Old tuning forks, pitch standards

[Mike and Jane Spalding]

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List,

Today an older gentleman at our church gave me 3 old tuning forks that =
had belonged to his wifes uncle, a piano tuner.  I am curious to know  =
their approximate age, and also what, if anything, they tell us about =
the history of pitch standards.

The largest, (and probably the youngest) fork is 125 mm overall length, =
with tines about 5mm x 6mm.  It is stamped"DEAGAN  CHICAGO", "A=3D440", =
"OFFICIAL PITCH A.F. OF M. 1917", and "ADOPTED BY U.S. GOVT. 1920". =20

The next smaller fork is 110mm overall, with tines about 4mm by 5mm.  It =
is stamped "INTERNATIONAL PITCH C 517.3" (which is the frequency of C52 =
when A49 is at 435).

The smallest fork is the same length, 110mm, but the tine cross section =
is 2mm by 5mm, and the 2mm dimenstion is very irregular as if it had =
been shaped by hand.  Probably due to the irregular cross-section and/or =
small size, it's sustain time is very short. It is stamped =
"PHILHARMONIC", and "A".  This fork is about 16 cents sharp of 440.

Are there any good written resources for learning more about the history =
of these forks, or their makers?  Anybody out there old enough to have =
personal knowledge?

thanks



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