I've just acquired a book published in 1959 which states that some West Coast areas use 50Hz supplies and that parts of upstate New York have 25Hz power.
Now I know from discussions here in the past that the Los Angeles area once had 50Hz power but switched to 60Hz in the 1930s, but just how many other areas used something other than 60Hz?
And were 50 and even 25-Hz systems really still in use as recently as the late fifties?
