The SciencesMarch 22, 1913
A Direct Current Motor from a Telephone Ringer
Stories by Guy Hubbard
The SciencesApril 27, 1912
What Inventors are Doing
Simple Patent Law; Patent Office News; Inventions New and Interesting
A Direct Current Motor from a Telephone Ringer
What Inventors are Doing
Simple Patent Law; Patent Office News; Inventions New and Interesting