How would you tunnel with no computers?

Question

how would someone tunnel thru a hill and come out within inches of where they wanted to, before lasers and crazy computer stuff?

like in the 1800's ?

-Phil

Answer 1

By surveying. Distance, direction and so forth. Computers just automate the process.

Answer 2

Good engineering and good surveying do not depend on computers. The tools or instruments have been around a very long time. Just like sailing a ship from England to a tiny island, and not getting lost before GPS. The GPS makes it easier but it was done many times before GPS.

Answer 3

Have a good surveyor.