Q. How do I open the marble door in the North Arcade, and the obsidian door in Burning Hall East?
A. This is another case where you have to figure out how to modify a ritual - that produces something like what you need - to get *exactly* what you need:

> recall granite solvent (found in Storage Nook, under lead hatch)
"TUCKER'S SOLVENT, which will DISSOLVE ONLY GRANITE: Begin with the Hermetic sealing,
and a mixture of muriatic and bamuriatic acids. Add some elemental earth; use a word of
anaphylaxis. Add a bit of slate - this being the symbolic opposite of granite - and conclude with
the Binding of Antipathy."

Hmm. How do we know that slate is the opposite of granite? This is how:

> recall facts
> recall periodic table of stone (found in Confusing Cracks, look through oculus)
"We are familiar with earth as a pure element in the Greek system. However, minerals need not
be considered as imperfect approximations of a Platonic ideal; each has an alchemical structure,
and we may discern relations between them. Thus, marble and obsidian are opposites - white
versus black, crystalline versus glassy, pelagic versus volcanic. Soapstone and basalt are another
light-dark pair. Other opposing pairs rely on different relations. Chalk and flint are found
together, but with different qualities. Granite and slate are formed by opposing geologic
processes; so too sandstone and malachite. Porphyry and quartz are an interesting case..."

So to make marble solvent, we use obsidian in the ritual (and vice-versa!) but first we need to make some bamuriatic acid:

> recall bamuriatic acid (found in Deep Stacks)
"THE SYNTHESIS of BAMURIATIC ACID: This substance is similar to muriatic acid, but even
more corrosive and toxic. Exercise caution! Prepare your retort with the mineral fluorspar in a
bath of vitriol. Invoke the sealing; heat until the crystal has entirely dissolved. Discontinue the
heat. Add saline solution, but be sure to first use a word of entension (to prevent a premature
reaction.) Once combined, a word of culmination will allow the reaction to complete in a
controlled manner."

Making bamuriatic acid seems simple enough, but just in case: Click here to show/hide ritual steps

So now you can gather the rest of the ingredients needed to make the marble solvent, and then: Click here to show/hide ritual steps

I'll leave it up to you to find out what's beyond the marble door. And then... it seems at first that all we need do to open the obsidian door in Burning Hall East is to make some obsidian solvent, drink fire-resistance to allow us survive the inferno in Burning Hall East, and that's it, right? Go ahead, try it. The trouble with that simple plan is that the inferno consumes everything but you, including that vial of obsidian solvent you're carrying around :-\ So we need to use the fire-devourer to put out the inferno first. You found that ritual under the lead hatch in the Storage Nook too:

> recall fire-devourer
"THE FIRE-DEVOURER (a potion to extinguish even the greatest conflagration): Prepare a
strong fiery environment - several influences should be combined for this ritual. Place a measure
of alcohol into the bound. Begin with a sealing word of passivity to oppose the alcohol's fiery
nature. Ignite the beaker with elemental fire; this will provoke combustion despite the
passivation. Conclude with the Greater Phlogistical Saturation. The resulting potion is of great
strength; one vial, flung into a burning building, often suffices to end the danger."

If you've just done the Dressing Room run, you'll need to reset again before making the obsidian solvent as it requires the fluorspar too. Anyway, I found out by experimentation that making the fire-devourer required 2 pieces of burning wood on the gestalt shelf to satisfy the "...strong fiery environment..." bit. I used: winter-oak and blackwood. And the "...sealing word of passivity..." refers to the phlegmatic sealing formula, which you found in Chasm, at Bridge, by looking through the oculus. So to make the fire-devourer, in the Nave: Click here to show/hide ritual steps

It can be a little tricky figuring out how to put out the conflagration in Burning Hall East. But as it's really just a matter of figuring out how to satisfy the parser, I'll save you the trouble:

> go to burning hall west
> pour fire-devourer on inferno
> e

Click here to show/hide spoilers concerning what you find beyond the obsidian door

Return to the main walkthrough