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SchtivanTheTrbl t1_j9g3rxw wrote

Reply to comment by lvl2bard in TIL of Macadam roads. These roads were convex, raised a few inches, and made of layered crushed rock; they were state-of-the-art for the 19th century. The rise of automobiles led to the dust issues that were solved by binding the roads with tar, leading to the invention of tarmac. by jamescookenotthatone

Just need to check one, then pocket that rock and use it as a template. Bigger than mouth rock? Goes in that pile. Smaller than mouth rock? The other pile over there.

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VeGr-FXVG t1_j9g7zyi wrote

Surely they had to recalibrate the mouth rock occasionally, to see if it still is up to spec?

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