The Optical Magic Lantern Journal (August 1900)

104 _ ‘The Optical Magic Lantern Journal and Photographic Enlarger. something that I can put inside my lantern ; well my friend you can have it, but bear in mind that such an apparatus can have no room for storage, and no provision for overmake or aftermake of gas ; fair results can be obtained, though great care must be taken, particularly to start slowly, for if once the production gains on the consumption the generator itself has no power of control, and gas is bound to escape into the room, and perhaps ignite as it issues from the generator. Of course such generators are only built to supply one burner, but even at this they are far superior to the best oil lamp and certainly no more trouble. 3. My third customer insists on light weight, but is not satisfied with the one burner generator as in No. 2, and to such I would utter a caution. You can have your wish, but remember that a light generator must, of necessity, be rather flimsy, and anything flimsy to hold gas is a constant source of anxiety; it needs very careful and constant examination, and before purchasing such, I would insist on every joint being not only seamed but soldered on both sides, and the outer part and gas holder inade of a tough ' mination as about equivalent in price to house gas at 5s. material such as hard brass or steel ; zinc and soft iron are unsuitable, being easily bent by even a slight blow, and in the bending the solder very | often gives way and a leak results. 4. Does not want to soil the hands in charging oremptying. He would like the carbide in some sort of a case just ready to put in, and when done with the machine could be just turned upside down and the lot emptied away itho or furth le ; i x uf smell urther troubles there as" a0 ' that such bas been produced commercially, but it is difficulty in making such a machine, if you do not mind the extra cost of working and the : trouble of piercing holes in the carbide container, ' while many of the advantages of a well-constructed generator could not be made to apply. 5. We next are confronted by the operator © who not only wants small size and light weight, . but very little water though he must have a good light ; this is a more troublesome customer, because we are obliged to rely upon thé system of dripping water on to the carbide, or else a generator of very small dimensions, with necessarily little or no storage. In such generators it is well-known that the action cannot always be relied upon to produce a steady and regular supply of gas, while in some of them overheating takes place to a considerable extent, and thus causes further deterioration of the light. No one can expect best results from such a machine, but if the user gets fair uccas3 and his chief want is supplied, then he must rest content. (To be continued.) RY onmeu ) Déles and Queries. NCAR” F. H.—Your stereoscopic lenses are not a pair, hence your trouble. Henry Fisher.—We note in the particulars of your | attempt at soft soldering, you have forgotten the flux. Pat a small quantity of muriatic acid into (say) a bottle, and into this drop some small pieces of zinc until all boiling effect has ceased. Clean the brass work, and on the surfaces to be soldered put a little of this flux. Lay a small piece of solder at the junction ard apply heat, either by means of a flame free from soot, or by means of the blow-pips. We do not know the style of work you are attempting, but if the surfaces are large it might be well to coat one or both with a thin layer of solder before placing together and applying the heat; in this case, as the solder melts pressure must be applied so as to ensure the surfaces being close together. For soldering zine use the acid only without the addition of any zinc pieces. consider illu Tllumination.—You may acetylene or 5s. 6d. per 1,000 feet. D. Yates.—We answered your question in last issue ; you surely could not have overlooked it. H, H. Ward.—Your article bas reluctantly been held over till next issue for want of space. Perplexed.—15 grammes are equal to 231 grains or 3 drachms and 61 grains. Ernest Jennings. —We note your suggestion that the heat given off from the lantern might be utilised for turning the lime. This suggestion has been made on several previous occasions, but we have never heard quite possible that some ingenious lanternist might have made suitable mechanism for his own uss. Of course, a small fan would have to be employed. H.—Messrs. Riley Brothers publish a small book called The Lantern Operator's Guide. Price 3d. Thomas Seymouy.—-We are sorry. we had to reply to you in the manner we did in last issue, but we tried our best to make out your meaning, without success, However, your second letter is clear. The shadows at the side of disc are caused by the light from the jet not being central to the axis of the optical system. Move the jet slightly sideways until the disc ia evenly illuminated. There is nothing mysterious about it. Screen.—We believe the particulars we published are absolutely correct. If you make some definite objection we can then go into the figures, but all the same we think you will find them correct. W. G. Clements and Others.—The silhouette slides described by Mr. Theodore Brown are not made by him for commercial purgoses, and it is open for any dealer to make aod supply them, as stated at the commencement of the series, the only return that Mr. Brown asks from any dealer so making them, is that one slide be eent on to him. You might apply to Mr. W. Cheffins, Holbeach, Lincolnshire, he has remarkable aptitude in the making of such slides.