The Optical Magic Lantern Journal (October 1895)

172 § have been choked as well as the delivery pipe. I enclose particulars for editorial inspection, and shal) be glad if ; you will say if my case and that referred to by ‘A Reader" are identical. Yours truly, THE WRITER OF THE ARTICLE. (You are quite correct in your surmise as to the name of the gentleman who was killed. Ep.] LANTERN SLIDE EXCHANGE, To the Editor. Srr,—I beg to thank you for your note in the September Journal, calling attention to the ‘‘ Lantern Slide Exchange.” Can you spare me epace to say, that I shall be glad to have a few more names of amateurs who have surplus slides they are desirous of exchanging for others. There are no fees or restrictions of any kind. The lists, drawn up on suitable forms by the members themselves, contain descriptions of slides ‘for | disposal,’’ or '' wanted " on almost every subject ; a number of complete lecture sets are also offered in exchange for others. These lists pass from member to member, and I have every reason to believe they have been found very useful. The Optical Magic Lantern Jour If any of your subscribers care to join us, I shall be | glad if they will communicate with me at once, in order that their lists may be included with the reat, now just etarting c ff on the first round of the season. I am, Sir, Yours, etc., A. M. HIDDON. 2, Thames Place, Putney. Notes and Queries. Flowers writes :—‘' I am engaged in making a series of negatives for reproduction as lantern slides of cut flowers, nal and Photographic Enlarger. of the firm. We think you did right, and you should see that you profit by the experience you have just gone through. Science.—2, St. Mary's-street, Manchester. H.C.M.—You will probably find the following satisfactory :—Cut the glass to the size desired, then place in cold water which bring to boiling point, allow to boil a while, then set away to cool, after which the glass can be removed. You should be able to obtain very thin glass in your town, get it about the thickness of thin card such as is used for printing visiting cards. W. J. Warren.—We thank you for kind invitation (including the refreshment) and regret that we are unable to be present to make the acquaintance of yourself and colleagues. W. J. Bearne.—All cylinders do not behave in the manner stated. We have a photograph of a cylinder which was in a Glasgow theatre fire, the heat melted the solder, which was sweatei round the valve screw connected with the cylinder, and the intense heat created by the fire with oxygen merely fused the end of the cylinder. Why the Bromwich one did not behave in the same way, we cannot say. S. L. Wilton.—You will pardon our saying you are not & very careful reader of this journal, else you would have found the very article you require described and illustrated on page 125 of our August number. W.C. Foster.—Having musical talent at hand, you cannot do better than have songs illustrated with slides ; such sets as the ‘‘Old maids from Lea," or the ‘‘ Blind beggars’’ are of an excelient type. Whilst miscellaneous slides are being shown, have soft music on the pianoforte. In every catalogue you will find short tales of a humorous nature, and keep in mind that three or four short pieces are much better than one long piece. Stories of the “Christie's old organ" class, ore far too heavy nowa days. Wind up with a few comics and chromatropes for the juveniles. . -H. C.. Owens (San Francisco)—Your former subscrip _ tion was sent on to London and your copy was sent from but unfortunately, sometimes, before I get the negiltive taken they have somewhat drooped, although I keep them in water. Can you advise me as to any chemical that I could put into the water so as to make them keep fresh @ longer time?'’ Ans.—If you puta little salt into the water this will, we think, extend the time to a great extent, 4.M.T.R. asks :—‘‘ Why is one maker's objective better than another?’ Ans.—We presume your question means: In various objectives by different makers why is i¢ that some are better than others. It is a case of curves, knowledge and painstaking, but to enter fully into the matter would require a volume, and perhaps after you ‘had read it you would not be much the wiser. E.B.—We wrote to ask you if, under the same | , conditions you mentioned, you could get definition when | Tove or lege wrecked scaghaw, there eeted te eee using the oil lamp with which the lantern was Originally | enn: : : fitted, so as to ascertain whether the fault lay with the objective or the new electric lamp, but we received no reply to this. this journa} to gland nuts in.connection with cylinder valves, and-aske what they are for. Reply.—The gland mut is used to tighten the packing round the vatve spindle so as to prevent leakage of gas. | J. Rawley.— Yes, we have heard of it, but must refuse to express any opinion. T.D.—Both are equally good. Caution.—Be careful in your dealings; we never heard | here, but it is now despatched by tome of our American agents; but as you say it reaches you regularly, that is the main thing. Dennis Sweeney.—Yes, after a few trials at home you should manage it. Better remove saturator trom lantern and try it in various ways when standing on a table so as to make sure that you thoroughly understand its mansgement. If wail is white aud screen thin, keep it a little way off, otherwise it does not mutter. T. Maywire.—1. There is no danger so to speak in using blow-through and gas bag, but any apparatus, even a knife, inthe hands of one devoid of experience is dangerous. 2. We consider a cylinder safer. 3. For an 8 feet bag 60 to 100 Ibs. weight. 4. Not with a blowthrough, but probably with a mixed jet. 5. The effect 6. Hard are better for all-ruund work. Forfex.—l. We think not, but during some experiments with a retort, we tried for and got an explosiun. 2. It Beginner writes that he hae seen frequent.reference in should be kept away from damp, and if this is done there is not. much smell, but the better plan would be to convey it in sealed jars or cans. 3. We should say “ yes,” provided there ie a sufficiency of calcium carvide and water, and the vessel was a weuk one with -no outlet. 4. We do not know whether tlie vapour is poisonous, but we know from experience that it is most unpleasant. 5. We tried the Bunsen’s style, but it was of no use. So far, in our hands, the smallest Brays has been the best. W.S.—Yes, above the average.