42ti COMPOUNDS OF CARBON, 



The burner should be provided besides with a metallic chimney 

 of four inches in height, without the wire gauze.* 



A result of the circumstances which determine the quantity of 

 light from different flames is, that the larger the flame till it begins 

 to be smoky, the greater the proportion of light obtained from the 

 consumption of the same quantity of gas. It was observed that 

 an argand burner, supplied with 1| cubic feet of gas per hour, gave 

 as much light as a single candle ; with 2 cubic feet per hour the 

 light was equal to 4 candles, and with 3 cubic feet to 10 can- 

 dles. Hence argands, bat-wings and other burners, in which a 

 considerable quantity of gas is burned together, are more econo- 

 mical than plain jets. The brightness of ordinary flame, which 

 depends essentially upon the consecutive combustion of hydro- 

 gen and carbon, is increased by everything which promotes the 

 rapidity and intensity of the combustion, without deranging the 

 order of oxidation, such as a rapid supply of air, and the substi- 

 tution of pure oxygen for air, as in Mr. Gurney's Bude light. 

 Not only is there then more light, because there is more com- 

 bustion in the same time, but the temperature of the flame 

 being greater, the luminous carbon is also heated to a higher 

 degree of whiteness. 



Olefiant gas, C 4 H 4 or C 4 H 3 , H. This gas was discovered in 

 17^6, by certain associated Dutch chemists, who gave it the 

 name of olefiant gas, because it forms with chlorine a compound, 

 having the appearance of an oil, from which the chlorides of 

 carbon were afterwards derived (page 375.) This gas is pre- 

 pared by heating together 1 measure of strong alcohol with 3 

 measures of oil of vitriol, in a capacious retort, till the liquid 

 becomes black and effervescence begins, and maintaining it at 

 that particular temperature. It is collected over water, which 

 deprives it of a portion of ether vapour and sulphurous acid, 

 with which it is accompanied. Olefiant gas burns with a white 

 flame, and contains a large quantity of combustible matter in a 

 given volume. It consists of 8 volumes of carbon vapour and 

 8 of hydrogen, condensed into 4 volumes, which gives for its 

 density 981. It is now viewed as a compound of the organic 

 radical acetyl with hydrogen, which is expressed in the rational 

 formula stated above. Several other compounds of carbon and 



* The form of argand recommended is known as the patent double-cone gas 

 burner. 



