What is "icyball"

IcyBall was a name given to two early refrigerators, one made by Australian Sir Edward Hallstrom in 1923, and the other design patented by David Forbes Keith of Toronto, Ontario, Canada (filed 1927, granted 1929), and manufactured by American Powel Crosley Jr., who bought the rights to the device. Both devices were unusual in design in that they did not require the use of electricity for cooling. They ran for a day on about a cup of kerosene, allowing rural users lacking electricity to utilise the benefits of refrigeration.