[Martin, Coal; encyclopedias; Gilbert H. Montague, The rise and progress of the Standard Oil Company, N. Y., Harper, 1903, $1; Ida M. Tarbell, The History of the Standard Oil Company, N. Y., 1904.]
8. Indicate on an outline map the distance from your home to which wheat could profitably be carried by different means of transportation. [See below, sect. 387, for convenient statistics.]
9. Character and value of wheat. [Edgar, Story, chaps. 1, 2.]
10. Explain the great fluctuations in the export of wheat from the U. S. in the nineteenth century. [See statistics in U. S. Statistical Abstract.]
11. Wheat in modern commerce. [Edgar, Story, chap. 4.]
12. Provision trade of the world. [U. S. Monthly Summary, Feb., 1900, vol. 7, no. 8, pp. 2297-2347.]
13. American canning interests. [Judge in Depew, One hundred years, chap. 57.]
14. What amount does an American household, your own for instance, spend in a year for each of the chief textiles: cotton, wool, linen, silk?
15. The cotton trade of the United States and of the world. [See above, sect. 378, for suggestion of a simple mode of treating a large subject; the topic may be amplified as time permits. F. Wilkinson, Story of cotton, N. Y., Appleton, $1; S. J. Chapman, The cotton industry, London, 1905; George Bigwood, Cotton, London, 1918; statistics in U. S. Monthly Summary, vol. 7, no. 9, pp. 2543-2635.]
16. The wool trade. [John H. Clapham, The woolen industries, London, 1907; Frank Ormerod, Wool, London, 1918.]