In France, tho chief scat of the industry is at Marseilles, while a not inconsiderable amount of common, and nearly all the toilet, soaps are made in Paris. In a report on the exhibits at Paris in 1878, it was stated that tha French soap-trade had been for some time stationary at about 220,000 tons per aunum, but was then declining, owing to practices not very creditable to the manufacturers.
In Germany, and other parts of the Continent, soft soaps are much more proportionately in vogue for laundry and other purposes, than in England, while the chief hard soaps made are for toilet purposes.
In the United States, Kirk &Co. of Chicago have probably the largest trade, but they are closely approached hy Babbitt & Co., and Colgate & Son, of New York. The changes that have lately passed over the trade in America have been already described (p. 1787). It may be said, without fear of contradiction, that while perhaps for fancy toilet soaps the palm must be given to France, England and the United States are pre-eminently the countries where the manufacture of tha different varieties of soap is most clearly understood, and carried out on the largest scale, and in the best manner.
and first of these consists essentially of a mixture of a more or less perfectly formed soap, water, carbonate of soda, and neutral fat, and is used on the axles of all locomotives, railway-carriages, and trucks that are provided with axle-boxes; while the mound is a soap of lime and rosin-oil, with or without water, and is used on all railway-trucks unprovided with axle-boxes, and for ordinary- road-vehicles.
The requisites for a good " locomotive-grease " for high velocities are :—(1) a snitable consistency, such that it will neither run away too rapidly, nor be too stiff to cool the axlee ; (2) lasting power, so that there may be as little increase of temperature as possible in the axles, even at high speedo ; (3) a minimum of residue in the axle-boxes.
In praetice, it is found that a grease containing 1.1-1.2 per cent. soda (100 per cent.) gives the best results. The process of manufacture is very simple ; Morfit's soap-pans, provided with stirrers, p. 1772, Fig. 1240, are the most suitahle vessels for the purpose. The fats, usually tallow and palm oil, are heated to 82° (180° F.), and into them, are run the carhonate of soda and water heated to 93i° (200° F.), and the whole is well stirred together, and run into large tubs to cool slowly. Many railway companies buy a curd-soap nnade from red palm-oil, dissolve it in water, and add thereto enough tallow and water to bring. the composition of the whole to the desired point. It is usual to allow 2i per cent. for loss by evaporation of water during the manufacture. The composition has to be slightly varied according to the season of the year ; the following formulm for mixing have stood the test of successful experiment ; the slimmer one ran 1200 miles. It should be carefully borne in mind that a chemical analysis of locomotive-grease is no test whatever of its practical value, which can only be determined by actual experiment.
The " waggon-grease " is thus prepared. A good milk of lime is made, and run through several overflow-tubs, where all grit is deposited ; it is then drained on canvas. If the grease is t,o be madc without water, the paste must be agitated with rosin spirit, which expels the water, and it is then thinned with a further quantity of rosin spirit. The aqueous milk of lime, or the mixture of lime and rosin-spirit, is then stirred together with a suitable quantity of rosin-oil in a tight barrel furnished with a shaft and stirrers, without tbe application of heat, after which, the whole is run out into barrels to set. Many other ingredients are often stirred in, sueh as " dead oil," petroleum residues, graphite, sea-weed jelly, silicate of soda, oil refiners' foots, micaceous ores, steatite, Irish moss, &e.
Glycerine (FR., Glycerine; GER., Oelsiiss, Oelzueker, Glycerin).— Few things in the history of chemical industry are more wonderful than the enormous development in the use of this substance, which, a few years ago, was thrown away as a waste product, but which now finds so many useful applications in the arts and sciences. The researches of Chevreul, which demonstrated the consti
tution of fats, showed that glycerine exists in nearly all neutral fats (see p. 1764) in a combined state, and small traces of it have lately been diseovered uneombined in palm-oil. It is formed, as Pasteur bas shown, in the process of fermentation, 100 parts cane-sugar forming 3.5 parts of glycerine. Re cent researches have also made it elear that its compound with phosphoric ncid is the starting-point of a number of complex constituents of the brain. For practical purposes, however, glycerine is always obtained ftom the bye-products of eandle-, and quite lately, of soap-factories. Cap worked out the first process for preparing it on a commercial scale from the waste liquor of the saponification of tallow by lime, in the first stage of stearic acid making (see Candle,, p. 579). Early in 1854, Tilgh man produced it by pumping an emulsion of 2 parts tallow and 1 part water through a coil of pipe heated to 322° (612° F.), after which, the emulsion separated into two layers, the upper one of fatty acids, and the lower of glycerine and water. Several modifications of this were afterwards patented, but the only 01.10 worked on a large scale was that of G. F. Wilson aud G. Payne, dated July 24, 1854, under which, enormous quantities of glycerine have been made by Price's Candle Co. In this process, neutral fats are put into a still provided with a fine stcam-morm, and a fractional con densing apparatue of largo traduce, similar to that deecribed Candles, p. 581; they are thou heated to between 2880 and 315° (550°-600° F.), and plenty of euperheated steam is injected ; mixed vapours of fatty acids, glycerine, and water aro carried over to the condenser, where the divisions nearest the still collect only fatty acids, while those farthest frum it yield mixtures of fatty acids with glycerine and water in various stages of concentration. Glycerine so made can be con centrated in a vacuum-pan. Care must be taken that the temperature does not exceed 315° (600° F.), and that plenty of steam is present, else some of the glycerine is decomposed, arid acrolein, a compound most irritating to the eyes, is formed— Glycerine = Water Aerolein C811,08 = 21E40 + Cal-140 Raw glycerine is also prepared from the water employed to wash the fatty acide after acidifica tion (p. 581) of the neutral fats. The acid liquid is neutraliz,cd by cash. lime, or earb. baryta, either of which may be added until effervescence ceases; it is thea concentrated t,o 23° B. in au open, shallow, cast-iron pan. Of late, however, glycerine has become sufficiently valuable to cause candle-manufacturers to adopt that method of preparing fatty acids which gives them the greatest yield of glycerine frorn neutral fate. This process, called the autoclave, as patented by De Milly on Nov. 19, 1856, is now very extensively used for glycerine making, both on the Continent of Europe and in England, and is thus conducted. About 1 ton of fat, usually mixed tallow and palm-oil, is heated with 2 per cent. lime and the fat-volume of water in an upright Papiu's digeeter to 8 attnos. pressum for 4 hours. The whole is then blown out into a tank, and the " sweet-water " is run off. The lime-soap is decomposed in the usual way with sulphuric acid, and the resulting fatty acids are either pressed, or acidified and distilled for etearie acid. (See Candles, p. 581.) It is then concentrated in a modification of the " Wetzel " evaporating pan (originally introduced fur sugar-boiling), constructed by Chenaillier, Paris. This ('vaporateur universal, ae he terms it, which is very economical and effective, is shown in Fig. 1279, and consists essentially of pairs of saucers set edge to edge upon a hollow central revolving shaft, through which, steam passes to the interior of the saucers (the waste steam from a high pressure engine will do); the lower edges of the saucers dip ill a jacketted trough of the liquid to be evaporated, and when they are revolved, layers of thie are brought up and speedily concentrated on their surface. It may also be worked in a vacuum as shown in Fig. 1280.