In every sense, the next journey is into unknown territory. I feel confident discussing early uses of isobaths, even the life and times of Charles Hutton, but after him, the story of contours emergence onto maps takes place variously in: France, Germany and Switzerland (before finally pitching up in Ireland) and my reading of various OS sources hasn’t caught up. So, in a side step, my eye caught on Lewis – which kept cropping up once the use of contour lines was ‘established’ in Britain. I sold it to my partner as a ‘holiday’, we’re heading to the Outer Hebrides next month. In that far off corner of Britain it appears the OS men went ‘off-piste’ contouring every 25ft instead of only every 50… WITHOUT PERMISSION. Why? They liked being there for sure, and were present long enough for their names to appear in the census. But why go for so much detail? I need the equivalent of a ‘trig point bagger’ (yes, they are a thing): a Bench Mark logger? I want to know why so many ascents on Lewis were marked with a slew of B.M.’s; did they really get the chisel out and mark so many random boulders and stones thus? There are plenty in ‘normal’ places as well: sides of buildings, along roads, but, there’s even one marked on the beach by the ‘Callernish Inn’ (sadly no longer a hostelry) 6.4ft above high tide, they didn’t expect that one to last, surely? So, I’m going in search of Bench Marks (weather and partner permitting), but please! If someone has already done this – and written about it – do let me know, then we can have a holiday instead.Finally, huge apologies to Callum McNeill-Ritchie for forgetting to credit his photos in the last post (and dissing his sausages in an earlier one).