In 1877, Samuel William Johnson hired Armsby to work as a chemist at the newly formed Connecticut Agricultural Experiment Station - the first in the nation - in New Haven. Armsby worked alongside Johnson's other assistant, Edward Hopkins Jenkins.[3] Armsby worked at the Station for four years, earned his PhD from Yale in 1879, and wrote the textbook Manual of Cattle Feeding (1880), which became a staple in the field of animal nutrition.[2]