Today, more about Ada, Babbage, and a dream
realized. The University of Houston's College of
Engineering presents this series about the machines
that make our civilization run, and the people
whose ingenuity created them.

When Charles
Babbage died in 1871, he left a puzzling array
of unfinished calculating machines. They fell into
two classes -- difference engines and analytical
engines. His difference engines were meant to
calculate math tables -- logarithms and trig
functions. His analytical engines would have been
the first computers, if they'd ever been built.

He never finished any of his engines. His funding
always ran out. He made only parts of each kind.
Worse yet, he wrote little about what he was doing.
Lord Byron's daughter Ada
did much to explain the class of analytical
engines. She published a series of notes about the
concept.

It seems pretty clear that the widower Babbage
loved Ada. But Ada was married. When she died,
still young, from cancer, her mother destroyed any
of her correspondence from Babbage. So we're left
to guess.

As for Ada, she loved mathematics and betting on
horses. She probably loved Babbage as well. She'd
learned much of her mathematics from him. She
helped preserve his legacy, but she told us only
about his analytical engines. What about his
difference engines?

A group at the London Science Museum has actually
built Babbage's last engine -- his Difference
Engine No. 2. It cost a half million dollars, and
it weighs three tons.

And it really works. It can calculate numbers to 31
decimal places. That's far more accurate than your
pocket calculator. Of course it's much slower. It'd
take 22 hours of cranking by hand to get that
result. Now the museum is trying to raise another
$360,000 to build the printer Babbage designed to
go with it.

The museum has used 19th-century materials and
technology. Not only did Babbage's mind run a
century ahead of its time. Now we see that Babbage
really could've built computers with 19th-century
resources, if only he could've mustered those
resources.

For years we've known about Babbage's so-called
Analytical Engine. In fact it was not one engine,
but a class of computers. He built parts of his
analytical engines just as he built parts of his
difference engines.

Ada Byron's notes fixed the Analytical Engine in
our minds as a single machine. She left us with a
keen sense of unfinished business. But by focusing
our vision of Babbage, she also limited it. Now we
begin to see that he was even more advanced than we
realized. With a little more government funding, he
might've changed the course of history.

I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.

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