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 ceramic stones (澄泥硯) which are manufactured by a process which is said to have been developed in Luoyang in Henan. Classical scholars had more than just the Four treasures in their studies. The other "Treasures" include the brush-holder (笔架), brush-hanger (笔挂), paperweights (镇纸), the brush-rinsing pot (笔洗), and the seal (圖章) and seal-ink (印泥). For painting, Chinese pigments are also used. 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