ART

A sketchbook of the British poet and artist William Blake that sold 125 years ago for the equivalent of $30 is expected to fetch about $875,000 when it comes up for auction next month at Christie’s in London. “The works of William Blake have been in such demand for so long that it is rare for anything by him to come to market now,” said the head of English watercolors and drawings at Christie’s. The sketchbook has come from an anonymous British source that Christie’s won’t identify. Blake, who died in 1827, earned a meager living as an engraver while writing and publishing poems on biblical and mythological subjects illustrated with his own colored engravings.