Heart magic notes (Dimension of Disaster)

The heart magic notes give information about how Zemouregal has enchanted Arrav's heart. They are found in the north-west bookcase in the New Varrock palace library during Dimension of Disaster/Defender of Varrock.

Transcript
Matters of the Heart

The soul of Arrav is more troublesome than I'd originally thought. If I move him too far from my base, I can feel him fighting against my will. I must find a way to strengthen my hold over him to subjugate him further, else it would be better to destroy him and be done with it.

I have been working on an enhancement prism, but the results with ordinary glass weren't enough - I needed a better material.

Thankfully, I believe I have found what I need in a volcano on Karamja - a rare black mineral called obsidian. I'll construct a prism from this.

The prism works and my spell is enhanced! Now, I can make better use of Arrav against Varrock. In life he was its protection, in death its destroyer... an example of all the fates of 'heroes'. The prism is very fragile though, so I'll need to lock it away from those clumsy zombies.