RFC 1925, "The Twelve Networking Truths", April 1996

Errata ID: 4939
Status: Reported
Type: Technical
Publication Format(s) : TEXT
Reported By: T Rogers
Date Reported: 2017-02-17

Section 2 says:

No matter how hard you push and no matter what the priority,
        you can't increase the speed of light.

It should say:

No matter how hard you push and no matter what the priority, 
you can't increase the speed of light. You can, however, 
slow it down.

Notes:

Light travels more slowly through media such as glass, and the speed depends on frequency - this is how refraction works.

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