1228
SULPHURIC ACID.
M. Clement-Desormes demonstrated the proposition relative to the influence °^ le ^. r eS,ature by a decisive experiment. He took a glass globe, furnished with three tubu sand put a bit of ice into it. Through the first opening he then introduced su ^ ) ! [ | e ofacid gas; through the second, oxygen ; and through the third, nitrous gas (deutox) jjazote). While the globe was kept cool, by being plunged in iced water, no sulph ul ‘ a 0#was formed, though all the ingredients essential to its production were present. B toexposing the globe to a temperature of 100° Fahr., the four bodies began immediareact on each other, and oil of vitriol was condensed in visible stria.
The introduction of steam is a modern invention, which has vastly facild®* on ]yincreased the production of oil of vitriol. It serves, by powerful agitation, n °^jnslto mix the different gaseous molecules intimately together, but to impel them a = ( j oB .each other, and thus bring them within the sphere of their mutual chemical attra „iyingThis is its mechanical effect. Its chemical agency is still more important. By sU '’j oD ofmoisture at every point of the immense included space, it determines the f° r ? ia lr y sul'hydrous sulphuric acid, from the compound of nitric, nitrous, sulphurous, and • jtsphuric acids. No sooner is this reaction accomplished, than the nitrous gas reSt Late 3oxygen, from the continuous atmospherical current, and becomes again fit to °^„ z ote)slike round of transmutations with sulphurous acid, steam, and oxygen. The nitrogen ( bywhich ought to be the only residuum in a perfectly regulated vitriol chamber, f^Llacedits relative lightness, at the opening c, in the roof, or, more properly speaking, is “ “by the influx of the heavier gases at the entrance-pipe. t j 0 n of
On the intermittent plan, after the consumption of each charge, and condens»^ B(ir ythe product, the chamber was opened, and freely ventilated, so as to expel lh e r 3isti° c ^azote, and replenish it with fresh atmospheric air. In this system there were ^°? 1 , c tilin?>stages or periods1. Combustion for two hours; 2. Admission of steam, and - ^psfor an hour and a half; 3. Conversion, for three hours, during which interval ^ tb eof strong acid were heard falling like heavy hailstones on the bottom ; 4. Purgingchamber, for three quarters of an hour. haffl* ,er5 ’
By the continuous method, sulphuric acid may be currently obtained in the C ^ r el0- it,sof the specific gravity T350, or T450 at most; for, when stronger, it absorbs a ^ e venpermanently much nitrous acid gas ; hut by the intermittent, so dense as i'OO ^ re coW'1-620 ; whence in a district where fuel is high priced, as near Paris , this e veU ' n
mended itself by economy in the concentration of the acid. In Great Britain , l an j ta l, oX emost parts of France , however, where time, workmen’s wages, and interest ol c * n eral tothe paramount considerations, manufacturers do not find it for their interest i® •- f a [ih etraise the density of the acid in the chambers above 1-400, or at most 1-500; as . j e ad e ®increase goes on at a retarded rate, and its concentration from 1-400 to 1-60°)pans, costs very little. , rs is m®
At about the specific gravity of 1-35, in Great Britain , the liquid of the f I ’® D1 r ,, e s it i nt “off, by the syphon above described, into a leaden gutter or spout, which disc® 8 sq" 3 ':a series of rectangular vessels made of large sheets of lead, of 12 or 14 lbs. t o ^ 2 rat
foot, simply folded up at the angles into pans 8 or 10 inches deep, resting ®" ^ wh |C ^made of a pretty close row of wrought-iron bars of considerable strength* a sep 3 Jthe flame of a furnace plays. Where coals are very cheap, each pan may ]o\VC-rate fire; but where they are somewhat dear, the flame, after passing an ^ uP' T3l |iypan of the range, which contains the strongest acid fat about 1-600), P r ° ca j s grad u ® jjwith a slight slope to heat the pans of weaker acid, which, as it concentrate-, ^^teirun down by syphons to replenish the lower pans, in proportion as their j„|jt line* ®dissipated. The 3 or 4 pans constituting the range are thus placed in» ?1 ’each at a different level, terrace like; en grading, as the French say. . jt m® 5 ?
When the acid has thereby acquired the density of 1-650, or 1-700 at ., w0 ’ u ]d b e ? in 1 .yremoved from the leaden evaporators, because, when of greater strength, 1 re f r jgerat ^corrode them ; and it is transferred into leaden coolers, or run through a o glass ^worm-pipe surrounded by cold water. In this state it is introduce^ 0 f T® ,’ r ts
platinum retorts, to undergo a final concentration, up to the specific S^en glass ret .. e5 jeven occasionally 1-845, in consequence of slight saline impurities. on fi re *j; r e-
are used, they are set in a long sand-bath over a gallery furnace, res ^ r0ta the (sunder which a powerful flame plays; and as the flue gradually asceni - heat .|j splace, near to which it is most distant from the tiles, to the remot 5Jv en plati® 31 ® ‘.^jpwith tolerable equality on the first and last retort in the range. W teC t t ^ e : ro n,are employed, they are fitted into the inside of east-iron pots, wine ^ t0 the Sjbottom and sides of the precious metal. The fire being applied ircn flr e
causes a safe, rapid, and economical concentration of the acid- ^ vitr effectwith their platinum interior, filled with concentrated boiling-h°t wa ter, to , jnlifted out of the fire-seat by tackle, and let down into a cistern of c ^oyg pac . „ jtthe speedy refrigeration of the acid, and facilitate its transvasion , int ° 0 j e( j by runn 3osier baskets lined with straw. Sometimes, however, the acid is