The Optical Magic Lantern Journal (January 1900)

As to the ‘few shillings "’ to which F. W.C. refers, surely if the lanternist is so foolish as to accept less than a proper adequate fee, he has only himself to blame. Cannot lanternists see that if they would only stand together a little, they would soon become absolute masters of the situation ? In any given town, large or small, how many men are thoroughly capable of a first-class exhibition, and available at short notice for engagements which perhaps involves travelling 30 miles and staying over night ? Yours truly, AN OPERATOR. GAS CYLINDERS. To Mr. J. Hay Taylor, Editor. Drak Srr,—There is an important question rc above about which I should much like to see expressions of opinion and advice in yourcolumns. Here is the case— say I pay a subscription to a firm for 500 or 1,000 feet of gas. I send my own cylinders to ba filled. When the cylinders are returned to me, I always test them as early as possible after their arrival. Very often they register 3, 4 or 5 feet short of the capacity of the cylinders, yet I am charged for the full quantity. Suppose a 40 fest cylinder if filled 10 times and 4 feet short each time, you have just 40 feet, or in other words I lose just one filling of my cylinder. Someone may be ready to say that the fault is with my valve or gauge, and in reply I would explain that the gauge registers 120 atmospheres when the cylinder is full. I am determined not to pay for more gas than I have. And why should I? If a butcher charges for a pound more meat'than you find he really supplies you would not pay him, why should I pay for more gas than I really have? When you have paid your subscription the firm can treat you as they choose, it seems. What is the remedy? What with cost of full cylinders home, and return of empties, together with price of gas, the expense is quite heavy enough now, without being charged for gas one never consumes. How often should cylinders be tested ? I am, yours truly, CONSTANT READER. —:0:—. ROY once. ad ‘ Détes and Queries. ft “CA” Ernest Elliott writes :—Can any brother lanternist tell me of anyone who is competent to take over a lot of effect slides and correct the registration? I am_ looking for someone who makes a trade of this kind of thing and charges fair prices for the work. T.—If it is your injention to both give the lecture and work the bi-unial, you will find it necessary to be very familiar with the subject, as a good deal of it will have to be given without looking at the manuscript. Rev. T, Perkins.—We thank you for the promise of a copy ofyour book ‘‘ Wimborne Minster and Christchurch Priory ’ when published. J. Jury asks :—Can limes be made by means of a tube 12 The Optical Magic Lantern Journal and Photographic Enlarger. with a serated or saw-like edge, or must the lime be turned in the ordinary manner on a lathe? Ans.— They can be made in the manner you suggest. Some years ago we knew of a person who fixed a tube such as you speak of a3 a bit in a drill stock and simply bored it as cften as possible into a large piece of lime. He vasa well-known exhibitor, and his exhibitions were always a success. We mention this because we quite expect letters in further reply to say that it is impossible to make limes in this manner, for some of the lime cylinder makers imagine that no one but themselves can possibly know anything about making limes for the lantera. Robert Slater writes:—Can you kindly give me an explanation of what conjugate focus means, not with regard to any particular lens of a given focus, but of any lens? Ans.—The second part of your query is not very plain, but anyhow, if you get a copy of this Journal for December, 1892, from our publishers, you will find a special article devoted to this subject together with a working diagram. If you cut out this diagram and attach the urms by means of pins, you will gain mora experience than you will by any amouat of reaaing. Theo Cooper.—We nots that no matter how much you ‘register’? your slides, you canno’ get the mats of all your cushion slides to appear so coincident as you wish, and that you want the opening of the mats when dissolving to be ‘dead steady.’’ In order to d> this you must make two mats (say) of zinc; these must be identical in size and fixed in front of the lantern condensers, and so registered, that when turning up one light and the other down it will appear as one, They must, of course, be a trifle smaller than your ordinary slide mata. Retired Manufacturer writes a long letter in answer to that of Mr. Perry, which appeared in our October issue. We cannot publish the letter in full as no good would be done, but it goes on to explain that ‘Retired Manufacturer '’ endorses everything he said in our issue for September, but regrets that he is unable to produce for the benefit of Mr. Perry the signed agreements and contracts of others relative to the controlling of certain quarries by lime cylinder makers, also that when he gave the information spoken of, he did so with the intention of preventing intending lime cylinder makers who have not had actual experience in this business from falling into certain difficulties of which only those who have been engaged in the business can possibly know anything about. A. H. Vidler.—You will find particulars of how to make an opaque foldable screen in our issue for December, 1897. That and otherback numbers can be obtained from our publishers. Inquisitive.—(1) Burning out the hydrogen cylinder should be left to Brins or other firms making a speciality of it. By buroing out you will get rid of the deposit which often results from keeping house gas under pressure for any prolonged period, this it is which causes the discolouration of the limes. (2) We believe Mr. Walter Tyler, of Waterloo Road, makes contracts for large supplies about the price which you quote. Rev. J. Thomas.—Your letter will have early consideration, but as it at present stands, it is simply an advertisement for the firm whose apparatus you so fully describe the working of. F. G. Payne.—We cannot tell you where to get ‘a good price’’ for yourold gas-bags. You can send them to Stevens’s Auction Rooms, Covent Garden, and you will certainly get rid of them, but you will have to ignore the ‘‘good price” idea. There is practically no market for old gas-bags. F. H. Rountud.—Your letter was sent on to Mr. Drew.