STEARIC AGIO 891 



combination is pretty complete. The stearate being allowed to cool to such a degree 

 as to admit of its being handled, becomes a concrete mass, which must be dug out with 

 a spade, and transferred into a contiguous tub, in order to be decomposed with the 

 equivalent quantity of sulphuric acid diluted with water, and also heated with steam. 

 Four parts of concentrated acid will be sufficient to neutralise 3 parts of slaked lime. 

 The saponified fat now liberated from the lime, which is thrown down to the bottom 

 of the tub in a state of sulphate, is skimmed off the surface of the watery menstruum 

 iuto a third contiguous tub, where it is washed with water and steam. 



The washed mixture of stearic, margaric, and oleic acids, is next cooled in tin pans ; 

 then shaved by large knives fixed on the face of a fly-wheel, called a tallow-cutter, 

 preparatory to its being subjected in canvas of caya bags to the action of a powerful 

 hydraulic press. Here a large portion of the oleic acid is erpelled, carrying with it a 

 little of the margaric. The pressed cakes are now subjected to the action of water and 

 steam once more, after which the supernatant stearic acid is run off, and cooled in 

 moulds. The cakes are then ground by a rotatory rasping-machine to a sort of mealy 

 powder, which is put into canvas bags, and subjected to the joint action of steam and 

 pressure in a horizontal hydraulic press of a peculiar construction, somewhat similar 

 to that which has long been used in London for pressing spermaceti. The cakes of 

 stearic acid thus freed completely from the margaric and oleic acids, are subjected to 

 a final cleansing in a tub with steam, and then melted into hemispherical masses called 

 ' blocks.' When these blocks are broken, they display a highly crystalline texture, 

 which would render them unfit for making caudles. This texture is therefore broken 

 down or comminuted by fusing the stearine in a plated copper pan, along with one- 

 thousandth part of pulverised arsenious acid, after which it is ready to be cast into 

 candles in appropriate moulds. See CANDLE. 



Moinier and Boutigny introduced a process by which the production of stearic acid 

 has been considerably increased. Two tons of tallow and 900 gallons of water are 

 introduced into a large rectangular vat of about 270 feet capacity. The tallow is 

 melted by means of steam admitted through a pipe coiled round the bottom, and the 

 whole kept at the boiling point for an hour, during which a current of sulphurous acid 

 is forced in. At the end of this period 6 cwts. of lime, made into milk with 350 gallons 

 of water, are added. The mixture soon acquires consistency, and becomes frothy and 

 viscid. The whole is now agitated, in order to regulate the ebullitions and prevent 

 the sudden swelling up of the soapy materials. The pasty appearance of the lime 

 soap succeeds, and it then agglomerates into small nodular masses. The admission of 

 sulphurous acid is now stopped ; but the injection of the steam is continued until the 

 small masses become hard and homogeneous. The whole period occupies eight hours, 

 but the admission of sulphurous acid is discontinued at the end of about three hours. 

 The water containing the glycerine is run off throiigh a tube into cisterns prepared to 

 receive it. The arrangements for producing sulphurous acid are retorts into which 

 are put sulphuric acid and pieces of wood ; upon the application of heat the sulphurous 

 acid passes off, and is conveyed by leaden pipes into the vessel containing the tallow. 

 The lime-soap formed is then moistened with 12 cwts. of sulphuric acid at 152 Fahr., 

 diluted with 50 gallons of water. The whole is thoroughly agitated, and the steam 

 cautiously admitted, so as not to dilute the acid too much until the decomposition is 

 general at all points. This occupies about three hours, and in two or three hours 

 more the sulphate of lime has collected at the bottom, while the fatty acids are 

 floating on the surface of the solution of the sulphate of lime. Several processes of 

 washing with steam and water are necessary to ensure the removal of the sulphate of 

 lime, &c., and after settling for four hours, the fatty acids are forced through a fixed 

 syphon into a vat, where they are again washed with water ; they are then syphoned 

 at last into a trough lined with lead, on the bottom of which are placed leaden gutters 

 pierced below by long pegs of wood. The fatty acids are then placed in cloths, and 

 subjected to pressure in the stearine cold press as described below. 



It is important for the fatty acids to cool slowly, for thus the confused crystallisation 

 is prevented, and the expulsion of the oleic acid facilitated. When the cakes are 

 solid they are placed between sacks of horse-hair, and submitted to a second pressure 

 at high temperature. The whole is covered with oil-skin, and the temperature raised 

 to 158'5 Fahr., when pressure is applied. The heat slowly falls to 113 Fahr., and 

 ultimately reaches 95 to 80 Fahr. This operation lasts about an hour. The cakes of 

 stearic acid are sorted according to colour and transparency, and about 20 cwte. are 

 then introduced into a vat constructed of wood lined with sheet-iron. This is boiled 

 by means of steam admitted through a leaden pipe, which is afterwards employed in 

 heating a stove. Water acidulated is first employed, and afterwards pure water. 

 When the materials are boiling, the whites of twenty-two eggs are introduced, and 

 the albumen is intimately mixed by the violent ebullition. As soon as the albumen 

 is congiilatetl, the whole is allowed to cool, and the stearic acid is removed to another 



