176 ATTRACTION. 



(a.) Furnaces, Black's, crucible furnace, table furnaces, Lewis', 

 air (furnaces, forge furnace. The general principles of all furnaces 

 are the same. The principal parts are an ash pit and register, a 

 grate, a body, a top, and a chimney. Argand's lamp, spirit lamp, 

 mouth blowpipe, table blowpipe or Artists', Dr. Hare's, compound 

 and hydrostatic, electric and galvanic apparatus, and burning lenses, 

 and mirrors are useful means of producing heat. 



3. Vessels to be used with heat. 



(a.) For fusion. Crucibles, Hessian, Wedgewood, Austrian or 

 black lead, charcoal, platinum, gold, silver. 



(b.) For mixture. All vessels may be employed for these pur- 

 poses, provided the agents do not act on them. For the solution 

 of salts in the cold, most vessels will answer ; with heat, they 

 must bear expansion and contraction. For metallic solutions, they 

 must generally be of glass or earthen ; a platinum crucible may 

 however be employed for many metallic solutions. 



(c.) For evaporations, distillations, sublimations. For evapora- 

 tion. Earthen pans, glass dishes, watch glasses, saucers, plates, and 

 porcelain, and metal capsules ; those of platinum are very valuable ; 

 bottoms of retorts and mattrasses are useful. Almost all vessels an- 

 swer for crystallizations. 



For distillations. Common still, with its worm and refrigeratory, 

 mattrasses, oil flasks, tubulated and plain retorts and receivers of glass, 

 iron, earthen ware, lead, silver, and gold or platinum ; bent glass tubes, 

 closed at one end. 



For concentration, decoction, digestion. Papin's digester, or other 

 strong boiler with tubes and stop .cocks ; occasionally, almost all ves- 

 sels are used for boiling. 



(d.) For sublimation.-*- Most of the vessels last named. Baths of 

 writer, sand, ashes, steam, oil, mercury, hot air, alcohol, brine, &c. 

 Alembics of glass, metal, &c. 



4. PNEUMATIC APPARATUS AND MISCELLANEOUS ARTICLES. 



!a.) Hydro-pneumatic cistern and air jars. 

 b.) Mercurial trough, usually of stone, furnished with tubes of 

 glass. 



Sc.) Air pump and its appendages. Condensing syringes. 

 d.) Gazometers of different sizes for different purposes. Eudi- 

 ometers and graduated glass jars, graduated tubes, detonating tubes, 

 Woulfe's apparatus, and Dr. Hare's improvements ; do. for impreg- 

 nating with carbonic acid gas. Stands, supports, &c. of iron and 

 brass ; barometer and thermometer ; instruments for specific gravity. 



5. MECHANICAL OPERATIONS PREPARATORY. 



(a.) Trituration. Mortars of marble, iron, steel, glass, porcelain, 



jr, porphyry, agate, wood, granite. 

 (b.) Levigation. The rubbing stone and muller. 

 [c.) Pulverization. Rasps, files, graters, hammers, anvil. 



