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TABLE OF FACTORS FOR COEFFICIENT.
151
The use of the coefficient , in Eq. XXI. et seq., considers the value of (Eq. ) evanescent, so that the prism at the moment of fracture has not risen through an appreciable angle, at the surface of fracture, and from the extremely small extensibility of mortar, stones, &c., this is sufficiently true to nature.
Table I.
Factors for the coefficient .
| Material | 1. Weight in pounds per cub. foot Sp. gr. |
2. Pounds per square inch Resistance to Pressure. |
3. Pounds per square inch Resistance to Tension. |
3. Authority for 1 and 2. |
|---|---|---|---|---|
| Limestone, Caserta, Naples | 170 | 8173 | 908 | Rondelet |
| Upper Limestone, Geneva | 169 | 4917 | 546 | Gauthey |
| Jurassic Limestone, Givry | 148 | 4232 | 496 | .. |
| Cretaceous Limestone (Compeigne) | 154 | 3007 | 334 | Rondelet |
| Lava, Hard Vesuvian | 166 | 8735 | 972 | .. |
| Lava, Soft Vesuvian | 107 | 2209 | 246 | .. |
| Lava, Piperno (Pozzuoli) | 162 | 8140 | 905 | .. |
| Travertino, Old Roman | 147 | 2297 | 255 | .. |
| Travertino, Pæstum | 141 | 3102 | 345 | .. |
| Peperino, Roman | 123 | 3135 | 347 | .. |
| Tufa, Old Roman | 78 | 797 | 89 | .. |
| Tufa, Naples | 82 | 718 | 80 | .. |
| Hard brick | 98 | 1851 | 206 | .. |
| Soft ill-burnt brick | 91 | 1200 | 133 | .. |
| Mortar, lime, and sand, unground | 102 | 423 | 47 | .. |
| Ditto, ditto, ground | 119 | 577 | 64 | .. |
| Mortar, Pozzolano, of Rome and Naples, unground | 92 | 503 | 56 | .. |
| Ditto, ditto, ground | 105 | 732 | 81 | .. |
| Mortar, Old Roman (Campagna) | 97 | 1047 | 105 | .. |
| Mortar, Old French (Bastile) | 94 | 753 | 84 | .. |
| Plaster of Paris (mean) | .. | 500 | 55 | Laisne |
It appears, from the few experiments that have been made, that the resistance of stones, &c., to tension, varies from th to th the resistance of the same material to
