290 THE SCIENTIFIC PAPERS OF 



water flowing through pipes, with a sufficient degree of accuracy 

 for practical purposes, and without destroying the pressure or head 

 of water column. In the course of considerable experience with 

 these meters, several important improvements have suggested 

 themselves, and opportunities have occurred of observing the 

 public importance of supplying water by meters, which the writer 

 thinks may not be without interest to the members of this 

 Institution. 



The chief difficulty that presented itself in endeavouring to 

 produce a practically perfect high pressure meter was not so much 

 to obtain a correct measurement under varying circumstances of 

 pressure, as to render the instrument sufficiently durable to resist 

 for years the action of the water and of the impurities carried 

 along with it. It was found necessary to protect all the working 

 parts against the chemical action of the water, to prevent deposit 

 of calcareous matter upon the measuring apparatus, and to com- 

 bine strength with lightness as far as possible in the construction 

 of the movable parts, in order that they might resist the force of 

 a high water column, and might yet be moved by the slender 

 stream produced by a leaky tap, which in the case of the smaller 

 meters may not exceed half a pint of water passing through per 

 minute. Cheapness and compactness of construction were other 

 important considerations not to be lost sight of. 



The improved meter, as at present manufactured by Messrs. 

 Guest and Chrimes, is- represented one quarter full size in Plate 28, 

 Figs. 1, 2 and 3. 



The meter consists of a cast-iron casing A, Fig. 1, divided by a 

 partition into two compartments B and C. The water entering 

 the compartment B through the pipe I) passes through a spout E 

 into the revolving drum F. The drum F, shown in the perspec- 

 tive view, Fig. 2, and the plan, Fig. 3, is formed of two stamped 

 disks of brass plate riveted and soldered together face to face, 

 each part containing similar spiral grooves or corrugations form- 

 ing channels for the water to pass from the centre to the cir- 

 cumference. The foot of the spindle G forms with the lower 

 portion of the drum a chamber H, into which enters a fixed stud 

 J. The point of the stud is of hard steel, and works in contact 

 with a bit of hardened steel let into the bottom of the spindle G-, 

 forming a support for the drum F. The chamber H is filled with 



