Matching heartbeat line tattoos on two wrists

The machine at the infirmary draws a line across a little green screen, and I have sat beside it for three nights now with Dad's hand going limp in mine. The nurse calls it his heartbeat, though it looks more like a hill that somebody has tried to climb in a hurry. Every so often the line bunches itself into a small round loop, like a heart folding in on itself, and then it goes flat again and tails away to nothing across the glass.

Mr Hebden from the pit came by with a basket of oranges and said the men have a collection going at the Miners' Welfare. Tell Mam I said thank you, and tell her I have not been eating enough, which she will know already because you will have told her. I asked the sister whether he would wake up and she said he was holding his own, which I have decided means yes.

I have been thinking about the paper strip that came out of the machine on Tuesday, the one the doctor folded into my coat pocket without a word. It has the whole night on it, every rise and drop, and I cannot stop running my finger along the peaks. I have had the idea that you and I should each carry one of those lines on our wrists, the same shape, so that whichever of us is sitting up with him next can look down and know the other is counting too.

Don't say I am being soft. Bring Mam's pen, the one with the fine nib, and come on the first bus. We can do it at the back of the Sunday school hall where Mrs Lowes does the stitching, if she still has her needle.

Your loving sister, Nell