AUTOGENOUS SOLDERING 



273 



ATTEMPERATOR. In brewing, the name of several arrangements devised 

 for the purpose of regulating the temperature to which the fermenting wort is exposed. 

 It is also employed to regulate the temperature of malting-rooms. "Without thorn it 

 is impracticable to make malt in the summer equal to that made in winter. In all 

 cases either air or water is the attemperating agent. 



ATTEITUATIO W. Brewers and distillers employ this term to signify the weak- 

 ening of saccharine worts during fermentation, by the conversion of the sugar into 

 alcohol and carbonic acid. 



ATTI.E. A miner's term for the ' deads ' or refuse-matter of a mine. The ' attle- 

 heap ' is the mine-burrow or rubbish-heap. 



AUGER. The auger is a tool for boring either wood or stone. The single-lip 

 avger is forged as a half-round bar ; it is then coiled into an open spiral, with the 

 flat side outwards. The ordinary screw auger is forged ; it is twisted red-hot ; the end 

 terminates in a worm, by which the auger is gradually drawn into the work as in 

 the gimlet ; and the two angles, or lips, are sharpened to cut at the extreme ends, and 

 a little up the sides also. The American screw auger has a cylindrical shaft, 

 around which is brazed a single fin or rib ; the end is filed into a worm, as usual, 

 and immediately behind the worm a small diametrical mortice is formed for the 

 reception of a detached cutter, which exactly resembles the chisel-edge of the centre-bit. 

 Holtzapffel. 



AUGITE. (aty)], brilliancy.') A sub-species of Pyroxene. The name is con- 

 fined to the opaque and greenish-black varieties, common in basaltic, doleritic, and 

 recent volcanic rocks, in which it forms an important constituent, but it is never found 

 in granite. It has a base of magnesia, lime, protoxide of iron, and alumina. The 

 term augite is often used by English geologists as synonymous with pyroxene. For 

 the means of distinguishing between augite and hornblende two minerals which 

 often closely resemble each other see HORNBLENDE. 



AURATES. Crystalline compounds of the peroxide of gold. 



AURIC ACID. (Aurum, gold.) A term sometimes used for the peroxide of gold. 



AURIFEROUS. Containing gold, as ' auriferous quartz,' ' auriferous pyrites,' 

 &c. 



AURINE. A red colouring-matter obtained from phenol, or carbolic acid. It 

 appears in commerce as a brittle resinous solid, having a beetle-green lustre, and 

 yielding a red powder. See CARBOLIC Aero. 



AURUIVI IMCUSIVU9X or MOSAICUM. MOSAIC GOLD. For the preparation 

 of Mosaic gold the following process is recommended by Woolfe. An amalgam of 

 2 parts of tin and 1 part of mercury is prepared in a hot crucible, and triturated with 

 1 part of sal-ammoniac, and 1 part of flowers of sulphur ; the mixture is sublimed in 

 a glass flask upon the sand-bath. In breaking the flask after the operation, the sub- 

 limate is found to consist, superficially, of sal-ammoniac, then of a layer of cinnabar, 

 and then of a layer of mosaic gold. 



Borgmann mentions a native aurum musivum from Siberia, containing tin, sulphur, 

 and a small proportion of copper. Dr. John Davy gave the composition as tin, 100 ; 

 sulphur, 56'25 ; and Berzelius, as tin, 100 ; sulphur, 52'3. 



Mosaic gold is employed as a bronzing powder for plaster figures, and it is said to 

 enter sometimes into the composition of artificial aventurine. 



AUSTRAIiENE, or AitstraterebintJiene. A liquid hydrocarbon resembling tere- 

 binthine, obtained by neutralising English turpentine oil with an alkaline carbonate, 

 and distilling the product. 



AUTOGENOUS SOLDERING. A process of soldering by -which metals are 

 united, either by the ordinary solders 

 or by lead, under the influence of a 

 flame of hydrogen, or of a mixture of 

 hydrogen and common air. 



The process of using air and hydro- 

 gen was invented in France, by the 

 Count do Kichemont. Hydrogen gas 

 is contained in a gasometer, to which 

 a flexible tube is connected, and air is 

 urged, from a bellows worked by the 

 foot, through another tube, and on to 

 the blowpipe, where the hydrogen is 

 ignited. By means of the flexible 

 tubes the flame can be moved up and 

 down the line of any joint, and the 

 connecting medium melted. Fig. 99. 



This process has been a good deal employed for plumbers' work, especially fn our 



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