She put the button in the center of the square of calico. She drew the cloth together over the button and wound a thread tightly around it and twisted the corners of calico straight upward in a tapering bunch. Then she rubbed a little axle grease up the calico and set the button into the axle grease in the saucer.
“Now we’ll wait till Pa comes,” she said.
Laura and Carrie hurried to finish washing the dishes in the gathering dusk. It was dark when Pa came in.
“Give me a match, Charles, please,” Ma said. She lighted the taper tip of the button lamp. A tiny flame flickered and grew stronger. It burned steadily, melting the axle grease and drawing it up through the cloth into itself, keeping itself alight by burning. The little flame was like the flame of a candle in the dark.
“You’re a wonder, Caroline,” said Pa. “It’s only a little light, but it makes all the difference.”
The Long Winter, Chapter 19: Where There’s a Will
A button lamp is a type of oil lamp that was used in the 19th and early 20th centuries, particularly during the winter months. It is named for its small size, typically no more than a few inches in diameter, and its resemblance to a button – or in the Ingalls case, literally a button.
Button lamps were commonly used in rural areas and in homes without electricity, as a source of light during the long winter evenings. They were small and portable, making them easy to carry from room to room or take outside. They were also relatively inexpensive and easy to use, making them accessible to many people.
They could be used with kerosene or whale oil, however the Ingalls used axle grease as they no longer had access to kerosene to use their regular lantern.