458 Mi;. J. B. L.\\Vi:s, dr. GTLBEBT, AM) ML I'l'CU OB 



5. M. G. Villk'h experiment* in which km, wo quantities of Ammonia vierc admitted 'nt'j 



the afinosphrrr of ' thr mefo imj apparatus. 

 Tn each of the three seasons 1850, 1851, and 1862, M. G. Villi had a duplicate 

 apparatus, enclosing, in each case, similar plants to those in the other, but with this 

 difference in the conditions — that ammonia was supplied to the atmosphere of the 

 second apparatus. As might be expected, the increase, both in dry substance* and in 

 Nitrogen, was much the greater, in relation to the amounts of them contained in the 

 seed or young plants, when ammonia was thus employed. Tn no case, however, did the 

 plants take up Nitrogen equal in amount, much less exceeding, the whole of that sup- 

 plied to the air in the combined form, as ammonia. The results have not, therefore, so 

 direct a bearing on the question of the assimilation of free or ?racombined Nitrogen, as 

 to require that we should quote them in any detail. Their chief interest was in show- 

 ing the influence of ammoniacal supply, not only upon the vigour and luxuriance of 

 growth generally, but upon the order, or course of development, of the plants, according 

 to the stage of growth at which the application was made. 



G. Comparison o/M. G. Ville's results with those ofM. Bolssingault wp to 1853 



inclusive. 



It will be remembered that, up to 1853 inclusive, M. Boussingault's experimental 

 plants had been grown either in free air — in which case they had fixed, from some source, 

 slightly larger amounts of Nitrogen than were contained in the seed, — or in fixed and 

 limited volumes of air (carbonic acid being added), in which cases no gain of Nitrogen 

 was observed. The gain of Nitrogen in the free air was, moreover, considered to be too 

 small to indicate, under all the circumstances, any assimilation of free or uncombined 

 Nitrogen. On the other hand, M. G. Ville's experiments up to the same period had 

 indicated an enormous gain of Nitrogen. The Nitrogen in the products, indeed, some- 

 times amounted to more than forty times that contained in the seed. 



Results so strikingly contradictory could hardly fail to excite great attention and 

 interest among Chemists and Vegetable Physiologists. But M. Ville's plants had been 

 grown in a constant current of renewed air, and not in only a fixed and limited volume 

 of it. This fact, and some other points, were alleged to account for the difference in 

 result. At any rate, on the one hand, M. Boussingault commenced in 1854, to expe- 

 riment with a current of air ; whilst, on the other, a Commission, composed of Members 

 of the Academy of Sciences of France, was appointed to superintend the conduct of a 

 new set of experiments by M. G. Ville. It has already been shown, that M. Boussix- 

 GAULT's new experiments in which a current of air was employed, did not indicate any 

 assimilation of free or uncombined Nitrogen, any more than did those in which the 

 plants had grown in limited volumes of air only. 



