Hygrometer, Daniell’s

A form of hygrometer consisting of a bent gla tube terminating in two bulbs, the one covered with muslin, the other of black gla , and containing ether and a thermometer. Ether being poured on the muslin, the black ball, cooled by the evaporation of the ether within, is soon covered with dew, at which moment the receding of the inclosed thermometer, compared with that of another in the air, gives the dew point. IMG:5166043906965201450_chap line.png: i.