Miscellaneous Ramblings

by Fred Ray on December 20, 2010 · 0 comments

In spite of having a lot of Civil War related material I have been missing in action for the last few weeks or so writing an article on the battle of Fort Mahone and updating a rescue book. However, I hope to have a bit more time to blog.

Some time ago I posted on Victorian calculators and computers. Now there’s a fellow who built a working copy (albeit not to Babbage’s degree of precision) out of legos! There’s also a nice explanation of how the “difference” math works.

Even cooler is a working model of the Antikythera Mechanism, which was built over 2,000 years ago in Greece, also in legos, along with a nice video of how it works.

An interviewer asks if it’s really a computer, and the builder, Andrew Carrol, replies.

Yes, but in a slightly different way than we’re used to using that word. It’s an analog computer, which means it can’t execute programs. But the word “computer” used to be the name given to people who could do tedious math. In the 19th century there were rooms of people called “computers” who were skilled at arithmetic, supervised by a mathematician, who would create tables at great expense that navigators and sailors would use. But when we finally had mechanical devices that could do similar things, they got that name: computer.

But analog computers were still very useful up through the 1940s. World War II battleships would have a mechanical computer in their artillery, so that when you wanted to fire, you’d turn cranks to figure out how many times is this gun to be fired, how far is the other ship, what’s the wind velocity, that sort of thing. And when you turned all the cranks, the gear ratios would tell you how to adjust your aim. So the Antikythera Mechanism, and my Lego version, are both just simple mechanical computers: you turn the crank at one speed and all the wheels move at a another speed, which you’ve calibrated to have a particular meaning — in this case, predicting the cycles of astronomical bodies.

I would add that mechanical analog computers continued to be used well into the 1980s in tanks. US tanks have, since the 1950s, had mechanical analog computers to figure the correct superelevation for the main gun using various types of ammunition. As a young armor officer I got to use these, which featured a steel “snail” cam to do the computing. Not until the mid-80s did the Army switch over to laser rangefinders and digital computers.

As for the Late Unpleasantness, there are a number of sites that are covering the sesquicentennial and the issues of the war. Nevertheless those same issues—secession and popular sovereignty—are still alive and well today.

Paul Rahe takes a look at secession and the legality thereof.

One hundred fifty years ago today, the state convention called by the legislature of South Carolina after the election of Abraham Lincoln to the Presidency voted for secession from the Union. Soon thereafter, it dispatched commissioners to urge the other southern states to follow its example, and in February, 1861 the first set of states to vote for secession formed the Confederate States of America. The Civil War began in April with the attack on Fort Sumter in the harbor at Charleston, South Carolina.

Although it makes a convenient marker today, Fort Sumter was only one of many incidents that eventful summer. What really set the country on the road to war, to my mind, was Lincoln’s call for 75,000 volunteers. This converted what had been essentially a local issue into a national one and forced everyone to choose sides.


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