He worked closely with Charles Eastlake and was a great friend of John Ruskin. He and Ruskin were suspected of conspiring to destroy many of JMW Turner's erotic artworks after Turner's death, though this story has now been discredited and it would appear that if they did conspire at all it was probably to preserve Turner's work from seizure under the then recently passed Obscene Publications Act.

There is an amusing story of how he once absentmindedly unbuttoned Queen Victoria's coat while showing her around the Gallery.

"Educated at London University, he left to read for the Bar but abandoned this to study painting for a time. In1834 he went abroad for six years to familiarise himself with the galleries of Munich, Dresden, Rome, Florence and Paris.

On his return to London he set up as a portrait painter without spectacular success but his important contributions to art journals prompted Sir Robert Peel to invite him to compose an official catalogue for the National Gallery. In 1855 he was offered the appointment as Keeper and Secretary.

Of average height he had a very powerful build, a large head carried a full mane of hair and he wore a full white beard. He captured the hearts of those real Londoners of his time, the cabbies and bus drivers and policemen. They referred to him affectionately as "Old Snowball" and in doing so they conferred no small honour on him."