Problem: Background: Zhang Heng (Chinese: Zhang Heng ; AD 78-139), formerly romanized as Chang Heng, was a Han Chinese polymath from Nanyang who lived during the Han dynasty. Educated in the capital cities of Luoyang and Chang'an, he achieved success as an astronomer, mathematician, scientist, engineer, inventor, geographer, cartographer, artist, poet, statesman, and literary scholar. Zhang Heng began his career as a minor civil servant in Nanyang. Eventually, he became Chief Astronomer, Prefect of the Majors for Official Carriages, and then Palace Attendant at the imperial court.
Context: Zhang Heng is often credited with inventing the first odometer, an achievement also attributed to Archimedes (c. 287-212 BC) and Heron of Alexandria (fl. AD 10-70). Similar devices were used by the Roman and Han-Chinese empires at about the same period. By the 3rd century, the Chinese had termed the device the ji li gu che, or "li-recording drum carriage" (the modern measurement of li = 500 m/1640 ft). Ancient Chinese texts describe the mechanical carriage's functions; after one li was traversed, a mechanically driven wooden figure struck a drum, and after ten li had been covered, another wooden figure struck a gong or a bell with its mechanically operated arm. However, there is evidence to suggest that the invention of the odometer was a gradual process in Han Dynasty China that centered on the "huang men"--court people (i.e. eunuchs, palace officials, attendants and familiars, actors, acrobats, etc.) who followed the musical procession of the royal "drum-chariot". There is speculation that at some time during the 1st century BC the beating of drums and gongs was mechanically driven by the rotation of the road wheels. This might have actually been the design of Luoxia Hong (c. 110 BC), yet by at least 125 the mechanical odometer carriage was already known, as it was depicted in a mural of the Xiao Tang Shan Tomb. The south-pointing chariot was another mechanical device credited to Zhang Heng. It was a non-magnetic compass vehicle in the form of a two-wheeled chariot. Differential gears driven by the chariot's wheels allowed a wooden figurine (in the shape of a Chinese state minister) to constantly point to the south, hence its name. The Song Shu (c. AD 500 ) records that Zhang Heng re-invented it from a model used in the Zhou Dynasty era, but the violent collapse of the Han Dynasty unfortunately did not allow it to be preserved. Whether Zhang Heng invented it or not, Ma Jun (200-265) succeeded in creating the chariot in the following century.
Question: When was it created?
Answer: 125

Background: Thomas Cowperthwait Eakins (July 25, 1844 - June 25, 1916) was an American realist painter, photographer, sculptor, and fine arts educator. He is widely acknowledged to be one of the most important artists in American art history. For the length of his professional career, from the early 1870s until his health began to fail some 40 years later, Eakins worked exactingly from life, choosing as his subject the people of his hometown of Philadelphia. He painted several hundred portraits, usually of friends, family members, or prominent people in the arts, sciences, medicine, and clergy.
Context: Eakins' first works upon his return from Europe included a large group of rowing scenes, eleven oils and watercolors in all, of which the first and most famous is Max Schmitt in a Single Scull (1871; also known as The Champion Single Sculling). Both his subject and his technique drew attention. His selection of a contemporary sport was "a shock to the artistic conventionalities of the city". Eakins placed himself in the painting, in a scull behind Schmitt, his name inscribed on the boat. Typically, the work entailed critical observation of the painting's subject, as well as preparatory drawings of the figure and perspective plans of the scull in the water. Its preparation and composition indicates the importance of Eakins' academic training in Paris. It was a completely original conception, true to Eakins' firsthand experience, and an almost startlingly successful image for the artist, who had struggled with his first outdoor composition less than a year before. His first known sale was the watercolor The Sculler (1874). Most critics judged the rowing pictures successful and auspicious, but after the initial flourish, Eakins never revisited the subject of rowing and went on to other sports themes. At the same time that he made these initial ventures into outdoor themes, Eakins produced a series of domestic Victorian interiors, often with his father, his sisters or friends as the subjects. Home Scene (1871), Elizabeth at the Piano (1875), The Chess Players (1876), and Elizabeth Crowell and her Dog (1874), each dark in tonality, focus on the unsentimental characterization of individuals adopting natural attitudes in their homes. It was in this vein that in 1872 he painted his first large scale portrait, Kathrin, in which the subject, Kathrin Crowell, is seen in dim light, playing with a kitten. In 1874 Eakins and Crowell became engaged; they were still engaged five years later, when Crowell died of meningitis in 1879.
Question: What was his first work of art?
Answer:
Eakins' first works upon his return from Europe included a large group of rowing scenes, eleven oils and watercolors in all,