Improved Method of Preserving Wines, &e. 65 



maximum height being regulated by the length of the 

 flexible tube attached thereto. 



It is of importance thus to limit the length of the tube, 

 for if the cistern be raised too high the hydrostatic pressure 

 might force out the bung, or burst the cask. A quantity of 

 clean water is put into the cistern, and the stopcock A is 

 opened, leaving free communication between the cistern and 

 the elastic sac in the interior of the cask. Any quantity 

 of liquid may now be drawn from the cask (limited, of 

 course, to the capacity of the sac under a given pressure), 

 and the cask will still remain full, that is, the space occu- 

 pied by the liquid so withdrawn is replaced by an equal 

 bulk of water in the interior of the sac. It will thus be 

 perceived that an} T loss by absorption, evaporation, con- 

 densation or any other cause, is simultaneously compensated 

 by hydrostatic pressure, and that the cellarman can at all 

 times, and with impunity, sample his wine without the use 

 of vent pegs or refilling the cask. 



As the elastic sac has necessarily a capacity less than that 

 of the cask itself, it occurred to me, when thinking over the 

 subject, that in wine-making establishments it would be 

 necessary to have the power of discharging the water and 

 filling up the cask without removing the bung, leaving the 

 whole apparatus ready for action de novo. 



This can readily be done, simply and effectively, also by 

 hydrostatic pressure, and for this purpose the stopcock 

 marked B, a small funnel, and a piece of elastic tube, are 

 necessary, the action being as follows : — 



Remove the cistern from its elevation and place it upon 

 the cask itself; attach the flexible tube with funnel at the 

 other end to the stopcock B, raise the funnel to the extent 

 that the length of the tube will allow, and pour the required 

 liquid into the funnel. The result is, that the water 

 contained in the sac is expelled by hydrostatic pressure into 

 the cistern again, the sac itself collapses and leaves room for 

 the liquid so poured in. The cistern can then be replaced, 

 and no further attention will be required till the cask 

 requires to be refilled, when the same operation may be 

 repeated. 



The elasticity and capacity of the bag, before use, is 

 ascertained by the hydrostatic pressure ; and the knowledge 

 of this capacity will enable the cellarman to determine what 

 quantity is required to fill up the cask, the time for doing 

 so being indicated by the cask itself, as when the bag is 



