This bit of news has been bouncing around the Interwebs for a few days, and justifiably so, if you have a sense of history: two grandsons of President John Tyler, 10th president of the United States, born in 1790, are still alive.It is not quite Abraham and Sarah territory, and it makes sense once you break it down: President Tyler had a son in 1853 when he was 63, and that son (and his wife, ahem) had sons when he was 71, in 1924, and four years later at 75. Both of those men are still living, and doing fine, according to New York magazine's interview with Harrison Ruffin Tyler.But this story still gives me that enjoyable frisson of historical proximity, that sense of the intervening years collapsing the mind's eye. I am easy in this regard: I get that charge from walking a 2,000-year-old Roman road, or viewing the relic of a saint.I wonder if this sensibility didn't come from sitting at my grandmother's knee and listening to her recall stories that her own father would tell of fighting in the Civil War (for the North -- phew). She'd pull out his letters, and souvenirs, like old mini balls, some of which wounded him. (He lost his leg three days before Appomattox.) It seemed so immediate, so close, and was, though I'm not sure everyone shares that view. (Not with today's media-induced amnesia.)My great-grandfather was born in 1841 -- the year Tyler became president -- and he had two sons with his first wife, who died, then a daughter in 1888, my grandmother, with his second wife, who survived him. (He worked in the customs house here in Brooklyn, and spent a year in Havana after the Spanish-American War.)My grandmother then had four children, and along came my mother at 45, a "change-of-life" baby, as they apparently said then. Hence my relatively few degrees of separation from the nineteenth century. But we got nothing on the Tyler dynasty.