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For my money, it is one of the more perverse facts of the physical universe that elemental mercury, which is so beautiful and has so many amazing and useful properties, is also so dangerous.

This fountain, commissioned by the Spanish government from Alexander Calder for the 1937 World’s Fair, pumps quicksilver instead of water. Today the entire fountain, located at the Fundació Joan Miró in Barcelona, is enclosed in a glass box to prevent exposure of visitors to the toxic metal. Professor David Eppstein at UC-Irvine has a nice gallery of pictures, including the above.


Sean Michael Ragan

I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I write for MAKE, serve as Technical Editor for MAKE magazine, and develop original DIY content for Make: Projects.



  1. anachrocomputer says:

    A few years ago, I saw an ingenious mercury pump in an exhibit at the Science Museum in London. It was demonstrating the technique that is used to pump molten sodium metal in nuclear reactors. Basically, a large electric current (hundreds of Amps) is passed through the metal, and a magnet is used to form a simple electric motor. The liquid metal is the only moving part.

    I think the pump is in storage now, because I didn’t see it when I visited the Science Museum last month.

    1. Alan! says:

      In Spain the average temperature is high enough to maintain gallium (outside) as a liquid. If I remember correctly this website in their first rendition of the Gallium video mentioned this fountain.

      It’s more likely gallium for two reasons, one if you were to use mercury, the vapors are poisonous, and secondly the mercury is more likely to amalgamate along the metal sides of the container meaning they would have to replace the container.

      1. In Barcelona the average summer temperature is 77F; in winter it is 50 F, both of which are markedly below the melting point of Gallium at 85 F. For this and other reasons, the metal in the Calder fountain shown here is emphatically not Gallium, and with all reasonable certainty is, in fact, mercury. The Calder fountain is important culturally and historically for Spain as it commemorates the wartime siege of Almaden, a Spanish town that used to be the foremost producer of mercury in the world. To fill it with something besides mercury would utterly defeat the point.

        Furthermore, at ambient temperatures the vapor pressure of mercury is incredibly low. It’s only in enclosed spaces and when it’s heated that metallic mercury begins to become really deadly to those in the area who are not in direct contact with it. Since the discovery of mercury’s toxicity, as mentioned above, the fountain has been enclosed in a glass box to reduce exposure of visitors to the metal.

        Finally, although mercury does form amalgams with many metals, it does not amalgamate with iron, which is almost certainly what the solid metal parts of the fountain are made of. This is also the reason that commercial mercury is stored and traded in iron flasks.

        1. Volkemon says:

          @Sean Michael Ragan-

          Way to get the facts straight!!!

          My respect to you. There have been some ‘contributing writers’, albeit under different titles, that have not been near as thorough or attentive to the posts they have made. IMO, you are a great asset to this blog, MAKEing it better and better.


          (and NO, I am in no way associated with this blog, SMR or O’Reilly publishing etc for the fact that I am a subsciber and MAKEblog reading fan.)

  2. Chris W says:

    Thanks for the article. I would love to see this fountain someday. The use of the word “deadly” in the title
    While the fumes of heated mercury are very dangerous to inhale, room-temperature liquid mercury is not readily absorbed by skin or ingestion (or even by injection if Wikipedia is to be believed). I would have been poisoned 40 years ago if touching mercury was so hazardous. We are surrounded by chemicals which are far more hazardous (antifreeze, bleach, isopropanol,…). There is a saying in Toxicology- “The dose makes the poison”. Even water can kill you if you drink too much of it.

    I do not work for Amalgamated Mercury, though I do like heavy metal.