That which is cutting edge technology eventually becomes a toy. In the case of the Magic Lantern, it took about 250 years. The Magic Lantern was invented in the early 1600's and by the mid-1800's had moved from using limelight (heated limestone that gave birth to the term "in the limelight") to slightly safer kerosene. I can't imagine a parent letting a child light up some kerosene today but in the 19th and early 20th centuries that was deemed safe enough.
Magic Lanterns used the light source to illuminate pictures on a wall. The heat source was inside a type of small oven with a small stove pipe which allowed the heat to exit. It was really pretty ingenious.The Magic Lantern was the parent of the slide projector and possibly the godparents of the cinema.
The above image shows a key wound version that allowed the images to move in front of the light source. Its a bit of a precursor to the movie reel. Here are some other images that I thought you would enjoy: