The Arc Mine is a book found in The Knife of Dunwall.
My experiments continue with what I've been calling the Arc Mine.
Initially, I began the work out of idle curiosity. Waking from a nap in the middle of the afternoon, during the Month of Clans, I wondered whether it might be possible to separate a flat disc filled with refined whale oil from an array of very short striking rods, until such time as sufficient weight be applied to the upper side of the device.
After turning to pragmatic situations, I imagined the arc mine might be used to incinerate some unfortunate member of enemy forces, approaching, say, a military encampment.
After early tests on livestock proved successful, I requested a live human subject, already scheduled for execution for crimes that were, I assure you, most dire. Burrows was more than happy to comply, assuming he could witness the demonstration. He brought a prisoner from Coldridge, someone named Vaughn, I believe, and we turned him loose in the test area blindfolded, stumbling about until triggering the device.
Burrows was most pleased, not only because of (the) arc mine's effectiveness as a lethal deterrent, but also because of its potential psychological impacts on enemy forces. Further, it left no gore or other mess, and Burrows is a strong supporter of anything clean and tidy.
"Lovely and terrifying, with nothing left to wipe up." Those were his exact words.
I've left notes to myself, assuming I pick up the project again, because there may be a way to produce a version of the arc mine that is entirely harmless, simply rendering the subject unconscious. Much more testing is required.
It can be found on a table near the window of the meat storage locker at the Rothwild Slaughterhouse.