Sentence:  An exceedingly minute portion of Prussian blue suspended in water was similarly affected with muriatic acid. A portion of the <WSD>squeezings</WSD> of the sponge, which exhibited a greenish colour, evaporated to dryness, and ignited, left a calx ... 
Meaning of the word marked with <WSD> tags:  That which is forced out by pressure; dregs.