Introduction: Fitzroy Storm Glass

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

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)

Step 2: Making the Storm Glass Content

Picture of Making the Storm Glass Content
Please take care when handling chemicals and wear PPE
  1. Dissolve the nitrate and ammonium chloride in the water in beaker 1
  2. Dissolve the camphor in the ethanol in beaker 2
  3. Slowly mix the two solutions beaker 1 into beaker 2
  4. Place beaker 2 in some warm water and stir until everything is fully mixed.
  5. Decant into your storm glass tube and seal.
It will take a possibly several hours depending in the current weather for anything to happen to the liquid.

Step 3: Making the Base

Picture of Making the Base

The base was turned on the lathe. Take you piece of wood and drill and 8mm hole* and mount on a screw chuck. Then using a fostner bit in the tail stock drill a 30mm* hole 10mm deep into the centre of your wood. Open up this hole using a flat ended box scraper so your glassware is a snug fit (not too tight as space is needed for glue). Now turn the outside shape, first using a spindle roughing gouge followed but a spindle gouge to introduce a pleasing shape. Then sand to 400 grit. I chose to embellish with two burnt lines by putting two v-grooves in using a skew chisel and then using thin wire create the burn mark. Another light sand to clean up the burnt line edges and then apply sealer and hard wax. Sand bottom flat once removed from lathe

*Sizes relavent to my equipment, please adjust for your own

Step 4: Final Assembly

Picture of Final Assembly

Glue the glass tube into the wooden base using epoxy glue.

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


mdutters (author)2017-11-04

Does denatured ethanol work or does it need to be lab grade? I made one with 100 proof vodka but want to see if they react differently.

pudtiny (author)mdutters2017-11-06

It should work, it may depend a little on what has been introduced to it to make it not drinkable (impure) .

Laral (author)2017-01-24

You may be astonished, as I was, to learn that the only chemical necessary for this is camphor. The other chemicals have no effect on its operation. I learned this from this study:

The chemical weather glass: composition and operation—Allan Mills. Department of Geology,. University of Leicester


He did a study of the composition trying just the other two chemicals, all 3, and just camphor. He found the other two chemicals alone did nothing, and camphor alone worked just as well as all 3 chemicals together.

Laral (author)2017-01-24

This has to be set outdoors for it to work. See Customer Reviews: Lily's Home Admiral Fitzroy Storm Glass.

For all those saying it "Just sits there"

ByJayon December 18, 2013

The Fitzroy Stormglass was intended to be used outdoors when invented. Leaving it inside in controlled conditions, well, you get no changes, because "nothing changed!"

Since temperature is the only thing that affects the crystallization, this makes perfect sense.

DarlingS1 (author)2016-01-19

Where can I get pure ethanol?

Laral (author)DarlingS12017-01-24

You can't because it would absorb water from the air as soon as it was made. The closest thing you can get is 95% ethanol—Everclear. It is very expensive. A cheaper solution is to use 100 proof cheap vodka. It is 50% ethanol. The required concentration is 40/(40+33) = 52%, so 50% is more than close enough for something like this. You would measure out 77ml of vodka for this formula.

pudtiny (author)DarlingS12016-04-30

pudtiny (author)DarlingS12016-04-30

sorry only just seen this, were in the world are you? you can get it on both eBay and Amazon in the UK

thisfilipina made it! (author)2016-05-13

also, could this work as the camphor? it is make up of 100% pure natural essential oil camphor according to the details. or does it have to be tablets like what you used?

