1 1 Observatio7is on Liebig's " Organic Chemistry." 



have put the presence of ammonia in rain water beyond all 

 doubt; as, when distilled in considerable quantity, sal ammoniac 

 was formed, on the addition of a little muriatic acid. The 

 presence of carbonate of ammonia in rain water shows the 

 benefit of preferring it in watering plants; the more recent the 

 better, as it is a very volatile salt. Water cannot easily be 

 saturated with ammonia. It will contain 468 times its volume 

 when saturated ; water from manure will therefore contain a 

 great quantity : it should be washed into the soil to prevent 

 volatilisation. Ammonia may also be detected, he says, in 

 snow water; and the ammonia contained therein has the offen- 

 sive smell of perspiration and animal excrements ; a fact which 

 leaves no doubt of its origin. The quantity of ammonia in a 

 given quantity of rain water will vary according to the quantity 

 of rain ; but the quantity of ammonia furnished will not vary 

 much. Any one, he says, may easily test the presence of am- 

 monia in rain water by adding a little sulphuric or muriatic 

 acid to it, and evaporating nearly to dryness in a china basin : 

 the ammonia remains in combination with the acid, and may be 

 detected by the addition of a little powdered lime, which uniting 

 with the acid, the ammonia is separated, and given off' with a 

 pungent smell. The ammonia removed from the atmosphere 

 by rain and other causes is replaced by the putrefaction of vege- 

 table substances containing gluten and albumen, and of animal 

 remains and excrements. In the solid excrements there is little, 

 in the urine most. The ammonia, he says, is taken up by the 

 roots, which he seems to think the chief way of their getting 

 ammonia ; though I cannot see how the same may not apply 

 to carbon ; both ammonia and carbonate of ammonia being of 

 less specific gravity than carbonic acid, and more likely to exist 

 in the upper strata of the air. 



Albumen, gluten, quinine, morphia, and cyanogen, with a 

 number of other compounds, are the principal substances in 

 plants, he says, which require nitrogen. The first is to be found 

 in seeds, around buds, &c. ; the second is to be found in wheat 

 and other giains, the inner bark of hollies, &c. ; the quinine 

 is obtained from Peruvian bark ; the morphia from poppies, 

 lettuce, &c. ; the cyanogen from daphnes and other plants 

 yielding prussic acid. 



The fact of ammonia being contained in the juices of plants 

 was first discovered by Dr. WiU)rand and himself, in 1834, 

 when investigating the quantity of sugar contained in diff'erent 

 varieties of maple growing on soils which were not manured. 

 On mixing the juice with lime, ammoniacal fumes were given 

 off", which they at first suspected to be from urine put in the 

 bottles collecting the juice, but were afterwards convinced by 

 the juice being taken from a wood several miles from any house. 



