FERMENTED AND DISTILLED LIQUOKS. 95 



15. DETERMINATION OF CARBON DIOXID. 



(a) BOTTLED GOODS. 



Pierce the cork with a champagne tap. a Connect with a suitable absorption appa- 

 ratus, placing an Erlenmeyer flask between the bottle and absorption tubes to allow 

 the bubbles to break and prevent them from passing beyond it. The accompanying 

 illustration (fig. 3) of an apparatus devised by Crampton and Trescot b answers admi- 

 rably for this purpose. Immerse the bottle in water in a suitable vessel such as an 

 ether can with the top cut away, as shown in the cut allow the gas to escape slowly, 

 and when it ceases to flow spontaneously heat gradually to about 80 C. and maintain 

 this temperature for about half an hour, shaking the bottle from time to time. Then 

 disconnect the bottle, replace it with a soda-lime tube and draw a current of air 

 through the apparatus. The increase in weight of the absorption tube gives the 

 amount of carbon dioxid. The volume of beer employed is also weighed or 

 measured. 



FIG 3. Apparatus for the determination of carbon dioxid. 



When the bottle containing the sample is closed with a patent stopper, the latter 

 may sometimes be replaced by a rubber stopper fitted with stopcock tube. Where 

 the pressure is so great that this is not practicable, such samples may be treated as 

 directed under "Bulk Goods." 



(b) BULK GOODS. 



Close a round-bottom flask of about 700-cc capacity with a two-hole rubber stop- 

 per fitted with two stopcock tubes bent at right angles one passing to the bottom 

 of the flask and the other ending just below the stopper. c Produce a partial vacuum 

 in the flask by means of an aspirator, and weigh the flask. Dip the end of one of 

 the stopcock tubes below the surface of the beer, or, better, attach it by means of 

 a rubber tube to a champagne tap or small faucet screwed into the cask, and 

 allow about 300 cc of the sample to enter the flask. Weigh the flask and contents, 

 and proceed as directed under "Bottled Goods." Somewhat better results may be 



Hassall, Food Adulteration S. & C. Used by Wiley (Am. Chem. .Jour., ISSti, 8, 200) in the examina- 

 tion of koumiss, and by Crampton in the examination of beer. Crainpton found.it necessary to 

 reurind the cocks and ream off the thread, leaving a smooth tube. U. S. Dept. of Agr., Div. of Chem., 

 Ilul. i:i, pt. 3, p. 294. 



' T. S. Dept. of Atfr., Div. of Chem., Bui. 13, pt. 3, p. 293. 



'Windisoh ( Das chemische Laboratorium des Brauers, p. 247), employs ordinary glass tubes pro- 

 vided with rubber tubing and screw cocks. 



