Radiation Measurements on the Eclipsed Moon.

Instruments-The measurements were made on the lunar eclipse of October 27, `939, with a thermocouple attached to the 20-inch telescope of 4o inches focal length. Sensitiv~ty.-The deflection on total radiation at the end of totality was 54 mm, more than 36 times that previously observed. Met/zod.-Both cover glass and water cell were used to determine the temperatures. Temperatures-For a point near the center of the disk which was chosen for meas- urement, the temperature fell from 3710 to 2000 K during the first partial phase and slowly dropped to ~750 K during totality. At the beginning of totality the temperature falls at the rate of 3Q0 C per hour, but at the end of the first hour the rate is 70 C per hour. Lunar radialion.-The rate of radiation is nearly proportional to the energy re- ceived, except for very low temperatures. A computation of the equivalent thickness of the radiating layer from the known physical constants of lava and the radiation data shows that about 2.6 cm will satisfy the conditions