Hello im doing a gothic horror setting ambiented in Late sXIX in Buenos Aires is for the aperture of a new club. The question is, How Treeat wirs science? As a skill or magic skill?

I've been introducing certain talents that present one with the ability of using a regular skill in a supernatural manner; e.g.:

Weird Science [Tier II?]

You can craft gadgets that allow your performing one certain Magic Action with preset Additional Effects per gadget, using the Engineering/Mechanics skill, as if it were a Magical Skill. The crafting check's difficulty and the gadget's encumbrance are equal to the Magic Action's difficulty.

I would probably refluff Arcana. But keep it as magic, much like Deadlands Reloaded in Savage Worlds.

I think the above ideas are spot on. Sufficiently advanced science is indistinguishable from magic. Just reskin the special effects into science.

I might suggest that Rune Magic from Terrinoth would be a better reskin than Arcana, because Rune Magic already relies on a "device" with a strong theme. E.g., the 'Ice Storm Rune' on pp 118 of Terrinoth could be reskinned as a Freeze Gun.

• Implement: Characters with ranks in the Weird Science skill can use the Freeze Gun to attack, create ice walls, slow their enemies, etc.
• Activation: Characters with no ranks in the Weird Science skill can still pick up the freeze gun and shoot a basic ice blast, using a combat skill. But they lack the finesse to do anything else with it.
• Non-Weird Science players must spend a maneuver to active the device before firing it, which seems like a good added expense.
• Device malfunctions and meltdowns could be handled by Threat/Despair, as usual.
• I don't want to reprint it here, but the Magic Actions allowed by Rune branch of magic feel right to me in terms of Weird Science -- although that's a personal preference.