John McNown’s “Canals in America”

By Jeremy Lane

In the 17th and 18th centuries, Britain experienced a boom in the creation of canals, going from around 650 miles of navigable waterways to about 4 times that in just two centuries. The primary means of transportation of goods on the waterways was by horse-drawn barges.  A single horse pulling a barge could pull as much as 50 tons, while the same horse on paved roads could only pull 2 tons; on unpaved roads, they could only pull up to 1200 pounds. The Americans, lacking even paved roads in most places, saw the clear advantage of the creation of canals and began to mirror this boom in the 1800s.

By the time the US started to create their canals, the engineering behind their creation was widely known. The cross-section of the canal is trapezoidal, where the height is relatively shallow: only 3 or 4 feet in most cases. The slope along the banks would be very shallow, greatly reducing the effects

Image from: History of the Canal System of the State of New York … / by Noble E. Whitford (Albany : Brandow Printing Co., 1906) — vol. 2, p. 1039

of erosion. The bottom and banks of the canal would be coated with a loam and sand mixture to prevent the water from seeping into the ground. Finally, overflow weirs would be placed at regular intervals to prevent flooding in the surrounding areas in the case of heavy rain.

 

In order to solve issues with connecting canals to other waterways at different levels, the Americans made use of the V-shaped lock. The V-shaped lock operates similar to a normal linear lock* but also makes use of two separate chambers that each have their own opening on the downstream side but sharing an opening on the upstream side. V-shaped locks have two main advantages over a linear lock.

First, the V-shaped lock could reduce the amount of water that was discharged downstream. When lowering the water on one side of the lock, they could discharge it into the other chamber, which would allow other boats to rise until they hit equilibrium at the halfway point. When this happened, they would be forced to discharge the rest downstream while continuing to fill the upwards moving side from upstream. This halves the amount of water lost downstream.

The second major advantage was that the stress on the lock would operate similarly to that of an arch. Because the edges of the lock joined together at a point, the pressure from upstream would push the walls of the lock towards the center, where they could then support each other. This made the whole structure much more sound than other formations would.

*In case you don't know how a lock works, here is a
video of a linear lock being used. Basically, there is
a small chamber that can hold a variable amount of water
connecting the two waterways. On one end of the chamber is
a gate leading upstream (towards the higher river) and the
other gate leads downstream. Whenever someone wants to go
upstream, they open the bottom gate while the water is at
the lower level and allow the boat to enter. Then they
close the lower gate and allow a small amount of water to
enter from the higher side, which will cause the chamber to
fill at a controlled rate. Then, when it fills to the
level of the other waterway, the upper gate can open.
Whenever someone wants to go down, they can discharge
the water slowly downstream to lower the level in the lock
and then open the lower gate.

In case you are interested in some of the canals in the US, here is a link describing their creation and some of the difficulties they faced.

616 words.

Eugene Ferguson on the Origin of Steam Engines

By Jeremy Lane


In Eugene Ferguson’s article, he explains that, while James Watt made significant improvements on the steam engine, it was Thomas Newcomen that was the creator of the original steam engine. So while most people might give Watt all the credit, Ferguson does his best to show that Newcomen made just as significant contributions to technology. This can be seen in oil wells that, even today, still use the “walking beam” that Newcomen invented as part of his Newcomen Engine.

The Newcomen Engine was invented to fill the need of miners in England during the 17th Century. The issue was, as mines went deeper and deeper into the ground, miners were increasingly running into water seepage, slowing or even preventing them from working. The Newcomen engine used a steam piston attached to a beam in order to pump the water out. As the steam was condensed on the bottom of the piston, the vacuum that was created pulls the piston down, which pushes the beam down and while the pump rod moved water up the other side.

Newcomen Pump

Savery PumpAnother inventor, Thomas Savory was building his own version of the steam engine around the same time for the same purpose. However, the way it worked was very different — it used the power of steam rising the create suction that would pull the water out and into the pump. Unfortunately, due to increased atmospheric pressure, Savory’s invention was not capable of working underground and was mostly relegated to pumping water into buildings and fountains. However, Savory’s engine was considerably cheaper than Newcomen’s or Watt’s engines, so for any work done above ground, it was the preferred machine.

Here is a cool link demonstrating the Savery Pump!

And here is one showing a Newcomen Pump working!

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Carlson’s “The Romans”

Introduction:

In the article, “The Romans”, Carlson explains goes over a brief history of the Roman’s with a focus on the technologies they made. The technologies that he goes over can be broken into two categories:  Military Technologies and Social Technologies.

Military Technologies:

When developing military technologies, the Roman’s focused on siege and artillery weapons, such as ballista, crossbows, catapults, and siege towers.

The manuballista, or hand-crossbow, was originally brought to Rome from China in the 4th Century BCE and allowed soldiers to shoot arrows more accurately over longer distances.

The carroballista (mounted cross-bow) was a much larger weapon. It used skeins made from human hair or animal sinews to produce tension. Once a projectile was placed in front of the drawstring, the soldiers would use a winch to create tension in the skein. When the tension was released, the projectile would be violently propelled forward.

Towards the end of the 4th Century BCE, the Romans had invented the onager, meaning “wild ass”. The onager worked by using a thick skein connecting a flexible throwing arm and a stable frame. The throwing arm would have a sling attached where heavy stones could be loaded. When the skein was tightened, the arm would be pulled back under heavy tension, where a catch would prevent it from firing until it was released. The onager could fire stones over 500 yards.

A comparison of ballista and artillery ranges

In addition to siege weapons, the Romans would also build walls, forts, and watchtowers along their frontiers to deter barbarian invaders and help control the local population. With these technologies, the Romans were able to rapidly expand their empire abroad while providing a steady stream of booty and plunder at home. Many generals, such as Sulla, Pompey, and Ceasar were able to rise in political power as a result.

Social Technologies:

After Augustus’s defeat in Germany in 7 CE, he abandoned the territorial conquest and began to focus on improvements within.  He shared power with many of the aristocratic families, reducing the risk of internal conflict while appointing governors to take control of the newly conquered provinces. During the first two centuries the new millennia, Augustus and his successors were able to bring about significant political and social stability, which allowed for unprecedented growth in technology.

During this time, the ideal citizen of Rome was thought to be a wealthy farmer with a large estate. Despite this, few inventions were made to make farming easier, as it was simpler to buy more land and hire more workers than make existing jobs more efficient. However, many aristocrats would also use their surplus wealth to undertake civic projects, such as making monuments, amphitheaters, aqueducts, the famous Colosseum.  Engineers trained when Rome was constantly at war became invaluable in organizing massive festivals and structures, such as man-made lakes to practice mock sea battles in.

Perhaps one of the more famous inventions during this time was the Roman Arch. Due to the curved shape of the arch, the weight of the building would push the columns together rather than apart. This allowed them to create large buildings with curved roofs or long bridges across a valley. One other variation of the arch was to make it continuously revolved around a center point, which would make a dome. This is how the enormous dome of the Pantheon was created.

Pantheon in Rome, inside view

In conclusion, the Roman’s had two great periods of technological prowess. The first era would have been from before Augustus when they dominated the military scene with their advanced ballistics, while the second era was that of peace after the fall of Ceasar and Augustus came into power.

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Here’s a link for a really cool video on Roman weapons.

And here is a link for a lot of other cool inventions made by the Romans! Some interesting inventions listed here would be the Julian Calendar and a postal service.

 

— Jeremy Lane