"a sound atheist, who used to read in the British Museum"

An atheist is someone who does not believe in supernatural forces or powers.  According to a 2005 Eurobarometer poll, approximately 20 percent of UK residents 'do not believe there is a Spirit, God, nor life force'.

Sir Hans Sloane
Public DomainSir Hans Sloane

The British Museum opened to the public in 1759 in Bloomsbury, an area in central London. The collection consisted of books, manuscripts, prints, drawings, flora, fauna, medals, coins, seals and cameos that belonged to the late physician and scientist Sir Hans Sloane, the inventor of hot chocolate. The collection was worth approximately £20,000. Today, the museum has more than 7 million objects, and the number of annual visitors has increased from 5,000 to nearly 6 million. 

British Museum
GNU Free Documentation LicenseBritish Museum