Thank goodness for collectors of Civil War memorabilia who advertise their wares on the Internet. Without them I would have had a hard time finding authentic tin buttons. And I absolutely needed these to carry out my research into Napoleon’s problems with the Russians and the Russian winters. After all, there is a burning question out there that has never been successfully answered. Were Napoleon’s soldiers able to keep their pants on, or were they not?
Here’s the often-repeated story. Napoleon had his problems with the Russian winter, particularly the winter of 1812, which was especially cold. His troops were already on the verge of defeat when an unusual bit of chemistry dealt the final blow. The buttons on the soldiers’ uniforms it seems were made of tin, a metal that exhibits an interesting property at low temperatures. It disintegrates! That’s because tin, like several other elements, can exist in more than one form. These “allotropes” (from the Greek meaning “other way”) can have dramatically different properties. Perhaps the most familiar examples are diamond and graphite, both of which are composed only of carbon, yet are decidedly distinct substances due to the different internal arrangement of the carbon atoms. Similarly, tin atoms can be packed together in two ways. Above 13.2°C (55.76°F) we have an arrangement that is characteristic of metals, and we have the shiny, malleable material recognized as tin. But as the temperature drops, the atoms rearrange, and the metallic tin slowly changes into a non-metallic gray powder. When this happens the metal is said to suffer from “tin disease” or “tin pest.”
There is no question that this is more than just a curious theoretical possibility. Just ask churchgoers in northern Europe, who have had to endure more and more false notes produced by church organs over the years. Tin has been favored as the ideal metal for organ pipes because of the appealing sounds it can produce when it vibrates. But in cold cathedrals over many years, the metal can slowly change into its crumbly non-metallic form. This of course changes the sound and in a few cases has resulted in complete destruction of the pipes. Before the chemistry of this allotropic conversion was understood, the destruction of organ pipes was attributed to be the work of the devil, who was doing his best to undermine devotion to God.
The fact, however, is that the devil never carried out his work over one winter. It took many years until the organs began to suffer from “tin plague.” That’s why the Napoleon story needs to be scientifically investigated. There is no doubt that dis integration of buttons would have made the waging of war a difficult venture. After all, it’s hard to fight, or indeed retreat, with your pants around your ankles. But could this have happened? I tried to answer this question once and for all. The tin buttons I acquired were put to task. A couple sat in my freezer, two others took up residence in the back of the fridge, and a few braved the Montreal winter outdoors.
The fridge is actually a very appropriate place to study the behavior of tin because, before widespread refrigeration, the tin can was an ideal way to preserve food. And while Napoleon may have let his soldiers (and their pants) down with tin buttons, he helped the whole world with his determination to find a method to preserve food for his armies. This determination eventually led to the tin can. Napoleon, as many other generals before him, had discovered that soldiers do not fight well on empty stomachs. And stomachs were often empty due to the difficulty of supplying food to massive traveling armies. What food there was was often spoiled or of poor quality. So the emperor offered a prize of 12,000 francs, a healthy amount of money at the time, to anyone who could come up with a viable method of preserving food.
Nicholas Appert took up Napoleon’s challenge. The son of an innkeeper, Appert had learned about brewing and pickling. He knew that these “fermentation” processes could be halted by heating, and began to wonder whether food spoilage could also be stopped in this fashion. After all, it was clear that cooked food kept longer than fresh food, although eventually it too would spoil. Years of experimentation led Appert to a critical discovery. If the food were sealed in a glass jar and then heated, it would keep for a remarkably long time. Long enough to please Napoleon, who awarded the prize to Appert in 1809. The method clearly worked, although nobody at the time understood why. Bacteria were not identified as the cause of food spoilage until another famous Frenchman, Louis Pasteur, came along later in the century.
Appert’s invention came to the attention of Peter Durand, in England, who was troubled by the use of glass jars that often broke. There had to be a better way! Why not a metal container? Iron was cheap and was the first choice. But it corroded, especially when exposed to acidic foods. A coating that would protect it from the air and contents had to be found. Tin, concluded Durand, would do the job! The metal had been known since antiquity and could be easily melted and applied as a coating to iron to make tin plate. And most important, tin did not corrode. By 1818, the British Company, Donkin and Hall, was mass-producing food in tin cans. When Admiral Parry sailed to the Arctic Circle in 1824, he sustained his crew on canned food. One can of roast veal apparently was not consumed, because it turned up in a museum 114 years later. Inquisitive scientists opened it and decided to check the effectiveness of the canning process. They were not quite brave enough to try the veal themselves, but the rats and cats that had the pleasure of partaking of the 114-year-old feast not only survived, but thrived!
This now brings us to the problem of the Tin Man in L. Frank Baum’s classic, The Wizard of Oz. A mystery even more confounding than the Napoleonic pants. When Dorothy firsts encounters him, he is a little stiff, to say the least. He has to be appropriately oiled before he can begin his quest for a heart. This implies corrosion, but tin does not corrode. And it is unlikely that he would have experienced low enough temperatures in Oz to undergo any allotropic conversion. In any case, then, he would certainly have lost some of his shine. So I’m afraid we are left with the conclusion that the Tin Man was really Tin Plate Man. That would explain it all. Scratches in the tin plate (an obvious possibility for an ax-wielding woodsman) would have exposed the iron underneath, causing exposure to air and moisture. This sets up a situation known as “cathodic protection,” whereby the thin layer of tin oxide on the surface of the metal is converted to metallic tin as the iron turns to rust! The inside corrodes, while the outside stays shiny!
I thought it worthwhile to check the scientific literature to see if anyone before had addressed the problem of the creaky Tin Man. Apparently not. But I did come across one item that was disturbing, and that may undermine my research with tin buttons. One spoilsport historian claims that only Napoleon’s officers had tin buttons and that common soldiers had buttons made of bone, which would have easily stood up to the bone-chilling Russian winter. And what did my own kitchen research show? The tin buttons were unaffected by the cold. So I guess the only thing that crumbles is the story about Napoleon’s soldiers and their falling pants.