In August 1927, a young engineer named Harold Black took a ferry
from Staten Island, New York, to work. To pass the time on that
summer morning, he jotted down some equations about a new idea.
During the next few months, he polished the idea and then applied
for a patent. But as so often happens with a truly new idea, it was
ridiculed. The patent office rejected his application and classified it as
another one of those “perpetual-motion follies.” But only for a while.
Black’s idea was negative feedback.
