Sentence:  Effulgence of my Glorie, Son belov'd, / Son in whoſe face inviſible is beheld / Viſibly, what by Deitie I am, / And in whoſe hand what by Decree I doe, / Second Omnipotence, two dayes are paſt, / Two dayes, as we <WSD>compute</WSD> the dayes of Heav'n, / Since "Michael" and his Powers went forth to tame / Theſe diſobedient... 
Meaning of the word marked with <WSD> tags:  To reckon or calculate.