Another BIGGIE use for urine was in the making of salt petre for manufacturing gunpowder.
http://www.wisegeek.com/can-you-really-make-gunpowder-from-urine.htm
Urine can in fact be used in the manufacture of gunpowder, and it has historically been a very important source of one of the crucial ingredients in gunpowder, saltpeter, also known as niter. This nitrate compound is what allows gunpowder to rapidly oxidize and catch fire, generating an explosion which can be used to fire munitions. In the modern era, there are less smelly ways to get saltpeter, typically through an industrial process which uses ammonia as a base.
While you cannot literally make gunpowder from urine, as you need several other ingredients to produce gunpowder, urine can certainly be used to produce one necessary element. In addition to saltpeter, however, people also need charcoal and sulfur. These ingredients are both readily available, unlike saltpeter, so the popular stories about making gunpowder from urine do have a rational basis. Until the First World War, before people learned to reliably synthetically produce niter, urine, guano, and manure were all collected to produce gunpowder.
In the movie “1776” there is a musical scene where John Adams, in Philadelphia for deliberations during the Revolution, is communicating with Abigail back in Massachusetts, urging her and the ladies back home to make and send salt petre to Philadelphia for producing gunpowder....to which Abigail replies that the ladies in Massachusetts need PINS. Send PINS! No pins - no salt petre!
P.S. The ladies GOT their pins! ;o)
Actually, that was a double entendre. He was telling her that he missed her, and the saltpetre was a reference to reducing the sex drive. She was saying no, you don't need saltpetre, you need to come home (pin=phallus...)because she had urges the same as him.