Saturday, October 24, 2009

Urban Stalactites

Spotted on the uptown-bound platform of the 4/5/6 last weekend. At first glance I took them for the usual peeling paint that can appear on the ceilings of the older subway tunnels (and given what paint used to be made of, isn't that an appealing thought?) but I soon recognized these miniature stalactites for what they are.

Natural stalactites are the result of dripping limestone elements that recombine in almost palindromic chemical reactions as they make contact with water and air, respectively. Stalactites can also form, however, on concrete, through a more rapid reaction fueled by the calcium oxide found in concrete. It's interesting how natural processes can inform a man-made structure -- we tend to focus on the reverse, but nature always has the last word.

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