APPENDIX, 



EXPERIMENTS OF WIEGMANN AND POLSTORF 



* This salt was made by boiling common peat with weak potash ley, and 

 precipitating, by means of sulphuric acid, the dark-colored solution. This 

 precipitate is that termed Torfsaeure (acid of peat), in the above analysis. 

 The salts of this acid, referred to in the analysis, were obtained by dissolv- 

 ing this acid in potash, soda, or ammonia, and by evaporating the solutions ; 

 the salts of magnesia, lime, peroxide of iron, and alumina, were obtained 

 by saturating this solution with their respective bases, by which means 

 double decomposition was effected. Humus is the substance remaining by 

 the decay of animal and of vegetable matters, which are seldom absent from 

 a soil. This was replaced by the acid of peat in the experiments of Wieg- 

 mann and Polstorf. When the acid of peat is boiled for some time with 

 water, it passes into an insoluble modification denoted above as insoluble 

 acid of peat, 



