LXII. W. E. COOK. 



cross breaking or permeability be unsatisfactory, the superintend- 

 ing officer may reject as many pipes, bends, junctions, etc., as 

 may, in his opinion, be of inferior quality. 



Adelaide. — In Adelaide, the pipes are examined for uniformity 

 and quality of burning and glazing. Every pipe is then tested 

 by passing a dummy into, and a ring over it. Every pipe is then 

 tested with an internal hydrostatic pressure, equal to a column of 

 water 28 feet high, and while under this pressure is struck 

 repeatedly with a wooden mallet. A pipe showing signs of 

 sweating or leakage is rejected. 



After the foregoing tests, the pipes may be tested for strength 

 to resist crushing, and for permeability. In practice the pipes 

 proved so very satisfactory that the latter tests were generally 

 omitted. 



About one per cent, only failed to pass the whole of the tests 

 imposed. 



Wellington. — In Wellington, N.Z., the pipes were tested: — 

 (1) For shape; (2) For uniformity and quality of burning, glazing, 

 etc. ; (3) Under hydrostatic pressure, equal to a column of water 

 25 feet high, while being struck with a wooden mallet ; (4) For 

 crushing, and must stand pressure of 100 ft>s. per square inch, 

 applied at centre of pipe ; (5) For porosity, and must not increase 

 more than 2 per cent, in weight after 24 hours immersion. 



The pipes were not tested to destruction, but many of them 

 were tested up to 60 lbs. per square inch internal pressure without 

 showing any defects. 



In Melbourne, Adelaide, and Wellington the constructing 

 authorities let crntracts for the supply and delivery of all pipes 

 at central depots, where every pipe was tested. The Sydney 

 practice has been to test pipes supplied for each particular 

 contract. 



For the purpose of comparison, the average results of sixteen 

 tests of 2 feet 5 inches x 1 foot 9 inches oviform Monier pipes for 

 sewer construction are added. The area of cross section is equal 



