Leprosy of tin

I first heard about tin pest (lèpre d’étain, “leprosy of tin,” in French) yesterday in the midst of reading a history of Singapore.

By the late 19th century, Singapore’s prosperity had risen dramatically, thanks in part to the opening of the Suez Canal, the extension of the telegraph from Europe, and the development of Malaya’s tin industry. Wondering why tin became a hot commodity, I turned to Wikipedia, where I encountered tin pest.

Tin is a soft, shiny metal that resists tarnishing and is nontoxic, which is why it has been used for more than a century to line steel food containers. The Wikipedia entry also told me about tin’s principal allotropes (structural forms). The useful metal, known as white or β tin, is the stable allotrope above 13.2 °C. Below that transition temperature, a brittle, fragile insulator called gray or α tin is the more stable.

The modest transition temperature might seem to rule out many practical uses for tin, including food storage. Fortunately, the α–β transition has a high activation barrier. Still, when the ambient temperature is low, objects made of white tin will transform readily, if slowly, into gray tin and disintegrate. You can hasten the transformation. In this video , where 1 second of screen time corresponds to 1 hour of real time, a tin ingot is chilled to −40 °C.

Organ pipes in Northern European churches fell victim to this tin pest; so, perhaps, did the tin buttons on the uniforms of Napoleon’s soldiers as they retreated from Moscow in the frigid winter of 1812 (the buttons story isn’t confirmed).

My former ignorance of tin pest brought to mind a 1956 short story by the science fiction writer Philip K. Dick . In Pay for the Printer, the residents of a future, war-torn Earth rely on docile alien beasts called Biltongs to make copies, in a chicken-laying-eggs way, of cars, TVs, and other otherwise unobtainable consumer items. The replicated goods don’t last, but that’s not a problem—until the Biltongs start dying off. Then, humanity realizes that it must shed its dependence on the Biltongs and recover its former ability to fend for itself.

I hope Earth is not ravaged by a war that wipes out our knowledge of how tin and other materials fare under not-so-extreme conditions. But as the world’s supply of hydrocarbons runs out, we could find ourselves relying more on traditional, sustainable materials like sisal and gutta-percha. And if that happens, we may need to relearn what our forebears knew of those materials’ natural vulnerabilities.