Chem. [mod. f. Gr. κρύο-ς frost, icy cold + -GEN taken as = producer.] A freezing-mixture, or a substance which when mixed with ice produces a freezing mixture.
1875. F. Guthrie, in Proc. Physical Soc., I. 76. By Cryogen I mean an appliance for obtaining a temperature below 0° C. In this paper it always signifies a freezing-mixture.
1881. Watts, Dict. Chem., VIII. 1005. The temperature of the mixture when used as a cryogen.
