The Optical Magic Lantern Journal (June 1896)

The Optical Magic Lantern Journal and Photographic Enlarger. 107 upset all the air currents at one time or another, and have not been able to detect any reduction of intensity, or even unsteadiness of light. An oil lamp, if treated as I sometimes treat the one before you, would nearly suffocate the operator with smoke, or go out altogether. Before leaving the subject of the mantle, allow me to state that up to the present I have found that no injury whatever is done to the mantle by burning oxygen as I describe, neither can I detect any lessening of its durability. Under ordinary care in moving the lamp about, even from one room to another, there is no reason why a mantle should not last an operator a whole season; indeed, I have had one in frequent use during three months, which is as good as when first lit. In order intelligently to express in figures the actual value of this light, I asked Mr. Ivison Macadam to make some careful photometric tests, which he was good enough to carry out at the expense of considerable time and trouble, extending over several evenings, at my own house, and also in his own laboratory; and on considering these figures, you will be good enough to bear in mind that they are comparative tests, inasmuch as where gases were used the hydrogen consumption was in all cases kept the same, namely, to the low quantity of 3 cubic feet per hour. (To be continued), :0: New Apparatus. ‘‘ BESSUS’’ GAS CYLINDER CASE AND STAND. Ever on the alert to bring out something useful, Messrs. Airs & Co. have just introduced a cylinder travelling case and stand combined. Fig. I. represents the case closed, and Fig. II. opened ready for use. To open it, it is simpl unlocked, the cap removed, the sides allowed to fall down as shown, when they at once form a series of firm struts for the cylinder, thus preventing it from falling, even should anything happen to collide with it. Within the cap and lower end of the case pads are placed which encircle the cylinder, so that under no circumstances can concussion to the case be communicated to the cylinder with any force. ACETYLENE BURNER, The following is a cut of the burner used with the acetylene gas generator described in last issue, and made by Messrs. Thorn & Co. X RAYS APPARATUS. Messrs. Newton & Co., of Fleet Street, are now supplying great numbers of complete apparatus for this interesting branch of photography. The set consists of battery, coil, and focus tube, which, with about three minutes’ exposure, will take a distinct photograph of the boncs. Fluorescent screens are also supplied by this firm, but are separate and distinct from the ‘‘set.’’ With these screens, the bones of the hand can be distinctly seen if placed in the X rays. With these screens, the following instructions are issued :— ‘The room must be quite dark; a coil giving at least a 6-inch spark, and ono of our § Special’ Focus Tubes must be used to obtain the best effects. The tube should be so fixed in a clamp that the rays from the flat platinum reflector are directed to the face of the observer. A large black paper screen should be placed close to the tube to stop any visible rays from reaching the eye. As close as may be convenient to this screen place the hand, or other object under inspection,and in close contact with this place the fluorescent screen with the fluorescent material turned towards the observer. The rays leaving the tube thus traverse first the opaque paper screen, next the hand or other object, and then come thrcugh the opaque back of the fluorescent screen, and affect the fluorescent material. It is sometimes necessary to warm the special Focus tube to obtain the best results. “Remove the glass front, and slightly damp the fluorescent surface before use. “With this arrangement, metal or glass objects can be readily seen when packed inside an ordinary leather bag, even if also enclosed in wooden or leather cases and wrapped up in thick papers. A coin can be seen through a