At around 5pm I left the Victoria and Albert Museum, walking through the galleries of the Northern European Renaissance, religious icons, intricate hand wrought metal working, with metal not produced in factories but small forges by master craftsmen (the period is 1400 to 1500, including those extraordinary years of discovery and invention between 1420 and 1460). And caught an underground train (electrification) to Liverpool Street, hurtling through tunnels largely dug out by hand in the 19th century. And into the vast cavern of Liverpool Street station itself; filled with thousands of people moving in every concievable direction; onto an overground train (railway electrification, replacing steam locomotion) to Manningtree. Where I was told I had no chance of a taxi (internal combustion engine). So started walking towards my destination, aware of the sea and the marshes to one side and a sky full of stars above, with planes(jet propulsion) circling on their approach to Stanstead. A church as a landmark, depicted with neon light and a sign marking a peace park. Beyond that, two huge towers with large red lights - phone masts? television transmitters? some part of the infrastructure of global communications.

The journey took 2 hours; I passed through six or more centuries of technical development.