[78-L] 2-sided record article (origins of)

[AllenAmet at aol.com]

Hi
 
  In about two weeks there will be an interesting article  published on the 
origins and early history of, two-sided records.
 
  One of the few remaining puzzles is how Colin McKenzie got a  Canadian 
patent for the concept in Dec 1904, when Ademor Petit already had it,  in 
Canada: 75705 (1901-1902).
 
Allen