YILLE'S EXPERIMENTS. 329 



to the ammonia in the atmosphere, and also to organic matters 

 in small amount which may have entered the case in the form of 

 very fine dust ; but, taking into consideration all the conditions 

 of the experiment, he was not inclined to the belief that an}' 

 nitrogen had been received by the plants from the free nitrogen 

 of the atmosphere. 



868. In 1855 and 1858 the same chemist experimented upon 

 certain plants which were supplied with a known amount of com- 

 bined nitrogen in some available form. The results of his ex- 

 periments have been formulated as follows: (1) There was no 

 appropriation of free nitrogen ; (2) There was a slight loss of 

 the nitrogen which had been supplied to the plant ; (3) The 

 amount of assimilation of carbon bore a close relation to the 

 amount of nitrogen taken up by the plant. 



869. From 1849 to 1854 Georges Ville, of Paris, conducted 

 experiments which were interpreted as showing that plants can 

 take from the nitrogen of the atmosphere a certain part of that 

 which they require. In the autumn of 1854 he carried on a 

 series of researches at the Jardin des Plantes, under the super- 

 vision of a committee appointed by the French Academy. To- 

 wards the close of the work an element of error crept into it 

 which could not then be eliminated ; but as to the result of 

 the investigation the committee reported, 1 that the experi- 

 ment made at the Museum d'Histoire Naturelle by M. Ville 

 is consistent with the conclusions which he has drawn from 

 his previous labors. 



870. In 1861 Lawes, Gilbert, and Pugh,- of England, pub- 



1 The report by Chevreul will be found in Comptes Kendus, xli. p. 757. 

 Results so directly in conflict as those of the two experimenters referred to in 

 the text led others to investigate this subject, and in 1857-1859 an exhaustive 

 series of investigations was carried on at Rothamsted, England, by Lawes, 

 Gilbert, and Pugh. 



Mene, in 1851, concluded from his experiments that plants do not appro- 

 priate the free nitrogen of the air. 



Roy interpreted the results of his own experiments as showing that free 

 nitrogen dissolved in water can be taken up by plants. 



Luca (1856) suggested that the air surrounding plants maybe ozonized, and 

 thus the nitrogen in it converted into nitric acid and made available for the 

 plants. 



Harting (1855) concluded that the free nitrogen of the air is not proved to 

 serve directly for the nutrition of the plant. 



2 Philosophical Transactions, 1861, p. 431. For an excellent description 

 and drawing of the complicated apparatus employed in this capital investiga- 

 tion the student may consult Johnson's "How Crops Feed," p. 30. 



