The foremost modern air conditioning system was developed in 1902 by a young electrical engineer known as Willis Haviland Carrier . It was designed to solve a humidity problem at the Sackett-Wilhelms Lithographing and Publishing Company in Brooklyn, N.Y. Paper stock at the plant would at times absorb moisture from the warm summer air, making it cumbersome to apply the layered inking techniques of the time. Carrier conditioned the air inside the building by blowing it over chilled pipes. The air is cooled as it is passed over the cold pipes, and since cool air is not able to carry as much moisture as warm air, the process reduced the humidity in the plant and stabilized the moisture content of the paper. Reducing the humidity also had additional benefit of lowering the air temperature and a new technology was born. Carrier realized he had developed something with extra potential, and it wasn't long before air-conditioning systems started appearing in theaters and stores...