577,703. Testing gases. PRESSED STEEL CO., Ltd., and NOLCKEN, W. G. Sept. 6, 1944, No. 16984. [Class 1 (i)] [Also in Group XI] In a lamp for detecting the leakage of halogenated gas from pressure containers &c. or other apparatus by the Beilstein test the detecting flame creeps from a well defined surface of copper or copper alloy maintained at all times while the flame is in operation at a temperature, say 1,000‹C., above that at which condensation of volatile copper compounds can occur, any other surface on which volatile copper compounds could condense being screened. Fig. 1 shows a Bunsen burner in which gas is discharged trough a tube 11 into a venturi nozzle 19 to mix with the air to be tested supplied through a flexible detector tube 20. The flame from the nozzle 19 passes through a copper tube 26 supported on the nozzle by a horizontal spider 29, a cylindrical steel screen 25, a vertical spider 28 and an upper plate 27. If the air to be tested contains chlorine or other halogen the flame issuing from the tube 26 is coloured. The inlet pipe 21 for the tube 20 is fitted with a strainer 22 to trap foreign bodies and with an air by-pass adjuster 23 to allow the contaminated air to be diluted when testing for a large leakage. Fig. 2 shows a liquid fuel burner in which the fuel in a pressure container 31 passes through a vaporizing tube 32 and issues from an orifice 54 into a pipe 44 where it is mixed with air supplied through a flexible detector tube 39, a strainer 37 and a pipe 40. The pipe 44 discharges into a dome 53 above a burner 41 formed with aperture 43 at which the flame burns to heat a copper cylinder 49 surrounded by an adjustable screen 41. A baffle 46 is arranged below the burner. Diluent air may be admitted to the pipe 40 at a valve 38.