GAS

550

GAS

ant gas is the heaviest, and with oxygen detonates more violent!}Ainu any of the rest.

Gas, Sulphurated Hydrogen. This has the properties of*n acid ; for when absorbed by water, its solution reddens vegeta-ble blues. It combines also with alkalies, earths, and with several■netallic oxides. It has an extremely offensive odour, resemblingthat of putrid eggs. It kills animals, and extinguishes burningj>odic>. When mixed with oxygen gas, or atmospheric air, it isinflammable. To obtain it, take dry sulphuret of potass, put it■nto a tubulated retort in a sand-bath ; or, supported over a lamp,direct the neck of the retort under the receiver placed in a pneu-matic trough ; then pour gradually upon the sulphuret dilutedSulphuric acid : a violent effervescence will take place, and sul-phurated hydrogen gas will be disengaged. When no more gas isproduced, apply heat by degrees till it boils, and gas will again beprocured abundantly. The water employed for receiving itshould he heated to about 80 or 90 degrees : at this temperatureU dissolves little of the gas; but if cold water be u-ed, avastJpiautity of it is absorbed. Water impregnated with sulphuratedhydrogen gas, slightly reddens blue vegetable colours. It is this8; ls which gives to the mineral-waters of 1 1 arrnwgate and Aix-la-Gliapelle their peculiar smell. Such waters may therefore be arti-ficially imitated, by impregnating common water with this gas, andadding the other constituent parts to it. This gas acts strongly onmost metallic oxides. Dip a slip of paper into a solution of lead,aud expose it to the action of sulphurated hydrogen gas ; and thepaper will instantly become blackened. Writing performed withbus solution is invisible when drv, buL becomes visible when im-■nersed in a botde idled with this gas.

Gas, Phosphorated Hydrogen, consists of phosphorus dis-S( dved in hvdrogc-n gas. It is the most combustible substance inuature. It is distinguished from all other gases bv tbe propertyH taking lire immediately when brought in contact with atmo-spheric air. When mixed with oxygen gas, or with oxygenatedmuriatic acid gas, it burns with great violence. When bubbles of'*• are suffeied to pass through water, they take fire in successionas they reach the surface of the ffuid. It has an insupportable°doiir, similar to that of putrid lidi. To obtain it, take a smallfetort, put into it one part of phosphorus and ten of concentratedelution of potass ; make tbe mixture boil, and receive the gas°ver mercury, or, if it be intended for immediate use, it mav becollected over water. In this process a decomposition of the wa-rn*' takes place. Its oxygen unites to part of the phosphorus,'onning phosphoric acid, which joins to the potass, and formsPhosphate of potass. The hydrogen of the water dissolves ano-, ler part of the phosphorus, and is converted into phosphoratedf'ydrogen. gas. In preparing this gas the body of the retort shouldJ e filled as nearly as possible with the mixture, otherwise the firstportion of gas which is produced inflames in the retort, a vacuum8 formed, and tire water is forced up into the retort, which endan-B er s the bursting of it. Phosphorated hydrogen gas is also lormedy nature. The air which burns at the surface of certain springs,?.ml forms what is called burning springs, and the ignis taUiusvJ'ack o’lantern), which glides along burying-grounds consist of thisB JS - If the hubbies of air w hich come from the retort ar’e sulfer-to escape into the atmosphere, they will burst witli a slight e.\-P osion, and produce flashes of fire. A circular dense whitejUioke rises like a ring, enlarging itself continually in an extreme-ly Beautiful manner, if live air be perfectly tranquil. r l his gasmils with a green light, in nascent oxvgeuated muriatic acid gas,r n< *er the surface of'water. Put into a deep glass some phospho-e l of lime, broken into pieces of the size ot a pea, and acid half asa * Ut 'B Oxygenated muriate of potass. Fill the vessel with water,ml bring into contact with the materials at the bottom of the fluide?t'i' e collc entrnted sulphuric acid. This may be most ronveni-, my done, by letting the acid fall through a long funnel reaching® die bottom of the vessel. As soon as the decomposition of themer, and that of the oxygenated muriate takes place, flashes of‘f <Wt from the fluid, and illuminate the bottom of the vesseltin ' a . B^miliful green light. A ribbon, impregnated with solu-11 °t gold, maybe gilt by the action of phosphorated hydro-gas.

5 ms > Nitrous. This name is given to 3n aeriform fluid, con-Ec -J’S °f a certain quantity of nitrogen gas and oxygen : tirst tie-mxl by Priestley, hut in some measure known Before to Hales.

