Fitzroy's Storm Glass - Weather Instrument Used on Darwin's Ship the HMS Beagle
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.
Step 1: Equipment
A piece of appropriately sized wood for the base. ( I used a piece of 70x70x40 Iroko)
Epoxy Glue to bond the glass to the base.
Lathe, Turning Tools and finishes
Printer and laminator to make info cards.
2 Beakers to mix chemicals in
Chemicals to make the storm glass contents are:
2.5 g potassium nitrate
2.5 g ammonium chloride
33 mL distilled water
40 mL ethanol
10 g camphor (natural not synthetic)
Step 2: Making the Storm Glass Content
- Dissolve the nitrate and ammonium chloride in the water in beaker 1
- Dissolve the camphor in the ethanol in beaker 2
- Slowly mix the two solutions beaker 1 into beaker 2
- Place beaker 2 in some warm water and stir until everything is fully mixed.
- Decant into your storm glass tube and seal.
Step 3: Making the Base
*Sizes relavent to my equipment, please adjust for your own
Step 4: Final Assembly
I then made little cards explaining what a storm glass is and what the different crystal structures mean.
The cards contain the following text:
Fitzroy Storm Glass
Admiral Robert Fitzroy was Captain of the HMS Beagle, the very same ship that ferried Charles Darwin around the Galapagos in the 1830′s.
While Darwin contemplated the origin of the species, Admiral Fitzroy was testing an hypothesis of his own. He was testing a new weather predicting instrument.
In a sealed glass, he mixed potassium nitrate, ammonium chloride, ethanol, camphor and water, and created the storm glass. Admiral Fitzroy observations were thus:
-If the liquid in the glass is clear, the weather will be bright and clear.
-If the liquid is cloudy, the weather will be cloudy as well, perhaps with precipitation.
-If there are small dots in the liquid, humid or foggy weather can be expected.
-A cloudy glass with small stars indicates thunderstorms.
-If the liquid contains small stars on sunny winter days, then snow is coming.
-If there are large flakes throughout the liquid, it will be overcast in temperate seasons or snowy in the winter.
-If there are crystals at the bottom, this indicates frost.
-If there are threads near the top, it will be windy.
The PDF attached has the cards properly formated