As the city is the center of business; there is the Custom-house, an article, which, as it brings in an immense revenue to the publick, so it cannot be removed from its place, all the vast import and export of goods being, of necessity, made there; nor can the merchants be removed, the river not admitting the ships to come any farther.

Here, also, is the Excise Office, the Navy Office, the Bank, and almost all the offices where those vast funds are fixed, in which so great a part of the nation are concerned, and on the security of which so many millions are advanced.

Here are the South Sea Company, the East India Company, the Bank, the African Company, &. whose stocks support that prodigious paper commerce, called Stock-Jobbing; a trade, which once bewitched the nation almost to its ruin, and which, tho' reduced very much, and recovered from that terrible infatuation which once overspread the whole body of the people, yet is still a negotiation, which is so vast in its extent, that almost all the men of substance in England are more or less concerned in it, and the property of which is so very often alienated, that even the tax upon the transfers of stock, tho' but five shillings for each transfer, brings many thousand pounds a year to the government; and some have said, that there is not less than a hundred millions of stock transferred forward or backward from one hand to another every year, and this is one thing which makes such a constant daily intercourse between the Court part of the town, and the city[...].

-- Daniel Defoe, A Tour Thro' the Whole Island of Great Britain, letter 5 (1724-1727)

There is no Place in the Town which I so much love to frequent as the Royal-Exchange. It gives me a secret Satisfaction, and in some measure, gratifies my Vanity, as I am an Englishman, to see so rich an Assembly of Countrymen and Foreigners consulting together upon the private Business of Mankind, and making this Metropolis a kind of Emporium for the whole Earth. I must confess I look upon High-Change to be a great Council, in which all considerable Nations have their Representatives. Factors in the Trading World are what Ambassadors are in the Politick World; they negotiate Affairs, conclude Treaties, and maintain a good Correspondence between those wealthy Societies of Men that are divided from one another by Seas and Oceans, or live on the different Extremities of a Continent. I have often been pleased to hear Disputes adjusted between an Inhabitant of Japan and an Alderman of London, or to see a Subject of the Great Mogul entering into a League with one of the Czar of Muscovy. I am infinitely delighted in mixing with these several Ministers of Commerce, as they are distinguished by their different Walks and different Languages: Sometimes I am justled among a Body of Armenians; Sometimes I am lost in a Crowd of Jews; and sometimes make one in a Groupe of Dutchmen. I am a Dane, Swede, or Frenchman at different times; or rather fancy my self like the old Philosopher, who upon being asked what Countryman he was, replied, That he was a Citizen of the World.

-- Joseph Addison, The Spectator no. 69 (Saturday, 19 May 1711)