PERMANENT SET IN DECIMALS OF AN INCH. TABLE I. Transverse Tests of 851b Rails for the C. B. & Q. R.R., made with the United States Testing Machine, at the Watertown Arsenal, Mass., McClure section. Delano section. .1096*.1100+ .1138 .1430 .139934 .0896 .0912 .0921 .1020 .0840 .0873 .0894 .0905 .1150 .1268* .1109 .1184 .1340 .1306 .11171⁄2 .0068 .0062 .0089 .0298 .01291. .1350 .0161 .0108 .0158 0850 .03194 .0099 .0164 .0412 .0326 .02504 .0880 .08554 .0030 .0026 .0031 .0099.00461 .0020 .0022 .0037 .0076.003834 .0030 .09754 .0037 .0038 .0051 .0162 .0072 .0035 .0040 .0067 .0121.0065 .0052 .0074 .0140 .0199 .011614 .0578 .0360 .0343| 132,000 .1695 .1640 .0190 .0693,1077 .0782 .1433 NOTE. * Indicates point at which scale starts off from vicinity of middle bearing. + Indicates point of approximate elastic limit. TABLE II. Prepared by Mr. Fred. A. Delano, in part from Table I. Showing the comparative deflections and set at 100,000 pounds; approximate elastic limits; test for hardness; height and weight of the different rails designated in Table I. The added carbon and phosphorus determinations were made by the manufacturers of the rails. NOTE. The "Delano" has greater "deflection" and less "set" than the "McClure" at 100,000 lbs. load. obtained Mr. Delano's permission to publish them in connection with my paper. It is proper to say here that my statement with regard to the stiffness of the New York Central 80-pound rail was made at the New York meeting of the Institute in February, 1889, prior to the rolling of the Chicago, Burlington and Quincy experimental sections. The tests of those sections, as given in Tables I. and II. (pp. 238, 239, and 240) indicate an excellent quality of metal, having a high elastic limit, probably exceeding 65,000 pounds per square inch, for the metal in the base of the rails. Comparing these tests with the single one of the lowcarbon 80-pound rail of the New York Central, it will be seen that the metal in the latter takes a permanent set at a much lower strain. Tests of the same grade of metal in rails nearly as heavy indicate that the elastic limit of the metal in the base of the rail will not exceed 40,000 pounds per square inch. The average of the results of the Delano section shows greater stiffness than the single test of the New York Central, except at 10,000 pounds. The "moment of inertia" of the latter is 26.96. At 20,000 pounds the Delano section is nearly 1 per cent. stiffer. The elastic limit of the steel was passed between loads of 60,000 and 70,000 pounds. The 80-pound section, the tests of which were reported in my paper, was a piece from the first 1000 tons rolled. The percentage of carbon specified was from 0.45 to 0.50. Why the makers allowed it to go below, I have never understood. The carbon has since been specified as 0.60 to 0.65, the stiffness and hardness of the rails being increased accordingly. Under the present heavy wheel-tonnage, rails are wearing more rapidly than formerly; the subject is being studied more carefully, and, as a consequence, rails of better physical properties are demanded. One railroad company, making tests of rails of its standard section as rolled by three different mills, was surprised to find a variation of over 20 per cent. in stiffness among the rails of the different makers. In hardness, the variation was even greater. It was clear, in this case, that the difference in physical properties could not be ascribed to differences in section, but was due to difference in quality of metal. This has since been verified by comparisons of the wear of the rails in the track under practically the same tonnage. The following is the letter accompanying the foregoing tables, received from Mr. Delano: MR. P. H. DUDLEY, C.E. CHICAGO, December 5, 1889, Dear Sir: I have read with a good deal of interest the paper on rails which you read at the Ottawa meeting of the American Institute of Mining Engineers; and in view of the fact that your paper is having pretty wide circulation in the railroad jourVOL. XVIII.-16 nals, I venture to correct a statement which you make in regard to the stiffness of your New York Central 80-pound rail. Last March the Chicago, Burlington and Quincy had 1000 tons of each of two different sections of 85-pound rail rolled at South Chicago for experiment; and, after the order was completed, four samples, four feet long, were cut at random from rails on which the heat-number was plainly stamped (i.e., four of each section), and sent to the Watertown Arsenal for test. A partial report of the test, made in September, has been received, and I have tabulated it (see Table I.). This, and the accompanying smaller sheet (Table II.), will, I think, satisfy you that each of these 85-pound rails is stiffer than the New York Central 80pound section, although you will note, from the actual weights of the samples tested, that the average weight of each of the groups is appreciably less than 85 pounds per yard. The vertical moments of inertia for these two sections are respectively 28.61 for the "McClure" and 27.34 for the "Delano" section. How do these compare with your New York Central 80-pound section? I think you will be interested in seeing that the "McClure" section, although having a higher moment of inertia, does not, from the Watertown tests, prove to be an appreciably stiffer rail. This is what I worked for and what I expected. In regard to the chemical analysis given, I warn you not to build too much upon it, as it is simply the determination of the rolling-mill from the test-piece of the same heat-number as the rails tested. The Watertown people have promised to make analyses from the actual samples, and these should be of value. Yours truly, FRED. A. DELANO. CONCENTRATION BEFORE AMALGAMATION FOR LOW- BY C. W. GOODALE, BUTTE, MONTANA, AND WILLIAM A. AKERS, (Colorado Meeting, June, 1889.) THE treatment of silver-ores of too low a grade to justify either smelting or preliminary roasting, and yet not "free" enough to permit of raw amalgamation, has ever been a serious problem. As bearing upon it, the operations of the Combination Mining and Milling Company of Black Pine, Deer Lodge county, Montana, during the past year may not be without interest. It is not claimed that the process to be described is not susceptible of great improvement, nor is any claim of originality made for it; but its use is, as yet, not very general, and it seems to offer a means of profitably working the large class of partially-decomposed argentiferous ores which, by reason |