math_fact: 8148 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
trivia: 8148 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
historical_date: April 22nd is the day in 1915 that the use of poison gas in World War I escalates when chlorine gas is released as a chemical weapon in the Second Battle of Ypres.