in one the arms are constructed entirely of steatite, in another they are made of such soft metal as easily to be bent back again into position with the fingers or pliers, in the third each arm is in two portions, screwing the one into the other. The second type is represented by the original Phôs burner, in which the curved arms of B are replaced by a pair of straight divergent arms of thin, soft tubing, joined to a pair of convergent wider tubes carrying the two tips. The third type is met with in the Drake burner, where the divergent arms are wide and have an internal thread into which screws an external thread cut upon lateral prolongations of the convergent tubes. Thus both the Phôs and the Drake burner exhibit a pair of exposed elbows between the gas inlet and the two tips; and these elbows are utilised to carry a screwed wire fastened to an external milled head by means of which any deposit of carbon in the burner tubes can be pushed out. The present pattern of the Phôs burner is shown in Fig. 9, in which _A_ is the burner tip, _B_ the wire or needle, and _C_ the milled head by which the wire is screwed in and out of the burner tube. [Illustration: FIG. 9.--IMPROVED PHÔS BURNER.] [Illustration: FIG. 10.--"WONDER" SINGLE AND TWO-FLAME BURNERS.] [Illustration: FIG. 11.--"SUPREMA" NO. 266651, TWO-FLAME BURNER.] [Illustration: FIG. 12.--BRAY'S MODIFIED NAPHEY INJECTOR BURNER TIP.] [Illustration: FIG. 13.--BRAY'S "ELTA" BURNER.] [Illustration: FIG. 14.--BRAY'S "LUTA" BURNER.] [Illustration: FIG. 15.--BRAY'S "SANSAIR" BURNER.] [Illustration: FIG. 16.--ADJUSTABLE "KONA" BURNER.]