世界最早的湿度计-天平式湿度计天平式湿度计，西汉人发明。在《史记.天官书》中有记载：其法是用两个重量相等而吸湿性不等的物体(如铁和石灰)，分别挂在天平两端。The world's earliest hygrometer - balance type hygrometer balance type moisture meter, the Western Han Dynasty invented. In the "historical records. Recorded in thebook:" days of official method is the use of two weight of equal and hygroscopicity ofunequal objects (such as iron and lime), were hung in the balance at both ends.
当空气湿度 不变时，两边不变，当变化时，由于天平两边物体的吸湿性不 同，重量就发生变化，使天平发生偏差。Both sides remain unchanged when the air humidity is unchanged, and when thechange, due to moisture absorption on both sides of the balance weight object is notthe same, changes, make the balance deviation.
天气干燥，天平向铁边倾斜，天气湿重天平向石灰边倾斜，从而指出空气朝湿的程度。 此计比国外(欧洲)早1600多年，是世界最早的湿度计。中国人太聪明了，这都想得到。The dry weather, the balance is tilted to the side of the iron weather wet weight balance tilted to the lime edge, thus points out the air in the wet degree. This planthan foreign (European) as early as 1600 years, is the world's earliest hygrometer.Chinese people are too smart, this wants.