Sir – Matthew Arnold saw his “Signal Elm” against “the orange and pale violet evening sky”, which means he was looking from the north, so it cannot possibly have been north-west of the track as suggested by Jim Tallett (Letters, March 12).

Nor is it significant that he called it an elm. He saw it from some distance, and all its lower branches had been repeatedly removed (hence its name of “Umbrella Tree”) so it would have been hard to recognize the species even from close up.

The tree was soon identified and it has been repeatedly photographed since the 1890s, providing a record of its remarkable history. It was eventually allowed to grow its lower branches, then lost its old top around 1970, so that it cannot now be called either a “signal” or an “umbrella” tree. It used to be a donnish sport to dispute the identity of the tree, but none of the alternatives fitted the poem, which by the evidence recorded an actual walk. Arnold's correspondence shows that he came to Oxford to lecture in the first week of December 1865, intending to write a memorial to Arthur Clough.

He walks past Chilswell Farm, remarking that “This winter-eve is warm, humid the air”. The records of the Radcliffe Observer show that the 6th of December was the warmest day of the month and that it had rained. As he goes up the track, he sees huntsmen coming down the hill, returning from hunting in Berkshire.

The Oxford Times for the week shows that there was a meet in Marsham that day.

He flees “into yon further field” — to his left, as there was a wood on his right, and there he saw the tree against the sunset sky.

Do the walk next December; you'll be convinced.

Philip Stewart, Boars Hill