DISTILLATION 



analyser in at the bottom of the lower compartment of the rectifier. Here it ascends 

 in a similar way, bubbling through the descending wash, until it arrives at F, above 

 which it merely circulates round the earlier windings of the wash pipe, the low tem- 

 perature of which condenses the spirit, which, collecting on the shelf at r, flows off 

 by the tube into the finished spirit condenser. 



In order still further to 

 economise heat, the water for 

 supplying the boiler is made 

 to pass through a long coil 

 of pipe, immersed in boiling 

 hot spent wash, by which 

 means its temperature is 

 raised before it enters the 

 boiler. In fact, the saving 

 of fuel by the employment of 

 this still is so great, that 

 only about three-fourths of 

 the quantity is consumed 

 that would be requisite for 

 distilling any given quantity 

 of alcohol in the ordinary 

 still ; and Dr. Muspratt esti- 

 mates that in this way a sav- 

 ing will be effected through- 

 out the kingdom of no less 

 than 140,000 tons of coal per 

 annum. 



Very few persons have any 

 idea of the enormous size of 

 some of the distilleries. One 

 of Mr. Coffey's stills at In- 

 verkeithing works off 2,000 

 gallons of wash per hour, 

 and one, more recently erected 

 at Leith, upwards of 3,000 

 gallons. 



Derosne's Stttlis very simi- 

 lar, in the principle of its 

 action, to Coffey's, differing 

 in fact only in the mecha- 

 nical details by means of 

 which the result is obtained. 



It consists of two stills, A 

 and B, Jiff. 625. The mixture 

 of steam and alcohol vapour 

 from A passes into the liquid in B, which it raises to the boiling point. The vapours 



626 



from B rise through the distillatory column c, and D (the rectificatory column) ; hence 

 they traverse the coils of tubing in E (the condenser and wine-heater}, and the alcohol 



