The Optical Magic Lantern Journal (March 1890)

74 The Optical Magio Lantern Journal and Photographio Enlarger. The Magic Lantern : Its Construction, Illumination, Optics & Uses. CHAPTER IX.—GENERAL MANAGEMENT OF THE LIGHT. (Continued from page 67). Oxy-Cacctum. ALTHOUGH this is commonly admitted to be somewhat inferior to the oxy-hydrogen light, yet if the jet be well and properly constructed there is no reason why the light produced by this method should be much inferior, certainly not so much as commonly accredited. Instead of the stream of oxygen playing through a flame of hydrogen or common gas, the flame in this instance is that of a spirit lamp burning alcohol. The spirit must be kept as cool as possible, hence the reservoir is placed outside of the lantern. This reservoir is constructed somewhat on the same principle as the water bottles for bird cages. It consists of two parts ; the inner receptacle, filled with alcohol, is inserted and lowered into the outer case. ‘This reservoir is supplied with a valve, which closes when it is inverted, thus precluding all chances of spil A mixed gas jet is the one to employ with this arrangement. A cylinder, or combination of cylinders, contains a woollen material capable of becoming charged with ether. The ends of one of the tubes having been unscrewed, about a pint of ether is poured into the saturator, and allowed to remain for a minute or two until the flannel which the cylinder contains has become saturated. The remainder of the ether is then allowed to drain out, and can be employed for future occasions. When the flow ceases, the saturator is ready for use. The supply of oxygen may be contained either in a bag or compressed in a cylinder, but it must be remembered that much more oxygen is required for this light than with any of the preceding. As it is necessary to divide the oxygen coming from the general supply,a T pieceof tubing (Fig. 36) is required, the lower leg of which is attached by tubing of the desired length to the supply. The right hand is similarly attached to the oxygen .ling ; but as soon as it has been lowered into its receptacle the end of the valve touches the bottom, and it is opened, allowing a small quantity of the alcohol to run out, which, as soon a8 it covers the mouth of the Teservoir, stops further supply until the spirit -has been consumed and allows a bubble of air to enter the chamber, which displaces the same bulk of spirit, and so on until it is all used. The spirit travels along a tube to the burner, where it finds its level, at which it is, as just described, maintained. The flame should be large, and the wick not too tightly packed in the burner. The other manipulations are similar to the blow-through jet. Where house gas is not obtainable this form will be found very convenient when the limelight is preferred to oil. ErHo-Oxycen Lime-.icHr. This is another form of lime-light. Briefly, it consists of an arrangement for rendering a portion of the oxygen combustible, whilst another portion is allowed to mix with it before being burned. Fic. 36. | side of the jet, and that on the left to one of the cylinders, which should be laid ona table at the back of the lantern (Fig. 36). The other cylinder of the saturator is connected with a piece of tubing to the hydrogen: side of the jet. This arrangement provides both a direct supply of the oxygen and also another supply after it has passed through the saturator. When about to light up, the oxygen tap of the jet should be closed, and that on the hydrogen side opened, then the tap of the gas receptacle should be opened. The gas is then lighted, and time allowed for the lime to become warmed, after which the oxygen may be turned on. If hissing or roaring ensues, the supplies must be delicately adjusted until it ceases. When using cylinders of compressed gas, they are Oft-times set on end, partly to economise the piping and partly because they are more easily accessible for turning off and on. It is well to tie