The last operations to which the beer is subjected are those of cleansing, fining and krausening. The beer passes from the settling vats to the storage casks, in which it remains from three to four months, when, after another winding journey through miles of pipes, it emerges bright and clear and brilliant, only to be racked, that is to say, filled into kegs which go to the retailers. The same continuity of operations which we have witnessed on the floors above ground, is also observed in the three tiers of cellars, and the relation between the latter is almost as close as that between the former. We have already indicated the character of the connection which exists between the different kinds of tuns, vats and casks into which the beer is filled at different stages after the brew is completed. We have seen that fermentation takes place in open vats, and is regulated by attemperators, fed by the refrigerating plant and by means of powerful pumps. Formerly, another means of restraining fermentation, which was applied manually, was resorted to; it consisted of conical cans, called swimmers, which the brewer filled with ice and placed in the fermenting liquid, where they floated about and depressed the temperature. When the desired results of fermentation are secured, then, and not until then, is the wort transformed into beer but before it becomes fit for consumption, it must rest for a considerable length of time, to be then transferred to the storage casks, where the processes of fining and krausening take place. For the former process, chips or shavings are used, usually those gained from the beech-tree, by which the muddy particles, resulting from fermentation and still remaining in the beer, are attracted and held, leaving the bulk of the liquid clear and translucent. While this is going on, large quantities of carbonic-acid gas continually escape from the lager-casks, and, ultimately, in order to re-enliven the liquid, a second fermentation must be produced by adding one-fifth of a new beer to four-fifths of the old. This is done by means of pipes which convey the new beer through two tiers of cellars to the lager-casks.