The roof of a steamboat cabin in the period 1850-1920 almost always was elevated from 3 to 8 feet and window glass inserted along the upper sides: such glasses were called skylights. None but the cheaply constructed boats went without this scheme of architecture. Daylight from outside was admitted the entire length of the cabin, on both sides, thereby. Frequently the glass was stained, or etched, or otherwise fancifully treated.