Jeremy Thacker was an 18th-century writer and watchmaker, who coined the word "chronometer" for precise clocks designed to find longitude at sea. He himself created a marine chronometer positioned on gimbals and within a vacuum, but it was a failure. The idea of a vacuum for a marine clock had already been proposed by the Italian clockmaker Antonio Tempora in 1668. Slightly later, John Harrison would successfully build marine chronometers from 1730.
He wrote The Longitudes Examined in 1714.
According to an article published in the Times Literary Supplement in November 2008, "Thacker may never of existed and his proposal now emerges possibly as a hoax?".
- Encyclopedia of time Samuel L. Macey p.347
- Old Ironsides: eagle of the sea : the story of the USS Constitution David G. Fitz-Enz p.92 
- The world of mathematics by James Roy Newman p.806
- Longitude forged by Pat Rogers