AGRICULTURAL CHEMISTRY AND GEOLOGY. 167 



tion during the whole course of their development. The apparatus was thus made extremely 

 simple, being nothing but a large glass globe, capable of holding some sixty or eighty quarts ; 

 he placed in the bottom of the globe (after having made it sufficiently humid) a certain quan- 

 tity of pumice-stone, pounded, which had been washed, heated red hot, and, after it had 

 cooled, mixed with the ashes of barn-yard manure and of seed similar to those about to be 

 planted. The opening of the globe was immediately covered with a cork, which was itself 

 covered with a caoutchouc cap. Forty-eight hours after this had been done the cork was 

 again removed, and enough pure water added to bathe the base of the pumice-stone, which 

 had been disposed in a heap. Then the seeds were planted they being inserted in a glass 

 tube, which guided them to the place where they should lie. After the seeds were introduced, 

 the tube was again closed, and, when the seed had germinated sufficiently, the confined atmo- 

 sphere was charged with carbonic acid gas, by substituting in the place of the cork a second 

 globe superposed on the first, having about one-tenth of the capacity of the first, and con- 

 taining the acid gas prepared beforehand ; the juncture between them was then filled with 

 sealing-wax, and half of the apparatus was buried in the ground. The experiment was now 

 abandoned to itself, and the experimenter had little more to do besides to observe the plants' 

 progress, to take advantage of the opportune moment to transfer them to his laboratory. The 

 result of M. Boussingault's experiments is, that there is no azote fixed in an appreciable quan- 

 tity during the course of the vegetation : the azote of the seed passed into the plant, the azote 

 of the air remained fixed in the air. M. Ville urges that a positive result is of more import- 

 ance than a mere negative result ; that he has, to sustain his position, the gramme of azote 

 which he discovered in the plants he reared on a perfectly sterile soil ; besides that, during 

 his experiments, he ascertained the circumstances in which M. Boussingault placed his plants 

 are peculiarly unfavorable to the health of the plant, and to the exercise of the function of 

 assimilating : they pervert the function whose office they both are studying. 



This discussion, although no positive results were attained, will nevertheless be read with 

 interest. 



The following is an abstract of a communication previously presented to the French Acade- 

 my by M. Ville, on the absorption of nitrogen : 



After stating that it has often been asked if air, and especially nitrogen, contributes to the 

 nutrition of plants, and, as regards the latter, that this question has always been answered 

 negatively, the author remarks that it is, however, known that plants do not draw all their 

 nitrogen from the soil, the crops produced every year in manured land giving a greater pro- 

 portion of nitrogen than is contained in the soil itself. The question which he has proposed 

 to himself for solution is, Whence, then, comes the excess of nitrogen which the crops con- 

 tain, and, in a more general manner, the nitrogen of plants, which the soil has not furnished ? 

 He divides his inquiry into the three following parts : 



First. Inquiry into and determination of the proportion of the ammonia contained in the 

 air of the atmosphere. 



Second. Is the nitrogen of the air absorbed by plants ? 



Third. Influence on vegetation of ammonia added to the air. 



1. The author remarks, that since the observation of M. Theodore de Saussure, that the air 

 is mixed with ammoniacal vapors, three attempts have been made to determine the proportion 

 of ammonia in the air ; a million of kilogrammes of the air, according to M. Grayer, contain 

 0-333 kil. ammonia ; according to Mr. Kemp, 3-880 kil. ; according to M. Fre*senius, of the air 

 of the day, 0-098 kil. ; and of night air, 0-169 kil. He states that he has shown the cause of 

 these discrepancies, and proved that the quantity of ammonia contained in the air is 22-417 

 grms. for a million of kilogrammes of the air, and that the quantity oscillates between 17-14 

 grms. and 29-43 grms. 



2. The author states that, though the nitrogen of the air is absorbed by plants, the ammonia 

 of the air contributes nothing to this absorption. Not that ammonia is not an auxiliary of 

 vegetation, but the air contains scarcely 0-0000000224, and in this proportion its effects are 

 inappreciable. These conclusions are founded upon a great number of experiments in which 

 the plants lived at the expense of the air, without deriving any thing from the soil. For the 

 present, he confines himself to laying down these two conclusions : 1. The nitrogen of the air 



