Envelope windows

In order to comply with recycling requirements for the state of
Georgia, I have to separate what I have assumed to be the "glassine"
portion of the window from the plain paper portion of the envelope
when disposing of my mail.  And this got me thinking about the
material from which the window is made.

So I'm on the airplane catching up on my reading during the
holidays, perusing The University of Chicago Alumni Magazine when I
discovered that Julius Regenstein (the ancestor of Joseph Regenstein
for whom the main library is named) invented the one-piece window
envelop in 1903. This was considered a boon because envelops would
not have to be individually addressed.  There was, however, concern
about the security of the item in an envelop with an open window.
So, according to what is written on page 29 of the December
magazine, "Julius created a plasticized varnish that penetrated the
fibers of the envelop and made it translucent, letting the address
show through."

Does anyone know if, in fact, that was the means by which early
window envelops were created?  Has my assumption about the current
material used for the windows been misguided?  I wasn't aware that a
"plasticized varnish" was ever a contributing element. I know
newspapers and alumni magazines don't always get it quite right so
I'd be grateful for any additional information.

There is, incidentally, in the same issue an article on the use of
Chicago's new Advanced Photon Source for examining archaeological
objects at the Oriental Institute
<URL:http://www2.uchicago.edu/alumni/alumni.mag>

Hilary A. Kaplan
Conservator
Georgia Department of Archives and History
330 Capitol Avenue
Atlanta, GA 30334
404-656-3554
Fax: 404-651-8471

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                  Conservation DistList Instance 12:56
                 Distributed: Tuesday, January 5, 1999
                       Message Id: cdl-12-56-017
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