The person who published New System of Chemical Philosophy" (1803) was born on what date?
Law of multiple proportions:  It is sometimes called Dalton's Law after its discoverer, the British chemist John Dalton, who published it in the first part of the first volume of his "New System of Chemical Philosophy" (1803). John Dalton: John Dalton FRS ( ; 6 September 1766 – 27 July 1844) was an English chemist, physicist, and meteorologist.
6 September 1766