APPENDIX I. 465 



By acetylenation-s-that is, by substituting three atoms of hydrogen, H 3 , in 

 methane by the remnant CH, we get acetylene, CHCH^O^ELj. 



If we have applied the principles of Newton correctly, there should not be 

 any other hydrocarbons contain ing two atoms of carbon in the molecule. 

 All these combinations have long been known, and in each of them we can 

 not only produce those substitutions of which an example has been given in 

 the case of methane, but also all the phases of other substitutions, as we shall 

 find frorn'a few more instances, by the aid of which I trust that I shall be 

 able to show the great complexity of those derivatives which, on the principle 

 of substitution, can be obtained from each hydrocarbon. Let us content our- 

 Selves with the case of ethano, CHgCHj, and the substitution of the hydrogen 

 *by hydroxyl. The following are the possible changes : 



1. CH 3 CH 9 (OH) : this is nothing more than spirit of wine, or ethyl 

 alcohol, C 8 H 5 (OH) or C 8 HeO. 



2. CH^OEOCSiOH) : this is the glycol of Wtirtz^ which has shed so 

 much light on the history of alcohol. Its isomeride may be CH 3 CH(OH) a , 

 but as we have seen in the case of CH(OH),j, it decomposes, giving off water, 

 and forming aldehyde, CH 3 CHO, a substance" capable of yielding alcohol by 

 uniting with hydrogen, and of yielding acetic acid by uniting with oxygen. 



If glycol, CE,(OH)GH..(OH), loses its water, it may be seen at once that 



it will not now yield aldehyde, CH 8 CHO, but its isomeride, CH 2^ 5H a' the 



oxide of ethylene. I have here indicated in a special manner the oxygen 

 which has taken the place of two atoms of 'the hydrogen of ethane taken 

 from different atoms of the carbon. 



8. CH 3 C(OH) 8 decomposed as CH(OH) 3 , forming water and acetic acid, 

 CH 3 CO(OH). It is evident that this acid is nothing else than formic acid, 

 CHO(OH), with its hydrogen replaced by methyl. Without examining 

 further the vast member of possible derivatives, I will direct your attention 

 to the circumstance that in dissolving acetic acid in water we obtain the 

 maximum contraction and the greatest viscosity when to the molecule 

 <CH 3 CO(OH) is added a molecule of water, which is the proportion which 

 would form the hydrate CHgC(OH)g. It is probable that the doubling of 

 the molecule of acetic acid at temperatures approaching its boiling-point 

 has some connection with this power of uniting with one molecule of 

 water. 



4. CH2(OH)C(OH) 8 is evidently an alcoholic acid, and indeed this com- 

 pound, after losing water, answers to glycolic acid, CH 2 (OH)CO(OH). 

 Without investigating all the possible isomerides, we will note only that the 

 hydrate CH(QH) 8 CH(OH) 3 has the same composition as CH^OHJCfOH)^ 

 and although corresponding to glycol, and,being a symmetrical substance, it 

 becomes, on parting with its water, the aldehyde of oxalic acid, or the glyoxal 

 of Debus, CHOCHO. 



6. CHCOH^CCOHa), from. the tendency of all the preceding, eorresporrdfli 

 with glyoxylio acid,, an aldehyde acid, CHOCO(OH), because th.e group 

 CO (OH), or carboxyl, enters into the compositions of organic acids, and the) 

 group CHO defines the aldehyde function. 



& C(OH) 3 C(OH) 8 through the loss of 2H,Q yields the bibaeio oxalic aci4 



