An Account of the Character and Distribution of Maryland Building Stones; Together with a History of the Quarrying Industry

An Account of the Character and Distribution of Maryland Building Stones; Together with a History of the Quarrying Industry

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1898 edition. Excerpt: ...figures obtained from these different experiments on material from the same localities, and concluded that the variations must be explained either on one or the other of three suppositions; 1st, that the strength of the different specimens of the rock is thus variable, and that consequently no certain reliance can be placed on its powers of resistance; 2nd, that the experimenting or the machines with vhich the testings were conducted were faulty', or 3rd, that the resistance to crushing for a unit of area at the base, increases in some ratio with the number of units composing that area, that is, with the actual area of the base.' Johnson favored the third explanation, but the second seems to be as much in accord with later results. Since these early experiments were conducted, great advances have been made in the manner, uniformity and accuracy of the testings, so that results obtained now are not to be compared or averaged with those of earlier workers. The conditions under which the testings are carried on cause the results to vary within wide limits. The experiments conducted in the preparation of the present report were made with the greatest care and under the same conditions. All of the specimens were two inch cubes, placed between two quarter-inch thick soft pine blocks in exactly the same position, and the testing machine was run at the same speed in each case. Almost all of the blocks were cut from the average stock of a well-known stone-yard. Some were crushed just as they were received from the stone cutter, while others were crushed after they had been submitted to absorption, freezing and thawing tests. The results are as follows: . Crack. Break. 1. Cockeysville marble, unoriented without immersion, _ _ _ _, 57,740...show more

Product details

  • Paperback | 44 pages
  • 189 x 246 x 2mm | 95g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236818024
  • 9781236818027