains but little alkali, and is gene- 

 rally thrown away; but as it contains a rather large quantity of salt, which, in France, 

 is an expensive article, it might be, and is sometimes, kept and used for preparing 

 fresh lyes. 



After the first epinage, the soap is treated twice again with salt-lye, followed of 

 course by two epinages ; but as the salt-lye used in these two operations is not exhausted, 

 it is always kept for preparing fresh lyes. 



The cleansing, that is to say, the removing of the soap into the frames, takes place 

 on the third day, at which time the operation called mad-rage is performed. For 

 that purpose a plank is thrown across the boiler or copper, and two or three men 

 standing on it, and therefore over the soapy mass in the copper, proceed to stir it up 

 for two or three hours, by means of long crutches, which they alternately move up and 

 down through it, the object being to keep the grains of soap well diffused through the 

 liquid, weak lyes marking only 8 or 10, or ordinary water, as the case may be, 

 being sprinkled from time to time into the mass, until the grains of soap have reab- 

 sorbed a sufficient quantity of water and have swollen to such a size as to have a specific 

 gravity very little greater than that of the liquid in which they float about. A 

 skilful workman knows by the appearance of the soap grains whether he should 

 use alkaline lyes or simple water, and this is indeed a most important point in the 

 manufacture of Marseilles soap, for upon it the success of the operation depends in a 

 commercial" point of view, that is to say, all things being equal in other respects, a 

 profit or loss on the batch of soap made will ensue. In effect, if too much water has 

 been added the soap will lose either the whole, or too great a portion of its mottling, 

 that is to say, the result will be either a dingy white curd, or a soap in which the 

 white portions will predominate to too great an extent over the blue streaks; a circum- 

 stance which so far deteriorates the market value, the buyer shrewdly suspecting then 

 that he would pay for water the price of soap. If, on the contrary, a sufficient quan- 

 tity of water has not been added, the soap grains remaining hard and dry, will form a 

 more or less friable soap, thereby causing also a deterioration of price, the buyer knowing 

 that such soap, by crumbling into small pieces every time he has to cut it with his 

 knife in selling it to his customers, will considerably reduce his profit, or perhaps 

 even entail a positive loss to him 



