44 SOURCE AND ASSIMILATION OF NITROGEN. 



upwards of 80 lbs. of ammonia, or 60 lbs. of nitrogen; for by 

 the observations of Schubh r, formerly alluded to, the annual fall 

 must be about 2,520,000 lbs. This is much more nitrogen than 

 is contained in the form of vegetable albumen and gluten, in 

 2,650 lbs. of wood, 2,500 lbs. of hay, or 200 cwt. of beet-root, 

 which are the yearly produce of such a field ; but it is less than 

 the straw, roots, and grain of corn, which might grow on the 

 same surface, would contain. 



Experiments made in this laboratory (Giessen) with the great- 

 est care and exactness, have placed the presence of ammonia in 

 rain-water beyond all doubt. It has hitherto escaped obser- 

 vation, because it was not searched for. All the rain-water em- 

 ployed in this inquiry was collected GOO paces south-west of 

 Giessen, whilst the wind was blowing in the direction of the 

 town. When several hundred pounds of it were distilled in a 

 copper still, and the first two or three pounds evaporated with the 

 addition of a little muriatic acid, a very distinct crystallization 

 of sal-ammoniac was obtained : the crystals had always a brown 

 or yellow color. 



Ammonia may likewise be always detected in snow-water. 

 Crystals of sal-ammoniac were obtained by evaporating in a ves- 

 sel with muriatic acid several pounds of snow, which were ga- 

 thered from the surface of the ground in March, when the snow 

 had a depth of ten inches. Ammonia was set free from these 

 crystals by the addition of hydrate of lime. The inferior layers 

 of snow resting upon the ground contained a quantity decidedly 

 greater than those upon the surface. 



It is worthy of observation that the ammonia contained in rain 

 and snow-water possesses an offensive smell of perspiration and 

 putrefying matter, — a fact which leaves no doubt respecting its 

 origin. 



Hiincfield has proved that all the springs in Greifswalde, Wiek, 

 Eldena, and Kostenhagen, contain carbonate and nitrate of am- 

 monia. Ammoniacal salts have been discovered in many m'neral 

 springs in Kissingen and other places. The ammonia of these 

 salts can only arise from the atmosphere.* 



• Pharmaceutical chemists are well aware of the existence of ammonia 



