FLAMES OF COMPOUNDS OF CARBON AND HYDROGEN. 



417 



artificial supply of air. Two methods occurred to me of effecting this object, so as 

 to convert the carbon into carbonic acid, without its intermediate separation in a 

 solid form. One was to burn the vapours of the substances under examination 

 in the Bunsen lamp ; but this I rejected as inconvenient, and perhaps even in 

 some cases dangerous, from the risk of explosion, where it would have been 

 necessary to boil highly volatile liquids in close vessels. The other was simply 

 to pass a stream of air through the flame by means of a table blowpipe. By 

 means of the latter expedient I succeeded so completely in preventing the sepa- 

 ration of solid carbon, as to obtain spectra with bright lines and dark spaces, 

 in the case of every compound of carbon and hydrogen which I have as yet sub- 

 mitted to examination. 



Comparison of the Spectra of the Flames of various Substances containing Carbon and 



Hydrogen. 



The hydrocarbon compounds which I have examined, and which are enu- 

 merated in the following table, may be divided into two classes ; one consisting 

 of substances containing only carbon and hydrogen, of which the general formula 

 is C r H s , and the other of substances containing carbon, hydrogen, and oxygen, 

 represented by the formula C r H 3 O t . 



C r H a 



Light carburetted hydrogen, 



Olefiant gas, 



Paraffin, 



Oil of turpentine, 



C H 2 



C 2 H 2 

 V 20 20 

 C 10 H 8 



C r H s O t 



Methylic alcohol. 



Alcohol, 



Ether, 



Methylic ether, 



Glycerine, . 



Spermaceti, 



Camphor, 



Wax, 



Tallow, 



Coal gas, . 



Coal naphtha, 



o 2 



o 

 o 



° 6 



o. 



C 10 H 8 O 



Of indefinite 

 composition. 



C 2 H 4 



C 4 H 4 



C 4 H 5 



C 2 H 3 



C 6 H 8 



C G4 H 66 



Of these substances, the light carburetted hydrogen was made by heating 

 acetate of soda, hydrate of potassa, and quicklime ; and the methylic ether from 

 wood spirit and sulphuric acid. The gases were generally burned from a platinum 

 jet, immediately after passing through a tube filled with pieces of quicklime. 

 The glycerine, a substance which burns with difficulty, was heated in a platinum 

 capsule ; and the paraffin, camphor, and spermaceti, which were colourless, crys- 

 talline, and apparently pure specimens, were also similarly treated, in order to cor- 

 roborate the conclusion stated at p. 415, that the lines observed in the spectra were 



