The "regulator" union-jet, which was the first notable burner produced by Messrs. Bray, has received, perhaps, a wider application than any other single gas-burner. It consists of a cylindrical brass case, screwed at one end for insertion into the fittings, and at the other containing a tip of "enamel"--a material invented by Mr. Bray, and apparently of somewhat similar composition to the "adamas" of Mr. Leoni--the "enamel" tip being perforated, in the usual manner, with two holes, set at an angle to each other, for the outflow of the gas. The distinctive feature of this burner is the introduction into the lower part of the brass case of a layer, or layers, of muslin; designed to check in some degree, and to steady the current or flow of the gas through the burner. At the time of its introduction, this burner compared very favourably, as regards the results it yielded, with other burners in common use; and its fairly good performances, together with the very low price at which it can be sold, cause it still to be extensively employed wherever the attainment, from the gas consumed, of the highest obtainable results may be subordinated to cheapness, or in situations where, from delicacy of construction or from the care and attention demanded, a more efficient burner may not be so suitable. But in the matter of developing the illuminating power of the gas employed, the "regulator" is far surpassed by the more recently introduced "special" burner of the same makers. [Illustration: UNION-JET. HOLLOW-TOP OR SLIT-UNION. BATSWING. FIG. 12.--BRAY'S "SPECIAL" BURNERS.]