After graduation, Clarke was drafted and spent his Army stint at Fort Monmouth, N.J., learning and teaching the guidance system of the Nike guided missile. A chemist who specialized in marketing research, Clarke worked for the Atlas Powder Co. — later AstraZeneca Corp. — traveling widely, speaking often at industry gatherings, and serving as president of the Chemical Marketing Research Association.
In retirement Clarke worked on a number of Earthwatch archaeological projects in places such as Moscow, Pompeii, and Mammoth Cave in Kentucky. He volunteered at Wilmington’s Faith Center, which provides counseling and financial assistance to low-income families and individuals facing immediate financial crises. He was also treasurer and a board member of the English Speaking Union.
Clarke died May 23, 2018, in Wilmington, Del., after a brief illness.