Sentence:  ... for what lady can abide to love a spruce silken-face courtier, that stands every morning two or three hours learning how to look by his <WSD>glass</WSD>, how to speak by his <WSD>glass</WSD>, how to sigh by his <WSD>glass</WSD>, how to court his mistress by his <WSD>glass</WSD>? I would wish him no other plague, but to have a mistress as brittle as glass. 
Meaning of the word marked with <WSD> tags:  A mirror.