GAS. 



phur and iron mixed together with a lit- 

 tle water, likewise afford it by distillation. 



Sulphuretted hydrogen is particularly 

 characterized by its offensive smell, re- 

 sembling- that of rotten eggs. Like the 

 other compounds of hydrogen, it deto- 

 nates if mixed with oxygen or atmosphe- 

 ric air, and then fired, and burns silently, 

 if inflamed as it comes in contact with 

 them from a small aperture. If three 

 parts of it be mingled with two of nitrous 

 gas, the mixture burns with a yellowish 

 green flame. 



This gas is decomposed by oxymuriatic 

 acid gas, by sulphurous acid gas, or by 

 being kept mixed with atmospheric air, 

 and its sulphur is precipitated. If passed 

 through ignited charcoal, it is converted 

 into carburetted hydrogen gas. It preci- 

 pitates all metallic solutions, except those 

 of iron, nickel, cobalt, manganese, tita- 

 nium, and molybdania. It tarnishes sil- 

 ver, mercury, and other polished metals, 

 and immediately blackens white paint. 



This gas is absorbed by water, which at 

 55 takes up .86 of its bulk, and at 85 

 only .78. The solution exposed to the 

 air becomes covered with a pellicle of 

 sulphur; and deposits sulphur even in 

 well corked bottles. A few drops of ni- 

 tric or nitrous acid likewise precipitate 

 the sulphur. 



It is remarkable that sulphuretted hy- 

 drogen, which contains no oxygen, con- 

 sisting, according to Thenard, of 29 hy- 

 drogen, and 71 sulphur, should possess 

 the properties of an acid, reddening lit- 

 mus paper, and uniting with the alkalies 

 and all the earths, except alumina and 

 zircon. These compounds are soluble, 

 and most of them are susceptible of crys- 

 tallization. They are at first colourless, 

 but by exposure to the air become green, 

 or of a greenish yellow, and deposit sul- 

 phur. At length, however, the solution 

 again becomes colourless, and the base is 

 found ultimately converted into a sulphate. 

 Acids disengage their sulphuretted hy- 

 drogen gas. Vauquelin, having lixiviated 

 a considerable quantity of soda manufac- 

 tured in France, found, after some weeks, 

 a white transparent salt, crystallized in te- 

 trahedral prisms, terminated by quadran- 

 gular or octangular pyramids. Its taste 

 was acrid and intolerably bitter, and it 

 had a slight hepatic smell. It did not 

 precipitate any of the earthy salts, except 

 those of alumina, zircon and yttria. Some 

 of the German chemists have classed it 

 as an acid, by the name of the hydrothian. 



The waters called sulphurous, or he- 

 patic, as those of Harrowgate, are solu- 

 tions of this gas. They are recommended 



as alteratives in cutaneous affections,, 

 against worms, in gout and jaundice, and 

 as deobstruents; but they are said to 

 have been very injurious in dropsy. 



GAS, muriatic acid. Muriatic acid exists 

 in a separate state only in the form of gas, 

 but its attraction for water is so strong, 

 that it can be received and confined only 

 over mercury. According to Kirwan, 

 water absorbs rather more than 420 times 

 its bulk, and is augmented by it about one 

 third : in Dr. Thomson's experiments it 

 took up 515 times its bulk at 60 Fahren- 

 heit. It liquifies ice very rapidly, and the 

 temperature is lowered. It lias a pungent 

 smell, is fatal to animals, and extinguishes 

 flame, first imparting to it a greenish 

 tinge. Its bulk is increased by a succes- 

 sion of electric shocks, which Mr. Henry 

 has shewn to arise from the decomposi- 

 tion of water, of which he infers, from his 

 experiments, 60 grains hold 1.4 in solu- 

 tions. On its coming into contact with at- 

 mospheric air, a white cloud is produced. 

 Brisson gives its specific gravity, atmos- 

 pheric air being 1000, at 1430, Henry at 

 1730, Kirwan at 1929. For its other pro- 

 perties, see MURIATIC ACID. 



GAS, oxygenized muriatic acid. This gas, 

 which is a compound of the preceding 

 with oxygen, presents another anomaly in 

 the theory of acidification; it was ob- 

 served that sulphuretted hydrogen re- 

 sembles an acid in many of its properties, 

 though it contains no oxygen ; and we 

 here find the radical of an acid, which, 

 with a certain proportion of oxygen, ranks 

 among the most powerful, so much weak- 

 ened in its properties, as even to be de- 

 nied by some a place among the acids. 



This gas is not invisible, as it has a 

 greenish yellow colour. It has apungent, 

 suffocating smell, and is very injurious to 

 the lungs; it extinguishes burning bo- 

 dies? a temperature of 40 Fahrenheit re- 

 duces it to a liquid form. Mr. Northmore 

 condensed nearly two pints in a receiver 

 of the capacity of 2 inches, in which 

 state it was a yellow fluid, so extremely 

 volatile, as to evaporate the instant the 

 screw of the receiver was opened. A 

 pint of this gas being injected upon half a 

 pint of oxygen, the result was a thicker 

 substance, that did not evaporate so soon, 

 and left a yellowish mass behind. Nitro- 

 gen in the same proportion gave a still 

 thicker substance, and of a deeper yel- 

 low. In both these experiments much 

 of the grease of the machine was carried 

 down. Into a receiver, of three inches 

 capacity, a pint of carbonic acid gas was 

 pumped, and then rather more than a 

 pint of oxygenized muriatic acid gas : the 



