I have an undated article from the “Handbook of Construction Techniques,” which McGraw Hill once published. The title was “Keeping a Cool Head.” Consider this in hindsight:
After experiencing severe headaches wearing his metal helmet in the hot sun, Ray Vaught, a foreman with E.E. Barber & Sons of Texarkana, Arkansas, came up with a cool idea to take the heat off his head. He put a one-foot-square piece of 3/16-thick asbestos cloth inside his hat as an insulator.
The marked difference between a lined and unlined helmet was clearly evident by touch. By strapping a thermometer inside his asbestos-lined helmet, Ray found that the temperature inside was as much as 20 degrees cooler than the temperature outside. It wasn’t long before everyone on the job had adopted his idea for keeping a cool head.