Sisy Wong

During the beginning of World War I, neither sides have effective methods that can pinpoint the location of the enemy artillery and they have no clue where were the big guns as there were usually placed outside sight. Thus, they created a tactic called Triangulation.

Triangulation is a technique for the soldiers to determine the location of a ship’s or aircraft, and the direction of roads, tunnels, or other structures under construction.  It is based on the laws of plane trigonometry, which state that, if one side and two angles of a triangle are known, the other two sides and angles can be readily calculated. One side of the selected triangle is measured; this is the baseline. The two adjacent angles are measured by means of a surveying device known as a theodolite, and the entire triangle is established. By constructing a series of such triangles, each adjacent to at least one other triangle, values can be obtained for distances and angles not otherwise measurable. This triangulation method has been used by the ancient Egyptians, Greeks, and other peoples in the early centuries.

This new triangulation method was conceived by the Danish astronomer Tycho Brahe before the end of the 16th century but was actually created by a contemporary Dutch mathematician called Willebrord van Roijen Snell as a science.

In 1669, a French astronomer called Jean Picard. He first used a telescope in determining the latitude and in measuring angles in triangulation that consisted of 13 triangles and extended from Paris 1.2° northward. His observations and results were very important as his length of the arc on a perfect circle corresponding to 1° were used by the English physicist and mathematician Sir Isaac Newton in his theoretical calculations to prove that the attraction of Earth is the principal force governing the motion of the Moon in its orbit.

Sources: https://www.abc.net.au/science/articles/2015/03/03/4183839.htm, https://www.britannica.com/science/triangulation-trigonometry

Sisy Wong

The church, St. Hedwing’s Cathedral is a Roman Catholic cathedral on the Bebelplatz in Berlin, Germany. It is the seat of the Archbishop of Berlin. St. Hedwig’s Church was built in the 18th century. King Frederick II was the one who donated the land on which the church was built. The church was created for Silesia and Brandenburg, Saint Hedwig of Andechs. The church was the first Catholic Church in Prussia after the Reformation. St. Hedwig was designed by Georg Wenzeslaus von Knobelsdorff and modelled after the Pantheon in Rome. It was built from 1747 to 1 November 1773. The construction stop several times due to the economic problems.

After the Kristallnacht pogroms that took place on the night of 9- 10 November 1938, Bernhard Lichtenberg, a canon of the cathedral chapter of St. Hedwig since 1931, prayed publicly for Jews at evening prayer. Lichtenberg was then caught by Nazis and past away during the way to the concentration camp at Dachau. The crypt at St. Hedwig’s was transferred from Lichtenberg’s remains in 1965. The cathedral was severely damaged by allied bombing in an air raid on 1 March 1943. Fortunately, only the damaged shell of the building was left standing. The reconstruction started in 1952 and on 1 November 1963, All Saints’ Day, the new high alter was consecrated by the Bishop of Berlin, Alfred Cardinal Bengsch.

Three impressive tapestries are now used in the reconstructed cathedral. All three share the motif of the heavenly Jerusalem but only one is set up and viewable at any one time. The tapestries of Erfurt’s former Bauhaus student, Grete Reichardt, were hand woven in 1963. It depicts a stylized city with the names of the apostles on the cornerstones. The tree of life represents God, and the character of the Lamb represents Christ.

Recourse: https://en.wikipedia.org/wiki/St._Hedwig%27s_Cathedral

Sisy Wong

Snellen eye chart is a chart that measures visual acuity by determined the visual level of different sizes of characters. It was invented in 1862 by a Dutch ophthalmologist called Herman Snellen. The Snellen eye chart is something where you can often see in the hospital or in physician and optometrist offices. It has 11 lines of block letters, which also called “optotypes”. Besides, they are constructed according to geometric rules and the size of the blocks is decreasing on each lower line of the chart.

In a common Snellen eye chart, it always starts with a letter “E” and following by other 9 letters: “C”, “D”, “E”, “F”, “L”, “O”, “P”, “T” and “Z”. The right way to test the visual acuity is to stand 20 feet away from the eye chart and read each line of the chart by using only one eye. Each line of the eye chart assigned a ratio of visual acuity and for a normal vision is 20/20 in the US. In some metric system countries, the normal vision is 6/6. The ratio that is less than 1 is assigned a worse sight and greater than 1 is assigned a better sight.

There are lots of different styles of the eye chart, like the one on the left-hand side, it’s a kids’ eye chart that using animal logos instead of the blocks to make children feeling interested in being an eye test. In my opinion, different styles of eye charts are making “eye chart” become interesting. However, in most of the block eye charts are using different letters, so people criticize that it’s not fair as different letters have different difficulties. Thus, the eye chart that uses for an eye test has changed into all letter “E” with different rotations.

Resource: https://www.britannica.com/science/Snellen-chart

Sisy Wong

Lithography printing is a planographic printing process that makes use of the immiscibility of grease and water. The printing process is using the ink to a grease-treated image on the flat printing surface. The ink will then directly print on the paper by a unique press or a rubber cylinder. The lithography printing was invented in 1798 by Alois Senefelder. He used a porous Bavarian as his plate. This technique was well-known when Senefelder published Vollständiges Lehrbuch der Steindruckerey.

There are two ways of lithography printing, one is fine art lithography and the second one is commercial lithography.

