Whew, it's Hot! How the temperature of the air could be measured was demonstrated by Galileo. He showed that a liquid, which expanded when it became hot, forced its way up a tube. A way of measuring atmospheric pressure came along with barometers. One of these was the wheel version (inset) made by Robert Hooke in 1665. Original artwork for the illustrations on p15 of L&L issue no. 966 (13 September 1980).