I went back to working on the mana crystal growth apparatuses for a few more months.  By mid-summer, I had finished the 16-foot crystal apparatus along with the two smallest apparatuses that I needed to replicate from the mountain.  It was at that time that I''d received news that the tunnel had reached the calculated length, but the two halves hadn''t actually met up yet.  I expected that to some degree, however, because the odds of getting the angle absolutely perfect between the two tunnels was very low, meaning I needed to go and make some final adjustments.


    So, I made my way over to the far side of the island, and after going to the end of the tunnel, I used tectonic sense to try to find where the other half of the tunnel was.  Unfortunately, I couldn''t find it despite how far my range was.  So, I ended up working with them for another month, until we found the other tunnel, and connected the two.  Ultimately, we were about 100 feet away in total, and most of that distance was horizontal.  However, to make everything connect well at the same height, we dug forward an extra 40 feet, and then connected the two tunnels.


    I think everyone was quite pleased with the fact we could now travel directly through the mountain in a pretty nice tunnel, though the work that needed to be done was far from over.  The tunnel on this side still needs to be widened, and now that I know exactly how much space we''re working with in the center area here, I have plans for how I want to expand it.  I want this central area to be a rest stop as the half-way point between the two sides of the island.


    As such, it needs to be carefully carved out to expand to meet both halves of the tunnel, complete with large support pillars, places to rest, and some amount of lighting.  I went and got a manascope to see exactly how much ambient mana there exists this far under the mountain.  The value came out to 0.006 CU, which means there is so little mana here that we probably can''t even use fluorite lighting.  This does, however, give me an opportunity to test something that I''ve wanted to test for a little while now.


    We''ve had a 2-foot mana crystal in the lab area for quite a while, and neither Tiberius nor myself have used it for any new research in a year at least.  So, I want to relocate that crystal to the central area, and let it sit for a few months while people drain it for construction and mining.  As they do so, I want to take readings of the ambient mana levels and see if the crystal actually amplifies the ambient mana, or if it can even reasonably recharge this deep underground.


    Back when I was an imp, I found that the mana crystals did recharge deep underground, but they recharged much faster near the surface, but I haven''t had a good chance to test how that actually affects the surrounding area.  It could either amplify the mana through some unknown mechanism, or it could drain the mana from the area, concentrating it in the crystal itself.  I doubt it''s the second option, based on the extra ambient mana on the surface when we install large crystals, but it just as well could be draining mana from further away, while amplifying the local area.  In either case, it''s something worth checking out.


    <hr>


    After bringing the 2-foot crystal to the central area under the mountain, I periodically checked the mana levels at a few different pre-selected points while the other demons worked to carve out the area I''d designated.  I measured right next to the crystal above the small water pool it was submerged in, about twenty feet away, where each tunnel meets the central area, and a few hundred feet down each tunnel.


    I found some interesting results.  Over time, the central crystal dimmed more and more, and it recharged incredibly slowly.  While it was bright, the central area had very elevated levels of mana with the highest levels being concentrated right above the crystal, which was expected.  As it dimmed though, an interesting pattern emerged.  The central area continued having somewhat amplified mana levels even after the crystal was essentially drained, reaching ambient levels of 0.012 CU, though the real interesting results came from a difference between each of the two tunnels.Unauthorized content usage: if you discover this narrative on Amazon, report the violation.


    The tunnel that was coming from the far side of the mountain had much lower mana values than the other side.  That had two obvious reasons that it could be happening.  The first was that there was some form of cardinality to the way mana flows, which I thought would be unlikely.  The second was that we currently had another 2-foot crystal sitting near the entrance to that tunnel, along with a few trays of smaller crystals.


    So, I did an easy test, and moved the second 2-foot crystal along with the trays into the opposite tunnel, and gave it a few days for the mana values to settle into a steady state.  Sure enough, now the opposite tunnel had a lower ambient mana value.  What it seems like, to me at least, is that the mana crystals seem to act like a magnet for ambient mana.  I also already know from experience that mana seems to flow more freely through air than rock.


    I thus concluded from those two observations that it''s likely that the mana crystal in the tunnel is essentially vacuuming up all the ambient mana that potentially would be coming through that tunnel.  In the opposite tunnel where there are no other mana crystals in the path, the ambient mana level forms a gradient along the tunnel, with the highest mana values near the surface which slowly declines within the tunnel until you reach the central area.  Interestingly, near the central area, the mana values climb again until you reach the mana crystal itself, almost like the mana is pooling around that central point.


    That brought up another question though.  If I move the other mana crystals to the central area as well, how would the mana in that area be affected?  How would the two crystals interact overall?  So, I did just that.  Obviously, all this moving of mana crystals did slow down the construction rate somewhat for the demons who were working to both expand the second tunnel and build the central area out, but the results of these experiments should help us be more efficient in the future with underground construction projects, so I think it''s worth the delay.


    What I found after another month of letting the second mana crystal slowly drain was that the ambient mana levels in the central area had nearly tripled from when there was only one crystal, up to 0.032 CU.  While that was still less than 3% of the surface mana values at night time, it did give me some idea as to how mana crystals affect ambient mana.  The gradient towards the central area was similar to when there was only one crystal, although the final mana level when entering the central area was higher, and it now had two tunnels feeding it, rather than one.


    What was more interesting, however, was that the large crystals themselves actually seemed to charge at about daytime mana values, meaning each crystal could essentially recharge a single demon at normal surface regen levels reliably.  The smaller crystal trays, however, barely recharged at all, mirroring the lower natural values.  So, I tried out a mixed method.  I kept the two 2-foot crystals in the central area, and moved the mana trays back to the charging area in the far tunnel.


    The central area did show a small drop in ambient mana, down to 0.026 CU, and the two crystals charged a little slower, but the trays themselves were recharging fast enough to keep up with the tunnel expansion, and the central crystals let the demons working on the central area work a little more efficiently.  I was a little intrigued by a new idea a that point, however.  What would happen if I periodically placed the small mana crystals from the tray along the length of one of the tunnels.  Would that increase or decrease the central mana?  Would it form a kind of conduit for the mana, or would it absorb most of it?


    Despite the grumblings of the demons who''s work I was disrupting, I tried that out as well.  It took two days to space out the dozens of mana crystals along the tunnel length, and what I found was that when spaced out like this, it seemed to have about the same effect as when they were all centralized, and I was getting a reading of 0.032 CU in the central area again.


    Whether that is because small crystals individually have a negligible effect, and only start to do something when tightly grouped, like magnets, or because of some unknown factor, I can''t say, but I can say that the small crystals do still seem to recharge mana faster than a demon would, so we could periodically place them in contact with zinc fluorite to install basic lighting down the tunnel, though it would probably negatively effect the central mana if we did so.


    Perhaps if we find another pocket of mana crystals, I can attempt to grow a 4 or 6-foot mana crystal to put in the central area to see how much that affects mana levels, by comparison.  For now though, I returned all the small crystals to their charging trays, and left the teams working on the tunnel and the central area in peace to finish their work.