At Harvard, Lewis also wrote a theoretical paper on the thermodynamics of [[blackbody radiation]] in which he postulated that light has a pressure. He later revealed that he had been discouraged from pursuing this idea by his older, more conservative colleagues, who were unaware that W. Wien and others were successfully pursuing the same line of thought. Lewis’ paper remained unpublished; but his interest in radiation and , and (later) in [[theory of relativity|relativity]], sprang from this early, aborted effort. From the start of his career, Lewis regarded himself as both chemist and physicist.
