Without modern surveying equipment,how did diggers know direction and depth to dig to in the city / spring?

Just read about the "Siloam Inscription" a 2700 year old tablet. It describes digging a tunnel from a water spring into the city of Jerusalaum in case of seige. It was 500 yards long. The diggers started at both ends and met "pickax to pickax". Without accurate measurements of relative heights and directions, how did they build the tunnel to meet with great accuracy. Tried to do the sums by trig and geometery, but need the missing numbers and can not figure out how they got these measurements, given the lack of modern survey equipments.

Without modern surveying equipment,how did diggers know direction and depth to dig to in the city / spring?
The pyramids were nbuilt without benefit of modern equipment. All they used was some knowledge, like a 3-4-5 triangle forms a right angle. And a tube of water in a U shape will seek its own level over distance no matter how long the tube. And a weight hung on a string forms a perfect vertical. Compass headings can be determined from watching the arc of a shadow made from a vertical stick and marking the arc made by the end of the shadow. You do not need sophisticated equipment to do some pretty nifty engineering. Again, I point to the pyramids, perfectly aligned and true.
Reply:Answer does not really answer the question but states the obvious. Report Abuse


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