290 CHEMICAL TRANSFORMATIONS. 



the component parts of water, the remaining ele- 

 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 constituents of a compound, is 

 quite analogous to the decomposition of inorganic 

 substances. When we bring sulphuric acid and ni- 

 trate of potash together, nitric acid is separated ia 

 consequence of the affinity of sulphuric acid for pot- 

 ash ; 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 com- 

 ponent parts of the body which is decomposed to 

 combine so as to form new compounds, of which 

 either both, or only one, combine with the acting 

 body. Let us take dry w^ood, for example, and moist- 

 en it with sulphuric acid ; after a short time the wood 

 is carbonized, while the sulphuric acid remains un- 

 changed, with the exception of its being united with 

 more water than it possessed before. Now this wa- 

 ter did not exist as such in the wood, although its 

 elements, oxygen and hydrogen, were present ; but 

 by the chemical attraction of sulphuric acid for wa- 

 ter, they were in a certain measure compelled to 

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

 carbon of wood was separated as charcoal. 



Hydrocyanic acid* and water, in contact with hy- 

 drochloric acidjf are mutually decomposed. The 

 nitrogen of the hydrocyanic acid, and a certain quan- 

 tity of the hydrogen of the water, unite together and 

 form ammonia; whilst the carbon and hydrogen of 

 the hydrocyanic acid combine with the oxygen of the 

 water, and form formdc acid, f The ammonia com- 



* See page 70. note. 



t Formerly called Muriatic Acid, obtained from sea salt and compos* 

 ed of Hydrogen and Chlorine in equal vols. H -J- CI. 

 X See page 70. 



