GAS FEOM REBUTS, ETC.] 



UNDULATORY FORCES. LIGHT. 



123 



ten times as great as that of his standard of gas from 

 ordinary Newcastle coal. As might be expected, the 

 illuminating power of this gas is "very high : indeed, Mr. 

 Wright has stated that it is about four times as great as 

 that of .common gas. He reports that, with a consump- 

 tion of one foot and a quarter per hour, it gives the light 

 of twelve sperm candles, each burning at the rate of 120 

 grains per hour. Our own experiments, however, are 

 not so satisfactory : they are recorded in the following 

 table : 



Burner used. 



Small fish-tail 

 Leslie's Argand . 

 Common Argand, 15 holes 

 Fine Argand, 70 holes ^ 

 Winfield Argand 



Consumption 

 per boor. 



. 1-30 

 2-25 

 3-50 

 275 

 3-50 



Illuminating: power 

 in sperm candles of 

 130 gn. per hour. 



. 8 

 . 11 

 . 14 

 . 12 

 15 



The advantages of tliis gas are, its freedom from 

 smell ; its not containing any sulphur compound ; its 

 not producing so much heat as ordinary gas for an 

 equal amount of light; and its easy production in an 

 apparatus which does not occupy much room. The 

 chief disadvantage is its cost ; for a shilling's worth of 

 kitchen-stuff will only produce about 40 cubic feet of 

 gas, which will not go farther than six or eight penny- 

 worth of coal gas. 



Portable Gcu. When oil-gas is compressed with a 

 power of from fifteen to twenty atmospheres, it is forced 

 into a very small bulk ; and the vessels containing it 

 may be moved about, and placed in any situation where 

 a light is required. A company was formed some years 

 ago for carrying out this object; and they condensed 

 the gas in globes and cylinders which were subsequently 

 placed in vases, columns, and other ornamental devices, 

 so as to be completely hidden from view. Burners were 

 fixed to the apparatus, and the gas was let out by 

 means of a stopcock of a peculiar construction. In the 

 act of compressing the gas, about one-fifth of its volume 

 underwent condensation into an oily liquid ; indeed, a 

 thousand cubic feet of good oil-gas yielded about one 

 gallon of it. This was made the subject of investigation 

 by Professor Faraday. It is a thin oily fluid, lighter 

 than water, sometimes transparent and colourless, occa- 

 sionally opalescent, having a red tint by transmitted, 

 ;iml a L'n-i'ii by reflected, light. Its specific gravity is 

 821. This fluid Mr. Faraday found to be a mixture of 

 various hydro-carbons of different degrees of volatility ; 

 and taking advantage of this circumstance, he was 

 enabled to separate them. The great bulk' of the liquid 

 distilled at a temperature of from 176 to 190; but a 

 portion also came over at a temperature of 98, and 

 another portion required a heat of about 200 to volati- 

 lise it. These liquids consisted of carbon and hydrogen 

 in various proportions. The most volatile was composed 

 of equal parts of carbon and hydrogen (C'H 1 ), and a 

 part of the intermediate portion consisted of two of 

 carbon to one of hydrogen (OH 1 ). The others were not 

 sufficiently examined to determine their exact composi- 

 tion, although there was every reason to believe that 

 thry were composed, like the first, of equal atomic 

 particles. 



M. Conerbe has also examined the liquor which is 

 produced by the compression of resin gas, and his result* 

 are quite as interesting as those of Professor Faraday. 

 He finds that the liquid contains six different fluid 

 hyilro-carboni; five of which consist of four atoms of 

 hydrogen and a proportion of carbon that rises in arith- 

 ;il progression from four to eight. The sixth is a 

 aontpotmd of twenty-eight atoms of carbon and twenty- 

 two of hy'l i 



Resin Go*. When it was found that oil could not be 

 profitably used for the manufacture of gas, attention 

 was naturally directed to other and cheaper gas-pro- 

 ducing substances. Resin was therefore selected ; but 

 it was noticed, that when this body was decomposed in 

 the apparatus commonly employed for the generation of 

 oil-gas, it produced a quantity of thick bituminous 

 matter whic*' choked the exit-pipe. This, at first, was 



regarded as an insurmountable difficulty; but it was 

 overcome by the late Professor Daniell, who contrived 

 an arrangement whereby the gas was delivered from the 

 bottom of the retort by means of a descending pipe. 

