Agricultural chemistry / [George Cox].

Cox, George

Date:: 1844

Credit: Agricultural chemistry / [George Cox]. Source: Wellcome Collection.

25/158 page 13

$The true cause is the assimilation, by the vegetable of the carbon of the carbonic acid, and the consequent liberation of its oxygen. For every volume of carbonic acid thus received, the atmosphere regains an equal volume of oxygen. That plants possess the power of decomposing carbonic acid, may be proved in the most easy manner. The leaves, and other green parts of plants, possess this property, independently of the plant itself, for if, after being separated from the stem, they are placed in a bell jar of water, containing carbonic acid, and exposed in that condition to the sun’s light, oxygen gas is emitted, and the carbonic acid disappears. Plants thus improve the air by the removal of carbonic acid, and the renewal of oxygen, which is immediately applied to the use of man and animals. Thus vegetable culture heightens the healthy state of a country so that a previously healthy country would be rendered quite uninhabitable, by the cessation of its cultivation.5' These changes take place only during the presence of solar light. At night the assimilation of carbon, and the liberation cf oxygen, ceases. Without the presence of light, vegetable organization has not the power to decompose carbonic acid. HYDROGEN. Hydrogen, when uncombined with other matter, always exists in the gaseous state. It is colourless, tasteless, and inodorous, a powerful refractor of light, and is the lightest body in nature. It is neither acid nor alkaline, and water dissolves only$

Agricultural chemistry / [George Cox].

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