Lantern-slide making and exhibiting ([pref. 1905])

80 LANTERN-SLIDE MAKING AND EXHIBITING. venient, and efficient. The principle of the lime- light is very simple : a stream of oxygen under pres- sure is caused to blow through a flame of hydrogen or spirit and impinge upon a disc of lime, which, under the great heat, becomes incandescent and pro- duces the lime-light. In the oldest form of jet, now prac- Ucally obsolete > a s P irit lam P tafces the place of the hydrogen flame. This form of jet is rather difficult to manage, and gives less light than any other, but only requires one bottle or bag of oxygen. It gives an excellent light for home use and also for small screens in public. In this pattern a fine stream of oxy- Thc Blow- _ en - g bi own through a large loose through Jet. , , , name ol hydrogen or house gas. It is the most popular form of the lime-light and is easily managed, and as the intensity of the light can be regulated, it is suited for either home use or public exhibitions. The intensity varies from 150 to 250 c.p. or over. Care must be taken to connect the respective gases to the proper tubes. In good jets the hydrogen connection is painted red, and the oxygen black. Before making the connection turn off both jet taps, a regulator, of course, being used on the oxygen bottle; if not, the oxygen tap must be left on and the supply of gas regulated from the bottle, otherwise the tubes would be blown off by the accumulating pressure. First turn on the house gas and slowly rotate the lime cylinder which should previously have been placed on the lime pin, until it is uniformly heated. Then on gradually turning on the oxygen the lime will become incandescent, the distance of the latter from the oxygen jet or