Friday, April 27, 2012

Boredom Creates Friction

Count Rumford (1753-1814)
Benjamin Thompson (born in Woburn, MA) was the American anti-Franklin. He was a prolific inventor and scientist but sided with Britain during the Revolution and left America after the War and lived abroad thereafter. He eventually settled in Bavaria where he changed his name to Count Rumford and then changed our understanding of the science of heat. And he did all this in the service of practical pursuits.

Rumford oversaw the boring of iron cannon from iron cylinders using a horse-driven drill. He was impressed by how much heat the drilling friction gave off and he designed experiments to measure this. With insulated cannons and submerged drilling experiments, he carefully measured temperature increases. He found that sustained drilling could heat and boil cold water! Collecting and weighing the iron filings, he established that the metal shavings had the same weight and properties as the unbored metal, so nothing had been "given off" as was then currently thought. Rumford concluded that the mechanical work by the horses was converted into heat. Rumford showed that mechanical action can generate indefinitely large amounts of heat, thus directly challenging the caloric theory of the great Frenchman, Lavoisier. 

Lavoisier, a contemporary, didn't live to appreciate Rumford's work--he was guillotined in the French Revolution--ironically for Royalist sympathies. Rumford wound up marrying his widow, Marie-Anne Paulze who was an unappreciated chemist in her own right.


  1. Seems like the French Revolution was pretty good to him.

  2. I guess the marriage didn't last though.

  3. Great piece on Rumford, never heard of him before. Lavoisier is such a tragic story. So glad his wife, who was also so brilliant, found another like minded man to marry.