John Landis Mason (1832 – 1902), was an American tinsmith and the patentee of the metal screw-on lid for fruit jars that have come to be known as Mason jars. Many such jars were printed with the line "Mason's Patent Nov 30th 1858".He also invented the first screw top salt shaker in 1858.
In 1858, Mason invented a square-shouldered jar with threaded screw-top, matching lid, and rubber ring for an airtight seal – the Mason jar. Until the 1830s, long before refrigeration and hothouse gardens, many fruits and vegetables had been available only seasonally, but the recent development of jars had made canning a practical alternative to drying, pickling, or smoking to preserve food.
Prior to Mason's innovation, jars had a flat, un-threaded top, across which a tin flat lid was laid and sealed with wax. It was messy, unreliable, and unsafe – if the wax was not applied properly it allowed deadly bacteria to thrive in the jar.
Mason's easy and re-usable jars made home canning popular among American settlers, homesteaders, and even in urban homes, but most Mason jars were manufactured by competitors after his patent expired in 1879.
His invention never made Mason rich – he was later accused (but not convicted) of having his home burned to obtain an insurance windfall, and he worked for many years as an accountant at Colonial Bond and Guaranty Company.
He was married and had six daughters. He died in poverty in a tenement house in New York City in 1902.