Read this excerpt from The Call of the Wild.
Charles was a middle-aged, lightish-colored man, with
weak and watery eyes and a mustache that twisted
fiercely and vigorously up, giving the lie to the limply
drooping lip it concealed. Hal was a youngster of
nineteen or twenty.... Both men were manifestly out
of place, and why such as they should adventure the
North is part of the mystery of things that passes
understanding.
Readers can tell that London is using direct
characterization to describe Charles and Hal because
he
shows how the men behave and react to their
environment.
states how the men look and says that they do not
belong in the North.
shows the men's actions and thoughts about the
adventure.
states the men's thoughts and words about the
harsh conditions.