Equinox, 1771 Edition

Yesterday was our autumnal equinox (no, I will not surrender my boreal chauvinism to call it “September equinox”). I’ve seen this day from Berkeley’s latitude for decades now, and it never really feels like fall. While the days are getting shorter and the light is slanting in more acutely day by day, it’s the warmest month of the year there, non-fall. The real herald of the seasons in the northern half of California is the arrival of the first substantial rain, and that can happen any time from now through the end of October in what we like to call a “normal” year.

Still, on every equinox, I go through the same exercise in my head of trying to imagine our planet in space, its axis tilted roughly 23 and a half degrees to the plane of our orbit around the sun (I think I have that right). And while I can recite what’s supposed to be happening out there from equinox to solstice to equinox to solstice, I honestly have a hard time wrapping my brain around it (believe me, I have done the kitchen table demonstrations of the axial tilt and how first one pole and hemisphere, then the other are inclined toward the sun (and how the inclination accounts for our terrestrial seasons). And I’ve played those demonstrations out mentally hundreds of times; maybe I have trouble imagining all this happening in 3D or something.

Anyway, it struck me yesterday that it might be amusing to compare how the equinox was defined by, say, Samuel Johnson when he compiled his dictionary in the second half of the 18th century and maybe compare that to some contemporary definition. I looked–by way of Google Books–and I didn’t think it was that amusing. But I found something better: an article on astronomy from the 1771 edition of the Encyclopaedia Britannica. And in the course of the long, long recounting of late 18th century astronomical knowledge–hey, they knew a lot back then–I came upon this: “Chapter VIII. The different Lengths of Days and Nights, and Vicissitudes of Seasons, explained.”

The chapter starts:

“The following experiment will give a plain idea of the diurnal and annual motions of the earth together with the different lengths of days and nights and all the beautiful variety of seasons depending on those motions. Take about seven feet of strong wire and bend it into a circular form, as abcd, which being viewed obliquely appears elliptical, Plate XLI fig. 3. Place a lighted candle on a table and having fixed one end of a silk thread K, to the north pole of a small terrestrial globe H, about three inches diameter, cause another person to hold the wire circle so that it may be parallel to the table and as high as the flame of the candle which hould be in or near the centre. …”

Read the whole thing for yourself, or just as much as you can handle, and let me know how you make out causing another person to hold your stiff wire circle. Just for fun, up above is the plate referred to in the suggested experiment, the description of which goes on and on.

Getting It Straight

The New York Times ran a nice little commentary Tuesday on the factual reliability of Wikipedia, the collaborative online reference to everything, and the Encyclopaedia Britannica, the hoary compendium of everything worth knowing. The Times mostly recapitulates the findings of a study published last month in Nature that compared science entries in the Wikipedia, which depends on community writing and editing, and Britannica, which relies on subject experts for its authority. An encyclopedia open to all comers to add to and alter at will would seem fraught with risk and likely to be rife with errors compared to a work created under strict editorial control. But the Nature study sampled 42 entries in both works and found that Wikipedia articles contained four errors per article on average; Britannica articles contained an average of three errors.

I’ve made my living in a media culture that believes in the importance of accuracy and quality and refinement — qualities best obtained, it is widely believed, by employing someone like me. At the same time, I’ve lived in terror of the blind, witless blunder that makes it into print; either under my name or worse, by my hand under someone else’s name. The fear comes from having learned that editorial perfection is a moving target: The state of knowledge on most subjects is ever evolving and changing. One minute someone has never had sex with that woman, Miss What’s-Her-Name; the next they’re apologizing for the sex they had with her. Follow that? It’s not so different, really, from trying to keep your facts straight on politics, history, religion, science, or theories of modern marketing. The best you can do is aim to be correct at a given moment and be ready to reassess your work the minute you see it out in the world.

So it’s not surprising to find the Encyclopaedia Britannica isn’t the unassailable tower of knowledge some of us might like to believe it is. What’s more surprising, to me, is that the masses, turned loose on a universal encyclopedia project, don’t do so badly. The Times’s commentary has a nice simile for how it works:

“It may seem foolish to trust Wikipedia knowing I could jump right in and change the order of the planets or give the electron a positive charge. But with a worldwide web of readers looking over my shoulder, the error would quickly be corrected. Like the swarms of proofreading enzymes that monitor DNA for mutations, some tens of thousands of regular Wikipedians constantly revise and polish the growing repository of information.”

“Thousands of regular Wikipedians” is the key. Editors are important. It’s just that they don’t need a special license or a paycheck from a publisher to do the work passably well.