SOAP 849 



In the best conditions, that is to say, by employing the best Gallipoli oil for the pur- 

 pose of producing Marseilles soap of first quality, 100 cwts. of olive oil yield 175 cwts. 

 of mottled soap ; by using mixtures of olive and rape or other seed oils, the yield of 

 soap is reduced to 170, or even less ; in either case the yield is reduced by 5 or 6 per 

 cent., when old or fermented is employed instead of new good oil. 



Tho manufacturing expenses are calculated at Marseilles at the rate of 17f. 25c. 

 (nearly 13s. IQd.) per 100 kilogrammes of fatty matter employed, which require 72 

 kilogrammes of soda for their saponification. 



Mottled soap has a marbled, or streaky appearance, that is to say, it has veins of 

 a bluish colour, and resembling granite in their disposition or arrangement. The 

 size and number of these veins or speckles, and the proportion which they bear to the- 

 white ground of the soap, depend not only on the more or less rapid cooling of the 

 soap after it has been cleansed, that is, transferred from the copper to the frame ; but 

 also on the quality and kind of the fat, grease, or oil employed, and on the manner in 

 which it has been treated in the copper. A soap which has not been sufficiently 

 boiled at the last stage of the manufacture is always tender. The blue or slate colour 

 of the streaks or veins of mottled soap is due to the presence of an alumi no-ferrugi- 

 nous soap interposed in the mass, and frequently also to that of sulphide of iron, 

 which is produced by the reaction of the alkaline sulphides contained in the soda-lye 

 upon the iron, derived from the soda-ash itself, and from the iron pans and other 

 utensils employed in the manufacture, or which is even purposely introduced in the 

 state of solution of protosulphate of iron. This introduction, however, is never re- 

 sorted to, we believe, in this country. The veins or streaks disappear from the surface 

 to the centre by keeping, because the iron becomes gradually peroxidised. A well- 

 manufactured mottled soap cannot contain more than 33, 34, or at most 36 per cent, 

 of water, whereas genuine curd soap contains 45, and yellow soap at least 52 per 

 cent, of water, and sometimes considerably more than that. It is evident, in effect, 

 that the mottling being due to the presence of sulphide of iron held in the state partly 

 of demi-solution and of suspension, the addition of water would cause the colouring sub- 

 stances to subside, and a white, unicoloured, or ' fitted ' soap would be the result. This 

 addition of water, technically called fitting, is made when the object of the manufac- 

 turer is to obtain a unicoloured soap, whether it be curd or yellow soap. After fitting, 

 the soap contains, therefore, an additional quantity of water, which sometimes amounts 

 to 55 per cent. : the interest of the consumer would, therefore, clearly be to buy 

 mottled soap in preference to yellow or white soap ; the mottling, when not artificially 

 imitated, being a sure criterion of genuineness ; for the addition of water, or of any 

 other substance, would, as was just said, infallibly destroy the mottling. To yellow or 

 curd soap, on the contrary, incredible quantities of water may be added. The writer has 

 known five pails of water (15 gallons) added to a frame (10 cwts.) of already fitted soap, 

 so that the soap, by this treatment, contained iipwards of 60 per cent, of water, to which 

 common salt had previously been added. The proportion of water in fitted soap has 

 also been augmented, in some instances, by boiling the soap in high-pressure boilers 

 before cleansing. As cocoa-nut oil has the property of absorbing one-third more water, 

 when made into soap, than any other material, its consumption by the soap-maker has, 

 within the last twenty-five years, augmented to an extraordinary extent ; and, more- 

 over, the patent taken in 1857 by Messrs. Blake and Maxwell, of Liverpool, for the 

 invention of Mr. Kottula, which will be described presently, has, we believe, in- 

 creased the demand for that species of oil in a notable degree. We said that the 

 mottling, inasmuch as it was indicative of genuineness, was the more economical soap 

 to buy ; unfortunately, mottled soap has the drawback of not being so readily soluble 

 v as yellow soap, and the goods washed with it are more difficiilt to rinse ; but the 

 process patented by Messrs. Blake and Maxwell enabling the manufacturer to manu- 

 facture with cocoa-nut oil a soap to which the mottling is artificially impaired, by 

 means of ultramarine, black or brown oxide of manganese, in such a perfect manner 

 as almost to defy detection, mottling has thus ceased to be a safe outward sign of 

 genuineness, as far as regards the article which it pretends to represent. That descrip- 

 tion of soap, however, has specific qualities : it is almost perfectly neutral, and it will 

 not bear more than a definite proportion of water ; so that, although it contains more 

 of that liquid than ordinary mottled soap, more than a certain fixed quantity cannot 

 be forced into it ; hence it also forms a standard soap, like the ordinary mottled, 

 although that standard is different from, and inferior to, the latter. The process in 

 question is briefly as follows : Take 80 cwts. of palm oil, made into soap in the usual 

 way, with two changes of lye, grained with strong lye, or lye in the usual manner, but 

 that the lye leaves the curd perfectly free ; pump the spent lye away, and add 32 cwts. 

 of cocoa-nut oil, 60 cwts, of lye, at 20 of Beaume's aereometer, and then gradually 

 14 cwts. of lye, at 14 Beaume. Boil until the whole mass is well saponified. Put 

 now from 6 to 7 Ibs. of ultramarine in water, or weak lye, stir the whole well, and 



VOL. III. 31 



