As mentioned in the post about Thomas Sharlow’s Lantern Slide Carrier, lantern projectors were developed in the 17th century and oftentimes used for entertainment or educational purposes. The projector consisted of a light source, a lens to focus the image and a slide containing pictures or paintings on transparent plates. Also known as magic lanterns, these projectors were popular until the mid-1900s when they were superseded by 35mm slide projectors.
This patent (1,108,256) was issued in August 1914 roughly four years after Thomas Sharlow obtained his for a slide carrier in January 1910. Even in 1914, the most common source of light for the projector was an oil lamp. As was the case with Thomas’ invention, Charles would address the risk of fire and propose a unique way to fabricate the slide carrier out of a single sheet of metal.
“The present invention is an improvement upon the form of slide carrier disclosed in Patent 945,619 issued to Thomas Sharlow January 4, 1910, the distinctive feature of which patent is the formation of the carrier of a single piece of sheet metal folded over fillers of so called non- combustible “fibrous” material inserted and rigidly secure to and between the side walls thus formed.”
The object of Charles’ invention was to attain a light weight, substantial, rigid carrier without the use of non-combustible fillers. In doing so, the carrier would be fireproof, less expensive to manufacture, stronger, and more durable.
As was the case with Patent 945,619 this patent included not just the slide carrier, but also the process by which the carrier would be manufactured. You can see and read more about Charles’ invention here: Charles Sharlow Lantern Slide Carrier.