In Fahrenheit to appear at the same time, the French column muir, 1683 ~ 1757) Also design and manufacture a thermometer. He thinks that the coefficient of expansion of mercury is too small for temperature measuring material. He concentrated on the advantages of using alcohol as a temperature measuring material. He repeatedly practice found that alcohol contains 1/5 of the water, between the freezing temperature and the boiling temperature of water, its volume expansion from 1000 volume unit volume increases to 1080 units. So he divided between freezing point and boiling point into 80, as the temperature of the thermometer dividing, this is the thermometer.  华氏温度计制成后又经过30多年，瑞典人摄尔修斯于1742年改进了华伦海特温度计的刻度，他把水的沸点定为100度，把水的冰点定为0度。 Later his colleagues le meur numerical upside down again, the two temperature points become now the percentage of temperature, namely the Celsius temperature, expressed in ℃. Fahrenheit and Celsius temperature relationship is ℉ = 9/5 ℃ + 32, or 5/9 ℃ = ( ℉- 32) 。 Multi-purpose Fahrenheit, British and American countries now Germany's multi-purpose column temperature, and the world in technology and the industrial and agricultural production, and most in our country, France and other countries are multi-purpose Celsius temperature. Zui thermometer is early in 1593 by the Italian scientist Galileo ( 1564 ~ 1642) The invention. His * thermometer is only a glass tube exposure at one end, and the other end with a walnut large glass bulb. When using heated the glass bulb first and then put the glass tube into the water. As the change of temperature, the water in the glass tube is mobile, based on what mobile can determine the change of temperature and temperature of high and low. Thermometer has the effect of heat bilges cold shrink so this kind of thermometer, is strongly influenced by the outside environment factors such as atmospheric pressure, so the measurement error is bigger. Later, Galileo's students, and other scientists, based on the iterative improvement, such as an inverted glass tube, the liquid on the tube, the glass tube sealing, etc. Leo are prominent French cloth made in 1659 thermometer, he reduced the size of glass bulb, and changing the temperature of material to mercury, the thermometer has now the prototype of the thermometer. After the Dutch warren hite using alcohol in 1709, in 1714 and measured by mercury as material, created more thermometer. He looked at the water's boiling temperature, the temperature of the mixed water and ice, salt water and ice when the temperature of the mixture; After repeated experiments and the approval, zui after a certain concentration of the temperature of the salt water freezes at 0 ℉, the temperature of pure water freezes at 32 ℉, a standard atmospheric pressure, the water to boil at a temperature of 212 ℉, with ℉ Fahrenheit temperature, this is Fahrenheit.