Hold up: Is our roof still randomly fireballing blue objects? If it is, priority number one is to A] contain this by getting all blue objects out of that floor and covering the windows.
Oh my word your ceiling is fireballing things and you forgot to remove everything blue from underneath it, and as a result, your house has burnt down!
Of course you've removed all the blue stuff from the room in question.
Also, see what it would take to make the stone permanently hot.
The spell can quite easily be modified to simply consume prepared Frogman Ash at a constant rate and not require recasting.
You do not possess an enchantment (a spell that will operate constantly without need for some form of input) that has the desired effects.
For now though, modify that fire spell to recast itself when the enchantment runs out. Also see if you can find an acceptable substitute for the frogman ash. Perhaps something else fire related like obsidian?
You have no idea where to start with substituting Frogman Ash, as you have no idea what it is or does. To have the spell recast itself at completion would be simple; fifteen minutes extra casting time at most. But you would need to supply it with a constant source of Frogman Ash.
Or we could try and analyze the composition of the Ash and reproduce it using Alchemy
You take a pinch of Frogman Ash and do some Alchemy on it. You dissolve it in water, heat it, cool it, stir it, add vinegar to it, add mercury to it- all have interesting effects, none of them tell you anything about it. A brief flick through your Alchemy textbook informs you that the Ash is 'probably magical', soluble, and not very reactive. It may also contain phosphorous.
Pfft, you people don't realize it's not frogman ash.
It's frog and man ash. There's just a word missing there. Therefore, I suggest the following: Let's go out and collect some frogs (Two dozen will do nicely) and a corpse (skeleton, decaying or otherwise). We'll incinerate these, collect the ash and then we'll have Frog&man Ash.
At the very least, it'll give us a component for a future spell. At best, it's the correct component!
You see no reason not to engage in this activity, except for the unfortunate fact that, despite rumours, your family did not and does not keep corpses in the cupboards.
Shoots beams of fire at anything blue? AWESOME!
No, no it is not! It is random magical fallout, and it goes against proper science!
Also it is beginning to wear off, and you tried taking down a bit of the ceiling to see if the effect is portable and it isn't, so it is not very useful unless you lure somebody into this room in the next few hours.
B] replicate the effects.
According to your Tome of Guidelines, Etherical Fallout is caused by interference between one or more spells and background Etherical Force. The effects hereof are random and unreplicable, as background Etherical Force is constantly changing; replicating the effects would be quicker if you designed them from scratch.
It is 39 days since you returned home. It is late afternoon.
One (1) fairly dusty old family home in the country
Crappy Forge
Vegetable Patch (growing vegetables)
Chicken Run (contains 5 hens)
Hidden Shack (empty)
Estates surrounding your dusty old family home (forests and hills)
£175 in cashe
£0 in banke account
Etheric Steamworks Lab:
-Decent Etherical Equipment
-Poor Steamwork Equipment
-Shitty Alchemical Equipment
-Shitty Physical Equipment
Book on Alchemistry
Book on Physics
Tome of Spells
Tome of Etheric Guidelines
Licence to Science
A note on things: Unless otherwise noted, you have enough things to do all small-scale experiments and design prototypes.
Assorted Magical Crystals
Magical Reagents
-Frogman Ash (a little)
Silver Wire
Samples of Rare Woods
Rusty Plumbing (Includes pipes, valves, boilers, ect)
Rusty Gears (mechanisms)
A further note on things: Many simple things can be found lying about the house. Your family did not throw things away.
Spells:
Local Fertility Boost: common herbs, uncommon herbs, animal sacrifice (>=chicken), 3 hours subtle preparation, 3 hours casting
Hot Stone Spell: Frogman Ash, a fire-proof object, 3 hours unsubtle preparation, 15 minutes casting.
Potions:
Spontaneously Combusting Goop: common herbs, uncommon herbs, 2 hours subtle preparation.
Beetle Killing Poison: common herbs, uncommon herbs, 3 hours subtle preparation.
Etherical Contraptions:
Powerful Affliction Implement that Neutralizes Gnawish Unyielding Nonscientists (Or PAINGUN): 1 uncommon gemstone, 1 piece of animal bone, 1 piece of plumbing, 1 gun stock/bits and pieces + 2 hours crafting, 3 hours crafting, 2 hours casting. Fires pain.
Steam Machines:
Medium Steam Engine: 10 pieces of plumbing, 1 boiler, some gears and pistons, 2 square meters of sheet metal, 1 big wheel, 4 days of crafting&forging. Consumes large amounts of coal, provides moderate power.
Small water pump: 25 pieces of plumbing, some gears and pistons, 1 water container, 2 days of crafting&forging. Consumes moderate power, provides moderate water.
Etheric Sciences (Lv3)
Steamworks (Lv2)
Spells cast:
Local Fertility Spell
Contraptions created:
The P.A.I.N.G.U.N.: Looks like a shoddily-constructed pistol. Fires magical bolts of pain on pulling the trigger.
Machines built:
Medium Steam Engine (Installed in Village)
Small Water Pump (Installed in Village)
Mundane Accomplishments:
£100 of Potato Farm
Fireplace Ironwork