McNown on Canals

Before the 16th century the most efficient way to transport materials was by natural waterways. However, these rivers or streams were non-navigable at some points thus transport was impossible. During the 16th century, European engineers began to expand the waterway network. They started by removing obstacles and digging canal loops around rapids or the obstacles. McNown writes at the beginning of the 17th century, there were 650 miles of navigable waterways and by 1760 there were over 1,200 miles of navigable waterways.

Later in the writing McNown explains what a barge canal is like. Barge canals were trapezoidal in shape and the bottom width was from 20 to 25 feet while they were only 3 to 4 feet deep. The trapezoidal shape helped to minimize the erosion of the shore. These canals were built on relatively flat ground and the contour changed when there was a change in elevation. To get up to the higher elevations a chamber in the canal needed to be constructed. The chamber would be filled with water up to the level of the canal above or emptied down to the level of the canal below.

In America, the canals were built to tap natural resources in the interior of the country, to reduce the length of voyages along the coast. McNown states that before the War of 1812 “many men of vision recognized the advantages of connections with the interior of the new nation. The United States was relatively large compared to the nations in Europe. On July 4, 1828 a ceremony was held to inaugurate the construction of the Chesapeake and Ohio canal. This canal linked the Washington and Baltimore through the Potomac river. The canal was a total of 186 miles. By 1834, 107 of the total 186 miles had been completed. However, the state of Maryland ran into some financial trouble had had to take a $3 million loan from the federal government.

This map shows the different roads, canals, and railroads in early America.

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At the same time that this canal was being constructed, railroads were starting to become increasingly popular and by 1831, 100 miles of railroad were across the United States, but by 1840 it had increased to 3,000 miles compared to 3,600 miles of canals.

Here is a short video explaining the rise of railroads and canals.

This link provides you with a comparison between railroads and canals. The article does a great job describing the differences between the two different systems of transportation as well as listing the pros and cons for each of them.

Astrolabe Research

The Astrolabe: Using the Stars to Explore the Earth

The astrolabe, which means star taker in Greek, is a scientific instrument to make observations and calculations. Because early man recognized that stars moved in patterns and could be used to determine dates, times, and celestial events, travelers developed tools such as the astrolabe, which utilized the stars. While difficult to pinpoint the exact origin of the astrolabe, scholars often credit Greek astronomer Hipparchus with this invention around 200 B.C.  Because the astrolabe did not depend on shadow or daylight, it was more accurate than previous tools such as the gnomon (Berthon 32). The gnomon is the part of a sundial that casts a shadow. Its scientific use extended into Europe and reached the West around the tenth century, and the Islamic world used it to ascertain prayer times and the direction of Mecca.  Scientists employed the planispheric astrolabe to observe celestial objects, measure positions, and determine time. Others, including geographers, timekeepers, surveyors, and navigators, used astrolabes. The use of the astrolabe was pivotal in navigation because its use improved the consistency of ships’ headings.

The astrolabe, often made of brass and measuring six to eight inches in diameter, has a base known as a mater, marked with lines indicating hours and degrees.  The mater encloses a plate, the tympan, with grid lines indicating altitude. Some astrolabes had interchangeable tympans to use at different latitudes (Watson).  The tool includes a star map, or rete, to signify positions of stars. As the user turns the rete, the stars rise and set.  Rotating rulers are on each side; the rule is on the front, and the alidade, a sighting device, is on the back (Watson). As users rotated these rings, they could determine time of day, predict sunrise or sunset, and determine altitude of celestial objects.

Sailors used a mariner’s astrolabe to determine the latitude of ships (Bullard).  The astrolabe allowed sailors to maintain consistent headings even with cloudy skies and without being within sight of land (Law). As nations set off on expeditions to find more land and riches, employing accurate forms of navigation allowed sailors to find and return to new lands. John Law, who analyzed Portuguese transoceanic expansion, concluded that the establishment of a scientific commission to produce rules to calculate latitudes and generation of a record of latitudes of  coastal features enabled the creation of practical instructions for sailing (241-3).  Better navigation benefited sailors with more accurate routes and lessening the possibility of being lost at sea.

