Page:A Practical Treatise on Brewing (4th ed.).djvu/71

Rh used in excess; iron is, therefore, the safest metal to use in the brewery, where metals cannot be dispensed with.

Copper, or zinc coolers, have lately been occasionally tried, but were found so injurious as to be very soon abandoned. Even iron coolers, although quite safe in some respects, will not be found so free from objection as the old wooden ones, when these are kept in good order. Perhaps slate coolers might be preferable to any if they could be kept quite tight. They could be easily cleaned, and liquids get much sooner cool, on account of the difference in the radiation of heat, when exposed in vessels having black than they do in those with white surfaces.

This was exemplified many years ago in Glasgow, during what was called the teapot war, which occurred during the residence of my friend the late Dr. Birkbeck there. Black porcelain teapots had then been lately introduced there, and were getting into use. The ladies, however, declared that their tea when made in these was by no means so good as formerly, and strongly objected to them on that account. The gentlemen ridiculed the idea, that it could make any difference in the tea whether it was made in a white or a black teapot. The ladies, however, stuck to their point, and the dispute ran so high that Dr. Birkbeck was appealed to on the subject; he, after due examination, gave it in