(Possibly the one that was used to reach Ember in the first place.) All they needed to do is mention this in the note for the rest of the Emberites and they'll all know to follow the proper course.
*** Not to mention, most of the technology was either too big (stoves, fridges, etc.), and even what wasn't would've been useless without electricity to power it. They didn't have any portable forms of light, remember?
Showing 15 edit(s) of 50