Moby Dick pg 19

"it maketh a marvelous difference, weather thou lookest out at from a glass window where the frost is all on the outside, or wether though observest it form a sashless window, where the frost is on both sides"

This is talking of a person or type of person. Ishmael is a sashless window considering his dreary outlook on life. He seems to enjoy dark, gloomy places without people and looks for a inn that is down a deserted street. Ishmael is not just looking at things that seem unpleasant like a glass window with frost on the outside, he is frosty on both sides like a sashless window.