The agriculture revolution in the nineteenth century involved two things:the invention of labor-saving machinery and the development of scientific agriculture.(1)_______________________.“In Europe”, said Thomas Jefferson,“the object is to make the most of their land, labor being sufficient;here it is to make the most of our labor, land being abundant”.It was in America, therefore,that the great advances in nineteenth-century agricultural machinery first came.(2)_______________________.By 1860，most of the machinery in use today had been designed in an early form.The most important of the early inventions was the iron plow.As early as 1890 Charles Newbolt of New Jersey had been working on the idea of a cast-iron plow and spent his entire fortune in introducing his invention.The farmers, however, would home none of it,(3)_______________________________.Nevertheless, many people devoted their attention to the plow,until in 1869, James Oliver of South Bend, Indiana,turned out the first chilled-steel plow.
