You can find the answer to this in Chapter 8.
In this chapter, Jim says he used to be rich. He says that he was once rich because he had $14. But he was not able to hold on to his wealth. Instead, he "speculated in stock." In his case, what that meant was that he bought a cow.
He bought the cow for $10 but it died. Then he took the remaining $4 (plus $1 of the $1.10 he got for the dead cow) and tried to invest it with a swindler. He lost his money that way.