West India merchant (Colonial - Caribbean)
Thomlinson's father, also John, was the original name partner with Barlow Trecothick
London merchant firm, correspondents and insurers or agents for insurance of e.g. the Newport Rhode Island slave-traders Samuel and William Vernon.
https://digitalcollections.nyhistory.org/islandora/search?type=dismax&f%5B0%5D=mods_name_creator_contributor_mt%3AThomlinson%5C%20and%5C%20Trecothick%5C%20%26%5C%20Co.