46 SCIENTIFIC AMUSEMENTS. 



storing it in tanks, this method of obtaining drinkable water from 

 sea-water or saline springs is of considerable importance. 



In default of any other apparatus, distilled water may be obtained 

 from impure or saline water by the aid of an ordinary kettle ; this 

 should be tilted slightly so as to bring the spout to a little higher 

 elevation, and the lid made as tight as possible by means of a little 

 clay or putty ; a piece of clean " Compo " or other metal tubing 

 should be fixed to the spout by jamming a cork therein, the central 

 part of which has been cut away so as to allow the tube just to 

 pass through. The tube should be cooled as far as possible by 

 wet cloths, &c., to promote the condensation of the steam. 



Expt. 38. To Extract Spirit from Wine or Beer. The chief 

 intoxicating ingredient in fermented liquors is the substance termed 

 alcohol, present in such fluids to very varying extents, according to 

 their nature and quality, but usually to the extent of from 3 to 6 

 per cent, or more in ordinary beer, and somewhat larger propor- 

 tions in wines, especially the stronger ones like port and sherry. 

 Ordinary home-made gingerbeer, prepared by means of yeast from 

 sugar, water, lemon-juice, ginger, &c. (Expt. 190), contains quite 

 enough alcohol to be quite as exhilarating a beverage as many kinds 

 of light ale. From any of these fluids weak alcohol may be ex- 

 tracted by distilling in a retort or larger vessel according to the 

 quantity of liquid available. When the boiling has been continued 

 so long that the distilled fluid measures one-fourth to one-third as 

 much as the liquid originally employed, practically all the alcohol 

 present has passed over along with some water ; the reason being 

 that alcohol has a lower boiling-point and is more easily vaporised 

 than water, so that when a mixture of the two is boiled the steam 

 coming off contains more alcohol-vapour relatively to the water- 

 vapour, and therefore yields on condensation a liquor stronger in 

 spirit than the original fluid. By this treatment all solid matters 

 present in the beer, &c., used are left behind in the still; by 

 repeating the distillation and collecting the first third that distils 

 a much stronger spirit is obtained, practically all the alcohol 

 originally present being thus concentrated into perhaps one-tenth 

 of the original bulk. 



Ordinary spirits, whisky, gin, rum, brandy, &c., are prepared in 

 very similar fashion, the flavour depending on the nature of the 

 fermentable matters used to produce the weak spirit in the first 

 place, and on the kind of flavouring materials (juniper berries, 

 &c.) used in certain stages of the process subsequently. 



Expt. 39. To make Anhydrous Alcohol. It is impossible to 

 bring about a complete separation of water and alcohol by distilla- 

 tion alone, the strongest spirit thus obtainable always containing a 



