The principles of hygiene; a practical manual for students, physicians, and health-officers . FlG. 2.—Daniells hygrometer : a, bulb surrounded with cotton cloth; b, ther-mometer; c, bulb containing thermometer. direct, as
What is the principle of a dry and wet bulb hygrometer? - Quora
What is the principle of a dry and wet bulb hygrometer? - Quora