We are indebted to Mr. J. M. Hazen, Assistant Plumbing Inspector at Minneapolis, Minn., for a blueprint of an apparatus he has designed for testing soil and waste pipes, from which the following illustration is made. Mr. Hazen describes his apparatus and his method of making a test as follows:

To prepare new work for this test, all the iron soil and ventilation pipes must be roughed in, running trap and fresh-air inlet included. If the water-closets have a trap, then calk in a 4-inch lead bend; otherwise, calk in the lead trap and solder a piece of heavy sheet lead over the top. Wipe on the trap ventilation and connect with vent pipes. Calk in ferrules in all openings for waste or ventilation, with a short piece of lead pipe wiped on. Pinch these ends and solder them. If the ventilation connects with stack before reaching the roof, then you only have to close the bottom and top of stack, put the proving apparatus on the fresh-air inlet, and apply the test,