SCIIULTZENSTEIN — NUTRITIVE CONSTITUENTS OF WATER. 117 



The water of the neighbouring Ecker, which is browner than 

 that of the Use, in 4 lbs. yielded 2^ grs. of very dark humous 

 extract. 



Two quarts of water of the black Elster, collected at Herzberg, 

 gave, after evaporation, a treacle-brown fluid, which, reduced 

 to perfect dryness, gave f gr. of saltpetre and 2| grs. of humous 

 extract. 



The Rhine, at Basle, passes 13,000 cubic feet of water per second 

 (which, reckoning | gr. of humus to the pound, contain 56 lbs.), 

 3360 lbs. per minute, 1832 cwt. per hour, and 43,968 cwt. per 

 day. 



The Granges, above its bifurcation at the Delta, near Sicligully, 

 passes in April, according to Prinsep, 21,500 cubic feet per second ; 

 at Benares 20,000. If there is only | gr. of humous extract per 

 pound, or 33 grs. per cubic foot, we shall have 



33 X 20,000= 660,000 grs. = 85 lbs. of humus,— 



5100 lbs. per minute, 306,000 lbs. per hour, and 66,764 cwt. per 

 day. 



The Indus, according to Prinsep, sends out at its bifurcation at 

 Tatta 80,000 cubic feet per second — that is, four times as much as 

 the Granges, which yields 267,056 cwt. of humus per day, if the 

 water has only the sixth part of the nutritious matter contained 

 in the water of the Elbe. 



The Mississippi, in the rainy season, passes 550,000 cubic feet 

 per second — that is, nearly eight times as much as the Indus ; and 

 supposing the same proportion of humus, it sends daily to the 

 sea 2,136,000 cwt. of humus. 



Since humus contains every constituent necessary for the sus- 

 tenance of plants — carbon, hydrogen, oxygen, nitrogen — the possi- 

 bility of their nutriment by means of the humus held in solution 

 by the water contained in the soil and streams is proved. "We 

 must, however, first examine the other views which have been held 

 respecting the agency of water in the nutriment of plants. 



Liebig and the more modern chemical physiologists regard 

 vegetable matters as hydrated carbons in which water is con- 

 densed and combined with the carbon of the carbonic acid which 

 has been received as nutriment. In this case the hydrogen and 

 oxygen must exist in all vegetable constituent parts in precisely 

 the same proportions in which they are found in water. This is 

 allowed by Liebig and many other chemists, since they find in 

 sugar and lignine nearly the proportions of hydrogen and oxygen 



