Page:A Practical Treatise on Brewing (4th ed.).djvu/237

Rh and other chemical processes, when no thunder-storms occur. For instance, it has been noticed by many intelligent brewers, that their fermentations are more brisk during frost than they are during soft and warm weather, though in the latter case we might expect them to be rendered more active by the concurrence of a higher temperature. Bakers have observed similarly active states of the fermentation of their dough during frosty weather, while in soft and warm weather their fermentations are sometimes dull, and their bread apt to become sour.

It has been noticed both by bakers and brewers, that their fermentations are brisk during high winds, and more especially during high winds from the east and north, when no change of temperature appears to be concerned. Many variations in chemical actions obviously take place, when no alteration of the temperature or other sensible qualities of the surrounding atmosphere can be observed, by which they might be produced. We are consequently inclined to think, that changes take place in the electrical states of the earth and air, not manifested to us by the phenomena of thunder and lightning, by which variations may be produced in chemical actions, and probably, chemical affinities brought into play, which might remain quiescent without their agency.