Whipped Cream Difficulties

I’ve stumbled across two articles in the past couple of days that I commend to your attention. At least, if you’re as fascinated with this kind of thing as I am.

1) If you own a Patek Philippe Caliber 89 watch (I know many of my readers do: if you happen to be one of the unfortunate ones who does not, Sotheby’s is auctioning one soon), you’re going to have to get it serviced.

Why? The Caliber 89 has a unique feature (or, as high-end watch folks call it, “complication”): it will tell you what day Easter falls on each year.

It turns out that computing the date Easter falls on is simultaneously two things:

a) Relatively hard to do.

Easter is one of the “moveable feasts” of the Christian calendar; it falls on a different date every year. The reason is this: the basic rule for Easter is that it falls on the first Sunday after the first full moon of Spring (that is, the first full moon after the Spring Equinox) and because both astronomical events are variable, the Easter date changes every year. (As with any calendrical irregularity, there have been various proposals over the centuries to just pick a single date, but so far nothing has stuck). For this reason, Easter can fall anywhere between March 22 and April 25.

b) Relatively easy to do for a digital computer. I think you could probably fit a program to do this in 4K of BASIC, or even run it on a good programmable calculator.

But the Caliber 89 is a totally mechanical watch. How does it calculate the date of Easter? There’s the problem:

A method for calculating the Easter date is called a computus; is it possible to make a true mechanical computus, rather than relying on a program disk? The answer is, “sort of.” The first true mechanical computus appears to have been made not long after Gauss came up with his algorithm, and it currently resides in a place more horological enthusiasts should know about: the great astronomical clock in the cathedral at Strasbourg, in Alsace, France. There have actually been three successive astronomical clocks there since about 1354, but the most recent was completed in 1843. Designed by Jean-Baptiste Schwilgué, it has a true mechanical computus – probably the first ever constructed. It’s not the only mechanical computus, but I haven’t been able to find anything in English on other computus devices (although a reprint of a review of a book on the Strasbourg computus mentions at least two other “similar” mechanisms).

Even if you are not a high-end watch person, there’s still a lot in this article that I think is interesting: mostly the discussion of how Easter calculations work, and of the Strasbourg clock (which I’d really like to see one of these days).

(Hattip: The YCombinator Twitter.)

2) I’m a fan of Stephen Hunter’s work, and one who wishes he had time to write more non-fiction. I enjoy his novels, but I also think he’s an outstanding non-fiction essayist and writer. (Mr. Hunter, if you’re out there: I’d buy a hardback collection of your shorter works.)

The most recent American Rifleman has a Hunter article that pushes several of my buttons at once: “A Battle At Barrington: The Men & The Guns”.

You may have heard of the “Battle of Barrington”, though not under that name. It is also covered in Bryan Burrough’s Public Enemies, a book both Hunter and I like a lot. This was the famous shootout between agents of what became the FBI and Lester Gillis, aka “Baby Face” Nelson. Gillis, his wife, and his partner John Chase were being pursued by (and shooting it out with) FBI agents when their vehicle was disabled: they were cornered by agents Samuel Cowley and Herman Hollis. In the ensuing shootout, Gillis killed Cowley and Hollis, and fled in their car: however, Gillis himself was mortally wounded by the agent’s gunfire and bled to death. (Chase and Mrs. Gillis were captured later: Chase spent 33 years in prison, and Mrs. Gillis served one year.)

The nice thing about Hunter’s article is that he addresses the firearms and tactics used by both sides. This sort of analysis is not a strong point of Burrough’s book: Hunter and his researcher actually went back to the old FBI files and turned up some new information.

The FBI’s records are full of fascinating facts about the event. For one thing: these guys weren’t just loaded for bear, they were loaded for bears, a lot of them. Found in the abandoned Model A: three bulletproof vests, five empty magazines for .38 Super automatics; two filled machine gun magazines (presumably Thompson 20 rounders); 200 rounds of loose .45 ammunition, three empty .351 magazines, three boxes of .30-’06 Sprg. soft-nose ammunition; one box of Springfield boattailed ammunition, five boxes, .45 Colt automatic ammunition, two boxes of Springfield bronze-pointed ammunition. One tan briefcase containing one loaded 100-round drum for the Thompson submachine gun; 10 boxes .22 Long Rifle; one Colt Ace .22 Long Rifle pistol and magazine. The last is a revelation: Chase had bought the M1911 variant with a lightweight .22 slide and barrel. Perhaps he and Les used it for low-cost practice on their various travels.

And, as you know, Bob, I love me some Thompsons. My one complaint about Hunter’s article, though, is that he consistently places the Miami Dade FBI shootout in 1987: it actually took place April 11, 1986.

This quote is for Karl (wink wink nudge nudge):

[Hollis] should have used his Super .38, firing prone, two handed, as that round’s velocity and straight-line trajectory could have gotten the job done, ending up center mass in Les. But he hadn’t been trained to two-handed prone shooting. In fact he hadn’t been trained to anything! The soon-to-be Bureau’s firearm training program didn’t begin until 1935!