[1] In 1862, he was appointed the first head of the Chemical Division in the newly organized U.S. Department of Agriculture, a unit that eventually became the Food and Drug Administration.

[citation needed] On March 5, 1871, he died in Bethlehem, Pennsylvania and was buried in the family plot at Laurel Hill Cemetery in Philadelphia.

[citation needed] He worked as a chemist, eventually becoming a chemistry professor at Lehigh University.

[citation needed] In 1862, President Abraham Lincoln appointed Wetherill the first chemist for the Chemical Division in the new Department of Agriculture.

[5] He made a chemical analysis of white sulfur water, and in 1860, he published the treatise, The Manufacture of Vinegar.