It is possible that John is the only surviving child of a set of triplets. He was listed in the 1860 census as age 8, and in the 1870 census as age 18. Strictly speaking, if he was born on 19 June 1852 like his sisters Mary and Nancy who died in infancy, he should have been reported as age 7 and 17, respectively, since he would have been 18 days shy of his birthday on June 1. But ages were more often reported as the date of the census visit rather than strictly according to the rules.