RAIR.D &TM1OCK (LONDON) LTD. 



Before commencing operations it is well to slightly moisten the rubber sheet (D) with water. This is not by 

 y means absolutely necessary, but causes a quicker gripping of bell-jar and rubber. The tap being in position 

 i. 2, and connected with a water-pump in full action, filtering is commenced by first filling up the filter nearly full 

 tli the liquid to be filtered, and then establishing communication between the pump and the bell-jar by turning 

 e tap to position No. i. During the operation of transferring the precipitate on to the filter it is often necessary 

 lessen the rate of filtration by diminishing or destroying the difference of pressure outside and inside of the bell- 

 i This can be quickly and easily done by giving the tap a half turn back to position No. 2, and thus allowing 

 r to rush in both to the pump and to the bell-jar. The use of the knee-piece (H) will be now apparent, for by it 

 r inrush of air is diverted away from the vessel inside, which might otherwise be blown against the side of the 

 11-jar and upset or broken. As it is, however, the vessel inside is not at all affected by the inrush of air, however 

 ddenly the tap be opened. 



2712 



712 Filter Drainers, German Porcelain. 



Diameter . . . . 10 



Price .. .. 7d. 



..6/6 



713 Soxhlet's Filter Tube, for use with asbestos 



2713 



12 



10d. 

 9/6 



14 

 1/6 



171- 



15 

 1/10 



21/- 



17 

 2/9 



32/- 



2714 



20 centimetres. 

 3/3 each. 

 37/- per doz. 



each 006 



714 Filtering Tubes, stoppered, with perforated bottoms, for reducing and weighing the 

 Cu 2 in sugar estimations . . . . . . . . . . . . each 



1 9 



2715A 



2715s 



2715c 



7 15 Glass Flasks, of best-quality Bohemian Glass, well annealed. (Forms A, B, and C same price.) 

 Capacity 

 Price 



Capacity 

 Price 



Form A. 



B. 



C. 



Bulb-shape turned-over necks. All sizes listed kept in stock. 



Welted necks. Sizes up to 2 litres only kept in stock. 



Round bottoms, turned-over necks. Sizes up to 2 litres only kept in stock. 



'CHEMICAL AND SCIENTIFIC APPARATUS AND PURE CHEMICALS- 



527 



