FAULTS 827 



hot water. More tallow will thus be obtained, and that considerably whiter and 

 harder than is usually procured by the melters. 



Dr. Ure stated that he found that chlorine and chloride of lime did not improve, 

 but rather deteriorated, the appearances of oils and other fatty bodies. According to 

 Apport, minced suet subjected to the action of high-pressure steam in a digester, 

 at 250 or 260 F., becomes so hard as to be sonorous when struck, whiter, and 

 capable, when made into candles, of giving a superior light. A convenient mode 

 of rendering minced tallow, or melting it, is to put it in a tub, and drive steam 

 through it from numerous orifices in ramifying pipes placed near the bottom. 

 Mr.. Watts' s plan of purifying fats, patented in March 1836, has been successful. 

 Ho employs dilute sulphuric acid, to which he adds a little nitric acid, with a very 

 small quantity of bichromate of potash to supply oxygen, and some oxalic acid 

 Those are mixed with the fat in the steaming tub. When the lumps of it are nearly 

 dissolved, he takes for every ton of fat, one pound of strong nitric acid, diluted with 

 one quart of water ; to which he adds two ounces of alcohol, naphtha, sulphuric ether, 

 or spirits of turpentine ; and after introducing this mixture, he continues the boiling 

 for half an hour. The fat is finally washed. 



Others have proposed to use vegetable or animal charcoal first, especially for rancid 

 oils, then to heat them with a solution of sulphate of copper and common salt, which 

 is supposed to precipitate the fetid albuminous matter. 



Mr. Prynne obtained a patent in March 1840, for purifying tallow for the candle- 

 maker, by heating it along with a solution of carbonate of potash or soda for 8 hours, 

 letting the whole cool, removing the tallow to another vessel, heating it by means of 

 steam up to 206 F., along with dry carbonate of potash (pearlash) : letting this mix- 

 ture cool very slowly ; and finally removing the tallow to a vessel inclosed in steam, 

 so as to expel any subsidiary moisture. 



A patent for a like purpose was obtained in June 1842, by Mr. H. H. Watson. He 

 availed himself of the blanching power of oxygen, as evolved from permanganate of 

 potash (chameleon mineral), in the act of its decomposition by acids, while in contact 

 with the melted fat. He prescribed a leaden vessel (a well-joined wooden tub will 

 also serve) for operating upon the melted tallow with one-twentieth of its weight of 

 the manganate dissolved in water, and acidulated to the taste. The whole are to be 

 well mixed, and gradually heated from 150 up to 212 F., and maintained at that 

 temperature for an hour. On account of the tendency of the dissolved manganate to 

 spontaneous decomposition, it should be added to the dilute acid, mixed with the fat 

 previously melted at the lowest temperature consistent with its fluidity. 



Mr. Wilson, of Vauxhall, has applied centrifugal action to the separation of the 

 liquid from the more solid parts of fatty matters, employing in preference the hydro- 

 extractors used by Seyrig and Co. for drying textile fabrics. Mr. Wilson applies a 

 stout cotton twill in addition to the wire-grating ; and in order to avoid the necessity 

 of digging the concrete parts, and to prevent them from clogging the interstices for 

 the discharge of the oily matter, he places the whole in a bag 8 inches in diameter, 

 and of such length that when laid on the rotating machine against the grating the 

 two ends will meet. The speed of the machine must be kept below that at which 

 stearic acid or stearine would pass : which is known by the limpidity of the expressed 

 fluid. To take advantage of the liquefying influence of heat, he keeps the tempera- 

 ture of his own room about 2 F. above that of the substances under treatment. 



The chemistry of fat will be found in Watts's ' Dictionary of Chemistry.' For 

 Imports, &c., see TALLOW. 



See also GLYCERINE ; MARGARINE ; OLEINE ; SOAP ; STEARINE. 



FATTliTS (Failles, Fr.), in mining, are disturbances of the strata, the name being 

 derived from the circumstance that these movements interrupt the miner's operations, 

 and render it difficult to discover where the vein of ore or bed of coal has been 

 ' thrown ' by the disturbance producing the fault. Any fissure in a rock accompanied 

 by a displacement of any kind is called a fault.' By a movement of the earth a 

 crack may be produced, but, if there has not been a movement, it is simply a fissure ; 

 while, if the rock on either side of the crack has been moved, it becomes a, fault. 



A mineral vein may be regarded as a fissure formed during the consolidation of the 

 rocks in which it exists, or by some movement of the entire mass, producing these 

 cracks at right angles to the line of greatest mechanical force ; these have been even- 

 tually filled in with the mineral or metalliferous matter which we find in them. After 

 this has taken place, there has sometimes been a movement of a portion of the ground, 

 and the mineral vein, or lode, has been fractured. A simple illustration of this is the 

 following, Jig. 842, where we have the mineral vein dislocated, and subsequently to 

 the dislocation there has been a formation of a string of spathose iron, following the 

 bondings of a crack formed by the movement, which, in this case, has been less than 

 the width of the lode. In the large majority of examples the ' heave ' or ' throw ' of 