Interest in the instrument peaked as astrolabes were produced commercially and became smaller and cheaper (Hayton) and remained a popular tool until the middle of the seventeenth century (“Nicholas Copernicus”) when other instruments such as telescopes and clocks replaced the astrolabe. The astrolabe was an early scientific instrument used primarily for astronomy, religious observation, and navigation.  Scientists using the astrolabe could tell time and predict celestial events with greater accuracy than earlier scientists.  Religious groups determined daily prayer time as well as future religious events, and sailors better navigated the seas.   Later navigational tools became even smaller and more accurate than the astrolabe.

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Works Cited

“Astrolabe History.” University of Hawaii, Institute for Astronomy. 18 Apr. 2000, Accessed 16 Oct. 2018.

Berthon, Simon and Andrew Robinson. The Shape of the World: The Mapping and Discovery of the Earth .Chicago: Rand McNally, 1991.

Bullard, Eric. “Astrolabe.” Salem Press Encyclopedia of Science, 2017. EBSCOhost, Accessed 16 Oct. 2018.

Harris, William. “The Technologies of Time.” How Stuff Works. 2012, Accessed 17 Oct. 2018.

Hayton, Darin. An Introduction to the Astrolabe. Accessed 17 Oct. 2018.

Law, John. “On the Social Explanation of Technical Change: The Case of the Portuguese Maritime Expansion.” Technology and Culture. vol. 28, no. 2 1987, Accessed 17 Oct. 2018.

“Nicholas Copernicus: Founder of Modern Astronomy.” Nicholas Copernicus: Founder of Modern Astronomy, Oct. 2004, pp. 10–42. EBSCOhost, Accessed 16 Oct. 2018.

Watson, Bruce. “The Astrolabe: Astronomy’s First Hot App: Loaded with Features, an Ancient Analog Computer Replicates the Sky’s Workings.” Sky & Telescope, no. 2, 2016, p. 24. EBSCOhost, Accessed 16 Oct. 2018.

Boulton Letter (Steam Engine)

In Matthew Boulton’s letter to Erasmus Darwin, Boulton discusses how the B & W steam engines differ from Newcomins engines. Later he states how the B & W engines have been improved upon.

Boulton begins his argument by writing how the two engines are different from each other. The way that the B & W engine operates is the acting power in the engine is the steam on the piston rather than using the atmosphere. The steam is also condensed in a separate vessel and the air is extracted by an air pump at each stroke. The vacuum is placed above and below the piston, therefore doubling the power of the engine.

Later in the letter he discusses seven points on how the B & W engines have improved. The engine is the “most powerful machine in the world,” it is the most tractable, it shews the strength of the steam, it registers the number of strokes it makes, and it is applicable to every purpose that requires either rotative or reciprocating motion. He goes on to support each of his seven claims with calculations or examples. He states that the steam engine is equal to the work of a thousand horses. He also says that the horses must rest, but the steam engine can keep going as long as it has fuel. The steam engine also has a multitude of uses, much more than a horse or man.

The steam engine was able to revolutionize the world by allowing a machine to do the work rather than by man or animals. From the original steam engine developed by Thomas Savery in 1689, the engine has been improved and innovated upon.

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This link takes you to a YouTube video that gives a brief background on the Watt steam engine and provides a great depiction of how the engine worked. It labels all of the parts of the engine and how they interact with one another.

This link will take you to a website that mainly focuses on the engineering methods that went into the development of the Watt steam engine. The article begins by giving a short biography on James Watt. He began the work on his steam engine after having to repair a model Newcomen engine. Watt’s idea for the engine was to add a separate condenser. He found that the Newcomen model was wasting a lot of energy because cold water was injected into the cylinder so that the steam could be condensed. The article then goes on to discuss the methods and procedures that were used to make the Watt steam engine.