THE SOTJECES OF THE NITEOGEN OF VEGETATION, ETC. 
451 
in a limited atmosphere, and supplied carbonic acid. The result was, that the plants 
thus gro-N^m, in a limited atmosphere, but in a good soil, were even more luxuriant than 
a parallel set, grown in a similar soil, in the open air. In both cases a large quantity 
of seed was produced. 
3. M. Boussivgaults exjpei'iments in 1854, with a current ofivashed air*. 
In this series of experiments, Boussixgault supplied his plants Avith a current of air, 
preAvously Avashed by passing first through vessels containing pumice-stone saturated 
with sulphuiic acid, and then through AA'ater. He also supplied carbonic acid from 
bicarbonate of soda acted upon by sulphuric acid, — the gas eA'oHed being passed first 
OA'er chalk, then through a solution of carbonate of soda, and lastly over pumice-stone 
saturated with a solution of carbonate of soda. The enclosing apparatus consisted of a 
metal-framed glass case of 124 litres capacity, Avhich Avas cemented doAvn upon a 
polished iron plate, upon Avhich the experimental pots Avere placed. Across one side of 
the case Avas a metallic joint-bar, in Avhich Avere apertures for the insertion of tubes for 
the admission of the A\ ashed air, and for the supply of AAmter and carbonic acid. On the 
opposite side was a similar joint-bar, to an aperture in which, a tube Avas attached con- 
necting the case with an aspirator of 500 litres capacity. By this apparatus, therefore, 
the plants could be supplied AA'ith a current of air freed from ammonia, Avith Avater, and 
with carbonic acid, at plcasme. During the experiment, the atmosphere in the Case 
generally contained from 2 to 3 per cent, of carbonic acid. Lastly, by means of one of 
the apertures any Avithered leaves AA'ere removed as they fell from the plants ; and they 
Avere then chied and preserved for analysis AAuth the remainder of the products. 
One of the experiments made in this apparatus Avas Avith a single Lupin, Avhich Avas 
alloAved to groAV for tAvo and a half months. The dry matter of the produce Avas more 
than six times that of the seed. The Lupin soAvn A\as estimated to contain 0'0196 
gramme of Nitrogen. The Nitrogen found in the products amounted to 0-0187 gramme. 
There Avas a loss, therefore, of nine-tenths of a milligramme of nitrogen. 
Four experiments AA'ere made Avith DAvarf Haricots, in three of Avhich single seeds, and 
in the fourth tAvo seeds, Avere soAvn. One experiment lasted over tAVO and a half months, 
and the plant floAvered ; one over three months, and the plant seeded ; one over three and 
a half months, in Avhich case also the plant seeded ; and another oA'er three and a quarter 
months. The dry sub stance of the produced plants Avas from three to four times as much 
as that of the seed soAvn. The total Nitrogen in the five seeds employed in the four expe- 
riments AA-as estimated at 0-1 G 72 ; the Nitrogen found in the total products amounted to 
0-1G61 gramme. There Avas therefore, upon the AA'hole, a loss of 0-0011 gramme of Ni- 
trogen. In tAvo of the experiments there Avas a loss of 1 milligramme each of Nitrogen ; 
and in the other tAvo a gain, amounting to less than 1 milligramme in each case. 
In the next experiment, one Lupin seed Avas soAvn to groAV, and another Avas steeped 
in hot Avater and applied as manure. The dry matter of the produce from the one seed 
amounted to nearly three times that of the tAVO seeds employed in the experiment. The 
* Ann. de Chim. et de Phys. ser. 3. tome xliii. 1855. 
