Page:A Practical Treatise on Brewing (4th ed.).djvu/50

34 have inquired into the cause, or adopted means to prevent this atmospheric, or other action, affecting beer during thunder-storms, or in the different electric states of the earth and atmosphere. The extreme rapidity with which the electricity is evolved during a thunder-storm, is strikingly exhibited in a distiller’s fermenting back. These fermenting backs are often made of cast iron, and either fixed in the earth, or connected with it by an intermediate iron vessel, employed in regulating the temperature. A very short time after a thunder-storm begins, or when the atmosphere is highly charged with electric matter, the appearance in the back altogether changes. The usual healthy character of the fermentation disappears; and it is now attended with a hissing noise and frothy head: and when samples are drawn and examined, is found to have risen, instead of fallen in gravity many degrees, and to contain 5 per cent. or more, of acid. Under these circumstances, the distiller has no alternative but to run off his wash into the stills, although they may be as high as 10 or 12 degrees above water, or occasionally of much higher gravity.

“But the chemical agency exercised by a highly electrical state of the atmosphere, is not conﬁned solely to the fermentation of vegetable substances; it affects even the smelting of iron. It is well known to iron-masters and smelters, that in certain conditions of the atmosphere, and particularly