APPENDIX.
COMPRESSIVE STRENGTH OF ANTHRACITE COAL.“
Owing to the general lack of knowledge among the engineers of the anthracite coal field as to the compressive strength of anthracite coal, and in view of the very important matters relating to the economy of mining of anthracite, which depend directly upon this subject, the Scranton Engineers’ Club, in July, 1900, appointed a committee to make a general investigation of the compressive strength of anthracite coal, having reference particularly to the northern anthracite field. This table contains the results of the efforts of that committee, in a condensed form. The committee sent circular letters to the various anthracite operators in the northern field, requesting them to contribute to the efforts of the committee by sending samples in triplicate to be tested. These samples were requested in three sizes, viz.:
Two inches square on the base by 1 inch high, indicated in the table as “1.”
Two inches square on the base by 2 inches high, indicated in the table as “2.”
Two inches square on the base by 4 inches high, indicated in the table as “4.”
These samples were requested to be prepared in each case with the base parallel to the bedding plane of the coal seam, and the height at right angles thereto.
Generous responses to this circular letter were received in the form of some 425 samples for testing, a few of which were defective and not tested. These samples were then divided and sent to the following colleges for testing, the professors named very kindly offering to assist the committee by making the tests:
To Prof. R. C. Carpenter, of the department of experimental engineering, Sibley College, Cornell University, Ithaca, N. Y., 133 samples.
To Prof. Mansfield Merriman, professor of civil engineering, Lehigh University, South Bethlehem, Pa., 177 samples.
To Prof. Louis E. Reber, dean of the school of engineering, Pennsylvania State College, State College, Pa., 113 samples.
After these samples were tested and the results returned to the committee, they were tabulated in a detailed way, forming an immense table, of which this accompanying table is a condensation. The following description of it is given, that the reader may the better understand it:
1.	The collieries from which the tests were taken are arranged in the column on the left, in order, according to the location of the collieries, beginning at the northerly end of the region near Forest City and ending with the southermost collieries ־from which tests were received, at Williamstown and Lykens, in the southern coal field.
2.	The coal beds are arranged at the top of the table in the order of their occurrence in tl!e measures, the highest beds being at the left, and the lowest beds at the right. Where local names for the beds differ from the general names, their local names are inserted in the body of the table.
3.	The tests are arranged in vertical double columns under the several coal seams, and each test is placed in the column under its respective coal bed and in the horizontal line opposite the colliery from which it was taken.
4.	Results given in this table are in pounds avoirdupois per square inch of horizontal area.
77
a Printed by permission.