[2] In 1783 he opened Merlin's Mechanical Museum in Princes Street, Hanover Square, London, a meeting-place for the gentry and nobility.

[11][12] As of 1763, Jérôme Lalande recorded that Merlin had helped to complete a large barrel organ which was built for the Princess of Wales.

In addition Merlin acted as a manager and curator of Cox's Jewelry Museum in Spring Gardens, which became a favored gathering-place of fashionable London between 1772 and 1775.

[18][19] Samuel Johnson asserts the underlying importance of such efforts, writing of a visit to Cox's Museum in 1772:[6]: 73 "It may sometimes happen that the greatest efforts of ingenuity have been exerted in trifles; yet the same principles and expedients may be applied to more valuable purposes, and the movements, which put into action machines of no use but to raise the wonder of ignorance, may be employed to drain fens, or manufacture metals, to assist the architect, or preserve the sailor.

Friend and musicologist Charles Burney commissioned his instruments,[5][22] and even played one of them in a courtroom to defend Merlin's patent.

[1] Even though she regarded him as a foreigner, novelist Fanny Burney wrote of Merlin with affection:[5] "He is a great favourite in our house...He is very diverting also in conversation.

[26][27] The Morning Post and Daily Advertiser of 4 March 1778 declared "Mr. Merlin, the mechanic" to be the most striking Character of the 900 people attending a masquerade ball at the Pantheon.

[2] Merlin appeared "as a gouty gentleman, in a chair of his own construction, which, by a transverse direction of two winches, he wheeled about himself, with great facility to any part of the room.

[2] Well-off Londoners could meet their friends at Merlin's Mechanical Museum in the afternoon or evening, pay to see the exhibits, and drink tea or coffee for another shilling.

An entry in the parish register of St. Saviour, Southwark indicates that Joseph Merlin married Ann Goulding on 17 September 1783.

The parish register for St. Andrew Holborn gives their address as Shoe Lane, not at the museum in Princes Street.

Ann Goulding predeceased Merlin, and was buried at Christ Church, Southwark on 22 November 1793, just ten years after their marriage.

[2] Merlin is noted for the manufacture of ingenious automata, in particular the Silver Swan that he developed with London jeweller and entrepreneur James Cox.

A pianoforte with a six-octave span he made in 1775 preceded by fifteen years Broadwood's five-and-a-half octave grand piano.

Supplied with these and a violin, he mixed in the motley group of one of Mrs Cowleys' masquerades at Carlisle House; when not having provided the means of retarding his velocity, or commanding its direction, he impelled himself against a mirror of more than five hundred pounds value, dashed it to atoms, broke his instrument to pieces and wounded himself most severely.

"[30]Other inventions of Merlin's include: a self-propelled wheelchair,[33] a prosthetic device for "a person born with stumps only",[30] whist cards for the blind,[5] a pump for expelling "foul air",[30] a communication system for summoning servants,[30] a pedal-operated revolving tea table,[5] and a mechanical chariot with an early form of odometer.