1-Vl MB. J. I!. LAWKS, DR GILBERT, AM) DR. I'UGII ON 



somewhat contracted. Finally, access of air from without was exclnded by bai 



of caoutchouc, which were BO secured as to render the whole apparatus air-tight 



In BUCh an apparatus, BOUSSINGAUI/T made five separate experiments with White 

 Lupins. In all he sowed thirteen seeds, which were estimated to contain '-r, 



0-2710 gramme of Nitrogen. The experiments extended over periods varying from 



to eight weeks. In one instance, hurut brick instead of pumice-stone was used as the 

 soil ; and in this case, as well as in one where pumice was used, bone-phosphate as well 

 as ashes was added as manure. The dry matter of the produce was about three times 

 as much as was contained in the thirteen seeds sown. The Nitrogen in the total pro- 

 ducts of the five experiments amounted to 0-2GG9 gramme. There was. therefore, a 

 loss, in the five experiments taken together, of about 4 milligrammes of Nitrogen. In 

 two of the cases there was a slight gain of Nitrogen, but in neither instance did it 

 amount to 1 milligramme. 



In a similar apparatus, two experiments were made with Dwarf Haricots, a single seed 

 only being sown in each case. One of the experiments extended over two months, and 

 the other over two and a half months. In both instances flowers were formed, and in 

 one of them seed. The dry matter of the produce was three to four times as much as 

 that of the seed sown. Taking the two experiments together, the Nitrogen contained 

 in the seed was estimated at 0-0G52 gramme ; and that found in the products amounted 

 to 0-0G37 gramme. There was a loss, therefore, of 1-| milligramme of Nitrogen. 



There was, then, in this third series of experiments with Leguminous plants, again 

 rather a loss than a gain of Nitrogen, — the supplies of it in this case being confined to 

 the combined Nitrogen contained in the seeds sown, and to the free or uncombined 

 Nitrogen in the fixed and limited volume of air within the apparatus. 



.Still in the same apparatus, Boussixgault sowed Garden Cress. Thirteen seeds were 

 sown, all of which germinated, but three plants only survived. The growth of these 

 extended over three and a half months; and flowers and seed were produced. The 

 Nitrogen in the products amounted to precisely as much as was estimated to be con- 

 tained in the thirteen seeds sown. 



The last experiment in this closed globular apparatus was as follows : Two AVhite 

 Lupins were sown to grow ; and eight others were applied as manure, after treatment with 

 boiling water to destroy their powers of germination. The experiment continued for a 

 period of between four and five months. The dry matter of the produce was nearly twice 

 as much as would be contained in the ten seeds involved in the experiment. The whole 

 ten seeds were estimated to contain 0T827 gramme of Nitrogen; whilst the total pro- 

 ducts yielded only 0T697 gramme. The loss of Nitrogen was here, therefore, 13 milli- 

 grammes ; or about one-fourteenth of the whole amount involved in the experiment. 

 Boussixgault considered that the loss was probably due to free Nitrogen being given off 

 in the process of decomposition of the organic matter employed as manure. 



In order to ascertain whether the limitation of growth in the foregoing experiments 

 was due to the limitation in the amount of air, or to a deficiency of available Nitrogen 

 in the matters used as soil, Boussixgault sowed Cress in a good soil, placed the vessel 



