The Optical Magic Lantern Journal (February 1890)

The Optioal Magio Lantern Journal and Photographio Enlarger. The bag is placed between hinged boards, and a sufficient weight put upon the uppermost one. This is to obtain a steady pressure. A lime (soft) having been placed upon the pin for the purpose in front of the burner, a sufficient length of india-rubber piping.is connected with the gas-bracket and the hydrogen tube of the jet, and another length of similar piping is made to connect the reservoir containing the oxygen with the oxygen jet. In order to prevent any leakage at the part where the rubber tubing is sprung on, many tie a piece of twine around the end to bind it, but the same object may be attained if the end of the piping be rolled back on itself. All being in readiness, the hydrogen is turned on and lighted, and the lime allowed to become gradually warmed, after which the oxygen may be played through the flame, and on the lime. A little adjustment of the supply of both gases will be necessary to get the most satisfactory results, and the lime itself must be allocated to its correct distance from the orifice of the burner. As the supply of oxygen in the bag becomes diminished, it may be necessary to increase the weight placed on the pressure board. _If_acylinder for the oxygen be used, the connections are made in the same way, but in this case it is desirable to attach a regulator to the cylinder, and it is to this that the piping is secured. The cylinder may, however, be employed without the regulator, but it entails recurrent attention to the tap forming the outlet, for, as the pressure becomes less, so does the intensity of the light ; and in attempting to put on a little more pressure it is a frequent occurrence to allowa sudden outlet of the gas, which invariably puts out the flame in the lantern. This much may be said, that if once a regulator is used, its advantages are so apparent as to necessitate its use in future. _MIxep Jer. When oxygen and hydrogen are mixed in certain proportions they will, in conjunction with the lime. give a light far surpassing in brilliancy that given by the form of jet previously described ; but with this light it is necessary that care be taken that all the instructions are complied with, for under certain conditions the admixture of these gases may cause a slight snapping explosion if a light be applied to them; but with care and attention to the requirements, it is quite safe, and, as 67 to be supplied from a bag, the hydrogen should also be contained ina like receptacle, or if a cylinder is employed for the oxygen, another should be used for the hydrogen supply, and under no pretext should the gas main and a cylinder of compressed oxygen be used in conjunction. With regard to the attachment of the piping, the remarks previously made will suffice. When the cylinders are used, on no account should “ regulators ” be omitted, as there might be a chance of the admixture of the gases if the pressure from one cylinder exceed that of the other. Care must be taken for the same reason that the weights are not removed from the bags until the taps both at the lantern and at the bags themselves have been turned off. Hard limes give the best light with the mixed jet. There are certain movements requisite for the proper adjustment of the jet, and the more these adjustments are under the easy control of the operatorthe more matters are facilitated, and the general management of the light simplified. The motions required are—a means of adjusting the proper distance between the limesand nozzleof the jet ; of turning, raising, and lowering the lime ; raising or lowering the complete jet, and giving a side motion to the same, moving it nearer to or further from the condenser, and of turning the gases off, excepting such as is allowed to go through a byepass ; and when ail these movements can be under control from behind the lantern without opening the door, so much the better. Mr. J. H. Steward has introduced a jet fulfilling all those requirements (Fig. 35). In the first form of this jet, the up, down, and side motions could oaly be brought into effect by opening the door of the lantern, inserting the hand, and adjusting the screws ; but in the latest models a set of bevel wheels have been added, by which the up and down motion is also controlled from behind, whilst a lever extended to the back of the lantern renders we have said, will produce a very brilliant light. In this light both of the gases must | the side motion also under control from the same be under similar pressure ; hence, if the oxygen is | 1 other movements. ( To be continued.) position as the