For fine art lithography, the earliest but not the only method of making lithographs are using the porous limestone. The art lithography method has changed in the Senefelder’s time. The image is created with tusche and litho crayon before the painting surface is fixed, moistened, and inked. Honoré Daumier is the first lithographers who use tusche instead of lithographic stone. The color lithography is called chromolithographs which were developed during the second half of the 19th century. In the twentieth century, people like  Max Beckmann, Ernst Kirchner, Henri Matisse, Edvard Munch, and Pablo Picasso made great impact and power on the media.

For the commercial lithography, it was used to show popular topical, historical, and religious subjects to a wide audience. Some of the well-known commercial lithography publisher was Currier & Ives of New York City. The lithographs were printed in black ink and were hand-colored by an assembly line of women. They were often shown in watercolor form. The early color lithographs were done in colored inks. The steam-driven lithographic press was created by Hughes & Kimber of England in 1865 and was introduced to United States in 1866. In 1853 the offset lithography was first patented by John Strather of England.

Resource:https://www.britannica.com/technology/lithography

Sisy Wong

Have you ever think about how color is important to the painting?

Back in the 17th century in Europe, Baroque is one of the most important painting movements in the history of Western art. During that time, Caravaggio, Rembrandt, and Vermeer are famous Baroque artists.

In the Baroque period, artists liked to use rich and vibrant colors for their color palette. The artists used mostly deep red, greens, and blues for the Caravaggio painting and deep and luminous in earth tones. The rich color was used to show the texture and surface of the object like gold, silk, and velvet. Therefore, the painting was shown with a tactile quality.

For the lights and shadows, the artists painted theatrically lit scenes, so the characters were spotlighted from the darkest shadow area. The juxtaposition of light and shadow made the subjects in the painting pop up and the contrast of black and bright color made the paintings clear. Paintings in the Baroque period tried to bring the emotion and power of the stage to the painting. In most of the paintings, the light in paintings like a spotlight on the stage. Thus, the theatre color and materials of theatrical costumes were evoked. Also, the artists in that period can paint the emotion that they have never painted before.

Using the combinations of deep red or green with gold and using extreme dark and light is a signature Baroque technique.

Red is a rich color. It was considered to be a color of intense emotions, ranging from anger, sacrifice, danger, and heat, through to love, passion, and sexuality.

Green is a color that closes to nature. Green is the color of nature and health and it also has close ties with emotions of empathy, kindness, and compassion.

Resource: https://ourpastimes.com/colors-in-baroque-art-12587828.html, https://www.dailyartmagazine.com/5-greatest-baroque-painters/

Sisy Wong

Have you ever thought about what kind of military weapons did people use during CA0 to CA1450?

Cast iron is one of the innovations during that period. It is an alloy of iron that contains 2 to 4 percent carbon, also includes silicon, manganese. The process of doing a cast iron is pouring the liquid iron into a thing called “pigs”, the pigs remelted with cupola furnaces and recast into molds, then cooling down its temperature and iron weapons will form. The cast iron first appeared in China in the 6th century BC, then appeared in Europe in the 14th century. Then it introduced to England in 1500.  In 1619, James River, Virginia was the place that Americans first established the ironwork. Later in the 18th and 19th centuries, cast iron was cheaper than wrought iron as it was fragile and has worse tensile strength even though it did not require intensive refining and working with hammers. It was the first essential structural metal because of its load-bearing strength and it was used in some earliest tall buildings. Then, in the 20th century, steel replaced cast iron, but it still used in many industrial applications. Cast iron was mostly gray iron or white iron, the color will show up when it fractured. For gray iron, it contains more silicon and it is less hard and more machinable than the white iron. Although both of them are brittle, a malleable cast iron produced by long heat treatment was introduced in France in the 18th century. Also, a cast iron was ductile as cast was invented in the United States and Britain in 1948. Nowadays, the ductile irons were constituted into a major family of metals that are used for gears, dies, automobile crankshafts, and many other machine parts.

Resource: https://www.britannica.com/technology/history-of-technology/China, https://www.britannica.com/technology/cast-iron

Sisy Wong

Have you ever thought about where does the iron comes from? Do you know who invented iron anyway? And why?

Iron is a metal that looks very common but needs a lot of skills to create it. It has a very long history in all countries around the world which began around 1200 B.C. Iron was starting invented form the collapse of the Bronze-Age civilisation of Mycenae. 

It has played important roles in both agriculture and military. During this era, Greek were busy to move out from their original settlements and settled a new place for them. Therefore, there was not much history about iron era in the books. 

The old Greek used iron products to build a trade relationship with people that came from other countries. Also, Greek Iron-Age was defined by art and agriculture. A case in point, pottery is one of the famous art history in Greece.

Back to iron investment, Greek used iron to create weapons. For instance, swords and knifes are the popular ones. Sword is a powerful weapon in the past and it was stronger than any of the metal products. The blade of the sword can be either straight or curved, they depend on different eras and countries. 

In the Greek Iron-Age, there were two types of swords: Thrusting Swords and Slashing Swords. The Thrusting Swords were straight with a sharp tip and the Slashing Swords were curved with cut edge on both sides of the blade. In the Greek history, people used swords for fighting against the enemies. The ancient Greeks were looking for a hard material to make better weapons (swords) so they could win wars. Because of that, the Greek took a great concern about the quality of the materials of the weapons. 

They finally found a material that was hard to break and useful. That is the history of iron in Greece.

Resource: https://study.com/academy/lesson/greek-iron-age-art-architecture.html