Hebrew calendar (astronomically called a lunar conjunction and, in Hebrew, a molad) is the moment at which the sun and moon are aligned horizontally with respect to a north-south line (technically, they have the same ecliptical longitude). The period between two new moons is a synodic month. The actual length of a synodic month varies from about 29 days 6 hours and 30 minutes (29.27 days) to about 29 days and 20 hours (29.83 days), a variation range of about 13 hours and 30 minutes. Accordingly, for convenience, a long-term average length, identical to the mean synodic month of ancient times (also
Thomas Fuller (mental calculator) skill was even used as proof that enslaved Blacks were equal to whites in intelligence, which fueled some pro-abolitionist discussion. When Fuller was about 70 years old, William Hartshorne and Samuel Coates of Pennsylvania were in Alexandria and, having heard of Fuller's powers, sent for him. They asked him two questions which satisfied their curiosity. First, when they asked him how many seconds there were in a year and a half, he answered in about two minutes, 47,304,000. Second, when they asked how many seconds a man has lived who is 70 years, 17 days and 12 hours old, he