Warning: this instructable involves wiring mains electricity and a hot light bulb, it can be a shock or fire hazard. If you have no experience with this, seek help of someone who does.
Step 1: Bring in the Power Cord
- add extra tube around the wire
- use insulated wires as shown in picture, don't confuse with speaker wire that has only one layer of insulation and should never be used to carry mains voltages
On hindsight, drilling in the corner between two glass panels would have been better.
Step 2: Connect Things Up
There is a hook inside the lantern, so I wrapped the cable around it to hang the lamp from, and I used an existing hole to put the switch through. I glued the cable to the side of the lamp, so it won't touch the light bulb.
Once everything is connected, use a multimeter to test the resistance between the leads and the case of the lamp. If there is any contact, check the wires again and do not use until you're sure everything is safe!
Once everything is wired and tested for electrical insulation, test whether the lamp doesn't produce too much heat. Close the lantern and turn on the lamp. Let it run for at least half an hour. Feel the outside of the lantern regularly. If it gets too hot to touch, lower the wattage of the lamp - or replace with an energy saving compact fluorescent or a LED bulb.
Step 3: Frosted Glass
If your glass panes are clear, you can either add a "privacy" film from the DIY store, or etch the glasses to give them a frosted finish (you can find a lot of Instructables on etching glass).