ALCOR (80 Ursae Majoris). Alcor, forever tied to Mizar, is hardly ever spoken of unless as “Mizar and Alcor,” a naked eye double in the tail of Ursa Major that are 11.8 minutes of arc apart and that the Arabs referred to as the “horse and rider.”
It was my design to comprise in it all that, before I set myself to write it, I thought I knew of the nature of material objects.