The Optical Magic Lantern Journal (May 1898)

The Optical Magic Lantern Journal and Photographic Enlarger. 71 Carelessness of Lantern Dealers.—In a letter received from Mr. Jas. Stewart, of Invercargill, New Zealand, he says :—*« I do trust you will stir up the makers of lantern apparatus to be more careful and particular as to the goods they supply, at any rate, to the Colonies. To give you an instance, I ordered from one of the oldest established houses in London a double set of lenses of 4, 6, 8, 10, and 12 inches focus, and —will you credit it?—I had to return three of them as they were not paired, one being 44, one 83, and one 123 inches focus. A lantern with one set of objectives was sent out with the condensers in their places, and being loose fitting (as they should be) had fallen out into the body of the lantern, and were both broken, while the burners (high-class) would not fit on the tray posts, and even the bore of the jets was two sizes of needles difference. All these errors in a £60 order, cash down! The same thing applies to saturators I have ordered; I cannot get anything definite from a single maker to whom I have applied. I have ordered saturators specially to suit so many inches of water pressure ; these were sent with a note saying :— ‘As we have no means of measuring the inches of water pressure, we think and hope what we send will meet with your approval.’ These saturators are still in my possession, but have never been used.” Read baad me Cuban War and Explosion of ‘‘ Maine.’’— Messrs. Riley Bros., of Bradford, have received a batch of negatives from their New York house relating to the late scenes in Cuba, the explosion of the ‘‘ Maine,” and also of American battleships. Slides have been made from these negatives and are published at the uniform price of 1s. each. The Cuban set comprises 40 slides, the ‘‘ Maine ”’ accident 20 slides, and the Battleship series 29 slides. We have seen a few of these slides, which are interesting and clear. The output will doubtless be large, especially as the subject will be a prominent one for some time to come. WE regret to have to record the death (from consumption) of Mr. Philipp Wolff, which took place at Barcelona. Mr. Wolff was well known in connection with his cinematograph films, and had business houses in Paris, Berlin, and London. This latter has since its commencement been under the entire direction of Mr. Hessberg, under whose management it will continue as before. EE Intercepting Heat Rays for Cinematographic Projection. { A) Nes ON HE usual method for {intercepting heat rays when projecting cinematographic pictures has been the use of what is termed the alum trough, which originally consisted of a solution of alum in water until it was found that water alone was just as effectual, when the use of the alum was discarded, and water alone used in a narrow glass trough placed between the illuminant and the celluloid film. Water, however, has the habit of boiling in a glass vessel at 214 degrees Fahr., and in a metal one at 212 degrees; the former must, of course, be used in connection with lantern work, but long before it reaches ebullition the trough becomes more or less filled with bubbles which destroy the clearness of the pictures projected. This necessitates attention in changing the supply of water occasionally. It has been found by Mr. Bellingham, a lecturer and amateur photographer of considerable fame (of Blackburn), and Mr. Holt, the electrical engineer of Blackburn Municipal Technical School, that more suitable solutions could be employed with advantage, so in the course of numerous experiments they decided that the most suitable was glycerine. This boils at 500 degrees I'ahr., and further, does not cause inconvenience by the formation of bubbles. Some further experiments resulted in placing a special form of trough containing glycerine between the illuminant and the condenser instead of the plan usually adopted for placing a trough, viz., between the condenser and slide, and in this position it was recently used during an exhibition lasting two hours with an arc light of about 2,000 candle-power, with a continuous current of over 15 amperes on a screen 20 feet square, the lantern being 95 feet distant. At the end careful notes were made, and it was found that the glycerine had only attained a temperature of 176 degrees Fahr. Should the trough be used between the lighi and the condenser, it is, we understand, necessary that the glycerine should be anhydrous, but if between the condenser and slide this is not essential. In the exhibition spoken of slides left for a somewhat prolonged period were only slightly warmed.