583 
deal of attention to a consideration of the value of nitrogen and nitrates 
in agriculture, has lately published the results of some very interesting 
investigations with regard to the formation of nitric acid in soils under 
different conditions. He finds that the slow combustion of organic 
matter in the soil is, in many cases, almost independent of the amount 
of oxygen in the confined air, but that it varies considerably according 
to the temperature. Thus, at an average temperature of 24° C. (75° F.,) 
more carbonic acid was formed than at an average of 16° C., (60°.8 F.,) 
that formed in the latter case being not more than one-half the quantity 
produced in the former. 
The amount of oxygen in the confined air had but a slight effect in 
the formation of nitric acid, but it was found that the formation varied 
with different amounts of moisture in the soils, and that it was much 
more variable in dry than in very moist soils. For example, in the case 
of nearly dry soil the production of nitric acid varied from 95.7 to 
246.6 milligrams per kilogram of earth; while in the case of earth 
which had absorbed a maximum amount of moisture, (24 per cent.,) the 
production varied from 199 to 225 milligrams of nitric acid per kilogram 
of earth. 
In his experiments upon the reduction of nitrates in the soil, M. 
Schloesing’s results indicate that not one-fifth the amount of ammonia 
was formed which should have been produced from the nitrogen of the 
nitrates present, and he concludes, from the facts observed, that there is 
always a loss of nitrogen in the decomposition of organic matter, what- 
ever may be the cause. 
RESPIRATION BY SUBMERGED AQUATIC VEGETATION.—In experi- 
ments with regard to this subject by Schutzenberger and Qninquand, 
, upon yeast and Elodea canadensis, they found that the former showed no 
other phenomenon than that of absorption of oxygen with production of 
carbonic acid. The extent of this absorption is not affected by light, 
but varies considerably according to the temperature at which it takes 
place. At 10° ©. (50° F.) it is almost inappreciable; it increases until a 
temperature of 50° C. (122° F.) is reached, but at the temperature of 
60° C. it is entirely stopped. . 
Light seems to have no effect in the respiration of Hlodea canadensis, 
the absorption being the same in the Jight as in the dark, but it differs 
from yeast in that during the diurnal respiration it gives off free oxygen. 
Ifa large quantity of the plant be immersed in a tolerably small quantity 
of water, and submitted to direct sunlight for an hour or two, numerous 
bubbles of gas will be liberated, and a supersaturated liquid will be ob- 
tained which may contain as much as 20 cubic centimeters of oxygen 
per liter. The manner of absorption is the same for both plants, but in 
case of the Hlodea the absorption is about ten times less. ; 
EUCALYPTUS GLOBULUS, its use in improving the salubrity of marshy 
and malarial districts—The many very interesting accounts which have 
been published with regard to the Eucalyptus globulus do not seem to 
have exposed all of its values. And we find in Comptes Rendus of 
Oct. 6 a note presented to the French Academy of Sciences by M. Gim- 
bert, in which he describes another value equally as great as those with 
which all are so familiar. From reports received from various reliable 
sources, it seems to have been determined that in localities where the 
Eucalyptus flourishes there has been a complete disappearance of in- 
termittent fevers. ‘A tree,” says the author, ‘springing up with in- 
credible rapidity, capable of absorbing from the soil ten times its weight 
of water in twenty-four hours, and giving to the atmosphere antiseptic 
5A 
