Sentence:  Paint Scotland greetin owre her thrissle; / Her mutchkin stowp as toom's a whissle; / An' damn'd excisemen in a bussle, / Seizin a <WSD>stell</WSD>, / Triumphant crushin't like a mussel, / Or limpet shell! 
Meaning of the word marked with <WSD> tags:  A still.