Sentence:  [I]n the month of May, a <WSD>mercurial</WSD> thermometer, having its bulb covered with paper, and blackened in a similar manner to the spirit one, was inclosed in a square bottle of thin glass, four inches wide, to protect it from the wind. 
Meaning of the word marked with <WSD> tags:  Of or pertaining to the element mercury or quicksilver; containing mercury. (from 16th c.)