William Joseph Hammer

[4] He was chief engineer when the English Edison Electric Light company built a central station in London to power 3,000 incandescent lamps on the Holborn Viaduct.

The collection eventually was purchased by General Electric placed in the Greenfield Village Museum, established by Henry Ford.

[10] In 1903, he and Dr. Willy Meyer used radium to treat an incurable tumor, and it was observed to shrink and become less painful, though the patient was not cured.

The essence of his idea was that a filament would glow within a glass envelope from which the air had been evacuated when electrically energized with direct current (DC).

After being heated to incandescence for a few hours, carbon from the filament would be deposited on the inside walls of the bulb, turning it black.

Hammer noticed the carbon seemed to be coming from the end of the filament that was attached to the negative terminal of the DC power supply, and seemed to be flying through the vacuum onto the walls of the bulb, a phenomenon that Edison observed in 1875.

That is, electricity was flowing not only through the filament but also through the evacuated bulb, a phenomenon initially reported in 1873 by Frederick Guthrie in Britain.

If the extra electrode (also called a "plate" or "anode") is made more positive than the hot filament, a direct current flows through the vacuum.

Ruth Plumly Thompson, author of the "Oz books" after L. Frank Baum died, made some references to Hammer in a fantasy context.

A note on the title page of Grampa in Oz (1924) reads: "This book is dedicated, with deep affection, to Uncle Billy (Major William J.