The Optical Magic Lantern Journal (December 1894)

226 Nothing is more annoying than to hear the lecturer at the end or even at the middle of some sentence say “next please,” or the sharp ting of a bell spoiling the thread of the subject, and calling off the attention of the audience. And the matter of the lecture should in a great measure be original, or gathered from every possible source and condensed. How pleasant it is to receive well-earned applause, to hear at the close of a journey entertainment, ‘‘ Why, sir! you must have enjoyed your trip through the country you have been taking us through to-night,’ when the lecturer had never been perhaps within a thousand miles of it. It is often possible to get a few local touches from someone who has been, and the introduction of some legends of the place, or poetry by a resident in the locality visited will give all that is needed. Iam really afraid, Mr. Editor, I have trespassed too much on your kindness, but should be sorry to see lantern lectures dio out. But I should like to see the cheap and nasty entertainer die out—the man with a 25s. lantern and some horrible lithographed or other abominable slides ; who cuts in with a very low price at which it is impossible to live—drags down the status of the lantern and levels it to the dust. With best wishes for the coming season to you, Sir, aud all lanternists who try their best to raise the tone of the whole show, I am, Very truly, Oxford, Nov. 1894. HENRY W. TAUNT. 10: — Notes and Queries. S. Goad writes :—'‘ Last season I purchased one of Butcher's lime-cylinders, and put it away at the end of seasou with a hard and soft lime in. When I went to it this season both the limes had turned to dust and had burst the cylinder open. Also some soft limes I put away in a brass cylinder had turned to dust. Can you tell me the reason?” Ans.—Hither the limes were not perfectly dry when put away, or the cylinder not being hermetically sealed, they had absorbed moisture. W. S. R.—Asbestos tipped wicks can be obtained from Philip & Co., of 82, Fleet-street, F.C. . Geo. Kilburn.—We learn that ‘‘Soap Bubbles" is not published by Longmans, as stated in last issuc, but by the Society for the Promotion of Christian Knowledge, London, W. Novice writes :—‘(1) A 40 ft. gas bottle fully charged is used twice, each exhibition with single lantern, blowthrough jet being used, lasting one and-a-half hours. Gas remaining in bottle 11 feet. What can be the reason of such an escape of oxgen? for I hold that it could not have been used. I cannot see any apparent escape either. (2) What must be the focal distance of an objective to project a 12 ft. picture at a distance of 40 ft. from the screen. (3) Who supplies the Hardazion limes?” 4ns.— (1) It is evident that your connections at (say) the cylinder are not gas tight. A not uncommon means of escape is at the gland valve. Try tightening the nut from which the spindle on which you place the key projects. (2) Use a lens of 10 inches equivalent focus ; see the ‘‘Lanternists’ Ready Reference Table,” which may be obtaincd from this office, post free for 24d. (3) The proprietor of the limes spoken of 1s Mr. A. Wrench, and it is from him that dealers, and dealers only, can get their wholesale supplies. John Lruelock.—Your friend is quite correct, you can use a blow-through jet with both gases from cylinders, or The Optical Magic Lantern Journal and Photographic Enlarger. if you like you can use both a blow-through and a mixed jet from the same cylinders at the same time, only you will find that it greatly simplifies matters if you use an automatic regulator on each bottle, and then adjust at the taps. J. Crombie.—It is simply nonsense and shows that the party did not undcrstand the subject about which he was trying to instruct you. A. Wilks.—We have tried the gauge and find that it does work. You say that it will not show anything on your cylinder, which has not been used since it was filled and which must consequently be full. We have returned the gauge, and if it shows nothing when it is attached to the bottle and the valve turned on, it is simply because there is little or nothing in the cylinder to show. It is not an uncommon thing for people to think that because the gas makes a good noise, rushing out when tho valve is turned on, to think that there must be plenty of gas. You may not have more than half-a-foot of gas in the cylinder. If you have had it standing by for any length of time, an exceeding small leak will tell materially on the contents of the cylinder. D.J.—Turn the gas jet taps off beforo turning the cylinder on and see if the regulator will then act. You have evidently been regulating with the key only, and have not been giving the regulators a chance of working. Turn a good head of gas on before opening the jet taps. P.S.D.—Had you read this column you would have learned that we will not recommend any one Saturator in preference to another, not even in the way you suggest by naming them A.B.C.D. You will find them all advertised in this journal. Write to the makers of the particular one that strikes your fancy, and make the best terms you can, and if you can get it on approval well and good. FP. H. Benham.—We know nothing of it. Saturator writes :—‘'(1) Is the Gridiron a good Saturator. (2) Is the Timberlake a good Saturator? (3) Is the Optimus a good Saturator? (4) Is the Lawson Saturator a good one? (5) Is Suiters ‘(Reliable)’ Saturator reliable? (6) Which of the five do you think is the best ?” Ans.—(1) Yes. (2) Yes. (3) Yes. (4) Yes. (5) We believe it was withdrawn almost as soon as it was introduced. (6) See reply to P. S. D. in this issue. W.C. H. J. writes:—'‘ Would it not be a good idea to have a limelight flash lamp for signalling purposes by means of flashing.” Ans.—I£ you mean would it be a good idea for you to possess one, you are the best judge. If you mean it as a new idea, it has becn in use for a long time past. W.H.—(1) Perhaps the leather washor has come out from your Clarkson regulator. See that the lcather used is free from grease. (2) For the bull-nose form a thin washer of lead may prevent leakage. Bi-unial.—(1) 40, Hanover Square, W. Subscriptions 10/perannum. The hon. secretary is Mr. W. Bashall, 21, Holland Villas-road, London, W. (2) To remedy the dissolver—seeing that screwing up will not do—take out plug, smear over it grease witha little fine emery, replace and grind it in, but remove it every tew moments in order to equalise the grinding. (8) Probably blacklead is what was put on previously. Messrs. Riley Bros. write respecting a ‘‘note” tnat appeared in last issuc, that they have had samples of oxygen from various inakers analysed, and from the certificate they send us we learn that the difference in quality amounts to merely a decimal. We are unable to publish the certificate of analysis of the different brands, as we declined to enter into names in the case of the ‘‘note’’ mentioned which had reference to a letter received from Mr. Hepworth.