CHEMICAL TRANSFORMATIONS. 



87 



condition; so much so indeed, that the pea- 

 sants here speak of it to this day, wondering 

 that old Miiller had so good a vineyard, and 

 yet used no manure. 7 



" Lastly, Wilhelm Ruf of Schriesheim 

 writes : 



'* s For the last ten years I have been 

 unable to place dung on my vineyard, be- 

 cause I am poor and can buy none. But I 

 was very unwilling to allow my vines to 

 decay, as they are my only source of sup- 

 port in my old age; and I often walked very 

 anxiously amongst them, without knowing 

 what I should do. At last my necessities 

 became greater, which made me more at- 

 tentive, so that I remarked that the grass 

 was longer on some spots where the branches 

 of the vine fell than on those on which there 

 were none. So I thought upon the matter, 



and then said to myself: If these branches 

 can make the grass large, strong, and green, 

 they must also be able to make my plants 

 grow better, and become strong and green. 

 I dug therefore my vineyard as deep as if I 

 would put dung into it, and cut the branches 

 into pieces, placing them in the holes and 

 covering them with earth. In a year I had 

 the very great satisfaction to see my barren 

 vineyard become quite beautiful. This plan 

 I continued every year, and now my vines 

 grow splendidly, and remain the whole 

 summer green, even in the greatest heat. 



" 'All my neighbours wonder very much 

 how my vineyard is so rich, and that I ob- 

 tain so many grapes from it, and yet they 

 all know that I have put no dung upon it 

 for ten years.' " 



PART II. 



OF THE CHEMICAL PROCESSES OF FERMENTATION, DECAY AND PUTRE. 



FACTION. 



CHAPTER 1. 



CHEMICAL TRANSFORMATIONS. 



WOODY fibre, sugar, gum, and all such 

 organic compounds, surfer certain changes 

 when in contact with other bodies, that is, 

 they suffer decomposition. 



There are two distinct modes in which 

 these decompositions take place in organic 

 chemistry. 



When a substance composed of two com- 

 pound bodies, crystallized oxalic acid for 

 example, is brought in contact with concen- 

 trated sulphuric acid, a complete decompo- 

 sition is effected upon the application of a 

 gentle heat. Now crystallized oxalic acid 

 is a combination of water with the anhy- 

 drous acid; but concentrated sulphuric acid 

 possesses a much greater affinity for water 

 than oxalic acid, so that it attracts all the 

 water of crystallization from that substance. 

 In consequence of this abstraction of the 

 water, anhydrous oxalic acid is set free ; but 

 as this acid cannot exist in a free state, a 

 division of its constituents necessarily en- 

 sues, by which carbonic acid and carbonic 

 oxide are produced, and evolved in the 

 gaseous form in equal volumes. In this 

 example, the decomposition is the conse- 

 quence of the removal of two constituents 

 (the elements of water,) which unite with 

 me sulphuric acid, and its cause is the supe- 

 rior affinity of the acting body (the sulphuric 

 acid) for water. In consequence of the re- 

 moval of the component parts of water, the 

 remaining elements 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 (sul- 

 phate of potash.) 



In the second form of these decomposi- 

 tions, the chemical affinity of the acting 

 body causes the component 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 wood, for example, 

 anc 1 moisten it with sulphuric acid ; after a 

 short time the wood is carbonised, while the 

 sulphuric 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 hydro- 

 gen, were present ; but by the chemical at- 

 traction 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 wood was separated as charcoal. 



Hydrocyanic acid, and water, in contact 

 with hydrochloric acid, are mutually decom- 

 posed. The nitrogen of the hydrocyanic 

 acid, and a certain quantity of the hydrogen 

 of the water, unite together and form am- 

 monia; whilst the carbon and hydrogen of 

 the hydrocyanic acid combine with the oxy- 

 gen of the water, and form 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, 



