posts, and caps depends on the thickness of the material, sixteen-penny and twenty-penny nails being those generally used. The battens are securely fastened over the various joints or seams with six-penny nails. Each box as completed is carefully set on the established grade and firmly held in position with wooden wedges. The remaining caps are put on whenever convenient. Where a flume connects with a ditch the posts for a distance of several boxes back are lengthened sufficiently to permit of the introduction of an additional plank on each side. The end boxes of the flume are flared, to permit a free entrance and discharge of the water. An outer siding, nailed to the posts, at the junction with a ditch, or wherever else a bank of earth is passed through, protects the flume and also strengthens it materially. When large amounts of lumber are to be used, it is occasionally economical for a company to erect a portable saw-mill and cut out the lumber. In most cases, however, it is cheaper to contract for the material required. All lumber should be inspected and measured by a competent scaler, whose duty it is to reject all knotty, sap, wind-shaken stuff, and slabs. As only dimension stuff is used, everything should be prepared at the mills of the exact sizes required, so that the flume can be constructed as rapidly as the material is received. The material should be delivered at the head of the flume, or at such convenient places as the engineer may direct. Lumber stored should be carefully piled, and spaced so as to permit a free circulation of air through the material. Sufficient water is generally obtained along the line of work, and is turned into the flume as fast as constructed, to assist in the delivery of the lumber which is floated. A few inches' depth of water is all that is necessary. One or two or more men are required to attend to the floating of the material, according to the distance. As occasion may demand, the flume is trestled, the main supports being placed every eight to twelve feet. The lumber, scantling, and struts for bents are used in accordance with the demands of the work. The foundations must be made secure 'to hold the superstructure, and no mortises used, heavy spikes and strong timber and braces being sufficient. Guy ropes are employed when necessary to prevent any vibration or movement of the flume caused by severe wind storms. It is the usual practice to distribute along the line of a ditch and flume a certain amount of lumber, to be ready, in case of accident, for repairing any breaks. Breaks on ditch lines, especially during the winter, are repaired more easily with pieces of flume than with dirt. A supply of ten per cent. of lumber is not an excessive amount to have on hand. The life of a flume, under the best of circumstances and care, will not exceed twenty years, and generally not over half that time. Lumber. The following tables show the amount of lumber required in the construction of twelve-foot flumeboxes of different widths and depths: TABLE IX. Flume two and one-half feet wide, two and one-half feet deep; twelve-foot box. TABLE X. Flume four feet wide, three feet deep; twelve-foot box. 4 inches X 5 inches X 3 feet 9 inches long.. 6 Planks, 6 Posts, Flume seven feet wide, four feet deep; twelve-foot box. 11⁄2 inches thick, 12 feet long.. =270 feet b.m. inches X 4 feet 4 inches long. = 52 Bracket Flume. A novel method of carrying flumes along the face of precipitous cliffs has been designed by W. H. Bellows and adopted on the line of the Miocene Mining Company's ditch in Butte County, to avoid the construction of a trestle-work one hundred and eighty-six feet high. The line of ditch was run some two hundred yards up the cañon, abutting against a perpendicular wall of basaltic rock, along the face of which, one hundred and eighteen feet above the bed of the ravine and two hundred and thirty-two feet below the top of the cliff, the flume was carried on brackets for a distance of four hundred and eighty-six feet. Fig. 16 gives a general view, and Fig. 17 shows the method of hanging the flume. The brackets are made of T-rails of thirty-pound railroad iron bent into the form of an L. The longer arm, |