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136 The Optical Magio Lantern Journal and Photographic Enlarger.
The Lucigraph—A New Marine Signal.
AN instrument termed the Lucigraph, intended for marine signalling at night, has recently been patented injAmerica and Europe. The Scentific American, in describing it, says it is adapted for use by the mercantile marine, by lighthouses, signal, coast-guard, telegraph and other stations, and for the use of lightships. It,is constructed on the principle of the stereopticon or magic lantern, and is worked by keys similar to the type-writer, each key being attached to a metal plate stencilled in any desired character, such as a letter of the alphabet or numeral. _ Each key is painted
flash code, and by exposing the bull’s-eye lens and working a special mechanism it can be made to signal quite as fast and to a greater distance than most of the patent flash code lamps in use.
It has been exhaustively tested by practical men in all weathers, and has received much favourable comment.
The screen should be of white duck or of some bright colour. A house may be used, or anything giving a flat surface confronting the point to be signalled to, but the most efficient device is probably a diamond-shaped duck screen located on the bridge, which may be hoisted or lowered at pleasure, and held in place by stays, as shown in the cut, so that it can be turned at pleasure toward any point of the compass.
with a character similar to that cut out of the plate to which it is attached, and when pressed, it projects the letter plate before the light, throwing the said character on a screen.
For ordinary use an Argand burner kerosene lamp isgsufficiently strong, as it is estimated that every five-candle power gives a range of vision of about a quarter of a mile on a bright moonlight night. Of course, for higher and better service, the electric or lime-light should be used in the lantern.
The signals can be read by any one without instruction, and when code letters, like those of the universal international code, are used, it can be read by any one using the code book carried on all ships. It would be found useful on pilot boats for signalling their numbers as well as for speaking ships. It also signals by any
Colouring Lantern Slides.— No. 2. By A. W. Scott.
(Continued from page 130.)
Madder Lake and Rose Madder.—Madder lake or pink madder is very similar in tint to rose madder. They are beautiful colours, permanent and perfectly transparent, and give brighter reds on the screen than crimson lake. Being very weak in colouring power, they are useless for dabbing. It is necessary to pile on the paint with the brush before any approach to a deep red is obtained. Prepared in oil, they require
| weeks to dry, unless a drying oven is used; but in
varnish they dry quicker, and are more intense. They