i8 



PROC. COTTESWOLD CLUB 



VOL. XIII. 



are unavailing, and it is only the circumstance that 

 rendered possible the construction of a tunnel that has 

 virtually opened the way for dealing with the whole bed 

 of the ravine ai)Ove its level. 



The process of working is this : — Gravel is forced into 

 the current of the river cither bv hydraulicking, sluicing, 

 or simple manual labour, and so carried on through the 

 tunnel ; and all, or nearly all, the gold it contains is 

 arrested in its passage along the bottom of the tunnel- 

 flume. This flume is specially constructed for this 

 purpose, and figures 2, 3, 4 show its elevation, plan, and 

 section. It is built of great strength, but not in the least 



il-^-- 



-d -d 



Fig. 1. — A flume. Htcvation. 



too strong, when it is considered that all the material 

 treated — sand, gravel, and boulders, many of the latter 

 weighing much over a ton, must be hurled along the 

 flume with enormous force and thrown out into the 

 stream at the lower outfall. The framework of the flume 

 is constructed in exactly the same way as any ordinary 



