BKKK. 



93 



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

 accompanying illustration (fig. 2) of an apparatus devised by Crampton and 

 Trescot answers admirably 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 weigflt of the absorption tube gives the amount of carbon dioxid. 

 The beer employed is finally either weighed or measured. 



When the bottle is closed with a patent stopper, the latter may sometimes be 

 replaced by a rubber stopper fitted with a stopcock tube. Where the pressure 



FIG. 2. Apparatus for the determination of carbon dioxid in beer. ' 



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

 below under " Bulk Goods." 



(b) BULK GOODS. 



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

 stopper 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. & 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 cf the sample to enter the flask. Weigh 

 the flask and contents, and proceed as directed under " Bottled Goods." Some- 

 what better results may be obtained by placing a reflux condenser between the 

 flask and absorption apparatus, and heating the flask over a burner to the boil- 

 ing point. Attach the stopcock tube to a soda-lime guard tube and pass a cur- 

 rent of air through the apparatus. The amount of carbon dioxid is ascertained 

 by the increase in weight of the absorption tube. 



U. S. Dept. Agr., Division of Chemistry, Bui. 13, pt. 3, p. 293. 



B Windisch (Das chemische Laboratorium des Brauers, p. 247) employs ordinary glass 

 tubes provided with rubber tubing and screw cocks. 



