CHAMBER LAND'S FILTER. 



75 



flask b and passes through one of the two perforations 

 with which the rubber stopper of the flask is furnished. 

 Through the other opening a similar tube proceeds to the 

 exhaust -pump. When the latter is put into action the 

 filtrate is sucked through the porcelain and passes over into 

 flask b. This apparatus is very good, but not suitable for 

 small quantities of fluid. 



(b) A very good apparatus can be arranged with a lamp 

 funnel and the porcelain bougie. These may be fitted up in 



FIG. 29. Chamberland's 

 bougie arranged with lamp funnel 

 for filtering a small quantity of 

 fluid. 



FiG. 30. 

 Bougie inserted 

 through rubber 

 stopper for same 

 purpose as in 

 Fig. 29. 



two ways, (i) An india-rubber washer is placed round the 

 bougie c at its glazed end (vide Fig. 29). On this the narrow 

 end of the funnel d, which must, of course, be of an appropri- 

 ate size, rests. A broad band of sheet rubber is then wrapped 

 round the lower end of the funnel, and the projecting part 

 of the bougie. It is firmly wired to the funnel above and 

 to the bougie below. The extreme point of the latter is 

 left exposed, and the whole apparatus, being supported on 

 a stand, is connected by a glass tube with the lateral tube 

 of the flask b ; the tube a is connected with the exhaust- 



