His periodicals, reports and textbooks led to him being raised to the dignity of serjeant at law in 1868 – rather than his modest practice as a lawyer.

He also founded or transformed the English journals The Field, bought cheaply from Benjamin Nottingham Webster,[2]and the Exchange & Mart; also The Queen, founded by Samuel Beeton and bought by Cox in 1862, merged in 1863 with Ladies' Paper, and edited by Elizabeth Lowe under Horace Cox (his nephew),[3] and the County Courts' Chronicle.

[7] The London Dialectical Society, founded in 1867, set up in 1869 a committee to investigate spiritualism, of which Cox was a member.

[12] In 1875, he founded the Psychological Society for Great Britain, with George Harris;[13] it was quickly dissolved after his death.

[14] Cox bought the fee simple (unfettered freehold) of the Serjeants' Inn in Chancery Lane at auction in 1877 for £57,100.

When one of his heirs offered their reversionary interest in Cox's probate estate for sale the advertisement listed the sources of income.

[18] Cox is an example of the wealthy early Victorian middle class men who established large landed estates.

He rebuilt the house as a Renaissance-style stuccoed villa to include a large main block with a carriage porch, and by 1873 owned 209 acres (0.85 km2) in Middlesex.

He and his son continued to add to the estate in Hendon and Edgware until it covered perhaps 2,000 acres (8.1 km2) of valuable land near London.

Cox kept a pack of hounds, and he and his son hunted over what are now Golders Green, Hendon, Mill Hill and Hampstead Garden Suburb.

[24] By his first marriage he was the father of Irwin E. B. Cox and a daughter known as the novelist Mrs H. Bennett Edwards (1844–1936).