Gas jets of the open - flame type continue to be used to some extent but the more efficient mantle lamp has very largely supplanted lights of this kind. In the past, these gas lights were made in a great many styles and were known under a variety of trade names - the fish-tail burner, the bats - wing burner and the Ar-gand burner - and were at times very generally used for gas lighting.

The common gas jet is illustrated in Fig. 193. The figure shows a bracket fixture which is generally fastened to a pipe in the wall. A swing-joint at A permits the flame F to be moved into different positions. The annular opening A permits the gas* to pass to the jet in any position to which the light is moved. The gas-cock C is a cone-shaped plug, which has been ground to perfectly fit its socket. It should move with perfect freedom, and yet prevent the escape of the gas. A slotted screw N permits the joint to be readjusted, should the plug become loose in the socket.

The gas-tips T are made of a number of different kinds of materials and are commonly termed lava-tips but tips for gas and gasoline are frequently made of metal. The bottom of the tip is cone-shaped, which permits it to be forced into place in the end of the tube with a pair of pliers. In size the tips are graded by the amount of gas which they will allow to escape in cubic feet per hour. For example - a 4-foot tip will use approximately 4 cubic feet of gas per hour. They are made in a number of sizes to suit the varying requirements.

Fig. 193. - Swing-bracket gas lamp with open-flame burner.