Walter Raleigh once made a bet in the court of Queen Elizabeth I that he could measure the weight of the smoke from his cigar. No-one believed that he could, and courtineers queued up to place their bets against him.
After all the bets came in, Raleigh first weighed his cigar. After recording the weight, he then proceeded to smoke the cigar, carefully dropping the ash into the scales, all the while regaling the court with witty tales of triumph. Once he'd smoked it to the end (ensuring that all the ash was in the scales), he placed the last of the cigar in the scales and incinerated it. He then subtracted the weight of the ashes from the original weight of the cigar, giving him the weight of the smoke.