ON THIS WIKI
Arc Amplification is an enchantment to Ethereal Familiar, which sets enemies on fire. Duration will double at each level. In order to upgrade the Familiar with a certain level, it has to be already upgraded with the previous level of enchantment.
Thaumcraft 4 Research Notes
Light it up
"When upgraded with Flash Burn, a familiar's energy is repurposed to generate a ridiculous amount of heat on attacking rather than dealing damage, lighting its foes on fire and leaving them scorchered and weak to the light of the sun.
Consumes 0.04 Ignis and 0.02 Ordo Vis per attack and level."Aspect the Ethereal Essence is related to has to match the Aspect the Ethereal Familiar is related to and the 4th aspect in the recipe. In this article it is
Flash Burn I
Flash Burn II
Flash Burn III