206 CHEMICAL TRANSFORMATIONS. 



ments enter into a new form ; in place of oxalic acid, we have 

 its elements in the form of carbonic acid and carbonic oxide. 



This form of decomposition, in which the change is effected by 

 the agency of a body which unites with one or more of the con- 

 stituents of a compound, is quite analogous to the decomposition 

 of inorganic substances. When we bring sulphuric acid and 

 nitrate of potash together, nitric acid is separated in consequence 

 of the affinity of sulphuric acid for potash ; in consequence, 

 therefore, of the formation of a new compound (sulphate of 

 potash). 



In the second form of these decompositions, the chemical 

 affinity of the acting body causes the component parts of the 

 decomposing body to combine, so as to form new compounds, of 

 which either both, or only one, combine with the acting body. 

 Let us take dry wood, for example, and moisten it with sulphuric 

 acid ; after a short time the wood is carbonized, while the sul- 

 phuric acid remains unchanged, with the exception of its being 

 united with more water than it possessed before. Now, this 

 water did not exist as such in the wood, although its elements, 

 oxygen and hydrogen, were present ; but by the chemical attrac- 

 tion of sulphuric acid for water, they were in a certain measure 

 compelled to unite in this form ; and, in consequence of this, the 

 carbon of the wood was separated as charcoal. 



Hydrocyanic acid and water, in contact with hydrochloric 

 acid, are mutually decomposed. The nitrogen of the hydrocy- 

 anic acid, and the hydrogen of a certain quantity of the water, 

 unite together and form ammonia ; whilst the carbon and hydro- 

 gen of the hydrocyanic acid combine with the oxygen of the 

 Water and produce formic acid. The ammonia combines with 

 the muriatic acid. Here the contact of muriatic acid with water 

 and hydrocyanic acid causes a disturbance in the attraction of 

 the elements of both compounds, in consequence of which they 

 arrange themselves into new combinations, one of which — am- 

 monia — possesses the power of uniting with the acting body. 



Inorganic chemistry can present instances analogous to this 

 class of decomposition also ; but there are forms of organic che- 

 mical decomposition of a very different kind, in which none of 

 the component parts of the decomposing matter enter into combi- 



