A day begins and ends at midnight, a revolution of the sun, three-hundred and sixty degrees or twenty-four hours; an hour, fifteen degrees of its revolution. The year begins the marrow of the vernal equinox and consist of three-hundred and sixty-five days divided into twelve months of thirty days with a head of months, or intercalary day, at the completion of every three months; resetting every vernal equinox. The first day of the year, a Sabbath, begins the one in seven cycle. Jubilee, the fiftieth year following seven weeks of years, the forty-nine-year cycle, is the first year of the subsequent cycle.