In 1843, a small party of engineers was sent from Belgium to study various British coal mines, in particular the English practice of tubbing (‘the lining of a pit-shaft or tunnel with a watertight casing’, OED). The Belgians toured the country, covering some 1500 km thanks to the ‘admirable rail network’, from London to Sheffield, then on up to Newcastle, across to Liverpool and Manchester, Birmingham, Swansea, and Bristol, before returning to London, where they visited the Museum of Practical Geology (est. 1837, one of the oldest single science museums in the world, and now part of the Natural History Museum). All their findings are detailed in a report, published in Mons in 1844:
But the extraordinary thing about the report is its presentation, as each gathering, and each plate, is printed on a different coloured paper: variously pink, green, peach, blue, or—occasionally—white. (And seemingly at random, too. Comparison with the British Library copy shows that the same gathering is printed on a different coloured paper in each copy.) The writers make no mention of why the report was produced in this way, but it makes for a beautiful-looking book.