Sometimes an unrecognized capability has been close at hand, with means readily available, but doesn’t actually come to fruition until years, decades, or even centuries later. Please consider some examples of what almost might have happened.

Aeolipile

Consider first a device called the aeolipile. This was a steam engine invented in ancient times. From Wikipedia, we find the following description:

It is not known whether the aeolipile was put to any practical use in ancient times, and if it was seen as a pragmatic device, a whimsical novelty, an object of reverence, or some other thing. A source described it as a mere curiosity for the ancient Greeks, or a “party trick”.

Aeolipile replica
This is a replica of an aeolipile, a steam engine invented in ancient times.

The ancient Greeks had advanced metal working, advanced ceramics, advanced fabrics, and they had discovered lodestone so they knew about magnetism. With all of those things at hand, they might have developed electromagnetics and constructed viable motors and generators, but it didn't happen.

Vacuum tube triode

Thomas Edison was experimenting further with his electric light bulb when he added a metal plate as in the following sketch.

Edison light bulb metal plate
Edison’s light bulb experiment included a metal plate.

Thermionic emission from the hot filament was inducing a current flow in the plate. Edison detected the current flow but he never understood why it was happening. If he had reasoned it out and had added a grid between the filament and the plate, he would have invented the vacuum tube triode decades ahead of the work of Fleming or DeForest, but it didn't happen.

Carbon dioxide gas laser

I took a course in lasers at Northeastern University in the summer of 1967. The instructor was Dr. Richard Seed, who had a company called Seed Electronics that specialized in diode and gas lasers. One day, he invited the class to his laboratory to see a working carbon dioxide gas laser. The device was built along the lines of the following sketch.

carbon dioxide gas laser
This is a diagram for a carbon dioxide gas laser.

The infrared wavelength was 10.6 microns at an output power of 20 watts. It was aimed at a large steel object, a kitchen refrigerator, which wasn't much affected by the impinging infrared. However, when he held a wooden yardstick in the beam path, the yardstick immediately caught fire.

It was in an impressive show. What struck me about all of the goodies being shown was that everything had all been available for many years. If one had sought to buy these things perhaps back in 1930, it would have been no problem, even for the monocrystalline NaCl window. Ergo, the construction of such a laser might have taken place many years before the first lasers were actually built, but it didn't happen.

Food for thought then: What today are we almost ready to devise if only we could think of it, but haven't?

John Dunn is an electronics consultant, and a graduate of The Polytechnic Institute of Brooklyn (BSEE) and of New York University (MSEE).