Herewith is a sketch of a stopcock key and sounding tube combined, which can be made easily and at a small outlay. An instrument similar to sketch has been in use for more than thirteen years at a large waterworks in tin; South of England, and lias been found very valuable for the detection by sound of waste; by using this instrument at the surface considerable success has been met with in localising underground leaks. The letter references in the illustration are explained as follows. A, face of ear-piece; B, 1/4-in. brass tube slide, 18 in. long; C, socket packed between brass bush D and nipple; E, iron tee; P, stopcock cover hook, 3 1/2 in. long-, screwed to tit loosely for convenience; G, section of 1/4-in. iron barrel; H, soldered joint.

Instrument for Locating Leakage of Water.