LAMPS 85 



Xi AXVXXTTIMC A&BTTM, or the dead nettle, is said by Leucus to afford from its leaves 

 a greenish-yellow dye. The L. purpureum dyes a reddish-grey with salt of tin, and 

 a greenish tint with iron-liquor. 



XiAXtXP-BXiACX. Every person knows that when the combustion of oil in a lamp 

 is imperfect it pours forth a dense volume of black soot. According to the quantity 

 of carbon contained in the material employed, so is the illuminating power of the 

 flame produced by combustion. If, therefore, we have a very brilliant flame, and we 

 subject it to any conditions which shall impede the progress of the combination of the 

 carbon with the oxygen of the air, the result is at once the formation of solid carbon, 

 or lamp-black. This is exhibited in a remarkable and often an annoying manner by 

 the camphine lamp. If oil of turpentine, resin, pitch-oil, or fat-oil, be burnt in lamps 

 under a hood, with either a rapid draught or an insufficient supply of air, the lamp- 

 black collects on the hood, and is occasionally removed. Sometimes a metallic roller, 

 generally of tin, is made to revolve in the flame, and rub against a brush. By the 

 cooling influence of the metal, the heat of the flame is diminished, the combustion 

 retarded, and the carbon deposited, and in the revolution of the cylinder swept off. 

 Camphor burning forms a very beautiful black, which is sometimes used as a 

 pigment. 



The common varieties of lamp-black are made from all sorts of refuse resinous 

 matters, and from the rejected fragments of pine-trees, &c. In Germany, a long flue 

 is constructed in connection with the furnace in which the resinous substances are 

 burnt, and this flue communicates with a hood, composed of a loose woollen cloth, held 

 up by a rope passing over a pulley. Upon this the soot collects, and is from time to 

 time shaken down. In the best-conducted manufactories about 3 cwts. of lamp-black 

 is collected in each hood in about twelve hours. In England, lamp-black is sometimes 

 prepared from the refuse coking coal, or it is obtained in connection with coke-ovens. 

 The lamp-black, however, obtained from the combustion of coal or woody matter is 

 never pure. See ANIMAL BLACK ; BONE BLACK ; IVOET BLACK. 



IiAIVXF, DAVY. See SAFETY LAMP. 



XiATOPSi Under ILLTJMINATIOK, will be found some notices of several kinds of 

 lamps, with especial reference to the quantitj' of light produced by them. 



Lamps are very varied in form, and equally varied in the principles involved. A 

 brief description, however, of a few of the modern varieties is necessary. 



The Moderator Lamp.- The spiral spring has been introduced into the moderator 

 lamps, for the purpose of forcing the oil up the wick of the lamp. This will be under- 

 stood by the following description .and drawings : The distinguishing character of 

 the moderator lamp is the direct transmission of the power, in the reservoir of oil, 

 to the resistance offered by the weight of the column of oil, as it rises to the cotton ; 

 and secondly, the introduction of a rectangular regulator, which equilibrates constantly 

 by the resistance of the oil and the force applied to raise it. In the reservoir (fig. 

 1309), is a spiral spring which presses on the disc or piston,,/?^. 1310, which is fur- 

 nished with a valve opening downwards. This spring is attached to a tooth-rack, 

 worked by a pinion wheel, by means of which it is wound up. The mechanical 

 force of the spring is equal to from 15 to 20 pounds ; and as this force is exerted upon 

 the disc, floating on the oil, this is forced up through the tube, and it overflows to 

 the argand burner, thoroughly saturating the cotton, and supplying a constant stream 

 of oil. This oil falls back into the reservoir, and is, of course, above the disc. When 

 the spring has run down, it is again wound up; and then the valve opening downward 

 allows the oil to flow back beneath the disc, to be again forced up through the tube. 

 As the pressure employed is so great, the oil would, but for the ' moderator,' flow over 

 with too much rapidity. This moderator, or regulator, is a tapering rod of iron-wire, 

 which is placed in the ascending tube ; and, as the pressure increases, it is forced more 

 into it, and checks the flow of oil ; whereas as it diminishes it falls, and being tapering, 

 allows more oil to rise. Several ingenious adjustments are introduced into these 

 lamps, as manufactured by the Messrs. Tylor of Warwick Lane, with which we need 

 not at present deal. The cylinders containing the oil are covered with cases in metal 

 or sometimes of porcelain. Two drawings of these are shown (fig. 1311 andfiff. 1312). 

 These lamps admit evidently of yet more elegant forms than have been given them. 

 The urn-shaped, from the antique, in very pure taste, is the last introduction of the 

 house above named. 



It would be tedious to enumerate the various modifications of form and action to 

 which the oil lamp has been subject, previous to its arrival at what maybe deemed its 

 perfect construction by Argand. The discovery of the mode of applying a new 

 principle by this individual not only produced an entire revolution in the manufacture 

 of the article, but threatened with ruin all those whom the patent excluded from 

 participation in the new trade ; so much so indeed, that Argand, who had not been 

 apprenticed to the business, was publicly persecuted by the tinners, locksmiths, and 



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