It is colourless, having no sensible taste, and is neither acid noralkaline: it cannot be respired. The greater number of combus-tible bodies cannot burn in it. It is nevertheless capable of sup-porting the combustion of somebodies. Phosphorus burns in it,when introduced in a state of inflammation ; pyrophorus takes firein it spontaneously. To obtain it, put into a small retort somepieces of copper, and pour on them nitric acid diluted with water ;an effervescence takes place, and nitrous gas will be produced.After having suffered the gas to escape for a few minutes, on ac-count of the common air contained in the retort, collect the gasin the water apparatus as usual. In order to obtain this gas in apure state, it should be shaken for some time in contact with wa-fer. In tliis process the aci/l undergoes a partial decomposition ;the metal robs the nitric acid of the greatest part of its oxygen,and becomes oxydated. This gas has the properly of absorbingthe oxygen of the atmosphere; on this property Priestley formed ■his eudiometers. See Eudiometer.

Gas, N itrous Oxide. This is sometimes called the gaseous oxideof nitrogen, a compound of nitrogen with a still less proportion of oxy- •gen than the preceding gas. It is a permanent gas. A candle burnsin it with a brilliant il.mie ami crackling noise: before its extinctionthe white inner llaijie becomes surrounded with a blue one. Phos-phorus introduced to it in a stale of inflammation burns with in-creased splendour, as in oxygen gas. Sulphur introduced into itwhen burning with a feeble blue flame, is extinguished ; but whenin a state of vivid inflammation it burns with a rose-colouredflame. Eighied charceal burns in it more brilliantly than in at-mospheric air. Iron wire with a small piece of wood affixed toit, and introduced inflamed into a vessel tilled with this gas, burnsrapidly, and throws out bright scintillating sparks. Nitrous oxideis rapfdly absorbed by water which has been boiled; a quantity ofgas equal to rather more than half the bulk of the water may bethus made to disappear: the water acquires a sweetish taste, but ■its other properties do not differ perceptibly from common water.The whole gas may be expelled again by heat. It does notchange blue vegetable colours. It lias a sweet taste, and a faintbut agreeable odour. "Phis gas is produced when substances, hav-ing a strong affinity with oxygen, are added to nitric acid, or tonitrous gas. It may therefore be obtained by various methods, inwhich nitrous gas or nitric acid is decomposed by substances capa-ble of attracting the greater part of their oxygen. The most com-modious anil expeditious, as well as the cheapest mode of obtain-ing it, is by decomposing nitrate of ammonia by heat in the fol-lowing manner : Put into a glass-retort some pure nitrate of am-monia, and apply to it an Argaml’s lamp ; the salt will soon li-quefy, and when it begins to boil gas will be evolved. Increasethe heat gradually, till the body and neck of the retort becomerilled with a milky white vapour. In this state the temperatureof the fused nitrate is betw een 340 and 480 degrees. After thedecomposition has proceeded for some nnnufes, so that the gas,w hen examined, quickly enlarges the llame of a taper, it may becollected over water. Care should be taken during the wholeprocess never to suffer the temperature of the fused nitrate to riseabove 500 degrees Fahrenheit, which may be easily judged offrom the density of the vapours in the retort, and from the quickebullition of the fused nitrate ; for if the heat is increased beyondthis point, the vapours in (lie retort acquire a reddish and moretransparent appearance, and the fused nitrate begins to rise; at700° or 8(10° it explodes. After it is obtained it should stand overwater several hours to render it fit for respiration, or other expe-riments. To experience its effects in breathing it, put about agallon into a large bladder, or oiled silk-bag, having a tube attach-ed to it of three-fourths of an inch in diameter. First, the com-mon air must be expelled from the lungs, before the tube is re-ceived into the mouth, and the nostrils must be accurately closedwith the hand. It must then he breathed backwards and forwardsinto the bag for a minute or two ; some have gone as far as four orfive minutes. It generally produces a pleasant thrilling, particu-larly in the chest and extremities, frequently with an inclinationto laugh, and sometimes an. irresistible propensity to gesticulationand muscular exertion. The mind meanwhile is often totally ab-stracted from all surrounding objects. Sometimes its effects arenot entirely dissipated for some hours; and it is remarkable, that,however strong they may have been, no sense of debiiitv or lan-guor is induced after they have subsided. On a few individuals,

however.