General Byrne clasped one of Piet’s hands in his own. “The Guild has done the Concord a great service here today.” He looked back down the line of markers toward the cart. “Is this the largest aura you can produce?”
“Very nearly,” Piet said. “The size of the field expands with the strength of the ferric current, but the more current we try to run the thicker the wires need to be, both in the coil and connected to it, in order to prevent a dangerous heat build-up.”
“Heat build-up?” The genral gave the philosopher a skeptical look.
Piet nodded. “Passing ferric current through a metal wire, or through any piece of metal really, causes the metal to grow warmer for reasons we don’t entirely understand yet. Different metals warm different amounts, but the more narrow the wire and the more powerful the current, the faster it warms and the hotter maximum temperature it will reach.” He smirked, looking slightly embarrassed. “There have been a few accidental fires. Small fires, but…”
Byrne cocked an eyebrow. “That sounds potentially useful. I assume it’s being looked into?”
“It is; Phylo Mula’s taken it on as his own project. Doesn’t have anything he’s willing to show us yet, but we’re hopeful.” Piet cleared his throat. “So, when we combine that issue with the additional coil height necessary to compensate for the increased attractive power of the aura, we start to run into portability issues. An emplaced coil might be made to protect a larger area, but this is about as large as we can build one that will move with an army.”
“So…” Byrne pointed a finger at the markers, counting them. “A little less than twenty paces. Equal in all directions?”
“Yes. Well, except up and down. We’ve figured they’ll each cover around a thousand men.”
The general’s brow furrowed in thought. “On the march, maybe, but not on the battlefield. Keep the edges empty or overlapping for safety, and we’ll only use the front half of the aura if we want to keep the men between the enemy and the cart.”
“Especially if the field contracts as it’s attacked.” Irandrya pointed at the boulder she’d thrown at the cart. “The last spell I cast landed a quarter-pace further down than the first one.”
Piet frowned. “That’s actually a product of time, not of the attacks. The lead-coil cells are much better at sustained current than the previous ones, but their output slows as they drain. We can load a hand-cranked current pump on each cart to extend the working time, and I have some ideas about using the cart’s axle to charge the cells on the march, but at the moment we’re limited to a little under an hour of useful protection.”
“So they won’t be useful for sieges,” General Byrne said, “not that it matters in this war.” He tapped the fingers of his right hand against his thumb a few times. “I’d say we’ll need one for every two centuries, then, even without spares or replacements.” He turned back to Piet. “We’ll start with a hundred, and build more as needed to reinforce and to replace those that get damaged or destroyed. How soon can you have them ready?”
“Ah…” Piet’s frown deepened. “Well, that would be the other issue. We probably have access to most of what we’d need, but copper’s getting harder to find in quantity. We’ve enough wire on hand to make maybe four more, if we steal current pumps to charge them from Phylo and Ceyx’s experiments, but the price had doubled the last time we went to buy more and the merchant in question was the only one in the market who even had any to trade.” He made the same counting gesture with his hand that General Byrne had. “I’d estimate there’s only enough copper for sale in the whole city to make another dozen coils.”
Byrne shook his head. “That’s obviously not going to be enough, even by your initial estimates.”
“Yes, General, I know.” Piet looked down at his hands.
Byrne turned to another member of the Euphentine delegation, the man Lares had identified to us as Councilor Mannius. “Can you think of any reason for the lack of copper?”
Mannius held up a hand, palm up. “I haven’t looked into copper specifically, but I know we’ve seen shortages of anything that’s either produced in the north or mainly imported, and I believe copper would fall into both categories.”
“We’ve discussed a number of possible solutions, none of them really feasible. The copper needs to be unalloyed, so re-purposing old temple roofs and melting down senators serving trays wouldn’t get us much extra. Most other metals either won’t carry the current or can’t be drawn thin enough. We could use gold for the coils instead of copper, but it would be prohibitively expensive, and carry problems of its own.”
“How expensive?” the general asked. “What sort of problems?”
The philosopher chuckled a little. “Provided Councilor Mannius’ totals are accurate, if we broke open the Treasury and stole every last coin we could probably make almost a hundred. They’d be smaller, because of the weight of the gold, but gold is less effected by the warming issue than copper is so a smaller coil could take more current, maintaining the same aura size. Until the cells drained, anyway, which would occur substantially faster.”
“So we’d beggar ourselves making them worse. All right.” General Byrne looked up, addressing the assembled delegates. “Any thoughts?”
The Floratovan delegate cleared his throat. “Floratova has a great number of deep, productive copper mines. I’m sure we’d be able to provide enough for a thousand coils, provided we could move it here.” He looked over at the Helvontovans, raising a questioning eyebrow.
The head of the Helvontovan delegation glared back at the Floratovan. “And, of course, Helvontova would be willing to allow the transport of the goods through our lands, provided they were escorted by at least as many Helvontovans as Floratovans.”
“Naturally,” said the Floratovan delegate, opening his arms wide. “We wouldn’t dream of marching forces into Helvontovan territory unannounced.” His tone was exaggeratedly friendly, mockingly so.
The leader of the Helvontovan delegation scowled, and was opening his mouth to speak again when the head Escanan delegate cut him off. “That’s well, then.” He turned to General Byrne. “And of course, Escana would be more than willing to allow the shipment through, but I don’t believe we can. Isina Pass is no longer safe to travel after the road washed away in last winter’s storms, leaving the Mendoscori Pass as the only route.”
“And we can’t use Mendoscori while the Fae hold it.”
The Escanan frowned. “Exactly.”
“Can we go around the mountains entirely?” Byrne asked. “Send the caravans to the south, and come up through the Ursane States?”
“About the only thing that could unite the Ursane States,” Councilor Mannius said, “is having Floratovan or Euphentine troops march into their territory. We’d either have to fight two wars at once, or wait for two years for the Ursane trading houses to finish scrapping over the transport rights for the shipments, or pay all of them to transport the copper through every damn canal in the States.”
Byrne shook his head. “At which point we might as well just use the gold to make the things directly.” He sighed. “So, we’ll just have to figure out how to take back the Mendoscori Pass, when we can hardly afford to pull a single man off of the front lines. Well.” He closed his eyes. “I suppose that’ll have to be a topic for the next meeting. We’ll assemble in the war room next-”
Sir Hagan raised a hand. “We’ll do it.”