n :  a sensitive test for arsenic in which a solution to be tested is treated with hydrogen so that if arsenic is present gaseous arsine is formed and then decomposed to a black deposit of arsenic (as when the gas is passed through a heated glass tube)
 
Marsh, James Ernest (1794-1846), British chemist. Marsh spent considerable time studying poisons and their effects. He introduced his test for arsenic in 1836.
 
 
 
Published under license with Merriam-Webster, Incorporated.  © 1997-2026.