...invented it in 1742. To convert degrees Centigrade (Celsius) to degrees Fahrenheit multiply by 9/5 and add 32. To convert degrees Fahrenheit to Centigrade subtract 32 and multiply by 5/9. Fahrenheit Centigrade 100 38 95 35 90 32 85 29.5 80 26.5 75 24 70 21 65 18 60 15.5...