"He had learned it didn’t pay to protect his secrets [with a patent]. "

NICK BILTON in the New York Times on 5 August 2012. writing on the Apple/Samsung patent business in ND Cal brought up a case from 1933:

Mr.[Horace] Goldin filed a lawsuit against the R. J. Reynolds Tobacco Company for using this magic trick in an advertisement and explaining how it worked. According to an article in The New York Times from March 1933, Mr. Goldin, who had won a patent for the illusion a decade earlier, asserted that the ad had adversely affected his ability to get people to see his shows. He asked for $50,000 in damages. (That’s about $865,000 in today’s dollars.)

Goldin of course lost. Bilton writes:

It seems that even if Apple wins the patent case against Samsung, it may find itself in the same pickle that Mr. Goldin did 80 years ago.

Although the federal court threw out Mr. Goldin’s claim in 1938, the damage had already been done. Besides the large legal fees, the news media brought more attention to how the magic trick of sawing a woman in half actually worked — it was no longer magical.

Goldin did not patent his next trick, relying instead on the vehicle of trade secret.

See Disruptions: At Its Trial, Apple Spills Some Secrets