Picture of Fitzroy Storm Glass
This instructable will take you through the steps of making a Fitzroy Storm Glass.

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

Picture of Equipment
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You will need a glass container that is seal-able. ( I used an old 100ml measuring tube and cork)
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)
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tneagle061 month ago
I have a question about where to place the storm glass. Inside, garage or outside? I would really like to keep it inside if possible.
pudtiny (author)  tneagle061 month ago
I keep mine inside out of direct sunlight and extreme temperatures.
AlexW202 months ago

Just wondering if the addition of a little glow-in-the-dark dye would affect it? Just thought it might add a little pazzaz!

pudtiny (author)  AlexW202 months ago
It sounds like a good thing to try, the only problem I can see is keeping the dye in suspension and it not settling at the bottom.
hardlec9 months ago

I would like to make some devices, but I have many questions, like:

do you use waxy camphor or camphor oil?

will silicone used as a sealing agent bother the mix?

can it go in a poly-carbonate or plastic vessle?

pudtiny (author)  hardlec9 months ago
I disolved camphor tablets, not sure oil would work. Silicone shouldn't affect the solution. I have never seen these in anything but glass, I can't think there would be a problem with polycarbonate.

Anatomika1 year ago

How would you go about sealing the corked end to the in a nice looking way? I'm trying to do something like this, but the liquid needs to be refilled once in a while, because the cork is not totally keeping the moisture in. Would you suggest dipping it in wax?

pudtiny (author)  Anatomika1 year ago
dipping in wax, coating in epoxy glue or even thin superglue should do the job
CMNDR1 year ago

What concentration of ethanol are you using in your solution?

pudtiny (author)  CMNDR1 year ago

99%+ its laboratory grade

konewt1 year ago
Why the 'natural' camphor vs. synthetic? I didn't know synthetic was available but just higher purity grades of natural. How pure should the 'natural' camphor be?
pudtiny (author)  konewt1 year ago
Neither did I but my research says that synthetic camphor exists but apparently contains a chemical that means it doesn't work as well
konewt pudtiny1 year ago
Thanks - i would like more info about that chemical if you don't mind. I've been in the flavor and fragrance business for about 40 years and a lot of that was in the analytical area using GC, GC/Mass Spec. etc. Generally, hight purity synthetic camphor is just that, high purity. Natural camphor is from plant sources and mother nature tends to make vegetable soup rather than purity. I would like to get the benefit of your research about the chemical that causes an issue where this doesn't work as well. It would seem that when this technique was invented quite a long time ago that purity processes weren't quite as sophisticated as today's techniques. Thanks for the instruct able! I look forward to making one or more of these and sharing my experimental data with you!
pudtiny (author)  konewt1 year ago
This is the Link: http://chemistry.about.com/od/weirdscience/a/fitzroy.htm

Quote of importance is "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"

Hope that sheds some light on the possible reason
konewt pudtiny1 year ago
Thanks, now I understand! it's the l-bornel impurity that is important. Appreciate the R&D!
ToolboxGuy1 year ago
Is this "advance warning" or merely current conditions?
pudtiny (author)  ToolboxGuy1 year ago
Suggestions seem to be possibly 1-3 days ahead
macgyver711 year ago
They've always fascinated me, and this 'able is just what I needed to make one of my own (short of the gorgeous wood base...no lathe here). Many thanks Pudtiny
I am sure that you could make a simple lathe for yourself, with a bit of effort.
Find an old foot pedal sewing machine stand, and you are halfway there to a tabletop lathe!
Machine1 year ago
Do the chemicals last a long time and have stability so that the glass stays indicating the weather for a long time, (years)?

