114 
Report on the Trials of Sheaf-Binders 
This valve is an improvement on one introduced by Mr. Webb on the 
London and North-Western Railway, and fully described by him in the ' Pro- 
ceedings ' of the Institution of Mechanical Engineers. 
The general appearance of the valve will be understood by the following 
drawings, which have been supplied by Messrs. Fowler themselves. For the 
description I am indebted to Mr. Anderson. 
Fig. 18. — Cross-Section of CliurcJia Valve. 
ii 
Fig. 19. — Plan-Section of ChurcTis Valve. 
The valve is circular, in plan like a cheese, and is free to revolve in 
the bridle a a, by which it is moved backwards and forwards like an 
ordinary slide valve. The ports of the cylinder are segmental, so as to 
coincide with the circular edges of the valve. The effect of this arrangement 
is that, if there is the least inequality of friction between the valve and 
