November 25, 2008

The science

A while back, in one of the various catalogs that find their ways to our mailbox, I saw a listing for Weem's Stormglass with the following text...
Fernlike crystals? Expect cold and stormy weather. Clear liquid? Fine and dry. The Stormglass has reliably predicted the weather for 250 years. (Admiral Fitzroy used it on board the HMS Beagle during his voyage with Darwin in 1750.) No one knows quite how it works, but it does, indoors or out, without batteries. Brass cylinder holds a sealed glass chamber filled with crystals. Optional display plaque bears a brass plate explaining how to read the crystals and know what weather is coming. Plaque rests on a desk or hangs on a wall. Simple assembly. 10" x 8".
That sounds like some intriguing chemistry, and the "no one knows quite how it works" sounds like utter bullpucky, so I went researching.

The search for Weem's Stormglass didn't turn up anything other than links to the Signals catalog, but searching for a stormglass was a lot more productive. gives a little more info, telling a bit of history of the stormglass. According to About...
Admiral Fitzroy (1805-1865), as commander of HMS Beagle, participated in the Darwin Expedition from 1834-1836. In addition to his naval career, Fitzroy did pioneer work in the field of meteorology. The Beagle's instrumentation for the Darwin Expedition included several chronometers as well as barometers, which Fitzroy used for weather forecasting. The Darwin Expedition also was the first voyage under sailing orders that the Beaufort wind scale be used for wind observations.

One type of barometer used by Fitzroy was a storm glass. Observing the liquid in the storm glass was supposed to indicate changes in the weather. If the liquid in the glass was clear, the weather would be bright and clear. If the liquid was cloudy, the weather would be cloudy as well, perhaps with precipitation. If there were small dots in the liquid, humid or foggy weather could be expected. A cloudy glass with small stars indicated thunderstorms. If the liquid contained small stars on sunny winter days, then snow was coming. If there were large flakes throughout the liquid, it would be overcast in temperate seasons or snowy in the winter. Crystals at the bottom indicated frost. Threads near the top meant it would be windy.
...and gives a list of ingredients as well as some instructions to construct a stormglass of your own...
Ingredients for Storm Glass

* 2.5 g potassium nitrate
* 2.5 g ammonium chloride
* 33 mL distilled water
* 40 mL ethanol
* 10 g camphor

Dissolve the potassium nitrate and ammonium chloride in the water; add the ethanol; add the camphor. Place in corked test tube.

Mark Ford, who has been making storm glasses for years, e-mailed me to add that man-made camphor, while very pure, does contain borneol as a by product of the manufacturing process. His experience is that the synthetic camphor doesn't work as well as natural camphor, perhaps because of the borneol.

Mr. Ford advises dissolving the nitrate and ammonium chloride in the water, then the camphor in the ethanol. Next, slowly mix the two solutions (adding the nitrate & ammonium solution to the ethanol solution works best). It also helps to warm the solution to ensure complete mixing. Mr. Ford never uses a cork, preferring to seal the mixture in small glass tubes.
You can also check out a graphic showing what the crystals should look like in various weathers. There is, of course, also a Wikipedia article on the stormglass (linking to the tempest prognosticator, the finest weather predictor based on leeches).

No where do I see any sort of actual research suggesting that the stormglass's crystalline changes actually correlate to weather prediction in the least. Nor, however, do I see anything that explains the changes in the crystalline appearance of the goop in the glass.

I'm intrigued...anybody know anything about 'em?

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