A review on the physiology of Insulin like Growth Factor-I (IGF-I) ... by Debnath, Surajit / Advances in Environmental Biology.
The spring piston airgun generates power using a powerful spring-loaded piston that is housed within a compression chamber. Cocking the gun (using a break barrel, side lever, or under lever mechanism) causes the piston assembly to compress the spring. When the spring is released it pushes the piston forward compressing a column of air in the chamber behind the pellet.
A book of 1655 inventions mentions a steam engine (called a fire engine) pump used to raise a column of water 40 feet [12 m], but there was no mention of whether it was portable. Colonial laws in America required each house to have a bucket of water on the front stoop during fires at night.