The Optical Magic Lantern Journal (February 1892)

14 The Optical Magic Lantern Journal and Photographic Bnlargor. expected will give an impetus to this mode of | lighting. How handy it will be when we ane to use the lantern merely to connect a wire and | move a switch. 2 s a Mr. Oscar S. Teace (New York), when sending a communication (see page 24) re “ Stercoscnpic Leffects on the Screen," states that he would be glad if new thoughts and experiments could be brought out, if they will in any way aid a solution, and that he will be pleased to answer an) question, or explain more fully, any of thei claims he has made, supplementing such explana: tions, if desired, with illustrations. We would : refer our readers to pages 146, 155, 171, and 185 of the past year, as this subject is one of interest. 2 2 ® Messrs. N&wton AND CoMPANY complain that Certain persons make a practice of colouring slides made by them and bearing their label, and after painting have replaced the label. The colouring in most cases (they state) is exceedingly bad, and calculated to injure their reputation as slide painters. They intend to adopt stringent measures to prevent this label being left on their slides after they have been painted by other firms. a 2 e Mr. J, Trait Taytor’s book, “ The Optics of | Photography and Photographic Lenses,” is now published. One interested in the subject cannot lnvest 3s. 6d. to greater advantage than by procuring a copy of this work from Whittaker and Co., Paternoster-square, E.C. Particulars will be found under Editorial Table. 2 e A new and enlarged edition of Mr. Walter Tyler's (Waterloo-road, S.E.) already large lantern catalogue has just been brought out. Numerous valuable additions have been made, and the catalogue now contains about 500 pages. | = J e THe Sunlight Soap Works are having a lantern built by Messrs. Archer and Sons, of Liverpool. It is intended to show across their new_ hall (Gladstone Hall, Liverpool). The distance between lantern and screen is to be 92ft. As it is desired that the pictures be 16ft. in diameter, the lenses are to be of about 18in. focus. The ‘apparatus is to be used for the first time in about ten days. The jets are to give a light of eight hundred candles. a 2 e WE are informed by Messrs. Negretti and Zambra that the C tubes of the gauges made by the Bourcon Company consist of a combination tube,a steel tube being welded to an outer tube of a composition of bronze. This they assert is better for gas at high pressure than the steel tube itself. Instructions for Inexperienced Lanternists. No. II. ‘IN our last we spoke of oil lamps as generally ‘employed, and will now mention the other modes of lighting, but will defer treating upon the optical system until later on. The spirit jet, commonly termed the oxyCalcium jet, seems of late years to have been relegated to a back seat, but when a jet of this nature is well made and properly used, there should be no reason why a light as good as from the ordi i Mary b/ow-through should not be obtained. The spirit jet, as its name implies, burns spirit (methylated), and a stream of oxygen is allowed to blow through the flame thus produced upon the cylinder of lime. in the ordinary form of this burner the spirit is contained in a receptacle some distance from the burner, partly as a safeguard, and partly because if the chamber were placed entirely below the wick it would cause the jet to be of a form which would be less convenient. The annexed sketch will afford a good idea of this style of burner. A is nothing more nor less than a tin can, which must be quite air-tight, provided with an opening at the lower end. Into this opening a valve is fitted, which falls open 8 a AAA A when the reservoir is held open end up. The spirit (about a pint) is poured into this opening, and the reservoir quickly inverted; the seating of the valve spoken of prevents the escape of the spirit. It is then lowered into the chamber B, which is also made of tin, but as soon as the wire which is connected to the valve touches the bottom of B, the valve is pushed up, and the entrance of a few bubbles of air displaces a certain quantity of spirit, which runs through the tube connecting the burner, and stands at a level about half-way between the tube and the wicks of the burner. As the spirit is consumed, more air enters the reservoir and allows more spirit to escape, so that a constant supply is thus brought to the wicks, much in the same manner as certain water bottles employed for bird cages. The wick used must be very loose, so as to