What exactly is a magic lantern?

	What exactly is a magic lantern? A beginners guide to the magic lantern Older people know the answer immediately. The young ones however have not the faintest idea what you're talking about. 'Er.... what kind of lantern?!!!'
Toy magic lantern.	In the Webster's Dictionary of the English Language we find under the headword magic lantern: magic lantern; an early form of projector, throwing an enlarged image of a transparency on a white screen. So it's a kind of slide projector. We name these early projectors 'magic lantern' because at first the audience did not understand where those colourful images on the wall or on the screen came from. The only explanation they could find for the strange phenomenon was magical power.
Toy magic lantern.	Image depicting Étienne-Gaspard Robert’s Phantasmagoria show. That must be magic!
Biunial.	The magic lantern was used by various groups, from priests to scientists, to teachers, to charlatans, to spiritualists, to entertainers and showmen and more, so you can confidently state that the device was a mass medium in those days. The magic lantern was invented about 1660; the chances are that the Dutch scientist Christiaan Huygens is the inventor. The magic lantern consists of, at least, a source of light, a lantern slide and a projection lens, in that order. The later magic lanterns contain more components. Variations. Due to the proceeding technical development and the special desires of the users, and also because of the fact that the many manufacturers of magic lanterns continually tried to surpass their rivals with improved designs, a huge number of variations exists. Small lanterns as a toy for children as well as large models for theatrical spectacles and instructional sessions. Single lanterns, biunials (one on top of the other) and even triunials. Broadly, two materials were used in the manufacture of lantern bodies, wood -nearly always mahogany - and metal. Larger lanterns have mostly some brass parts. The description below deals with a single, large lantern, made of metal, but most comments are relevant to all types.

	Components of a magic lantern from the last turn of the century but one: a. objective or projection lens, usually attached to the lens holder (a1) by means of a screw thread; b. focus knob (moves the lenses to focus the image by a rack and pinion system); c. filter slot (e.g. for a coloured glass filter) at the front of the projection lens; d. hinged flap (to soften the light and protect the lens); e. condenser housing with condenser lenses (to condense the light in an efficient way onto the slide); f. chimney or cowl (to provide an updraft for oil burning illuminants and to carry off smoke and heat); g. Side door (adjustments to the burner were made through here), mostly provided with an inspection window (h), fitted with dark tinted glass); i. lamp house; j. ventilation slots; k. hinged back door; l. clasping slide stage that holds the wooden slide carrier (m); n. illuminant (burning oil, gas or electricity) the oil lamp is moved a little bit backwards to show the controls; o. knob to move the optical part. Many magic lanterns use a parabolic mirror at the back, to reflect the light of the burner, and sometimes a heat-absorbing filter in front of the lamp to protect the condenser. Several lanterns are mounted on a wooden or metal baseboard, often with adjustable legs on the front.
Candle light.	Illuminants. A huge variety of sources of light was used to light the slide, from a simple candle to ingeniously constructed electric systems. The use of large oil burners was already a considerable improvement, but the use of limelight advanced the popularity of projected entertainment by its ability to project big, bright images for large audiences. The intense white light was produced by heating a small cylinder of lime, generally with a flame of combined oxygen and hydrogen gasses.

Note: Limelight was also employed for stage lightning, giving rise to the still common usage of the expression 'being in the limelight'. One of Charlie Chaplin's most famous movies was titled 'Limelight' too.	Mixed-gas jet. The two gasses are fed in from outside, by a pipeline system. Two control knobs are used to equal the pressure of both gasses. The gasses mix in a chamber. A nozzle is set near to a cylinder of lime which is fitted on a steel rod protruding through a brass disc, on which the lime rests. The jet is fitted with a mechanism with lever taps and cogwheel adjustment for turning and raising the lime block. The flame from the nozzle heats the lime block, which thereupon glows white hot. This limelight produces up to 1,000 candles.
	Optics. On their way from the lamp to the screen the beams of light meet two optical systems. First the condenser and finally the projection lens.
	Condenser, using two plano-convex lenses and a projection lens.
	Condenser. The purpose of the condenser is to collect as much light as possible and focus it through the slide. It is positioned directly in front of the illuminant and consists of one, two or three lenses. Usually two plano-convex lenses were used, mounted with their curved faces facing each other in a brass collar. Objective or projection lens. The objective is the adjustable lens unit in front of the lantern and nearest the screen. It organises the rays of light by refraction, to produce a sharp and colour-correct picture on the screen. The number and form of the elements vary according to the design and the cost price of the lantern.
	Slides. The slides were initially hand painted on strips of glass, either oblong or square. Later on a kind of transfers were placed on the glass, printed by means of a lithographic process. Usually four or five round images were printed on a single strip, but also one panoramic picture frequently occurred. Some lanterns showed images from a glass disc. Later photography took over. The image was printed directly onto the glass and often hand-tinted with a watercolour paint or ink. Moving slides were usually placed in a mahogany frame.
a strip of glass printed with a transfer, a so called decalcomania.
a single slipping slide that was used to simulate movement of the image.
	Remarkable. Strange to say the well-known Encyclopaedia Britannica has no headword 'magic lantern' at all. In articles like 'The history of motion picture' and 'Quality of the film image' the magic lantern is only mentioned incidentally. We learn about Athanasius Kircher that 'a number of discoveries and inventions (e.g. the magic lantern) have sometimes been mistakenly attributed to him'. We have to guess at the true inventor. Under 'Christiaan Huyghens', probably the first one who constructed a real magic lantern, unfortunately this fact is not stated. The Dutch Woordenboek der Nederlandse Taal (WNT), the largest dictionary in the world, describes the magic lantern (Dutch: toverlantaarn) extensively. Besides the normal definition 'an apparatus for an enlarged projection of images painted on glass, on a wall or screen', there are two more given. In the past the word 'toverlantaarn' was used as a nickname for the misshapen, lame persons who went through the country presenting their magic lantern shows, and, even worse, it was also used for a girl of easy virtue. We had better confine ourselves to the first description.