🚀 go-pugleaf

>From article <50...@convex.convex.com>,
by da...@convex.com (Anthony A. Datri):
> 
> As I understand it, the Analytical Engine would have been a digital, not
> analog, machine.

There is a very common misperception that Babbages analytical engine was
never built and that his difference engines never came to much.  This is
FALSE.

Babbage never completed his large-scale plans for the difference engine,
but he did get sections of it to work, and he did publish descriptions
of his work (most notably in the Edinburgh Review?)  During Babbage's
lifetime, a Swede who read one of his articles got so excited by the idea
that he built a working difference engine and exhibited it at a world's
fair type exhibition in London (read about it in Babbage's "Reflections
on the Life of a Philosopher).  Babbage traces the machine to the US Naval
Observatory -- where is it now?  A copy of the machine was built and put
to use by the British government -- again, where is it now?

By 1910, difference engines were being routinely used for the purpose
Babbage originally intended, evaluating interpolating polynomials to
produce mathematical tables.  I found one German book of tables of higher
mathematical functions that included a photograph of the hand-cranked
printing difference engine they'd used to produce the tables in the
book, along with a 20 page description of exactly how it was done.
They didn't cite Babbage at all, but it's hard to imagine there not
being a link.

Babbage's son (Willian Henry Babbage?) built a scaled down version of
the analytical engine sometime around the turn of the century.  It's
in the Royal Science Museum in London today.  I've seen photos of it, and
it is beautiful.  The microcode is on a music-box mechanism near the
hand crank that runs the engine, and the entire mill (cpu to use modern
terms) is built on top of a nice looking Victorian-era oak desk.
Apparently the engine was used to compute a table of logarithms, but one
writer said it kept jamming.

Maurice Wilkes, the modern re-inventor of microcode, says (in his book
"Menoirs of a Computer Pioneer") that if he'd only known of Babbage's
work, he'd have gotten his first computer working years sooner than he
did.

Sadly, there were mathematicians who did remember Babbage at that time.
I found another table of mathematical functions, published in the late
1930's, with a photo of "Babbage's Analytical Engine" as a frontspiece,
and a dedication that read something like "In the hope that Babbage's
dream of mechanical computation will someday be realized."

				Doug Jones
				jo...@herky.cs.uiowa.edu