Laral (author)thisfilipina2017-01-24

I don't think so either. This depends on the camphor crystallizing. The oil won't crystallize.

pudtiny (author)thisfilipina2016-05-14

I don't think so as it is not pure camphor. The oil would affect the storm glass.

teorock70. (author)2016-08-24

thank you a lot fo your article

Lorddrake (author)2016-05-21

am i interpreting the storm glasses in your intro picture correctly ? frosty and windy day

pudtiny (author)Lorddrake2016-05-24

That would be my interpretation

thisfilipina (author)2016-05-13

thank you so much. i hope you dont mind the questions.

for this specific experiment, can i combine ammonia and hydrochloric acid to make the ammonium chloride? if so, what what are the measurements?

pudtiny (author)thisfilipina2016-05-13

It is possible to make ammonium chloride from ammonia and hydrochloric acid, how successful it would be for this I'm afraid I don't know. Depending on the purity of your reagents will depend on the outcome. As ammonium chloride is easily available and the reaction releases gas and is exothermic, I would suggest it is safer to just buy it. I'm afraid I can't comment on specific quantities needed, or the exact procedure, but you will probably find information on YouTube.

thisfilipina (author)pudtiny2016-05-14

how about the camphor? would it be necessary to use natural essential oil camphor?

thisfilipina (author)2016-05-12

How necessary is decanting the soloution into the storm glass? Why is this important?

pudtiny (author)thisfilipina2016-05-12

I made a larger volume of solution than would fit in one storm glass, so I was decanting the solution into several.

thisfilipina (author)2016-05-06

I have an end of the year project for my AP chemistry class and have decided to make a storm glass for my experiment. I have a few questions about equipment and finding them.

Does the container have to be in a tube-shaped glass or can it be in a flask shape? Where can I get natural camphor? Does Walmart sell them? Are there any convenience stores that might sell natural camphor used for the storm glass?

Thanks in advance.

pudtiny (author)thisfilipina2016-05-06

the last ones I made, I used glass stoppered reagent bottles with epoxy on the stoppers.

thisfilipina (author)pudtiny2016-05-07

Thank you so much. I appreciate the help.

pudtiny (author)thisfilipina2016-05-06

you can use any container you like as long as you can seal it to prevent evaporation. I got my camphor on eBay, but I'm sure it must be available elsewhere.
Look at this on eBay

what a great school project

AmandaD85 (author)2016-04-29

Where do I find all the chemicals to make this? i want to try but I have no idea where to find all that.

pudtiny (author)AmandaD852016-04-30

all available on eBay or Amazon in the UK

보림강 (author)2015-11-14

can I use a plastic instead glass?

pudtiny (author)보림강2015-11-14

I have never seen them in plastic but that's not to say it wouldn't work. Plastic generally isn't as transparent as glass.

tneagle06 (author)2015-07-24

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)tneagle062015-07-24

I keep mine inside out of direct sunlight and extreme temperatures.

AlexW20 (author)2015-06-22

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)AlexW202015-06-24

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.

hardlec (author)2014-11-14

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)hardlec2014-11-14

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.


Anatomika (author)2014-03-02

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)Anatomika2014-03-03

dipping in wax, coating in epoxy glue or even thin superglue should do the job

CMNDR (author)2014-01-18

What concentration of ethanol are you using in your solution?

pudtiny (author)CMNDR2014-01-28

99%+ its laboratory grade

konewt (author)2013-12-27

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)konewt2014-01-02

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 (author)pudtiny2014-01-02

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)konewt2014-01-02

This is the Link:

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 (author)pudtiny2014-01-02

Thanks, now I understand! it's the l-bornel impurity that is important. Appreciate the R&D!

ToolboxGuy (author)2014-01-01

Is this "advance warning" or merely current conditions?

pudtiny (author)ToolboxGuy2014-01-02

Suggestions seem to be possibly 1-3 days ahead

macgyver71 (author)2013-12-19

They've always fascinated me, and this 'able is just what I needed to make one of my own (short of the gorgeous wood lathe here). Many thanks Pudtiny

ToolboxGuy (author)macgyver712014-01-01

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!

Machine (author)2013-12-25

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.

cyndielou (author)2013-12-20

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!

juicyjay (author)cyndielou2013-12-21

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)juicyjay2013-12-22

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.

About This Instructable




Bio: I am a senior laboratory technician in a analytical facility by day and by night I make and fix things. I prefer to work with ... More »
More by pudtiny:Pucket (Le Passe-Trappe) GameSuncatcherLight Up Display Shelf
Add instructable to: