Watercolour world map on upper back

The ink went over on the second night out of Liverpool, so the Atlantic is a bit wet on the chart I'm meant to be finishing. Mr Pellow says it adds character. He is the captain's cousin and paints the Americas blue because he has never been further than Dublin, and he says the sea is always blue. I have been given the job of colouring the rest because my hand is steadier with a damp brush, or so the chief steward told me in the same breath he docked my wages for the spoiled tablecloth.

Anyway, here is the trick, which I wish you'd let me show you at Mam's. You lay the wash wet on wet and let the colour run where it wants. Purple bleeds into the shadow of the Urals, green creeps across Persia like moss, and the pink I used for the Cape of Good Hope has spread into half of Siberia. Nobody will ever check. The lines are only the start. Where the paint pools it drips over the edges and down the paper, and I have stopped trying to stop it.

Last night the purser stood over me with a lamp and asked which country I had been to. I told him none, and he laughed and said that was the best way to draw one. I thought about you in the kitchen, scraping the bread board, and how we used to trace the coast of Africa with our fingers on the steamed window. I have put a small blot on Lagos for you, the size of your thumbnail. When we dock in Lisbon I will post this with the rest of the chart, so it travels with the ship and not with me.

Your brother, Tom