Chemistry and Physics. 425 
‘band ‘7 of a cub. cent., in two others, 4 and 5 cub. cent.; this gas, 
however, was not nitrogen, for it was inflammable. This result shows 
that caution should be exercised in the determination of nitrogen, and 
that both carbon and hydrogen may escape combustion and create a 
loss, falling of course mainly upon t n. G. C. 8. 
O 
pure protoxyd of nitrogen. For the sake of comparison, seeds were 
Plants of the cress were then introduced into the gas; on the third 
day they became yellow, and at the end of a week they drooped. 
_ Brought into the air, they resumed in a few days their green color and 
erect position. 
_ From these experiments, the author concludes that the protoxyd of 
nitrogen favors neither the germination of seeds, nor the vegetation of 
plants already forward, that the gas is not decomposed by the leaves, 
even under the direct rays of the sun, and that seeds do not lose their 
vitality by a short exposure to its influence. ~ oe 
These conclusions are true for the pure gas, but it by no means is to 
be inferred that the gas is altogether unfavorable to vegetation; we are 
persuaded that the contrary will be found true. In a similar manner, 
Braconnot, not long since, demonstrated that salt was injurious to vege- 
tation: plants coated with a tolerably strong solution of salt, withered 
and died; ergo, salt was injurious ! C8. 
10. On the Volatile Oils of the Crucifere ; by F. PuEss, (Liebig’s 
Annalen, lviii, p. 86.) —The leaves and seeds of the aspt arvense 
yield, by distillation with water, a volatile oil, which, on examination, 
Proves to be a mixture of oil of mustard and oil of garlic. This oil 
dges not preéxist in the plant. ince, Let 
The leaves and seeds of Alliaria officinalis give a similar mixture 
of these two oils, although the oil of garlic is sometimes absent. 
» The oil of mustard alone is formed from the leaves of Iberis amara, 
and in very small quantity from the seeds of Capsella bursa-pastoris, 
(shepherd’s purse,) Raphanus raphanistrum, (charlock,) and. Sisym- 
oC sire, % a Z 
The same reaction is observed with the roots and seeds of the radish, 
and the seeds of the Brassica napus, Cochlearia draba and Cheiranthus 
annuus, (stock jilly.) sire ABLE My 
Jl. On the Oil of Monarda; by A. E. Anrrs, (Liebig’s Annalen, 
viii, - 41.)—This ‘oil, the product of the Monarda punctata, (horse- 
Mint,) was brought from the United States. It consists of a fluid oil 
andastearoptene. The former is a yellowish-red fluid, with the odor 
Srconp Serizs, Vol. Il], No. 9.—May, 1847. 54 
