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- "Well, it stands to reason that Merlin would want the device to be interactive on both sides, this and the alternate dimension. Now, the interactivity on this side is difficult to access. Now, I'm guessing as a type of safeguard against just anyone using the device."
- — Daniel Jackson
Arthur's Mantle is an interdimensional travel and computing device used by Merlin.
The device has three tiers of keys situated in front of a holographic display area and is powered by a small power crystal. The device as a fluctuating E.M. output which when stabilized creates a localized effect and transports anyone nearby out of phase where they cannot interact with any objects besides the buttons on the device. The holographic display can only be viewed while out of phase. A subspace link is maintained to everywhere taken out of phase, so they do not have to be near the device to be put back in phase. (SG1: "Arthur's Mantle", "Line in the Sand")
Merlin used the device to plan a weapon to be used against the Ori out of sight of the ascended Ancients. The device was left in the vault under Glastonbury Tor until 2005 when it was found by Stargate Command. Months later the device was being examined by Col. Samantha Carter and Dr. Bill Lee. Col. Carter and Col. Cameron Mitchell were both taken out of phase by the device when it was activated finding the device emitting holographic writing in Ancient but neither could translate it. Dr. Daniel Jackson figure out what happened and using the keys on the device was able to communicate with Carter and Mitchell, trying to decipher the writings, but it was slow work. Jackson was then brought out of phase as well and translated the information. (SG1: "Arthur's Mantle")
Months later the device was taken to P9C-882 and modified to create a much larger field to take the village planet out of phase. When the Ori forces arrived ahead of schedule, the device was activated but only took a single room out of phase, Carter instructed Mitchell on how to modify the settings and take the village out of phase, saving them from destruction moments before the Ori ship opened fire. Carter was experimenting with modifying the device further to take a large object out of phase and was accidentally pulled through into an alternate reality. In this reality she offered to help the people by using the device to take their whole planet out of phase when Ori ships arrived, channeling the entirely to the United States power supply into the device. The ships opened fire but the energy passed through the planet without harming a thing. (SG1: "Line in the Sand", "The Road Not Taken")
The power crystal