"Liquid air is air reduced to a liquid form. Liquid air when pure has a bluish tinge, but the liquid form of ordinary air has a somewhat cloudy appearance owing to the presence of solid carbon dioxide and other matters. If a kettle containing liquid air be placed on a block of ice, boiling will again take place and the addition of ice to the contents of the kettle will make the boiling proceed more rapidly."—(Charles Leonard-Stuart, 1911)

Liquid Air Boiling on a Block of Ice

"Liquid air is air reduced to a liquid form. Liquid air when pure has a bluish tinge, but the liquid…