Miscellanies. 155 
13th. Again, vegetables, under certain circumstances, decompose 
carbonic acid, and restore oxygen to the atmosphere, but this is de- 
pendent not upon the respiratory but the digestive system ; it arises 
in part from the decomposition of water, but chiefly from the de- 
composition of carbonic acid, absorbed either in the form of gas, or 
_in combination with water either by the roots, or leaves, or both. — Its 
analogy to animal digestion is obvious, for to both plants and animals, 
carbonic acid, though deleterious when breathed, is invigorating to the 
digestive system when absorbed as food.—Idem. 
8. Ammonia in native oxide of tron.—( Ann. de Chimie, t. xlii, 
p- 334.)—In the mine of Cumba, near Marmato, a large vein of 
bydrated oxide of iron, in syenitic porphyry, is worked as a gold ore. 
In a part of this mine, called por a fuera, where the work proceeds 
with activity, about a foot of mineral was broken down at the end of 
the excavation, so as to expose a fresh surface, and then a hole was 
bored in the very middle of the vein; after being carried eight inches 
deep, the powder of the ore was collected carefully in a basin, placed 
under the hole, and touched by nothing but the.tool. Four ounces 
of this ore were then bruised and rubbed in distilled water, the fil- 
tered liquor was acidified by muriatic acid and evaporated ; it left 
fifteen grains of residue, which being introduced into a glass tube 
with a piece of quick lime slightly moistened, and heated, gave am- 
monia, sensible not only to test papers, but also by its strong odor. 
ence it results, as M. Chevalier has stated, that the natural oxides 
of iron contain ammonia, and this fact, conjoined with that of Austin, 
that ammonia is formed by the oxidation of iron in contact with air and 
Water, acquires a certain degree of geological importance. —Jdem. 
9. Salicine—(Leroux, Ann. de Chim.)—This substance is in the 
form of very fine nacreous white crystals, very soluble in water and 
‘leohol, but notin ether ; it is very bitter and partakes of the odor 
of willow bark. In order to obtain it, three pounds of the bark of 
the willow, (Salix Helix,) dried and pulverized, are to be boiled in 
fifteen pounds of water, with four ounces of carbonate of potash, for 
0 hour ; it.is to be filtered, and when cold, two pounds of solution 
of Sub-acetate of lead added: when settled, it is to be filtered, treated 
With sulphuric acid, the rest of the lead precipitated by sulphuretted 
hydrogen, the excess of acid neutralized by carbonate of lime, again 
filtered, the liquid concentrated and saturated by dilute sulphuric acid, 