Love your instructable.
cyndielou1 year ago
i have been wanting to make one of these for a couple of years. are the chemicals readily available? do not doubt its accuracy!

i have 8 jars of rendered bear grease as well as chicken. they sit in my window and accurately forecast weather conditions from a day to a week in advance. they even tell me a day in advance an earthquake is going to happen, and i have learned to judge the intensity. i live in texas, i have picked up earthquakes in new mexico, oklahoma, arkansas, ans missouri. how do i know? i always check the earthquake maps!

i have a cataloge here now with the fitzroy glass. but maybe i will make a dozen. i love homemade weather stuff!
Temperature change is the sole cause of crystal growth in storm glasses. It's success of prediction is no better than random probability. You believe they work because of confirmation bias.
pudtiny (author)  juicyjay1 year ago
I'm afraid the evidence suggests its multiple factors that effect the crystal growth. I kept my first glass in a temperature controlled environment and there was still change.
weren't they in use for several years? to me, that suggests they were fairly accurate

".Clear liquid means bright weather; dim liquid, rain. Crystals at the bottom presage frost. Large flakes mean overcast or, in winter, snowy skies. If the liquid contains small dots, humid or foggy conditions can be expected.

As its name implies, many believed the instrument was especially sensitive to the coming of stormy weather. Thus, if small stars are seen in dim liquid, thunderstorms can be expected. Threads in the upper part foretell wind. If the substance lies to one side, expect storm or wind from the opposite direction.

FitzRoy included a storm glass as part of the FitzRoy barometer assembly. These barometers were distributed to every British port so that it could be consulted by seamen before embarkation. Many of these stone huts housing these mercury barometers are still visible in many fishing harbours. The storm glass, glass cylinders with brass caps, can be seen clamped onto the lower left of the barometer assembly." wiki

i want 2 o r3 regardless!!
pudtiny (author)  cyndielou1 year ago
Chemicals can be found on ebay and amazon. Homemade weather instruments are fun
jimg161 year ago
I am a 'literal' type.
I see you made several tubes. Do you need only one or all of them for this project to work?
Great 'ible!
pudtiny (author)  jimg161 year ago
You just need one i was making multiple glasses for Christmas presents
Where did you get the chemicals. Ive bought a lot of things in my life but I wouldn't even know where to get some of those.
pudtiny (author)  shizumadrive1 year ago
The dry chemicals are all available on ebay or amazon,
Ammonium Chloride maybe in a good hardware store for soldering iron tip cleaning and metal prep.
Potassium Nitrate is used both in fertiliser and for meat preservation

thanks for the info
r-philp1 year ago
That's fascinating. I've always wondered what was in the storm glass liquid.
How accurate are you finding their predictions to be?
pudtiny (author)  r-philp1 year ago
Now we are in winter it seems quite accurate at the momemt
pudtiny (author)  r-philp1 year ago
It seems to be reasonable accurate, it depends a bit on its postion there is suggestion that putting them outside gives a better result. I have also heard of people calibrating there glass to location or slightly changing the recipe.
Seems like it would have to be outdoors and exposed to ambient temperatures, since the only 2 variables that could affect the phase changes would be temperature & pressure. (My parents have one & the package said Fitzroy mounted his on the mast).
pudtiny (author)  dsweitzer1 year ago
I think you are right for the optimum result outdoors would be best
kymyst1 year ago
These glasses would definitely attract people's attention and curiosity. The accuracy of their predictions has never been established scientifically, but it would appear that changes in temperature are the major factor causing the crystals to change their form. It looks as though the corks are not airtight, so atmospheric pressure changes may also play a part. There are several variations of recipes to be found on the internet which would be worth investigating. A very nice project, I will add it to my to do list.
pudtiny (author)  kymyst1 year ago
I agree its possibly more of a conversation piece than accurate weather predictor.
How tight should be the cork in it? Airtight (sealing wax on it), or has it to 'breath' a little?
pudtiny (author)  tanacsdavid1 year ago
I superglued them in for safe transit. I don't think it needs to breath as other versions I have seen used sealed glass tubes
This is fantastic. It's a cool looking project and I learned something new today :D
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