Herman Hollerith conceived of this machine when traveling on a train with a friend. He noticed that the conductor punched his ticket differently from his friend's, even though they were going to the same place. Hollerith asked the conductor why, and the conductor responded that the spaces on the ticket corresponded to hair color, eye color, height, and other characteristics of the passenger, so that people could not pass on their tickets. Hollerith thought the same thing would work for counting the census.