Page:A Treatise on the Culture of the Vine and, and the Art of Making Wine.pdf/192

 the grapes with a tube, the surface of which he had freed from all globules of air, by agitation in the mercurial bath. To whatever degree the heat was raised, the must underwent no fermentation; but, while the heat was between 70° and 75°, he introduced some bubbles of oxygen gas, and in a few minutes, the fermentation was established to such a degree, that the bell was filled with carbonic acid.

It follows, from this fine experiment, that the first movement of fermentation is determined by the air, and that afterwards it continues without the aid of this external agent. The contact of some bubbles of air, determines a first combination of its oxygen with carbon; from that moment, the equilibrium among the constituent principles of the must is destroyed; their combination is imperfect, and nature is employed in forming new ones from them.

The air is, then, the first ferment which commences the decomposition of the must; the reaction of its constituent principles gives birth to new compounds, which change its primitive nature.

The air of the atmosphere being then only necessary till the commencement of fermentation, if it is advantageous to establish a free communication between it and the must, it is that garous substances which are formed during fermentation