1 pound avoidupois = 16 ounces avoidupois = 7000 Grains
1 pound troy = 12 ounces troy = 5760 Grains
The feathers are 1260 havier.
Sam Loyd, Cyclopedia of Puzzles, 1914, p16
Now, how old would the speaker be?
Hunter, Fun with Figures, Problem 122