Vis (Thaumcraft 4)

Vis is the main form of energy harnessed in Thaumcraft 4. It is stored in wands (as well as scepters and staves) or Amulets of Vis Storage. It can be harnessed from mobs as small motes of light that replenish 1 point of their respective aspect or through Aura Nodes. The only vis that can be harnessed are those of the six primal aspects: Aer, Aqua, Ignis, Terra, Ordo, and Perditio. It is generally used for crafting items at an Arcane Worktable that require magical energy, completing some magical devices, or utilizing wand foci.

Centivis
Once enough research has been done via the Thaumonomicon, the player will be able to create Energized Nodes that can release vis in the form of centivis (CV). Vis in this form cannot be directly harnessed by wands (though Amulets of Vis Storage can be charged in this manner). Its primary purpose in this form is to power certain magical devices to start them up (e.g. Focal Manipulator) or hasten their processes (e.g. Essentia Crystallizer and Infernal Furnace). If a device is within 8 blocks of the Energized Node it is able to absorb centivis directly from the node; otherwise, Vis Relays will have to be used to connect the two.