On Saturday 30 August I will be leading a walking tour to explore the many London-focused aspects of the longitude story. The aim is to share some of what is displayed in the Ships, Clocks & Stars in the locations in which they actually happened, reminding us of the local geography that shaped efforts to tame global geography.

The London coffee house evoked in Ships, Clocks & Stars The London coffee house evoked in Ships, Clocks & Stars

As well as being an opportunity to get the thrill of being close to the very spot where John Harrison laboured to improve the tricky H3, where William Whiston lectured to a paying public about longitude or where Newton and Halley discussed the motions of the planets, it will also show how close and connected many key locations were.

Focused on the City centre, Fleet Street and the Strand, we will see centres of imperial power next to instrument makers' workshops, places of discussion and of scientific communication. Coffee houses, the Royal Society, East India House, the Royal Exchange, the Navy Board and more were all clustered together on the north bank of the Thames.

Walking round this area of London, it's obvious how much has changed. Perhaps above all we have lost the sense of London as a port, connected by sea to the rest of the world

The South East Prospect of London From the Tower to London Bridge. 1746 (PAH2186) The South East Prospect of London From the Tower to London Bridge. 1746 (PAH2186)
View west from London Bridge, 2014 (Rebekah Higgitt) View west from London Bridge, 2014 (Rebekah Higgitt)

But navigating the streets with the aid of an eighteenth-century map, such as that by John Roque, shows how many features are still recognisable and leads you into courts and alleyways normally passed by. These often reveal historic spaces that one might assume had been destroyed by bombing or development. Testing out my route the other weekend, I felt I was seeing the city that I've lived in for many years through new eyes.

Detail of the Roque 1746 map of London (Wikimedia Commons) Detail of the Roque 1746 map of London (Wikimedia Commons)

There are a few Blue Plaques to collect along the route, but a lot of this walk will rely on stories, people and places uncovered during the research done on the Longitude Project. I can promise despairing longitude projectors, successful businessmen, scientific and technological innovation, locations of power and finance, historic taverns and a statue of a cat.

Blue plaque marking the workshop of Thomas Tompion and George Graham, Fleet Street (Rebekah Higgitt) Blue plaque marking the workshop of Thomas Tompion and George Graham, Fleet Street (Rebekah Higgitt)

Those who are interested in joining me on the 30th can book online and meet me outside Adelaide House, the last building on the north bank before London Bridge crosses the river. Our first stop will be the river itself, a vital communication point not just to the world beyond but also down to Greenwich and up to Westminster. Longitude is both a global and a local story.