SUL

SUL

( 3

mixed with its own bulk of common air andkindled, it takes lire and burns with a blueflame without detonation. During the com-buftion fulphur is conitantly depofited, and afulphureous l'mell is perceived. When previous-ly mixed with oxygen and kindled, it explodeswith home violence, though lefs in degree thanan equal quantity of hydrogen in fimilar circum-ftances. A mixture of equal parts of fulphu-retted hydrogen and nitrous gas burns with agreenifh-yellow lambent flame, and fulphur isdepofited. According to Sennebier this gasmixed with common air cannot be kindled bythe eledhic fpark.

This gas is diftinguifhed by the depofition ofall or part of its fulphur whenever it is decorn-pofed, whether by combuftion or acids, or inany other way; for as it confifts limply ofhydrogen holding a quantity of fulphur infolution, and as in all thefe decompofitions thehydrogen is the fubftance firft ailed on by thedecompofing fubftances, at the inftant of de-compofition it quits its fulphur before the latterhas an opportunity of undergoing its peculiarchanges. Thus in the combuftion of this gaswith a large portion of common air, the hydrogenunites with part of the oxygen of the air, andproduces water, and at the fame inftant part ofthe fulphur undergoes combuftion with anotherportion of the oxygen, and produces fulphu-reous acid, as is obvious to the fmell, but thereft of the fulphur is precipitated in its naturalform.

Sulphuretted hydrogen is readily abforbed bywater, and in confiderable quantity. Mr. Kirwaneftimates that at a moderate temperature waterwill take up about three fourths of its bulk ofthe gas as procured from fulphuret of iron, andby long continued agitation it may be made toabforb as much as-twice its bulk. The wholeis again expelled at a boiling heat. Hydro-ful-phuretted water has a fweetifti naufeous tafte,and a Very ftrong fetid fmell, but the difguftexcited at firft tailing it, goes off very loonwhen daily ufed, as it is medicinally. Thiscombination is found native in many fprings, allthe cold fulphureous mineral waters, fuch asthofe of Harrowgate, Moffat, See. being naturalfolutions of fulphuretted hydrogen in water.A much fmaller quantity of the gas than can beartificially condenfed in water is fufficient torender water moft powerfully fulphureous tothe tafte and fmell, for the Harrowgate, whichis fo celebrated, contains no more than aboutof its bulk of the gas. Hydro-fulphuretted

56 )

water if expofed to the air for a fhort timegrows turbid, and the fulphur is flowly ciepofit-ed on the Tides of the veffel in the form of athin yellow film. A fimilar decompofition takesplace, though in a longer time, even when keptin a clofe veffel. The water after this lofes itspeculiar feent. Hence in ufing, thefe watersmedicinally it is necefl'ary to drink- thenr-at thefpring head, or very foon after being drawn.

Hydro-fulphuretted water reddens the infu-fion of litmus, which feems to fliew fome acidproperty. On adding a few drops of fulphu-reous, nitric, or oxymuriatic acid to the water,fulphur is immediately depofited, which is theonly way of extradling the fulphur from it infubftance. Thefe acids feparate the fulphur bycombining with the hydrogen. But if a greatexcels of oxymuriatic acid is ufed, the fulphuritfelf becomes oxydated, and converted into ful-phuric acid, fo that the liquor becomes againtranfparent, and the newly generated fulphuricacid may be precipitated, and its quantity (andconfequently that of the fulphur) eftimated bya barytic folution. Hydro-fulphuretted waterdoes not affedt lime-water till after Handing forfome time, and then the precipitate is fulphurand not lime, and hence is not rediffolved byweak muriatic or any other acid. This formsa decifive teft to diftinguilh this gas from car- ■bonic acid or any admixture of the two. Thiswater or any other folution of fulphurettedhydrogen alfo immediately blackens the folutionsof lead, filver, and bifmuth, and produces otherpeculiar effects on metallic falts, which will beprefently mentioned.

The following effedls were produced by themixture of this with the other gaffes, c theexperiments being performed over mercury.

Equal parts of fulphuretted hydrogen andcommon air mixed together remained unalteredfor feveral days, with a diminution of only—-^in bulk, and a blackening of the furface of themercury. The fame took place when pureoxygen gas was fubftituted to common air, andafter eight days the mixture exploded whenfired. Very little atftion therefore takes placebetween thefe gaffes unlefs water be prefent.

Equal parts of fulphuretted hydrogen andmuriatic acid gas remained unaltered, and themercury was not blackened.

No aiftion enfued on mixing this gas withcarbonic acid gas.

On adding five cubic inches of fulphureousacid gas to one of fulphuretted hydrogen, inlefs than a minute, without agitation, the tides

c Kirwan.