The forked tube, _o_, is attached to the girdle of the workman, and the regulating cocks, _n_ and _p_, are so placed, that by using one hand, the man can allow the exact proportions of air and gas to issue. By stopping both cocks, the flame is of course extinguished. The beak, _s_, may be exchanged for others of every variety of form, so as to produce jets of flame adapted to any kind of work. Fig. 3 is a tool formed like the rosette of a watering-pot, capable of producing a most intense flame of jets. [Illustration: Fig. 3.] [Illustration: Fig. 4.] Fig. 4 allows a length of flame instead of a point to be produced; _n_ is the hydrogen gas-pipe and cock; _p_, the air-pipe and cock; _r_, the tube, in which air and gas mingle; _u_, a pipe with a longitudinal slit on one side of it; and _v_, another pipe covering _u_, and exactly fitting over it. Gas and air escaping from the slit, on being ignited, will produce a long strip of flame, which may be lengthened or shortened by sliding off or on the covering tube, _v_, on the slit tube _u_. [Illustration: Fig. 5.] Fig. 5 is a soldering tool, to be used where a jet of flame is not available, as in joining zinc. In this arrangement, the hydrogen and air flame heats apiece of copper, _y_, with which the work is performed. _w_ is the tool, with a hollow handle and stalk; air being supplied by the pipe _p_, passes through the hollow handle and stalk; _x_ is a small tube which passes down the hollow handle and stalk, _w_, and conveys gas from the pipe _n_ to the extremity of _w_, where it mingles with the issuing air, and, on being ignited, the flame will heat the piece of copper, _y_, (which, of course, may be of the shape of any soldering tool required,) held by the arms, _z_. Advantages of the Improved Method of Soldering Metals. One great advantage to the public at large to be derived from the general introduction of “autogenous soldering,” will be the diminution of the number of cases of the escape of water and gas, which every day occasion so much inconvenience and even danger as regards the stability of buildings, the maintenance of the public thoroughfares, and the security of life. The disuse of charcoal and tin by plumbers will have the important effect of rendering their trade less unhealthy, the fumes from their brasiers, and the arsenical vapours emanating from impure tin, being a very common cause of serious maladies.