Given the fact that John Henry Cox, born somewhere around 1750 who died in China on 5 October 1791 charted Tasmania’s Great Oyster Bay Maria Island and Marion Bay in 1789, you might expect to find biographical details somewhere like the Australian Dictionary of Biography, but as things turn out his sojourn at Great Oyster Bay was a relatively insignificant incident in a rather strange narrative.
Cox was the son of a London jewellery merchant whose factory in Shoe Lane specialised in the clocks and musical timepieces (sing-songs) used as bribes for Chinese mandarins in control of the merchants Europeans were obliged to deal with in Canton. His father’s A Descriptive Inventory of Several Exquisite and Magnificent Pieces of Mechanism and Jewellery (London 1773) would cast further light on that side of things if further light is needed. When James Cox died towards the end of the 1770s, his son approached the East India Company for permission to stay in China for three years to sell off the remainder of his father's stock of clocks.
Granted permission to operate as a private merchant apart from John Company’s monopoly in May 1780 he arrived in Canton in February 1781. He was originally given two years, and when that time was up applied for an extension. He, or possibly his father’s gadgets, had apparently been of some use in delicate negotiations, and he got his extension.
He was, however, something of an entrepreneur, and relocated to Macao, where he teamed up with a Scotsman who had become a naturalised Austrian and served as his adopted country’s consul (John Reid) and another Scot (Daniel Beale) who was the Prussian consul in the same jurisdiction. These apparently incongruous consular roles allowed them to bypass the East India Company’s restrictive monopoly.
1784 saw Cox branching out and into the fur trade on the northwest coast of America around Vancouver Island and Nootka Sound. The business went well enough for Cox and his associates to start up the Bengal Fur Society in Calcutta, and that venture was successful enough to get up the East India Company’s nose. Cox headed back to England, where a new scheme looked to exploit the Russo-Swedish War of 1788–90.
Visiting the Swedish court at Gothenburg, he proposed to use his recently purchased brig Mercury, newly purchased from naval architect Marmaduke Stalkartt at Deptford, as a privateer to raid the eastern Russian coast and the Muscovite fur and skin operations in Alaska. With the Swedish crown looking to collect ten percent of the prizes, the Swedish king (Gustaf III) granted the requisite permission, and Mercury was rebranded as the Swedish naval brig Gustaf den Tredie (which, predictably translates as Gustav III).
Having acquired that licence, Cox sailed from Gravesend under English colours on 26 February 1789, planning to keep the destination secret. The original notion was to travel via Cape Horn, but something (presumably the diplomatic arrangements) delayed the departure, and the route via the Cape of Good Hope seemed the better option.
There’s a reasonably thorough account of the voyage, courtesy of Lieut. George Mortimer of the Marines (Observations and remarks made during a voyage to ... the North West Coast of America ... and from thence to Canton, in the brig Mercury commanded by John Henry Cox, Esq). The presence of an English military man on a Swedish privateer has one scratching the noggin once again, but he was the man on the spot, and much of what follows comes from his narrative.
Cox doesn’t seem to have been in a hurry to get on with the privateering side of the voyage. It took him around a month to sail from Gravesend to Teneriffe, another month to reach the Equator and a further month to pass Tristan da Cunha, coincidentally around the time Fletcher Christian and the Bounty mutineers were casting Captain Bligh adrift at Tahiti.