1870.) Beer, Scientifically and Socially Considered. 311 



Plate, and above and between the rows runs a long tank, in which 

 the superfluous yeast is collected. This is done by means of a 

 " swan-neck " pipe, a syphon acting inversely, and the arrangement 

 will be understood from the following woodcut (Fig. 10), where a 



Fig. 10. 



is one of the barrels containing the incompletely fermented beer, 

 b the swan-neck, c a portion of the long tank or receptacle for the 

 yeast (Fig. 10). The latter continues to rise slowly whilst the 

 beer remains in the barrel, being carried upwards (as during active 

 fermentation) by the escaping carbonic acid gas, and having risen 

 into the " swan-neck," it may be seen slowly bubbling over into the 

 tank. The temperature of the beer during this process is regulated 

 by a flow of water through an ingeniously contrived tubular 

 apparatus, which can be inserted into or withdrawn at pleasure from 

 the barrel, through an oblong aperture in front (see Fig. 10) ; and 

 when the beer is cleared of the remaining impurities it is drawn off 

 by boys who creep underneath the barrels and open a tap attached 

 to a pipe, first into large vats and then into casks for sale. 

 The object of allowing the barrels in which fermentation is com- 

 pleted to revolve, is simply that they may be cleansed after each 

 operation. 



It has, of course, been impossible for me within the short limits 

 of an essay, professing to deal with the social as well as the scientific 

 aspects of this question, to describe fully either the principles or 

 practice of brewing ; but I hope enough has been said to convey to 

 the reader a fair idea of both : and there now remain to be con- 



