1343

## **Working backward for the horses of the Stonehearth College**

### *The Stonehearth College at work*

The Stonehearth College had become the engineering finishing school for the SMC – and to some degree, a growing contingent of “others.” By **1343**, the pipeline and cooperation between the pure research of the College and the applied science of the SMC made two key contributions that greatly improved the practicality of the state-of-the-art steam engine.

This new design saw instant application in deeper mines, where the old pump wasn’t powerful enough. There were downsides: the pumps weren’t very efficient, nor were they very safe, especially the Stonehearth College’s engine. Part of its cycle required steam under pressure supplied by a boiler, and given the technology of the period the pressure vessel could not be made strong enough and so was prone to explosion. Still, the design was so simple and durable that improved versions would be produced for more than a century.

### *Criteria for measurement: the “horse power”*

Prior to the last few years in Baldur’s Gate, the most prevalent way to get work done in Faerûn was to throw a yoke on a horse, attach a strap to a wheel or a level and give them a swat. It wasn’t exactly elegant, but the power of a horse had been way things traditionally got done.

The Stonehearth College rolled with it. They measured the average output of a horse, and standardized it: the unit of one Horsepower was 550 foot-pounds per second.

### *The Atmospheric Engine: 100+ HP*

The *Stonehearth College* made impressive progress, and if the market was looking for it, the new steam-driven pumps would’ve been greater than sliced bread. As it were, people didn’t necessarily fear it – but it may as well have been magic to them. …*And if it was magic, it was beyond them*.

One of the first things the College started looking at was pressure vessels. They also took a new view of the work of the vacuum. Their idea was to use the vacuum on a piston instead of the water itself. This took the shape of a reciprocating beam engine installed at surface level driving a succession of pumps at one end of the beam. The engine, attached by chains from other end of the beam, worked on the “atmospheric” (vacuum) principle.

Leading the charge was Thaum Gnomcomen, a brilliant gnomish transplant, staying in Baldur’s Gate specifically to study at the Stonehearth College school of engineering. In his first version, the upper end of the cylinder was open to the atmospheric pressure, and when the vacuum formed, the atmospheric pressure above the piston pushed it down into the cylinder. The piston was lubricated by a trickle of water from the same cistern that supplied the cooling water. Further, to improve the cooling effect, they sprayed water directly into the cylinder.

The piston was attached by a chain to a large pivoted beam. When the piston pulled the beam, the other side of the beam was pulled upward. This end was attached to a rod that pulled on a series of conventional pump handles in the mine. At the end of this power stroke, the steam valve was reopened, and the weight of the pump rods pulled the beam down, lifting the piston and drawing steam into the cylinder again.

Using the piston and beam allowed the Newcomen engine to power pumps at different levels throughout the mine, as well as eliminating the need for any high pressure steam. The entire system was isolated to a single building on the surface. Although inefficient and extremely heavy on wood (compared to later engines), these engines raised far greater volumes of water and from greater depths than had previously been possible.

With the combined College behind him, the Atmospheric Engine took leaps forward. Mechanical tolerance was now the mantra among the engineers.

* First, the level of leakage and steam escape was lowering pressure, wasting steam, water and work. They improved the seals, nearly tripling its efficiency in the first year.
* Second, the beam was durable, but it was huge. Size alone made it impractical to fit into manufacturing houses where space was already at a premium. They adapted the beam to use wheels instead for transferring power from the cylinder, which made the engines more compact.

The incredibly rapid rate of improvement set them back; the progress becoming more chaotic as it progressed faster. The principles defined, illustrated and explained, the perfect experiments to prove (or disprove) theory and refine the models.

One of the keys was understanding every tiny detail, then maximizing it in the application of the engineering. This led the College steam team to develop a rigorous theory of steam engine design of operation. They worked backward from the intended role to calculate the amount of power that would be needed for the task, the size and speed of a cylinder that would provide it, the size of boiler needed to feed it, and the amount of fuel it would consume. These were developed empirically after studying dozens of their engines.

By the end of the year, the Stonehearth College built dozens of experimental (later working) engines into the 100 hp range.