Levitation. It holds such promise. But this machine doesn’t make things levitate. It just makes them weigh less. The article describes some possible uses of such an anti-gravity machine:
If a 12-ton girder was to be raised to the top of a skyscraper with a derrick of 10 tons capacity, the mechanism would obliterate the two tons of weight.
The element of gravitation in any object being overcome to the extent of one-sixth or a greater degree, it would be possible to make the human body so “light” that it could be propelled with a very small fraction of present effort.
Steamships could ride more lightly on the sea in the same way. The speed of railroad trains could be increased by the contrivance reducing the friction of the wheels on the tracks.
An aeroplane caught high in air with a broken engine could be made to float there indefinitely by turning a button and starting the “concentrating dynamo.”
Farrow never filed a patent for his device, and no construction plans have been found. The book The Spirit of Invention: The Story of the Thinkers, Creators, and Dreamers says:
Observers watched as the indicated weight of the book dropped by three ounces, or one-fifth. “This is revolutionary — even sensation,” marveled one of the editors invited to see the invention in action. It almost certainly wasn’t antigravity, though, not in the sense Farrow intended… Modern speculation has accepted that it was based around electromagnets.
HOW TO OVERCOME GRAVITY BY HERTZIAN AIR WAVES: New York Engineer and Inventor Thinks He Has Discovered a Secret of Science on Which He Began Work at West Point Nearly 40 Years Ago. (PDF)
From July 16, 1911