His father James had a factory in Shoe Lane, which specialised in the manufacture of clocks and automatons (known as "sing-songs" in pidgin English), designed as bribes for Chinese mandarins who were in control of the native merchants with whom Europeans were obliged to deal in trade negotiations in Canton.
[5] Cox, wanting to capitalize on this discovery, acquired and outfitted a small 60 ton brig named Sea Otter, commanded by James Hanna.
Evidence of their activity remains in the "Columbia" and Washington medals, which Boston merchants struck to celebrate the sailing in September 1787 of these two US vessels for the northwest coast of America.
Cox, at this stage, having already considerably overstayed his welcome, thought it wise to disappear to England for a spell but was soon back with newly hatched plans.
He paid a visit first to Gothenburg, where he made good use of the services of the Swedish East India Company's representatives there, William Chalmers, Lars Gotheen and J.A.
Through these men he was able to make contact with Baron Erik Ruuth who was Secretary of State for Commerce and Finance to the Swedish king.
The king was apparently very enthusiastic about Cox's quite fantastic proposal which was in effect to put his brig Mercury, newly purchased from the renowned Marmaduke Stalkartt, Deptford, at the disposal of Sweden and with her act as a privateer to raid both the eastern Russian coasts and their North American fur and skin establishments, for which Sweden would earn ten percent of the prizes.
[7] The Thames was still suffering under extreme weather conditions that winter, with the river frozen, and Mercury was not able to leave Gravesend on her prospective long voyage before 26 February 1789, but under English colours, as her destination was to be kept secret.
On 25 March they sailed from Tenerife, crossed the Line in 20 degrees West and on 28 April they were passing Tristan da Cunha.
Just about then, Captain William Bligh of HMS Bounty and the loyal members of the crew were being forced into the long boat by the mutineers led by Fletcher Christian.
On 29 May Mercury reached their first objective, Amsterdam Island in the Roaring Forties, halfway between Africa and Australia, discovered in 1522 by del Cano during his circumnavigation.
Mortimer communicated the intelligence to the Admiralty in respect of the probable destination of the Bounty mutineers, "as it is hoped will enable Captain Edwards of the Pandora frigate to bring them to that condign punishment they so justly merit".
Apparently he had considered returning at a more suitable time, but the Russian-Swedish Treaty of Värälä signed on 14 August 1790 precluded any such plans.
If Cox had gone prowling further afield round the North Pacific he might have found unexpected and surprising opposition; the Empress Catherine II had commissioned an expedition to carry out exploration work in the far east of Siberia and the Bering Sea.
[22] Cox appears to have intended to use the Swedish contract more as a talisman with which to confound the East India Company rather than wreak any damage on the Russians.