Of the bacterial isolates found in the Arctic that are able to degrade PCBs, none used compounds such as 2-chlorobiphenyl, 3-chlorobiphenyl, camphor, citronellol, cymene, dehydroabietic acid, limonene, methanol, n-hexadecane, pentachlorophenol, phenol, or pinene as primary growth substrates (Master and Mohn 1998).
In the 20th century, demand for electricity led to the consideration of geothermal power as a generating source. Prince Piero Ginori Conti tested the first geothermal power generator on 4 July 1904, at the same Larderello dry steam field where geothermal acid extraction began. It successfully lit four light bulbs. Later, in 1911, the world's first commercial geothermal power plant was built there.
Leonardo da Vinci at the beginning of the 16th century was credited with inventing the first hygrometer that used a ball of wool to provide this indication of humidity level. First Mechanical Air Cooler. Da Vinci was likely the first to use a mechanical air cooler. This air cooler consisted of a hollow water wheel with an air passage constructed to guide the air from the water wheel to his patron's wife's boudoir. The air was cooled by the splashing and evaporation of water during operation of the water wheel.