The Sky-Math Garden

[Images: Via Peter Moore’s piece on “dueling weathermen” over at Nautilus].

As mentioned in the previous post, I recently had the pleasure of reading Peter Moore’s new book, The Weather Experiment. There are many interesting things in it—including the London “time ball,” of course—but one scene in particular stood out for its odd design details.

In 19th-century Philadelphia, Moore explains, climate scientist James Espy began building a miniature model of the earth’s atmosphere in his back garden on Chestnut Street. This microcosm was a nephelescope, or “an air pump attached to a barometer and a tubular vessel—something of an early cloud chamber.”

Espy’s larger goal here was to understand the sky as a complexly marbled world of colliding fronts and rising air columns, “an entire dynamic weather system” that could perhaps best be studied through replication.

The sky, that is, could be modeled—and, if correctly modeled, predicted. It was just a question of understanding the physics of “ascending currents of warm air drawing up vapor, the vapor condensing at a specific height, expanding and forming clouds, and then the water droplets falling back to earth.”

Under different atmospheric conditions, Espy realized, this system of vaporous circulation was capable of producing every type of precipitation: rain, snow, or hail. His task then became to calculate specific circumstances. What temperature was needed to produce snow? What expansion of water vapor would produce would be required to generate a twenty-mile-wide hailstorm?

Why not construct a smaller version of this in your own backyard and watch it go? A garden for modeling the sky.

I love this next bit: “To work with maximum speed,” Moore writes, “he had painted his fence white, so he could use it like an enormous notebook.” The entire fence was soon “covered with figures and calculations,” Espy’s niece recalled, till “not a spot remained for another sum or calculation.”

Espy’s outdoor whiteboard, wrapped around a “space transformed into an atmospheric laboratory, filled with vessels of water, numerous thermometers and hygrometers,” in Moore’s words, would make an interesting sight today, resembling something so much as a set designed for an avant-garde theatrical troupe or a student project at the Bartlett School of Architecture.

Indeed, Espy’s lost sky-math garden suggests some interesting spatial possibilities for a sort of outdoor scientific park, a piece of urban land replicating the atmosphere through both instruments and equations.

The London Time Ball

timeball[Image: The London “time ball” at Greenwich, courtesy Royal Museums Greenwich].

Thanks to the effects of jet lag getting worse as I get older, I was basically awake for five days in London last week—but, on the bright side, it meant I got to read a ton of books.

Amongst them was an interesting new look at the history of weather science and atmospheric forecasting—sky futures!—by Peter Moore called The Weather Experiment. There were at least two things in it worth commenting on, one of which I’ll save for the next post.

This will doubtless already be common knowledge for many people, of course, but I was thrilled to learn about something called the London “time ball.” Installed at the Greenwich Royal Observatory in 1833 by John Pond, England’s Royal Astronomer, the time ball was a kind of secular church bell, an acoustic spacetime signal for ships.

It was “a large metal ball,” Moore writes, “attached to a pole at the Royal Observatory. At 1 p.m. each day it dropped to earth with an echoing thud so that ships in the Thames could calibrate their chronometers.” As such, it soon “became a familiar part of the Greenwich soundscape,” an Enlightenment variation on the Bow Bells. Born within sound of the time signal…

timeball1[Image: Historic shot of the time ball, via the South London Branch of the British Horological Institute].

There are many things I love about this, but one is the sheer fact that time was synchronized by something as unapologetically blunt as a sound reverberating over the waters. It would have passed through all manner of atmospheric conditions—through fog and smoke, through rain and wind—as well as through a labyrinth of physical obstructions, amidst overlapping ships and buildings, as if shattering the present moment into an echo chamber.

Calculating against these distortions would have presented a fascinating sort of acoustic relativity, as captains and their crew members would have needed to determine exactly how much time had been lost between the percussive thudding of the signal and their inevitably delayed hearing of it.

In fact, this suggests an interesting future design project: time-signal reflection landscapes for the Thames, or time-reflection surfaces and other acoustic follies for maritime London, helping mitigate against adverse atmospheric effects on antique devices of synchronization.

In any case, the other thing I love here is the abstract idea that, at this zero point for geography—that is, the prime meridian of the modern world—a perfect Platonic solid would knock out a moment of synchrony, and that Moore’s “echoing thud” at this precise dividing line between East and West would thus be encoded into the navigational plans of captains sailing out around the curvature of the earth, their expeditions grounded in time by this mark of sonic punctuation.