182 



DISCOVERY REPORTS 



The apparatus (Fig. 3) consists of a tank a into which three tubes, b, c and d, pass 

 from below. The tube c passes into an inner receptacle, the walls of which are not as 

 high as those of the tank. Tube b is the water-supply pipe, tube c the waste pipe, and 

 tube d the delivery tube. The delivery tube d is 

 connected to a down tube/. The down tube /is 

 connected to a T-piece which in turn is con- 

 nected to a tube which passes through a hole in 

 bung j of receptacle i by a short length of tube 

 and two rubber junctions. The upper rubber 

 junction carries a screw clip e with a large knurled 

 head, and the lower one carries a spring clip h. 

 The side limb of the T-piece is joined to the gauge 

 tube g, which is bent through a right angle to 

 bring it vertical. The bung/ of receptacle i has 

 two holes, to one of which is connected down- 

 tube/, as described above, while to the other is 

 connected the levigator tube n by means of a 

 short length of tube and a rubber junction. At 

 its upper end the levigator tube n is joined to the 

 levigator funnel / by means of a rubber junction 

 bearing a spring clip. The rubber junctions at 

 the upper and lower ends of the levigator tube 

 are of the same internal diameter as the tube. 

 The levigator funnel / has a very short tube, of 

 the same diameter as the levigator tube, and 

 a wide tube passes from the side of the upper 

 part of it. A wide-mouthed funnel m is fixed 

 below the outlet of the side tube. The apparatus 

 is levelled so that the tubes are vertical. 



-g 



f- 



Method of use 

 When the water is turned on at the supply 

 pipe b the water rises in the tank to the level of 

 the top of the walls of the inner receptacle. The 

 excess water overflows into the inner receptacle 

 and is conducted away by waste pipe c. A con- 

 stant head of water free from the irregularities 

 of pressure of the supply is thus maintained above the delivery tube d. The water 

 flows down the tube/ into the receptacle i, rises up tubes g and n and fills the funnel /, 

 overflowing through tube o into funnel m. By means of the screw clip e the amount of 

 water passing through the apparatus is regulated until the rate of flow in the levigator 

 tube n is 7 mm. per second. The tubing used in this investigation was 8 mm. in 



Fig. 3. Levigator. a, tank; b, supply tube; 

 c, waste tube; d, delivery tube; e, screw clip; 

 /, down tube; §, gauge tube; h, spring clip; 

 /, lower receptacle; /, bung; k, spring clip; 

 /, levigator funnel; m, wide-mouthed funnel; 

 n, levigator tube; o, side tube; s, removable 

 septum. 



