Liebigs Organic Chemistry applied to Agriculture. 551 



amounts to 40,000 lbs. According to Berzelius, these materials ab- 

 sorb from the atmosphere in 24 hours, 40,000 lbs. of water ; conse- 

 quently in 120 days, during the period of vegetation, 4,800,000 lbs. 

 of water. To these are to be added 700,000 lbs. of rain, which 

 raises the quantity to 5,500,000 lbs. of water. In this way the plants 

 receive 2,200 lbs. of lime saturated with humic acid, which is equal 

 to 2,016 lbs. of humic acid, or to 1,169 lbs. carbonic acid. Now the 

 corn and straw grown on the acre contain, according to Liebig, 

 1,020 lbs. carbonic acid. There is consequently, still left 149 lbs. 

 to account for the carbonic acid consumed in forming roots and 

 the lower part of the haulm. Again, according to the opinion of 

 the author, the atmosphere always contains ammonia, which is 

 readily absorbed by humus, and forms that salt which is most solu- 

 ble and contains the greatest proportions of humus. If, for the 

 formation of humate of ammonia ten times the same quantity of 

 water is required, that quantity (700,000 lbs.) brings to the plants 

 70,000 lbs. of humate of ammonia. This quantity contains, accord- 

 ing to the calculation of Mulder, 42,000 lbs. of carbonic acid, and if we 

 suppose that only one-tenth of the water is used in the nourishment of 

 the plants, they receive still 4,200 lbs. of carbonic acid. I could 

 wish to learn from Dr. Liebig what the plants are to do with 

 this immense surplus of carbonic acid } 



On the other hand, the author at page 13, has made calcula- 

 tions which render it in the highest degree improbable that plants 

 are nourished by humus contained in soil. After having repeated 

 the old observation, that in forests or meadows, in despite of the 

 crops annually taken from them, the soil continually increases the 

 proportion of humus without the assistance of manure, he produces a 

 calculation, according to which equal spaces of ground, whether 

 used for the growth of forest- trees, grass, corn, or turnips, pro- 

 duce annually nearly the same quantity of carbonic acid. If this 

 was true, it would prove that the production of carbonic acid is 

 entirely independent of the mode of cultivation and the application 

 of manure. The facts on which this calculation rests are not within 

 my province, but Dr. F. X. Hlubek, in his examination of this our 

 author's book, has proved, in a very satisfactory way, that these 

 facts are mere fancies of Dr. Liebig. 



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