Much of what was needed was there already: the two great stone wheels that did the grinding. The thick axle that turned the upper stone and the system of cog-wheels that transmitted power from the river to the wheels. That changed it from horizontal to vertical rotation, following the very latest developments. All that was needed was a new motive force. “Like a big sail, on four arms,” said Udd. “There’s sail-cloth in the boat-house.”
“It won’t work,” said Herjolf, listening. “The river always flows in the same place. Wind can come from anywhere. I grant you, here it comes mostly from the mountains, the north-west. But if you set it up and the wind changed, it could tear your wheel off its supports.”
“I know how to fix that,” said Udd with the confidence that came to him when faced with a technical problem. “Think of the way we made the catapults rotate. We put them on small wheels and turned those on a larger wheel. We can do the same thing here. Make the whole mill rotate. It can be trained round by a beam, as we turn the trail of the new mules.”
In other circumstances, again, some scoffer would have laughed the matter off. There were no scoffers here. Herjolf hesitated, then said, “Well, let’s try it.”
Soon most of the community was outside, dismantling the old mill, helping to build the shell of the new one, sent off to the main forge to make the heavy nails and bolts that were needed. Shef, thinking back over the event in later times, noted again how many valuable skills were present among the people there. Many were perfectly familiar with heavy weights, not daunted at all by the process of lifting the mill-wheels and taking them to the new site. Hagbarth, who had lifted and laid many a ship’s keel made all of one timber, directed operations. For several days all energies were directed to the mill, even the grinding of the grain put aside by common consent till there was a better way of doing it.
Finally all was in place, and Udd was allowed to slip the retainer catch that had held the wheels from turning. He did so. The wind blew, filled the sails, they turned the vertical wheel that was to turn the horizontal one that was to turn the mill-wheel. Nothing happened except a great straining of timber. Udd slipped the catch back again.
“We need bigger sails,” he said.
A day later the process was in full stream, Herjolf rubbing his hands as he thought of the profits that might be made by setting up mills of this kind all over Scandinavia. Nearly all of it country unsuited to water-power, but a ready market for a mill that would grind all year. Priests of the Way, it was their boast, supported themselves by working rather than by claiming tithes and landholdings like the priests and monks of the Christians. There was no objection, furthermore, to priests becoming rich by their knowledge—as long as they shared it.
Yet the success of the first windmill seemed only to whet Udd’s appetite. As soon as the first one was working, he was at Herjolf’s ear with plans for another: this time, to drive the trip-hammer that he had sketched out for Shef the year before in Kaupang. Herjolf listened dubiously, at first, not hostile, but not able to understand what Udd was proposing.
The appeal was clear enough. Iron, though well-known and well understood everywhere in the Western world, remained if not a precious metal, a valuable one. One reason for the dominance of the Franks’ and Germans’ armored lancers was the weight of metal they carried. This was a great investment in a world where the peasant’s spade characteristically had only an iron tip over a wooden blade, and where many plows as well were little more than iron-shod scratching-sticks. Iron was expensive not because it was hard to find, like gold or silver, but because it took so many man-hours to work. The ore had to be heated again and again and beaten by hand with hammers until the slag was worked out of it, then being smelted in the crude charcoal-burning ovens. The iron of Jarnberaland was the best in the world. Still, it needed working, as did every grade of iron except the very rare pieces taken from fallen thunder-stones. Herjolf had fuel, he had ore. If the hammering time could be cut he would have the more trade-goods in the spring. But how could a turning wheel make a hammer go up and down?