Sentence:  To November 1 add 7, and the ſum will ſhew, that the ſeventh day of <WSD>Thoth</WSD> fell, that year, upon the eighth day of November. 
Meaning of the word marked with <WSD> tags:  The first month of the later ancient Egyptian civil calendar and Coptic calendar, corresponding to the first month of the season of Akhet. Since 25 BCE, when the calendar was reformed to include leap-days, Thoth has been in roughly September.