Rocket-borne observations of the extinction of solar hydrogen Lyman-alpha radiation made during the solar eclipses of 20 May 1966 at Karistos for normal and 44~ visibility and o f 7 March 1970 at East Quoddy for normal. 10ud ` and 0.6ud visibility have been used to study the variation of temperature in the mesosphere during these events. It is seen that near the mesopause the decrease of temperature at Karistos is by 20 ~ K for 44ud ,,isibility and at East Quoddy by 100O K for 0.6% visibility. Possible causes of these temperature variations visa -vis molecular oxygen and pressure variations have been briefly discussed.