456 MR. J. B. LAWES, DR. GILBERT, AND DR. PUGH ON 
and ignited sand, sand and brick, or sand and charcoal, with the addition of the ash of 
the plant to be grown. He planted seeds or plants, the composition of which was esti- 
mated by the analysis of parallel specimens. Several pots were for the most part 
enclosed in an iron-framed glazed case of 150 litres (or more) capacity, through which a 
current of air equal in amount to several times the volume of the vessel was aspired 
daily. Carbonic acid and distilled water were supplied as needed. In some cases the 
air admitted into the apparatus was only previously freed from dust; and then the 
amount of atmospheric ammonia that would be brought in was calculated according to 
the determination of the proportion of ammonia in the air, above alluded to. In other 
cases the aspired air was previously freed from ammonia by washing. In some experi- 
ments, ammoniacal gas was passed, in known quantities, into the air of the apparatus. 
Lastly, others were made, in which combined Nitrogen was added to the soil in the form 
of nitrate, or of ammonia salts; and in these cases the plants were allowed to grow in 
free air, only shaded from rain and dust. 
3. M. G. VILLE's experiments in 1849 and 1850, in which the plants were supplied 
with a current of unwashed air. 
In 1849, sand was used as soil; three pots of plants were grown for two months; 
namely, one of Cress, one of large Lupins, and one of small Lupins. The air admitted 
into the apparatus was not previously deprived of its natural ammonia. The dry sub- 
stance of the produced Cress plants amounted to more than sixteen times that of the 
seed sown. ‘The Nitrogen in the Cress seeds amounted to 0:026 gramme; that in the 
products to 0-147 gramme. The Nitrogen in the products was, therefore, between five 
and six times as much as that in the seed; and the actual gain of it amounted to 0-121 
gramme. In the case of the large Lupins, the dry matter of the produce was about 
3% times as great as that of the seeds sown; but there was neither gain nor loss of 
Midehes, The small Lupins gave. Qx times as much dry substance in the produce as 
was supplied in the seeds; and of the Nitrogen of the seeds sown, there was an apparent 
loss of rather more than one-fourth, during the experiment. 
The total gain of combined Nitrogen in the apparatus, taking the three experiments 
together, was 0:103 gramme. The Nitrogen in the ammonia of the current of unwashed 
air, was, however, , estimated at only 0:001 gramme. M.G. VILLE concluded, therefore, 
‘that the Cress had appropriated a considerable quantity of the free or uncombined 
Nitrogen of the atmosphere. 
The plants experimented upon in 1850, were Colza, Wheat, Rye, and Maize. In the 
case of the Colza, the experiment commenced with young plants, but in the other cases 
with seed. The four pots were placed in an apparatus similar to that used before, and 
the conditions supplied were also the same as in 1849. 
The dry matter of the produced Colza plants amounted to between forty and fifty 
times as much as that of the young plants when taken for experiment. The Nitrogen 
was also increased more than forty-fold. The dry matter of the Wheat plants was about 
