76 



SCIENTIFIC AMUSEMENTS. 



it is effervescing pour the liquid into the cylinder so as to fill it 

 one-third or one-quarter full; or similarly, partly fill it from a 

 siphon. The carbon dioxide gas escaping from the solution will 

 displace the air from the upper part of the cylinder, so that by 

 lowering into it a lighted taper tied to a wire or string as in fig. 

 41, the light will be extinguished, because carbonic acid gas does 

 not possess the power of keeping up the chemical actions 

 effected by the air during the process of burning. 



Bottled beer, zoedone, champagne, sparkling Moselle, 

 aerated lemonade, and similar effervescing drinks, evolve 

 gas on being poured out, for exactly the same reason as 

 soda-water; they all consist of fluids (mostly water con- 

 taining more or less alcohol, sugar, and flavouring matters, 

 &c., dissolved therein), in which more carbon dioxide is 

 also dissolved under pressure in the bottle than the liquid 

 can retain dissolved when the pressure is relieved by un- 

 corking. In the case of many such liquids the aeration is 

 artificially conducted in a machine similar to that used for 

 soda-water ; and much inferior or spurious sparkling wine 

 Fig. 41. - g | 1US manu f ac tured. Genuine champagne, like bottled 

 ' beer, on the other hand, becomes impregnated with gas in 

 virtue of chemical changes (fermentation, Expt. 189) going on 

 inside the bottle after the liquid has been introduced and the 

 bottle securely corked up, no aerating machine at all being used ; 

 but the end result is the same so far as producing an effervescent 

 fluid is concerned. 



Expt. 72. To make Aerated Water for Home Use. An 



instrument called a 

 " gasogene " is often 

 employed for the 

 production of ae- 

 rated water in small 

 quantities for table 

 purposes (fig. 42). 

 This consists of a 

 large hour - glass 

 shaped vessel of 

 thick glass with a 

 piece of wide por- 

 celain or glass tubing 

 cemented into the 

 narrow part joining 



lig. 42. Gasogene. 



the two bulbs, A and B, in such a way that liquid will stand 

 in the upper bulb without running down into the lower one. 



