Preliminary flight tests

[Z'kron]

Aka the High Sage's Laboratory

TS - Early Kalendryas, shortly after appointment to office

Why did fire go upwards? The druid sat and watched the ruins of his burning carrot experiment was a sad expression. The whole rack of carrots had simply caught alight when his last burning rage-carrot had gone off, the attempt to have the secondary carrot having a dampening attempt failing miserably. It seemed he simply wasn't skilled enough to handle arcane triggers of the nature he needed. With a sigh, the druid flapped his wings. Things never went quite the way he wanted them to. Waddling out of his cave between the bushes, he took a second glance at where his farmhouse had used to be before that unfortunate incident with the meteor. Fire was something he would have to contemplate. Perhaps some sort of anti heat coating. Or some way to make it go downwards. Regardless, it was getting early, and the druid had an appointment in the Imperial Forum to meet. With solemn wing flaps, the druid set out towards his offices.

- Several days later

Heat rose, the druid had decided. It was something he had first noticed while experimenting with burning rage spells while trying to cook on his wanderings; and how even when he turned the carrot upside down, the flame would still attempt to go up. There wasn't any easy way round it. Fire would always try to burn upwards; singing the holder of the carrot. Or heating the air so that it stung the holder regardless. Heat that made the air waver around, making it harder to see through. He wondered why that was. But the basic fact that heat rose was undeniable. He had been aware of it on a basic level for some time now- he'd just not been able to put it all together. It was why the lids on kettles jumped up when the water turned to steam. It was the fire in the steam trying to burn upwards, and the lid getting in the way.
When he flew, the druid often tried to catch updrafts of warm air. Was that just heat buoying him up, or was is warm air itself rising? It was difficult to tell, or measure. It would need an experiment.
Air could, in most cases, be approximated to water. Water was just like air, except slower moving and not breathable unless you were a fish. Or so Z'kron thought. He could try and heat colored water and see if the hot colored water moved up when mixed with the cold water. Or would they just blend? A blending would prove very little to him.
If he flew over Aslan's forge, he would be able to tell for sure, though. If the air was warm enough to feel, he'd be able to tell the difference from when he flew over the volcano in the updrafts, and when he was in a colder area. If he dropped quicker in a downdraft, he would have his answer.
The druid took out a map. Aslan's forge would be something of a trek, even with his various advantages. If he wanted to test his theory out, it was best he got on with it. He had been planning to return to Natura briefly irregardless. The volcano would simply be a detour.

A return from the forge

The druid sat in the laboratory playing with his kettle. He didn't drink tea as a general rule; preferring water and other similarly clean substances. But in this case he was perplexed by the question of steam.
A simple experiment might help, perhaps?
The druid pondered for a moment. A little time passed, before he reached for two jars, each of an identical size. Into one he poured cold water from a carrot, and into the other hot water from the kettle- in equal amounts. He shook his head. No, that wouldn't work. He thought a little more. He shrugged, and put the kettle back to boil, idly stirring the cold water jar with a finger. This would take a little more thought. Water splashed around. He kept thinking.
Could it be from the principle of buoyancy? The same way liquids worked? The druid wasn't sure. Buoyancy was a fairly complex idea to think about, though he'd brushed it several times in his studies. Sorcerers had to know some of these things; though his trust in the sorcerous worldview had diminished somewhat since the utter discreditation of the atoms and nuclei world view in favor of the vis-strand model. Regardless, he would have to do some research.
He worked through the ideas carefully in his head. When the water heated, it turned into steam. Simple. And the steam could move upwards, pushing the lid of the kettle up. Or the heat moved upwards, pushing the kettle up. Heat tried to move upwards. What could he do with that, and why would heat move upwards?
He sat down to think once again. In the meantime, he was going to order some heat-resistant material. If heat tried to move upwards, perhaps very hot material would become lighter and want to float.

Several cycles later...

