### I have a cold

Mar. 6th, 2014 11:04 pmOn Saturday I learned that there's an Asimov book called

*An Easy Introduction to the Slide Rule*. My copy arrived on Monday, way faster than I expected, and I read through as much as I could follow without having a slide rule in hand.

My slide rule arrived today, fresh from eBay. It's the oldest object I own by a wide margin (fossils excepted, I suppose), a Keuffel & Esser rule made in 1940. Keuffel and Esser, after slide rules stopped being a thing, kept making regular rulers and other drafting equipment, under the name K&E, until I was a kid. My father always had a bunch of their stuff laying around from surveying.

I don't really know how to do much yet. I can multiply numbers and find square roots, that's about it. The thing is actually pretty handy: you slide the middle part so that one end is lined up with one of the numbers you're multiplying, and the answer is under the other one. The way it works is that they're not linear rulers, they're log scales. Anyway, it's an interesting tool because of what it doesn't do: in order to work at all, it only deals with numbers between 1 and 10. So, you have to track the decimal points yourself, which isn't actually that hard. It's also limited in how precise it can be (being, you know, a piece of wood and all), so really what it is is a quick way to estimate answers, more accurate than an order of magnitude (since you have to track that part yourself anyway) but less accurate than getting the actual answer with arithmetic.

House-wise, we have no internet yet, because of a dog, but we finished putting together my desk today, and moved some more boxes over. This weekend (assuming I get over being sick) I hope to move all the board games over, and the electronics table in my room.