SIR WILLIAM SIEMENS, F.R.S. 281 



successful results obtained by this meter, which the writer had not 

 even an opportunity to adjust previous to its official trial, were 

 t linught strong proofs in favour of the principle involved. He was 

 indebted for the admirable first execution of his idea, and some 

 valuable suggestions, to his brothers at Berlin. 



In attempting, however, to put the meter into regular service, 

 under a working pressure of upwards of 200 feet column of water, 

 subject to violent concussions, and acted upon by mechanical 

 as well as chemical impurities in the water, he, and the spirited 

 manufacturers, Messrs. Guest and Chrimes, of Rotherham, had had 

 to encounter many serious difficulties, which had to be dealt with 

 one after another, but which finally determined them to adopt for 

 smaller meters the more simple arrangement of a spiral curve, or 

 Barker's mill. 



The two arrangements now actually adopted are shown in Plates 

 25, 2G, and 27. Plate 25 shows a double screw, or balance meter 

 capable of measuring 100,000 gallons per hour, or above two 

 million gallons per day. 



Fig. 3, Plate 25, is a sectional elevation of the meter ; and Fig. 4, 

 Plate 26, is a transverse section through one of the screw propellers. 



This meter consists of a cylindrical casing A, which is lined 

 throughout with a brass tube drawn to a precise gauge, and is con- 

 nected by its flanges B B to a line of piping of 8 or 9 inches in 

 diameter. 



The measuring apparatus contained in this casing consists of 

 two hollow drums E E, carrying on their circumference, the one a 

 set of right-handed, and the other a set of left-handed screw 

 blades ; of the conical blocks H H, armed with radial projections or 

 guide-blades K K ; a central bracket L, containing support for the 

 bevel wheels N N, on upright spindles, and the wheels M M, on 

 the horizontal spindles of the screw drums ; also two double in- 

 verted cones at contractions R R, and a grating P, at one end 

 only. 



The spindle of the wheel N passes upward through the hollow 

 arm of the central bracket L, into a close chamber F, carrying 

 an endless screw U, which is geared to a pair of reducing 

 wheels V Y. 



The spindle of the latter wheel is ground air-tight into a socket 

 of the strong metallic plate T, and passes into the upper chamber 



