LANTERNS AND THEIR MANIPULATION 121 



FlG. 67. Four-way Tap 



General experience, however, does not go in the direction 

 of any triple dissolver, but prefers an ordinary bi-unial dis- 

 solving tap for a pair of the lanterns, and a separate four-way 

 tap (fig. 67) for the other one, which turns on or cuts off both 

 gases as required. 

 A very usual plan 

 is to have pieces 

 of brass tubing 

 plugged at the top, 

 fixed up each 

 corner of the back 

 of the lantern, cut 

 where the top 

 lantern joins on, 

 but connectedwith 

 an inch or two of rubber so as to act as one. The supply- 

 tubes are stretched over the bottom ends of these pipes, and 

 small side nozzles level with the dissolving taps connect with 

 these. Rubber tubes connect the dissolving taps with the 

 jets as usual. This is decidedly the most popular plan ; 

 but some experienced exhibitors prefer for each lantern to 

 have its own single four-way tap, governing its own jet alone, 

 supplied from brass mains as in the preceding case. Each 

 tap has a double arm (that is, one extending on each side of 

 the plug), and the upper pair of arms are connected by a 

 brass rod on one side, and the lower pair by a rod on the other 

 ends. The rods pass through sockets with pinching screws 

 fixed on the arms, so as to work any given arm at pleasure, 

 or slide loose when the screw is slackened. The result is 

 that either the top pair or bottom pair of lanterns can be 

 dissolved together at pleasure, the third being left independent 

 for separate use. Or the pairs can be changed in a moment 

 from top to bottom pairs if required. 



66. Bi-unial and Lantern Effects. A bi-unial lantern is 

 necessary for many other effects than dissolving views, as 



