Wang Chong (; 27 – c. 100 AD), courtesy name Zhongren (仲任), was a Chinese meteorologist, astronomer, and philosopher active during the Han Dynasty. He developed a rational, secular, naturalistic and mechanistic account of the world and of human beings and gave a materialistic explanation of the origin of the universe. His main work was the "Lunheng" (論衡, "Critical Essays"). This book contained many theories involving early sciences of astronomy and meteorology, and Wang Chong was even the first in Chinese history to mention the use of the square-pallet chain pump, which became common in irrigation and public works in China thereafter. Wang also accurately described the process of the water cycle.
Han-era astronomers adopted a geocentric model of the universe, theorizing that it was shaped like a sphere surrounding the earth in the center. They assumed that the Sun, Moon, and planets were spherical and not disc-shaped. They also thought that the illumination of the Moon and planets was caused by sunlight, that lunar eclipses occurred when the Earth obstructed sunlight falling onto the Moon, and that a solar eclipse occurred when the Moon obstructed sunlight from reaching the Earth. Although others disagreed with his model, Wang Chong accurately described the water cycle of the evaporation of water into clouds.
Kublai (; ; ) was the fifth Khagan (Great Khan) of the Mongol Empire ("Ikh Mongol Uls"), reigning from 1260 to 1294 (although due to the division of the empire this was a nominal position). He also founded the Yuan dynasty in China as a conquest dynasty in 1271, and ruled as the first Yuan emperor until his death in 1294.
The Song dynasty is divided into two distinct periods, Northern and Southern. During the Northern Song (Chinese: 北宋; 960 -- 1127), the Song capital was in the northern city of Bianjing (now Kaifeng) and the dynasty controlled most of what is now Eastern China. The Southern Song (Chinese: 南宋; 1127 -- 1279) refers to the period after the Song lost control of its northern half to the Jurchen Jin dynasty in the Jin -- Song Wars. During this time, the Song court retreated south of the Yangtze and established its capital at Lin'an (now Hangzhou). Although the Song dynasty had lost control of the traditional ``birthplace of Chinese civilization ''along the Yellow River, the Song economy was still strong, as the Southern Song Empire contained a large population and productive agricultural land. The Southern Song dynasty considerably bolstered its naval strength to defend its waters and land borders and to conduct maritime missions abroad. To repel the Jin, and later the Mongols, the Song developed revolutionary new military technology augmented by the use of gunpowder. In 1234, the Jin dynasty was conquered by the Mongols, who took control of northern China, maintaining uneasy relations with the Southern Song. Möngke Khan, the fourth Great Khan of the Mongol Empire, died in 1259 while besieging the city of Chongqing. His younger brother Kublai Khan was proclaimed the new Great Khan, though his claim was only partially recognized by the Mongols in the west. In 1271, Kublai Khan was proclaimed the Emperor of China. After two decades of sporadic warfare, Kublai Khan's armies conquered the Song dynasty in 1279. The Mongol invasion led to a reunification under the Yuan dynasty (1271 -- 1368).

Question: What was the position of the person who defeated the last Song emperor of the country the person who was able to describe the process of evaporation was in?
Answer: Khagan