The Universe of Disco

Why no disco balls

A couple of months ago I asked why the disco ball had to wait until the 20th century:

The 17th century could produce mirrors by gluing metal foil to the back of a piece of glass, so I wonder why they didn't. They wouldn't have been able to spotlight it, but they certainly could have hung it under an orbiculum. Was there a technological limitation, or did nobody happen to think of it?

I think the lighting issue is the show-stopper. To make good use of a disco ball you really do need a dark room and a spotlight. You can get reflections by hanging the ball under an orbiculum, but then the room will be lit by the orbiculum, and the reflections will be pale and washed out, at best.

Long ago I attended a series of lectures by Atsushi Akera on the hidden prerequisites for technological adoption. For example, you can't have practical skyscrapers without also inventing elevators, and you can't have practical automobiles without also inventing windshield wipers. (And windshields. And tires. And … )

This is an amusing example of the same sort. You can't have practical disco balls without also inventing spotlights.

But now I kinda wonder about the possibility of wowing theatre-goers in 1850 with a disco ball, lit by a sort of large hooded lantern containing a limelight and a (lighthouse-style) Fresnel lens.

[ Addendum: Apparently, nobody but me has ever used the word “orbiculum”. I don't know how I started using it, but it seemsthat the correct word for what I meant is oculus. ]

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Benjamin Wade

Yesterday Katara asked me about impeachment, and in mentioning the impeachment of Andrew Johnson, I realized that I didn't know who would have assumed the presidency, had Johnson been convicted. Who was Johnson's vice president?

Well, I couldn't remember because he didn't have one. Until the ratification of the 25th Amendment in 1967, there was no provision for the replacement of a vice-president except through a normal election.

Under the Presidential Succession Act of 1792, next in line was the President Pro Tempore of the Senate. This is a largely ceremonial position, filled by a senator, and elected by the Senate. The President Pro Tempore in 1868 was Benjamin Wade, senator from Ohio. Wade, as a senator, would be voting on Johnson's conviction and therefore had an enormous conflict of interest: if Johnson was removed, Wade would assume the presidency.

There were calls for Wade to abstain from voting. Which he did. Not! Ha ha, of course he didn't. He voted to convict.

The conviction, famously, fell short by one vote: it went 35–19 in favor of conviction, but they needed 36 votes to convict. Suppose it had gone 36-18, with Wade's vote being the 36th, and Wade taking over the presidency as a result? Wikipedia claims (with plausible citation) that at Wade told at least one other senator what cabinet position he could expect to receive in exchange for his vote to convict.

1. How could those 1792 folks not have foreseen this? Sheesh.

2. Government is hard. Really, really hard.

3. Thinking about the Civil War era of U.S. history, I always have ambivalent feelings. First, hope and relief: “Our current situation could be much worse than it is”, followed by dread: “Our current situation might get much worse than it is”.

[ Maybe I should also mention that many sources suggest that Johnson would have been removed had his successor been someone less divisive than Wade. ]

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