Farmer on a Train

A scientist gets on a train to go to New York. His cabin also has a poor farmer in it. To pass the time the scientist decides to play a game with the guy.
"I will ask you a question and if you get it wrong, you have to pay me 1 dollar. Then you ask me a question, and if I get it wrong, you get 10 dollars. You ask me a question first." The farmer thinks for a while.
"I know. What has three legs, takes 10 hours to climb up a palm tree, and 10 seconds to get back down?"
The scientist is confused and thinks long and hard about the question. Finally, the train ride is coming to an end. As it pulls into the station, the scientist takes out 10 dollars and gives it to the farmer.
"I don't know. What has 3 legs, takes 10 hours to get up a palm tree and 10 seconds to get back down?"
The farmer takes the 10 dollars and puts it into his pocket. He then takes out 1 dollar and hands it to the scientist.
"I don't know."