A look of disgust on the druid's face. No matter how much he heated the mildly-weighted crumbled-up ball of asbestos when he put it in water, it refused to float any better or worse. Heat simply didn't seem to affect it. The cloth stayed the same. It didn't burn, true, but he couldn't see it getting any lighter. Experiments with scales had shown the same. When measuring two folded bundles of asbestos against eachother, the heated one was no lighter. He needed to think again. A new experiment, perhaps. Maybe solid objects wouldn't change. But liquids? The next step.
The next day, the druid had a hollowed, weighted carrot submerged in a tank of water. Allowing it to sink to the bottom, the druid waited for a few moments. He then gradually began heating the water inside the carrot up, hoping to make the water lighter so it would rise up, carrying the carrot. To his dismay, nothing happened. When the druid eventually retrieved the carrot from the tank, he noticed it was cracked along the side. Food for thought.

A cycle or two later

Something different this time! He would put water inside a tightly closed bag of waxed cloth; so that when it was put weighted underwater it would not allow external water to leak in. Then he would heat the water, and see if it made the bag rise up. Hopefully this time there would be a modicum of success. Unfortunately, the stitches at the bottom of the bag seemed to lack the required strength and water simply leaked there. The druid was left searching for a new solution. Eventually, he found one.
A small, hollow, half-water-filled ball of wood, created with the druid's own warp wood spells. Normally, this ball would float; but in this case the druid introduced a small lead weight to counterbalance it. If placed in the water, the ball would very slowly descend. A way to measure whether heat caused substances to rise would be to heat the water inside it, and then see.
Finally. Sucess. Placed in cold water, the small wooden ball would rise when the water inside was heated. Peculiarly though, when placed in warm water, the wooden ball would sink even when the internal water was warmed somewhat. This made the druid think. Perhaps the rising of the heat was due to the differences in the heat levels rather than any intrinsic property? Time for more experiments? Would this work in air as well? His experience flying over hot areas indicated that, yes, hot air did rise. And it would be due to the differences in heat levels. But why had that carrot cracked? Had the heat somehow caused the water to press outwards and do damage? Maybe the heat was trying to balance out somehow?
....
This segment put on hold for the moment

TS: 5th Cycle Immanis, Era XXIII, Winter

The druid looked at the woven bundle of thin reeds with an appraising eye. Each was thin and well formed- personally grown by the druid himself in the days before the experiment. Together, they formed the frame for his newest contraption- a tiny hot air balloon, which would measure the feasibility of at least some of his plans for new airborne craft. It had taken him several attempts to design it correctly- he'd spent a reasonable amount of the previous day using the warp wood and growth spells to compensate for his lack of advanced engineering skills- but eventually it had reached a level which he felt was adequate. Being green wood, it was still fairly non-flammable, something that was reassuring.

The idea behind it all was quite simple- an application of scientific principle. Hot air rises- and most particularly, hot air rises within cool air. The same way that wood will rise in water; providing the wood was lighter than that mass of water (something the druid had noticed once when he had attempted a barkskin spell to try and help him float and it had been entirely ineffectual due to the density of the armor). Regardless, the more hot air and the hotter the air, the more it will try to move upwards. And when surrounded by a container, it would give the balooon upwards lift. It would be the same as the wood ball that bobbed upwards in water. The same science, on a larger scale.
All that was needed was a method of reheating the air. And that was where magic would come in, providing a continual heat source when the standard sources were unuseable. The druid had specially prepared several tiny activatable low-intensity single-charge long term "burning heat" items which would heat the air without producing actual flame over the last few days. This was a variant on the spell he had first learnt as an initiate, and which was only now becoming useful. Aside from this, the druid himself could maintain the flame indefinitely.

The druid had also chosen a form for the trip... a tiny "winged" squirrel creature; with great folds between its arms so that it could slow its fall if necessary. It was a compromise between being able to perform basic manipulations with his paws and being able to survive falling out of the balloon.
Of course, it wouldn't be a particularly practical craft for horizontal travel. There was no way for the druid to actually steer the craft, and it could only move in wind direction. But it would still go up. The cloth he was using for this project was asbestos. A little expensive, but the best natural flame retardant he could think of. Hanging over the frame in gores, the balloon had sufficient expansive capacity that, when inflated, it should easily be able to carry the squirrel-weight. Walking around his contraption, the druid examined it for flaws. None were immediately apparent. It was time for ignition.