The student of the history of commerce is often forced to turn to narrative political histories for information. Among the general histories of Europe in the nineteenth century may be mentioned Charles D. Hazen, *Modern Europe, N. Y., Holt, 1920; C. M. Andrews, *Modern Europe; N. Y., Putnam, 1899; Seignobos, **Pol. hist. Much has been written, of course, on the progress of the century in various technical lines. Ure’s Dictionary, various editions, describes the advances of the first part of the century; and the student will probably find one of the modern encyclopedias (Britannica, with Supplement; International) the most satisfactory source of information on recent progress. No attempt can be made in this or the following chapters to cover the great field of technical literature. Jevons’ **Coal question should, however, be mentioned as still of great interest and value. Nicolls, * Story; Edward A. Martin, *Story of a piece of coal, N. Y., Appleton 1896; or R. Meldola, *Coal and what we get from it, N. Y., Young, 1897 can be assigned for reading by the class. Edwin C. Eckel, Coal, iron and war, N. Y., Holt, 1920, is an interesting and suggestive study in the physical bases of national industry. On the steam-engine, Robert H. Thurston’s History, N. Y., Appleton, 1902 will probably be found most useful. The biographies by Samuel Smiles are a valuable history of technical progress, interesting and trustworthy. Of more recent books, designed for popular reading, George Iles, Flame, electricity and the camera, N. Y., Doubleday, 1900 contains attractive accounts of many features of technical progress. CHAPTER XXIX MACHINERY AND MANUFACTURES =327. Development of agriculture.=—Pursuing now our survey of the technical advances of the century, we must notice first the oldest and perhaps the most important branch of production, agriculture. An American reader does not need to be told that farm work has been greatly changed by the introduction of improved tools and machinery. Even an implement so old and apparently so simple as the plow will do now better work with half the force formerly required. Cultivating and harvesting machines of various kinds spare land and labor. The introduction of artificial fertilizers has given new freedom and efficiency to the agriculturist.