## Electric “Brain” Weighs Three Tons (Aug, 1935)

Electric “Brain” Weighs Three Tons

Computing Machine Can Run Rings Around Einstein in Solving Mathematical Kinks of the Way that the Universe OperatesTHE “Brain Trust” now runs a risk in the competition of the big, complex machine shown above, which was recently built in the school of electrical engineering at the University of Pennsylvania, in Philadelphia, by C. W. A. workers with government funds. Now, it is said, the U. S. Army wants another like it, and would ask to take this over in case of war. The explanation is that it is a machine for solving the most complicated mathematical problems, and doing this in a hurry. In fact, it can solve problems too complicated for any living mathematician to work outâ€”with an answer not always guaranteed mathemically exact, but at least good enough for practical purposes.

The purpose is to show what will happen when several continually changing factors enter into the case; in other words, to perform operations in the calculus, when they become exceedingly intricate. The “fire, control” machines, now used to plot the flight of shells from modern guns in moving ships, against moving targets, deal with practical conditions like this; and the machine pictured could answer a question of this nature, as well as a good many others less specialized. For instance, three or more heavenly bodies (like Earth, Sun, and Moon) are moving in their orbits at different rates of speed and varying distances, attracting each other. What will be the combined result of their forces, in changing the positions of each, in a given period? It is an enormously difficult proposition for the best mathematician in the world. With this machine, its ten “integrators” would be adjusted (by setting dials) to represent the varying factors of the problem, and then started turning. The friction discs and gears of the machine would operate on each other, each of them with an effect proportioned to the energy and speed it represented; and, on the final chart at the “answer table” of the machine (see illustration) a curve would be drawn by a metal pen, representing the formula desired (not necessarily a physical picture of the motion of one of the heavenly bodies, but a mathematical picture of it). The machine operates on the principle of one designed by Dr. Bush, of the Massachusetts Institute of Technology, three years ago (as illustrated in this magazine at the time) but is much larger.

5:35 amAnd it worked by turning gears. It was about ten years later that the electronic ENIAC was built.

8:03 amI have always had a warm spot in my heart for the DA. They competed with computers up until the early 60’s for cost and reliability. One of our local universities still had a working one in the early 70’s. If’n you would like to see one work I suggest the George Pal movies ‘Destination Moon’ and ‘When Worlds Collide’.

10:25 am“an answer not always guaranteed mathemically exact, but at least good enough for practical purposes.”

Sounds like a Pentium predecessor for sure. Neat.

12:06 pmjmyint

Good catch! I should have referenced those movies myself (I’m a Pal fan from way back).

Here is a website that has animated pictures of a differential analyzer in action. http://web.mit.edu/klun…

12:20 pm“Computing Machine Can Run Rings Around Einstein in Solving Mathematical Kinks”

Albert was notoriously bad at advanced math but knew it and always sought mathematicians’ help it finding the proofs he needed.

4:43 pmI used to have the instruction manual for DA, and I could have had the thing itself at one point. But, I was 23 and foolish and didn’t do that.

Anyway, it is not in Destination Moon, but in

“When Worlds Collide”. In that movie it plays itself.

In “Earth vs the Flying Saucers” it plays a translation machine.

Penny

To build something like it, one should look in the

Amateur Scientist column of Scientific American–now available on CD. One needs to make a “force amplifier”.

Bush’s original was made from a British Meccano Set, by the way. He was a true mechanical genius.

4:44 pmAn electronic differential integrator is easy to make with op amps, and heathkit used to sell one–which I owned.

It was a lot of fun.

Penny

4:48 pmJmynt,

Would that local uni be UCLA–where I could have had mine in 1978-79?

Penny

It was being thrown out at the bottom floor junkpile of the Engineering building–where I was a Hedrick math prof–and I was astonished to see it.

It was like meeting an old friend, as I had built a small scale version earlier–after reading the SA article, and I had seen those movies.

4:52 pmBush was traveling in England, and Norbert Wiener suggested the idea to him–as an MIT project. He then tested the idea by going to a toy store and buying a Meccano Set.

That anyone could build a test D.A. from a toy

construction kit blew my mind.

Penny

Later MIT build the one shown in the article.

Bush and Norbert were the people who made MIT a great place. Norbert was a great mathematician who was not above dealing with engineers in a period when this was quite infradig. Another example of the same thing was Charles Proteus Steimetz, but

Wiener was a much greater mathematician.

8:01 pmPennyI have the “Destination Moon” DVD and a (if not THE) DA appears early in chapter 4 at 19:44 to 19:47.

I doubt if the soundman used the actual sound and used Yatzee dice in a cup instead.

1:35 amIt is my understanding that a moth in one of the relays of a Navy gun computer caused a failure… thereby originating the use of the term “bug”.

8:49 amWidely believed but a bit more involved than that http://en.wikipedia.org…

11:01 amDear J,

Thanks. I will look.

It is not good movie-writing, because later, when they change the launch window, the celestial mechanics expert is shown recomputing the trajectory using a SLIDE RULE.

” Give him a cup of hot coffee and all the assistance that he can use.”

Always happy to see DA in another movie!

11:06 amAt least they understood the CONCEPT of a mathematical trajectory computed from differential equations!!! We still had good high schools in America back then.

Could you imagine that in Star Trek?

” Mr Sulu, a course to Starbase 11 365 mark 3.”

“Sulu, what is he talking about? I will compute the usual maximizing geodesic in our 11 dimensional

warped product Lorentzian Hypermanifold.”

“Aye, Aye Sir”.

–Penny

7:37 amHello,

I am planning to publish a paper on the state of computers in 1935. I presented this paper in April 2011, at a symposium held by Hofstra University to celebrate their founding in 1935.

I included the photo above that shows three men using the Big Brain. The photo, however, will not reproduce well. Can you e-mail me a high-quality photo of Big Brain? I would also like your written permission to utililize this better photograph in the published paper.

I would greatly appreciate your providing with this information. Thank you very much.

Philip M. Sherman

pmsherman[email protected]