Limnology zoologist) and Einar Naumann (a Swedish botanist) co-founded the International Society of Limnology (SIL, from Societas Internationalis Limnologiae). Forel's original definition of limnology, "the oceanography of lakes", was expanded to encompass the study of all inland waters, and influenced Benedykt Dybowski's work on Lake Baikal. Prominent early American limnologists included G. Evelyn Hutchinson, Ed Deevey, E. A. Birge, and C. Juday. Physical properties of aquatic ecosystems are determined by a combination of heat, currents, waves and other seasonal distributions of environmental conditions. The morphometry of a body of water depends on the type of feature (such as a lake, river,
Four Treasures of the Study Four Treasures of the Study Four Treasures of the Study, Four Jewels of the Study or Four Friends of the Study is an expression used to denote the brush, ink, paper and ink stone used in Chinese and other East Asian calligraphic traditions. The name appears to originate in the time of the Southern and Northern Dynasties (420–589 AD). Chinese culture is very fond of four word couplets, and the Four Treasures is another example: "文房四寶: 筆、墨、紙、硯," (Pinyin: "wén fáng sì bǎo: bǐ, mò, zhǐ, yàn") ""The four jewels of the study: Brush, Ink, Paper, Inkstone."" In the couplet mentioned,