Sentence:  The mixture was then extracted with alkali and with water following which the carbon tetrachloride was distilled on a Vigreux column , a 25 % center <WSD>cut</WSD> being retained which was then degassed under vacuum in the presence of * * f . 
Meaning of the word marked with <WSD> tags:  a trench resembling a furrow that was made by erosion or excavation