Fire of Isengard ?

[Boromir88]

Ahh the Fire of Orthanc...always an interesting topic.

I think it's fair to say that Saruman had improved upon the 'explosives' to use for his own destructive purposes. You can't talk about Saruman's explosives without mentioning Gandalf's Fireworks, as both work with the same elements yet one uses them for entertainment the other for destruction. I think both Gandalf and Saruman use magic and some sort of explosive (probably gunpowder) to create their 'devices.'

As Gandalf states he simply 'can't just melt snow'. There has to be something there for Gandalf to work with. However, I do think Gandalf uses his magical abilities to enhance the fireworks. I work for a fireworks company and we are struggling with making smiley face designs. Gandalf has his fireworks explode into a mountain and a dragon...I'd say there has to be something magical about it.

Now onto Saruman's 'Fire of Orthanc' where I believe he also used magic to enhance the explosives he used at Helm's Deep:

The basic motive for magia - quite apart from any philosophic consideration of how it would work - is immediacy: speed, reduction of labour, and reduction also to a minimum (or vanishing point) of the gap in time between the idea or desire and the result or effect.~Letter 155

Magia is used to increase speed, efficiency, and reduce the amount of labor. Saruman wanted to break down the defenses of Helm's Deep as quick as was possible. And using his magic would increase the potency of the explosives and do just that.