1889.] on an attempt to apply to Chemistry, dr. 521 



What I have said appears to me sufficient to show that the 

 principle of substitution adequately explains the composition, the 

 isomerism and all the diversity of combination of the hydrocarbons, 

 and I shall limit the further development of these views to preparing 

 a complete list of every possible hydrocarbon compound containing 

 thi-ee atoms of carbon in the molecule. There are eight in all, of 

 which only five are known at present.* 



Among those possible for C"H^ there should be two isomers, 

 propylene and trimethylene, and they are both already known. For 

 C"H^ there should be three isomers : allylene and allene are known, 

 but the third has not yet been discovered ; and for C"H- there should 

 be two isomers, though neither of them are known as yet. Their 

 composition and structure is easily deduced from ethane, ethylene, 

 and acetylene, by methylation, methylenation, by acetylenation and 

 by carbonisation. 



1. C^H* = CH^CH-CH^ out of CH^CHs by methylation. This 

 hydrocarbon is named propane. 



2. C^H^ = CH^CHCH- out of CH^CHs by methylenation. This 

 substance is propvlene. 



3. C^H^ = CH-CH-CH- out of CH^CH^ by methylenation. This 

 substance is trimethylene. 



4. C^H* = CH^CCH out of CH^CH^ by acetylenation or from 

 CHOH bv methylation. This hvdrocarbon is named allylene. 



5. C^H-^ = CHCH out of CH^CH^ by acetylenation, or from 



CWCW by methylenation, because CH-CH = CHCH. This body 



CH Cff 



is as yet unknown. 



6. C^H^ = CH-CCH- out of CH-CH- by methylenation. This 

 hydrocarbon is named allene, or iso-allylene. 



7. C^H-^ = CHCH out of CH^H^ by symmetrical carbonisation, 



C 

 or out of CH-CH- bv acetvlenation. This compound is unknown. 



8. C-H- = C("' out of CH^CH^ by cai-bonisation, or out of CHCH 



CH^ 

 by methylenation. This compound is unknown. 



If we bear in mind that for each hydrocarbon serving as a type 

 in the above tables there are a number of corresponding derivatives, 

 and that every comi)ound obtained may, by further methylation, 

 methylenation, acetylenation, and carbonisation, produce new hydro- 

 carbons, and these may be followed by a numerous suite of derivatives 

 and an immense number of isomeric bodies, it is possible to under- 

 stand the limitless number of carbon compounds, although they all 



* Conceding variable atomicity, the structurists must expect an incomparably 

 larger number of isomers, and they cannot now decline to acknowledge the change 

 of atomicity, were it only for the 'examples HgCl and HgCP, CO and CO-, PCP 

 and PCP. ' 