 His patent was taken out for this contrivance about 

 thirty years ago, and Messrs. Taylor and Martineau 

 were the first to put it into operation on a large scale. 

 The retort was set in the furnace in the usual manner, 

 and was charged with coke in order to increase the 

 heating-surface. Across the extreme end of the retort 

 there was a diaphragm, which was open at the top ; and 

 beyond this was the communication with the down- 

 going delivery-pipe. The diaphragm served to prevent 

 any of the coke from falling into the exit-tube. The 

 resin was dissolved, or rather liquefied, by the aid of 

 heat, in a small quantity of oil of turpentine, or of the 

 volatile oil produced by the decomposition of the resin 

 in a former process. The proportions were about twenty 

 pounds of resin to a gallon of oil. This mixture was 

 kept hot and fluid, in a reservoir placed over the fire 

 above the retort ; and when the contents of the latter 

 were red-hot, they were allowed to run through a syphon 

 tube, and to drop upon the incandescent coke at the 

 nearest end of the retort. The vapours which were thus 

 produced passed along the whole length of the retort, 

 and were completely decomposed before they escaped 

 over the diaphragm into the descending pipe. A part of 

 these vapours was liquefied by the cold of the condenser, 

 and such appeared as a limpid volatile oil ; the other 

 portion passed on as gas ; and, after having been puri- 

 ried by washing with lime-water, was collected in the 

 gasometer. This process of Daniell's was considered to 

 be very complete, though it has been modified in certain 

 particulars by subsequent patentees : thus, Mr. Richard- 

 son has proposed that the resin should be mixed with 

 sawdust and some alkali, as lime, potash, or soda ; and 

 that it should be put into the retort in thin sheet-iron 

 vessels of a cylindrical form. In these the first distilla- 

 tion take* place, and the volatile products are conveyed 

 into other vessels, or retorts, charged with coke, lime, 

 or broken bricks, kept at a red heat. By these means it 

 is thought that more gas, and less volatile oil, are ob- 

 tained. Mr. Webster generates the gas in another way. 

 He passes the vapour of coal-naphtha over a bed of 

 heated coke, and thence over a quantity of melted resin. 

 The volatile matters so obtained, traverse another vessel 

 filled with incandescent coke, and there they undergo 

 decomposition. 



A pound of resin will yield about ten cubic feet of gas ; 

 or, more correctly speaking, a hundredweight of resin 

 will furnish from 1,000 to 1,200 cubic feet of gas, and 

 about three gallons of oil The gas has a specific gravity 

 of from 660 to 850 ; and its illuminating power is but a 

 little inferior to that of oil-gas. When it is imperfectly 

 made, it does not contain more than eight or ten per 

 cent, of condensible hydro-carbons; and it was found by 

 Dr. Fyfe to have a durability of fifty-three minuter and 

 twenty seconds : its value, therefore, is about the same 

 as that of gas from Wigan cannel. As in the case of oil- 

 gas, this illuminating agent does not contain a particle 

 of any sulphur impurity. 



Although the production of gas from resin is not 

 practised in this country, in consequence of the more 

 economical source of coals, yet in many parts of America, 

 where resin and crude turpentine are cheap and abundant, 

 the process is still worked with advantage. 



Hydro-carbon Oat. This name is given to the mixed 

 gases which are generated from water, together with 

 substances that are rich in hydro-carbons, as tar, resin, 

 fats, oils, and the better kinds of cannel coal. 



Although this description of gas has but recently been 

 made on the large scale, yet the principles of its manu- 

 facture were known and appreciated many years ago. 

 In the year 1830, Mr. Donovan took out a patent for the 

 generation of gas from steam, by passing it over red-hot 

 coke or charcoal, and subsequently naphthalising it at the 

 burner, by means of turpentine or coal-tar. Since that 

 time many improvements have been made in the process : 

 and we may refer to the names of Manby, Val-Marino 



