Sentence:  But from thine eyes my knowledge I derive,/ And constant stars in them I read such art/ As 'Truth and beauty shall together thrive,/ If from thyself, to store thou wouldst convert';/ Or else of thee this I <WSD>prognosticate</WSD>:/ 'Thy end is truth's and beauty's doom and date.' 
Meaning of the word marked with <WSD> tags:  To predict or forecast, especially through the application of skill.