Black Friday (shopping) corner the gold market. When President Grant learned of this manipulation, he ordered the Treasury to release a large supply of gold, which halted the run and caused prices to drop by eighteen percent. Fortunes were made and lost in a single day, and the president's own brother-in-law, Abel Corbin, was ruined. The earliest known use of "Black Friday" to refer to the day after Thanksgiving occurs in the journal, "Factory Management and Maintenance", for November 1951, and again in 1952. Here it referred to the practice of workers calling in sick on the day after Thanksgiving, in order to
Leap year starting on Friday share this characteristic. Leap years that begin on Friday, along with those that start on Sunday, occur most frequently: 15 out of the 97 (≈ 15.5%) total leap years in a 400-year cycle of the Gregorian calendar. Thus, the overall occurrence is thus 3.75% (15 out of 400). Like all leap year types, the one starting with 1 January on a Friday occurs exactly once in a 28-year cycle in the Julian calendar, i.e. in 3.57% of years. As the Julian calendar repeats after 28 years that means it will also repeat after 700 years, i.e. 25 cycles. The year's