368 



GAS GAS-LIGHT. 



many natural phenomena, we will describe a few of 

 the most interesting and important species. The 

 following are a few of the most remarkable : 



1. Atmospheric air. This is now well known to 

 be, not a simple element, as was long supposed, but 

 to be constituted by a mixture of several gases and 

 of watery vapour. This is very simply and evidently 

 ascertained in the following manner : If a quantity 

 of common atmospheric air is inclosed in an inverted 

 glass over mercury, and burning phosphorus is intro- 

 duced into it, and its introduction repeated till it 

 ceases to burn, it is found, upon measurement, that 

 the portion of air enclosed hi the glass is diminished 

 twenty-one parts in the hundred, while seventy-nine 

 remain ; and this residue will not support combus- 

 tion, or maintain animal life, for fire goes out, and 

 animals are suffocated, upon being placed in it. 

 These twenty-one parts consist, as is found by many 

 experiments, of a peculiar kind of air or gas, first 

 discovered in 1771 4, which, from its being neces- 

 sary to the support of life and combustion, was 

 termed vital air, but which, in the reformed chemi- 

 cal nomenclature of Lavoisier (a great portion of 

 which remains unchanged, a noble monument of 

 his fame), was named oxygen, from its being found 

 to enter into the composition of all acids then known. 

 The remaining seventy-nine parts consist of another 

 peculiar gas, called azote, or nitrogen gas. Com- 

 bustion, with a very few exceptions, takes place only 

 when oxygen gas is present ; and the substance 

 burnt is found, upon examination, to have formed an 

 intimate combination with the base of the gas, while 

 the heat, or caloric, which, we have seen, entered 

 into its composition as a gas, is given out in the 

 shape of blaze or fire. And combustion takes place 

 with much greater rapidity and brilliancy in pure 

 oxygen than in atmospherical air, because in the last 

 a greater proportion of nitrogen or azote gas is in 

 contact with the burning body, which it has a con- 

 stant tendency to extinguish. If a half-extinguished 

 taper is introduced into pure oxygen gas, it blazes up 

 at once ; a red-hot wire will burn in it with brilliant 

 scintillations, and burning phosphorus immersed in 

 it throws out a light as dazzling as the sun itself. 

 Oxygen, although necessary to the support of animal 

 life, will destroy it in tune, if respired in a state of 

 purity ; for it stimulates so highly as to induce in- 

 flammatory and other diseases. Bodies burned in it 

 are changed to acids, as sulphur, carbon, phosphorus, 

 &c. ; and, in fact, if any substance must be named 

 as the master spirit of chemistry, it is certainly oxy- 

 gen gas. 



2. Azote gas has no properties by means of which 

 its action can be subjected to actual inspection ; but 

 it is nevertheless important, from the combinations 

 which it forms. Some of these are aqua fortis, ni- 

 trous acid, and the still more remarkable nitrous 

 oxyde gas. This peculiarly exhilarating substance 

 is one of the compounds of azote with oxygen, and 

 is one of the most singular substances in nature. 



3. If the vapour, or steam of water, is made to pass 

 over iron filings, or wire, heated to redness, in an 

 earthen or iron tube, and the air which escapes at 

 the end of the tube is collected, we obtain another 

 species of gas, which is called hydrogen, which is in- 

 flammable, of an offensive odour, and is a constituent 

 part of water. When mixed with oxygen gas, it 

 explodes upon the application of fire, and water is 

 the result of the explosion. The proportions in 

 which they are mixed, to produce water by explo- 

 sion, are two volumes of hydrogen, and one of oxy- 

 gen. This experiment should be tried only in a 

 strong bottle, otherwise it would burst. When pure, 

 hydrogen gas is fifteen times lighter than atmospheric 

 air, and, upon this account, is used for filling balloons. 



This gas retains its gaseous form when combined 

 with carbon, sulphur, and phosphorus. Some of 

 these gaseous compounds, especially those into which 

 carbon enters as a part, are of some importance in 

 the arts, furnishing the gas for lights, &c. 



4. W hen carbon is burnt in oxygen gas, the gas 

 does not appear to diminish in quantity, but it pre- 

 sents a set of entire new properties, and is found to 

 be changed into carbonic acid gas. It extinguishes 

 burning bodies, and is fatal to animal life. It is so 

 much heavier than common air, that it can be kept 

 iu an open jar, and poured from one vessel to an- 

 other. From this property, it also sinks always to 

 the lowest place to which it has access, and is thus 

 found at the bottom of caves, wells, &c. It is this 

 gas which is so destructive to the lives of those shut 

 up with burning charcoal, and which is also found in 

 brewers' vats, in cellars, wells, drains, &c., which 

 have been long unopened, and into which it is unsafe 

 to descend till they have been ventilated by dashing 

 down buckets of water, or swinging a large board or 

 fan in them. It is absorbed in large quantities by 

 water, to which it communicates a grateful pungency, 

 in which form it constitutes the mineral or soda water 

 of the shops. Thus, by a singular coincidence, does 

 the same gas afford a fatal poison, and a luxurious 

 refreshment. Many natural mineral waters are im- 

 pregnated with the same gas, as those of Saratoga, 

 Spa, Pyrmont, &c. It was first discovered in 1755- 

 and has since become familiarly known. 



5. Another still more important gas is the disin- 

 fecting, bleaching gas, called chlorine, (q. v.) This 

 is procured by the decomposition of muriatic, acid, 

 or of salts which contain it, and is highly valuable 

 from its contributions to the health, convenience, and 

 luxury of man, in the cases above referred to. For 

 the purpose of bleaching, it is united with water : 

 see an account of the process in the article Bleach- 

 ing. For a more minute account of the above-men- 

 tioned and all other gases, we must refer to the 

 separate articles. 



GAS-LIGHT ; The application of carburetted 

 and bicarburetted hydrogen, i. e. oleftant gas, to the 

 lighting of buildings and streets. In 1739, the Rev. 

 Mr Clayton published a paper in the Philosophical 

 Transactions, detailing his experiments on the inflam- 

 mable nature of the gases obtained by the decompo- 

 sition of pit-coal in heated close vessels, but he had 

 made the discovery long before, as he alludes to it 

 in a letter addressed to the society, in May, 1688. 

 Yet no practical application of this discovery was 

 even hinted before 1792. In this year, Mr W. Mur- 

 doch, a native of Cumnock, in Ayrshire, but at the 

 time of which we speak residing at Redruth, in 

 Cornwall, in the employment of Messrs Watt and 

 Boulton, made extensive experiments on the illumi- 

 nating properties of gases obtained by distilling coal, 

 wood, peat, and other combustible substances, which 

 led him to the idea of collecting these gases in vessels, 

 and expelling them through jets for light, as a sub- 

 stitute for lamps or candles, and on this principle he 

 lighted his own house. From want of leisure he did 

 not resume the consideration of the subject for nearly 

 five years; but, in 1797, he lighted his house at 

 Cumnock, and in the following year he erected a gas 

 apparatus on a large scale at Soho foundry. On the 

 rejoicing for the peace of Amiens in 1802. the whole 

 front of the Soho works was illuminated by Mr 

 Murdoch's gas apparatus. In the same year, M. La 

 Bon lighted his house in Paris by gas obtained 

 from wood and coal, and made a proposal to supply 

 the whole city, but Lampadius had hinted at the 

 practicability of such a thing, the previous year, in a 

 lierman work on mining, published at Gottingen. 

 In 1803, Mr Winsor, who borrowed his knowledge 



