[4] Bulletin de l’Association des Chimistes de Sucrèrie, No. 2, pp. 7, et seq. [5] Proceedings of the Twelfth and Thirteenth Meetings of the Society for the Promotion of Agricultural Science, p. 140. [6] Chemical Division, U. S. Department of Agriculture, Bulletin 43, p. 341. [7] Rapport adressé par le Comité des Stations agronomiques au sujet des Methodes à suivre dans l’Analyse des Matières fertilisantes. [8] Die Landwirtschaftlichen Versuchs-Stationen, Band 38, S. 303. [9] Vid. op. cit. 6, p. 341. [10] Zeitschrift für analytische Chemie, 1890, S. 390. [11] Vid. op. cit. 6, p. 342. [12] Chemisches Centralblatt, Band 2, S. 813. [13] Transactions of the American Institute of Mining Engineers, Vol. 21, p. 165. [14] Phosphates of America, p. 144. [15] Vid. op. et loc. cit. 13. [16] U. S. Geological Survey, Bulletin No. 47. [17] Vid. op. et loc. cit. 14. [18] Vid. op. et loc. cit. 13. [19] Vid. op. cit. 14, p. 147. [20] Transactions of the American Institute of Mining Engineers, Vol. 21, p. 168. [21] Phosphates of America, p. 153. [22] Die Landwirtschaftlichen Versuchs-Stationen, Band 34, S. 379. [23] Zeitschrift für analytische Chemie, 1892, S. 383. [24] Zeitschrift für angewandte Chemie, 1894, Ss. 679 und 701. [25] Vid. op. cit. supra, 1889, p. 636. [26] Vid. op. cit. 24, 1891, p. 3. [27] Rapports presentèes au Congrès International de Chimie Appliqué, Bruxelles, Août, 1894, p. 26. [28] Vid. op. et loc. cit. 20. [29] Le Stazioni Sperimentali Agrarie Italiane, Vol. 23, p. 31. [30] Crookes’ Select Methods, p. 538. [31] Journal of Analytical and Applied Chemistry, Vol. 5, p. 671. For additional authorities on these methods consult Meyer and Wohlrab, Zeitschrift für angewandte Chemie, 1891, Ss. 170 und 243. Gruber, Zeitschrift für analytische Chemie, Band 30, S. 206. Shephard, Chemical News, May 29, 1891, p. 251. Vögel, Zeitschrift für angewandte Chemie, 1891, Band 12, S. 357. [32] Journal of the American Chemical Society, April, 1895. [33] Vid. op. cit. 21, p. 150. [34] Transactions of the American Institute of Mining Engineers, Vol. 21, p. 170. [35] Vid. op. cit. supra, p. 173. [36] Comptes rendus, Tome 54, p. 468. [37] Crookes’ Select Methods, p. 500. [38] For details of method see Fresenius quantitative Analysis. [39] U. S. Department of Agriculture, Chemical Division, Bulletin 43, p. 341. [40] Letter to B. W. Kilgore, Reporter for Phosphoric Acid to the Association of Official Agricultural Chemists. [41] Die Landwirtschaftlichen Versuchs-Stationen, Band 38, S. 304. [42] Communicated by Dr. Solberg. [43] From the Official Swedish Methods; translated for the author by F. W. Woll. [44] Methoden van Onderzock aan de Rijkslandbouw-proefstations, 1893, p. 4. [45] Zeitschrift für analytische Chemie, 1893, S. 64. [46] Journal of the American Chemical Society, Vol. 16. [47] Zeitschrift für angewandte Chemie, 1894, S. 678. [48] Journal für Landwirtschaft, Band 30, S. 23. [49] Vid. op. cit. 47, p. 544.