Some people have called World War I 'the Chemists' War' for its use of substances like chlorine and mustard gas, and one of the less successful weapons was a flamethrower using gasoline. This was unsuccessful, as it burned too fast. During World War II, American scientists reinvestigated this weapon, in a team led by Professor Louis Fieser, who older generations of chemists will associate with an organic chemistry textbook. Just like the Byzantines, they found that adding a thickening agent to the fuel created something that burned longer and also tended to stick to surfaces; their thickening agent is reportedly a soap-like material based on aluminum naphthenate and aluminium palmitate. The name napalm was derived from the first parts of the words naphthalene and palmitate. When they mixed this with gasoline, they got a viscous sticky brown liquid which burned more slowly and produced higher temperatures, making it a very effective weapon for fire-bombing cities, for example. After that war, further developments took place.