32 



AGRICULTURAL CHEMISTRY. 



were obtained by evaporating in a vessel 

 with muriatic acid several pounds of snow, 

 which were gathered from the surface of 

 the ground in March, when the snow had a 

 depth of 10 inches. Ammonia was set free 

 from these crystals by the addition of hydrate 

 of lime. The inferior layers of snow which 

 rested upon the ground contained a quantity 

 decidedly greater than those which formed 

 the surface. 



It is worthy of observation that the am- 

 monia contained in rain and snow water 

 possesses an offensive smell of perspiration 

 and animal excrements, a fact which leaves 

 no doubt respecting its origin. 



Hunefield has proved that all the springs 

 in Greifswalde, Wick, Eldena, and Kosten- 

 hagen, contain carbonate and nitrate of am- 

 monia. Ammoniacal salts have been disco- 

 vered in many mineral springs in Kissingen 

 and other places. The ammonia of these 

 salts can only arise from the atmosphere. 



Any one may satisfy himself of the pre- 

 sence of ammonia in rain by simply adding 

 a little sulphuric or muriatic acid to a quan- 

 tity of rain-water, and evaporating this 

 nearly to dryness in a clean porcelain basin. 

 The ammonia remains in the residue, in 

 combination with the acid employed; and 

 may be detected either by the addition of a 

 little chloride of platinum, or more simply 

 by a little powdered lime, which separates 

 the ammonia, and thus renders its peculiar 

 pungent smell sensible.* The sensation 

 which is perceived upon moistening the 

 hand with rain-water, so different from that 

 produced by pure distilled water, and to 

 which the term softness is vulgarly applied, 

 is also due to the carbonate of ammonia 

 contained in the former. 



The ammonia which is removed from the 

 atmosphere by rain and other causes, is as 

 constantly replaced by the putrefaction of 

 animal and vegetable matters. A certain 

 portion of that which falls with the rain 

 evaporates again with the water, but another 

 portion is, we suppose, taken up by the 

 roots of plants, and entering into new com- 

 binations in the different organs of assimila- 

 tion, produces albumen, gluten, quinine, 

 morphia, cyanogen, and a number of other 

 compounds containing nitrogen. The chemi- 

 cal characters of ammonia render it capable 

 of entering into such combinations, and of 

 undergoing numerous transformations. We 

 have now only to consider whether it really 



* Since the appearance of the last edition, this 

 experiment has been repeated by many in France, 

 Germany, America, and England, and the exist- 

 ence of ammonia in the atmosphere has been 

 completely confirmed. The assertion that this 

 ammonia possesses the "offensive smell of per- 

 spiration and animal excrements," has been ridi- 

 culed by many as fanciful 'by none, however, 

 who have made the experiment. The experiment 

 is so exceedingly easy to perform, that any one 

 may convince himself of the accuracy of the state- 

 ment. ED. 



is taken up in the form of ammonia by the 

 roots of plants, and in that form applied by 

 their organs to the production of the azotisecl 

 matters contained in them. This question 

 is susceptible of easy solution by well-known 

 facts. 



In the year 1834, 1 was engaged with Dr. 

 Wilbrand, professor of botany in the uni- 

 versity of Giessen, in an investigation re- 

 specting the quantity of sugar contained in 

 different varieties of maple-trees, which 

 grew upon soils which were not manured. 

 We obtained crystallised sugars from all, by 

 simply evaporating their juices, without the 

 addition of any foreign substance ; and we 

 unexpectedly made the observation, that a 

 great quantity of ammonia was emitted from 

 this juice when mixed with lime, and also 

 from the sugar itself during its refinement. 

 The vessels which hung upon the trees in 

 order to collect the juice were watched with 

 greater attention, on account of the sus- 

 picion that some evil-disposed persons had 

 introduced urine into them, but still a large 

 quantity of ammonia was again found in 

 the form of neutral salts. The juice had no 

 colour, and had no reaction on that of vege- 

 tables. Similar observations were made upon 

 the juice of the birch tree ; the specimens 

 subjected to experiment were taken from a 

 wood several miles distant from any house, 

 and yet the clarified juice, evaporated witlr 

 lime, emitted a strong odour of ammonia. 



In the manufactories of beet-root sugar, 

 many thousand cubic feet of juice are daily 

 purified with lime, in order to free it from 

 vegetable albumen and gluten, and it is 

 afterwards evaporated for crystallisation. 

 Every person who has entered such a 

 manufactory must have been astonished at 

 the great quantity of ammonia which is 

 volatilised along with the steam. This am- 

 monia must be contained in the form of an 

 ammoniacal salt, because the neutral juice 

 possesses the same characters as the solu- 

 tion of such- a salt in water ; it acquires, 

 namely, an acid reaction during evaporation, 

 in consequence of the neutral salt being con- 

 verted by loss of ammonia into an acid salt 

 The free acid which is thus formed is a 

 source of loss to the manufacturers of sugar 

 from beet-root, by changing a part of thff 

 sugar into uncrystallisable grape sugar and 

 syrup. 



The products of the distillation of flowers, 

 herbs, and roots, with water, and all ex- 

 tracts of plants made for medicinal purposes, 

 contain ammonia. The unripe, the trans- 

 parent, and gelatinous pulp of the almond 

 and peach emit much ammonia when treated 

 with alkalies. (Robiquet.) The juice of the 

 fresh tobacco leaf contains ammoniaca. 

 salts. The water which exudes from a cm 

 vine, when evaporated with a few drops of 

 muriatic acid, also yields a gummy deli- 

 quescent mass, which evolves much ammo 

 nia on the addition of lime. Ammonia exisst 

 in every part of plants, in the roots (as ia 



