alastaircox Posted 10 January , 2016 Share Posted 10 January , 2016 Picked up for a couple of quid at a local antiques market: Celluloid Mark II Protractor, broad arrow stamped, 1917 Patent, Celluloid Printers Ltd London. A couple of nice touches: it is personalised to AO PETTET (Hants/Wilts TF Sgt) and it slightly worryingly says "1 Kilometer = 1094 yards = 0.63 Mile (=5/8 Mile NEARLY)". Nearly?! Link to comment Share on other sites More sharing options...
Chris Henschke Posted 10 January , 2016 Share Posted 10 January , 2016 You lucky chap, I've been after one of them for yeas! Well done. Link to comment Share on other sites More sharing options...
trajan Posted 10 January , 2016 Share Posted 10 January , 2016 Not my thing at all - but if I had seen it I would have bagged it! A very nice item to have - and probably fun to use next time you go on a country walk,,, I have my uncle's bakelite prismatic 1944 compass which I always use when teaching students the basics of surveying and they tend to be fascinated by the use of relics like this - and slide rules, for that matter! Link to comment Share on other sites More sharing options...
Dai Bach y Sowldiwr Posted 10 January , 2016 Share Posted 10 January , 2016 ... "1 Kilometer = 1094 yards = 0.63 Mile (=5/8 Mile NEARLY)". Nearly?! Yes, nearly. What's wrong with that statement? 1100 yards by my reckoning is 0.625 or 5/8 of a mile. Link to comment Share on other sites More sharing options...
alastaircox Posted 10 January , 2016 Author Share Posted 10 January , 2016 It just looks an odd thing to put on a protractor albeit correct. Link to comment Share on other sites More sharing options...
Dai Bach y Sowldiwr Posted 10 January , 2016 Share Posted 10 January , 2016 Yes. I can see that, but it's 1100 yards which is 5/8 mile, not 1094 yards. Modern day OS Explorer 1:25000 maps still have a reminder that 1 mile = 1.6093 kilometres, and that 1 kilometre is 0.6214miles. And the conversion is just a guide, it wouldn't be used for serious distance conversions. It would be fine for marching and driving distances. Serious calculations like artillery distances would have been done exclusively in yards or feet, off a Sheet map that was based on 1000 yard squares, even though the scales were marked off in yards and metres. 1917 was an age when fractions were far more commonly expressed than today. And most of the men had never heard of a kilometre until they got to France. So expressing a kilometre as being nearly 5/8 mile is understandable. I doubt that many had the capacity or the need to figure out the exact conversion to 4 decimal places. Link to comment Share on other sites More sharing options...
Chasemuseum Posted 10 January , 2016 Share Posted 10 January , 2016 It actually looks very much like the WW2 examples which we were using as Army cadets in the early 1970s. Australia had gone metric in 1970 and by the mid 1970s the army was using new metric equipment but the cadets had been left the old imperial stuff - all the maps were 1-inch to the mile (1/63,640). Then in 1975 the socialist government closed the cadet system so I expect all the old stores were burned as having no scrap value. Certainly both WW1 and WW2 examples are quite uncommon here. Cheers RT Link to comment Share on other sites More sharing options...
Dai Bach y Sowldiwr Posted 10 January , 2016 Share Posted 10 January , 2016 the cadets had been left the old imperial stuff - all the maps were 1-inch to the mile (1/63,640). 1:63,360 Link to comment Share on other sites More sharing options...
Chasemuseum Posted 10 January , 2016 Share Posted 10 January , 2016 1:63,360 My bad. In my defence, it is a very long time since I have actually used imperial maps for navigation Cheers Link to comment Share on other sites More sharing options...
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