World map tattoo on a forearm

The barge is tied up below Calder Lock and the kettle has been on the back ring since breakfast, because the damp gets into everything once the sun goes behind the poplars. I've been at the atlas again, the battered one from the church jumble, colouring the continents the way you did when you were eight and wouldn't stay in your seat on the Sunday run to Oxford. South America is pink now, Africa red, the bit of Asia the atlas squeezes into the top corner is yellow, and I've left the oceans pale so the ink doesn't bleed. A map that isn't coloured in is only a list of names.

Your postcard came on Tuesday with the Valparaiso harbour on the front, all those painted houses stacked up the hill as if someone had emptied a paint tin down the slope. You wrote that the ship leaves for Auckland in March and that the cook makes a sponge on Sundays. I laughed out loud on the towpath and the lock keeper's dog barked back at me.

So I've started a new page. I've drawn your route in grey pencil, one fine line from the Humber past the Canaries, round the bulge of Brazil, then the long empty stretch where the ship will be out of sight of anything. Each night I trace it with my finger and tell the cat where you are.

This morning the gates groaned open and a single narrowboat came through, her crew waving at me as if I were the one going somewhere. I waved back. Then I came inside and pressed the atlas flat under the tin of tea, so it will be dry when you come home and want to see where you've been.