what substance did umberto boccioni believe that the artist must infuse into each work of art?
Umberto Boccioni, (born October 19, 1882, Reggio di Calabria, Italy—died August 16, 1916, Verona), Italian painter, sculptor, and theorist of the Futurist movement in art.
Boccioni’s first major Futurist painting, Riot in the Gallery (1909), remained close to pointillism and showed an affiliation with Futurism mainly in its violent subject matter and dynamic composition. The City Rises (1910–11), however, is an exemplary Futurist painting in its representation of dynamism, motion, and speed. The swirling human figures in its crowd scenes are repetitively fragmented according to the Futurist style, but the rhythmic muscular energy they generate is unrelated to the Futurist cult of the machine.
26. See F. C. T. Moore, Bergson: Thinking Backwards (Cambridge: Cambridge University Press, 1996), 91–96.
42. See Sebastiano Barassi, “A Pioneer of Avant-Garde Sculpture,” in ‘We, the Moderns’: Gaudier-Brzeska and the Birth of Modern Sculpture (Cambridge: Kettle’s Yard, 2007), 5–59; and chaps. 10 and 15 in Evelyn Silber, Gaudier-Brzeska: Life and Art (London: Thames & Hudson, 1996).
John Singer Sargent also spanned the change of century, but he rejected overt Impressionism and Post-Impressionism. He was the most successful portrait painter of his era, using a mostly realistic technique often effused with the brilliant use of color. He was equally apt at individual and group portraits, particularly of upper-class families. Sargent was born in Florence, Italy to American parents. He studied in Italy and Germany, and in Paris. Sargent is considered to be the last major exponent of the British portrait tradition beginning with van Dyck.  Another prominent American portraitist who trained abroad was William Merritt Chase. American society painter Cecilia Beaux, called the “female Sargent”, was born of a French father, studied abroad and gained success back home, sticking with traditional methods. Another portraitist compared to Sargent for his lush technique was Italian-born Parisian artist Giovanni Boldini, a friend of Degas and Whistler.
Gu Kaizhi, one of the most famous artists of the Eastern Jin dynasty, instructed how to reflect the sitter’s characteristics through accurate portray of the physical features in his book On Painting. He also stressed the capture of the sitter’s spirit through vivid depiction of eyes. 
The Glorious Sculpture of Greece
The glory of Greece was its sculpture. The roots of Greek sculpture reach into the earlier cultures of Crete, Mycenae, and even Egypt. The figures of the 7th and 6th centuries BC lack life and movement; their faces wear the frozen smile peculiar to archaic sculpture. Even so, these early craftsmen, whose names are lost with the temples they decorated, show sensitivity to the qualities of marble and a superb sense of design. As if to make up for the lack of life in their statues, archaic sculptors sought naturalism by painting them.
Greek sculpture rose to its highest achievement in the 5th century BC, when the spirit of Greece itself was at its height. ( see Greek art for examples )
From an article by Jack Bookbinder, former Director of Art Education, Philadelphia Public Schools and by Christopher Lyon, Editor, Department of Public Information, The Museum of Modern Art, New York.
Yet if fears of such lurking ills worry Saudis, so does the kingdom’s economy. Last year’s oil-price fall has hit the government hard, though it can draw on ample foreign reserves, which are so far down 10% from last year’s peak of $737 billion. Its debt is negligible, so it can easily issue more. What has hurt ordinary Saudis, who are avid punters, is the local stock index. It has sunk by 30% over the past year. Even the opening of the market to foreign investors in June failed to stem the decline.
The gambling boom is linked to the Italian government’s difficult financial situation. Faced with large debts, successive finance ministers have seen in gambling a juicy source of tax receipts. Nearly half of what Italians lose goes to the treasury. Governments have legalised one form of betting after another. Wagering on the outcome of football matches came first, then gaming machines and, in 2009, online betting. By 2014 gaming machines (including video lottery terminals) were to blame for half the gambling losses of Italians.