the host has the wrong timezone (+0000, should be -0400), and is ?2 hours slow.
is a bad Date: enough to fool it ?  ( note that time is mutable in us )

$ wget http://thomas.loc.gov/r107/r107.html
--11:55:59--  http://thomas.loc.gov/r107/r107.html
           => `thomas.loc.gov/r107/r107.html'
	   Connecting to cache.visi.com:3128... connected!
	   Proxy request sent, awaiting response... 200 OK
	   2 Age: 21396
	   3 Accept-Ranges: bytes
	   4 Date: Wed, 15 May 2002 10:59:23 GMT
	   5 Content-Length: 80877
	   6 Content-Type: text/html
	   7 Server: Apache/1.3.9 (Unix) ApacheJServ/1.1
	   8 Last-Modified: Tue, 14 May 2002 22:22:11 GMT
	   9 ETag: "809-13bed-3ce18e13"
	   10 Via: 1.1 c720-2-mpls (NetCache NetApp/5.3)
	   11

The sizes do not match (local 99273) -- retrieving.
The sizes do not match (local 99273) -- retrieving.
The sizes do not match (local 99273) -- retrieving.
--12:27:06--  http://thomas.loc.gov/r107/r107.html
           => `thomas.loc.gov/r107/r107.html'
	   Connecting to cache.visi.com:3128... connected!
	   Proxy request sent, awaiting response... 200 OK
	   2 Age: 92
	   3 Accept-Ranges: bytes
	   4 Date: Wed, 15 May 2002 17:25:34 GMT
	   5 Content-Length: 81238
	   6 Content-Type: text/html
	   7 Server: Apache/1.3.9 (Unix) ApacheJServ/1.1
	   8 Last-Modified: Wed, 15 May 2002 12:25:46 GMT
	   9 ETag: "809-13d56-3ce253ca"
	   10 Via: 1.1 c720-2-mpls (NetCache NetApp/5.3)
	   11