Incidentally, I finally figured out what to do about my burnt-out lights. Months after the first burned out, and a week after the second, I remembered I live in faculty housing, a set of a couple hundred apartments built to only a few variants on the same design. And there's the convenience store in the complex, which caters nearly exclusively to the faculty housing, and to which I go basically every two or three days. And they stock everything from frozen ``bagels'' to bamboo poles for laundry. So, yes, they had light bulbs. And as I say, I've only been fussing with one burned out light since November. Don't go telling me advanced mathematics degrees leave you unable to solve ordinary household problems.
These new bulbs -- circular, hooking on by three metal clasps that hold by friction, instead of what I'd like, resting on clamps themselves screwed in to the ceiling -- look brighter than the old, probably just because they're whiter. I don't know the specs of my old lights, but these are ``40 Watt, Daylight 6500 K'', from Panasonic, which I didn't know made light bulbs. I kind of thought light bulbs just grew at Hannaford's, then came home to my ceiling fan in the Troy apartment, where they burned out in two weeks.
I just bought one the first day, and took it home -- in a box about the right dimensions for a pizza, which I kept holding horizontally -- and found these bulbs were the right size. So when I went back the next day to buy a new one, the cashier (naturally) remembered me, and wondered what was wrong. I explained the other light had also burned out, and he was sorry and offered to replace the previous day's. I tried to explain that I had two lights of the same kind that are burned out. He didn't seem to believe me that the two would burn out so close to one another, and while they didn't, I felt like it'd be too ridiculous to tell him what really happened, so I just said it was an odd coincidence, but probably natural if the old bulbs were installed at the same time. He accepted that, but I think he was being polite.
Trivia: If two positive integers are picked at random the probability they will be relatively prime is 6/π2. Source: Mathematical Recreations and Essays, WW Rouse Ball and HSM Coxeter.
Currently Reading: Gotham: A History of New York City to 1898, by Edwin G Burrows, Mike Wallace.