APPENDIX.
In speaking of the inclination of a bed, or of a fault, or any other plane, it is common in South Staffordshire to describe it by saying how many inches it deepens, or dips, in a yard. In many other districts this is done by saying how many feet or yards it dips or inclines in Geologists usually describe the dip by stating the number of degrees of the angle included between the plane of the bed, &c. and the plane of the horizon. It is often very useful in field surveying to know at once, roughly, how these things correspond, for which purpose I wrote out the following table for my own use, and add it here, as it may be useful to others:—
Nearest degree of dip, or each 1 in 100, answering to each inch in a yard.
| Inches in a yard. |
In 100. | Nearest degree. |
| 1 | 2.78 | 1½° |
| 2 | 5.56 | 3° |
| 3 | 8.34 | 5° |
| 4 | 10.12 | 6° |
| 5 | 13.90 | 8° |
| 6 | 16.68 | 10° |
| 7 | 19.46 | 11° |
| 8 | 92.24 | 12° |
| 9 | 25.02 | 14° |
| 10 | 27.80 | 16° |
| 11 | 30.50 | 17 |
| 12 | 33.36 | 19° |
| 13 | 36.14 | 20° |
| 14 | 39.92 | 21° |
| 15 | 41.70 | 23° |
| 16 | 44.48 | 24° |
| 17 | 47.26 | 25° |
| 18 | 50.04 | 26° |
| 19 | 52.82 | 28° |
| 20 | 55.60 | 29° |
| 21 | 58.38 | 30° |
| 22 | 61.16 | 32° |
| 23 | 63.94 | 33° |
| 24 | 66.71 | 34° |
| 25 | 69.50 | 35° |
| 26 | 72.28 | 36° |
| 27 | 75.06 | 37° |
| 28 | 77.84 | 38° |
| 29 | 80.62 | 39° |
| 30 | 83.40 | 40° |
| 31 | 86.18 | 40½° |
| 32 | 88.96 | 41° |
| 33 | 91.74 | 42° |
| 34 | 94.52 | 43° |
| 35 | 97.30 | 44° |
| 36 | 100.00 | 45° |
When the inclination is greater than 45° it is commonly sufficient to say that a bed, &c, dips two yards in a yard, three yards in a yard, &c., &c.
| Now | 1 in 1 = 45° | |
| 2 in 1 = 63° | nearly. | |
| 3 in 1 = 71° | nearly. | |
| 4 in 1 = 76° | nearly. | |
| &c. &c. |
Another way of describing the inclination of the beds is also not unfrequently used, namely by saying that they dip at the rate of one
