H) From co-latitude to latitude. Steps A through G produce what is called a 'co-latitude'. A co-latitude is the angle which when added to the latitude equals 90° that is 90° - co-latitude = latitude. To derive the calculated latitude from this observation Lewis subtracts the co-latitude from 90°. 90°00'00"- 44°08'00" 45°52'00" LATITUDE 45°52' Latitude to nearest arc minute per this observation (about 3 miles too far south) 45°55°' Latitude of camp determined from map analysis 45°23'23" Lewis's calculated latitude using incorrect index error of 2°40' instead of 2°11'40"
