156
LEAD.
light equal to very nearly twelve wax or sperm candles of three or four to the pound;and in so doing, it consumes exactly one imperial pint of spirits of turpentine (valuesixpence retail) in ten hours, hence the cost per hour for a light equal to ten suchcandles is one halfpenny; whereas that from wax candles would he nearly sixpence?from spermaceti ditto, fivepence; from stearine ditto, fourpence; from Palme! sspreading wick ditto, nearly threepence ; from tallow moulds 2jd.; from sperm oil inCarcel’s Mechanical French Lamp, 1 |d.
“ One peculiar advantage of the Vesta lamp is the snowy whiteness of its light, whichis such as to display the more delicate colors of natural and.artificial objects, flowers?paintings, &c., in their true tints, instead of the degraded hues visible by the light oicandles and ordinary oil lamps.
“The size of the flame from which so much light is emitted in the Vesta lamp?is greatly smaller than that of oil or gas argand flames of equal intensity; a circus 1 'stance to be accounted for from the difference in chemical composition, between spir ltsof turpentine and fat oils. The spirits consist entirely of carbon and hydrogen; inproportion of 88j of the former element, and 11J of the latter, in 100 parts; and the)consume 328 parts of oxygen; whereas, sperm and other unctuous oils consist of 1 ,parts-of carbon, llj of hydrogen, and 10J of oxygen, in 100 parts ; and these consul 1 ®only 287-2 of oxygen, in being burnt; because the oxygen already present in the 01neutralizes 2-6 parts of the carbon and 0-4 of the hydrogen, thus leaving only 85i P a {Vof the combustible elements for the atmosphere to burn. For this reason, 87 J parts byweight of spirits of turpentine, will consume as much oxygen as 100 parts of spe r ®oil; and will afford, moreover, a more vivid light, because they contain no oxide,®fat oils do, which serves to damp the combustion. In the spirits of turpentine, 1 * 1affinity of its elements for oxygen is entire, whereas in fat oil the affinity is partial yneutralized by the oxides it contains; somewhat as the flame of spirits of win e 1weakened by their dilution with water. , ,
“Among the many applications of science to the useful arts, for which the pi' e£ ?age is so honorably distinguished, few are more meritorious than the Camp 111Lamps, by which we can produce a snow-white flame from the cleanly, color!®spirits of turpentine—a pure combustible fluid, in place of the smeary rank 0which contain a seventh part of incombustible matter. Being so rich in hydro-car* 1 ’the spirits require peculiar'artifices for complete consumption and the developmenttheir full power of yielding light without smoke or smell. This point of perfect*seems to be happily attained#by the invention of the two parallel flat rings, in. j.Paragon Lamp, a larger and smaller, forming a .cone round the margin of the w lC ’which cause a rapid reverberation of the air against the flame: thus consuming e' r fparticle of volatilized vapor, and adding energy to the luminous undulations. -" e " a3rthe Patent Paragon Lamp in full action emits a light equal to that of sixteeni *candles three to the pound, but of better quality, approaching in purity to that oisun-beam—therefore capable of displaying natural and artificial objects in theircolors. p 0 r
“One imperial pint of rectified spirits of turpentine, value 6d. retail, will burn^.twelve hours in this lamp, affording all the time the illumination of eleven wax can“ The Paragon Camphine lamp is attended with no danger in use.
“ The cost, as compared with other Lamps or Candles, is as follows : viz.: 1
. pEB- H 0 ® 11 '
Paragon Camphine Lamp (equal to 11 wax candles) less than One Halfpenny-Wax Candles - - - - - - - - - - gjj’
■Spermaceti ditto ---------- A
Adamantean wax (Stearic Acid ) ------- tl
Palmer’s Spread-Wick Candles. ~
Cocoa Nut Candles - -- -- - - --^l
Carcel’s Lamp, with Sperm Oil -------
See Illumination, cost of, for a description of an excellent oil lamp. _ ^ ; n
LEAD. The total produce of the lead mines of Great Britain was esti® at1S22, at 31,900 tons, which were distributed as follows :— „ * „<•
, 3 ri Kfl0 tO^ 5
Wales (Flintsliire and Derbyshire) ----- 0?. n
Cornwall and Devonshire ------■•
Shropshire OO 0
Derbyshire ---------- L° o0
Cumberland, Durham, and Yorkshire -----
31,90°