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| Height in feet | Distance in Miles | Height in feet | Distance in Miles |
| .582* | 1 | 30 | 7.25 |
| 1 | 1.31 | 35 | 7.83 |
| 2 | 1.87 | 40 | 8.37 |
| 3 | 2.29 | 45 | 8.87 |
| 4 | 2.63 | 50 | 9.35 |
| 5 | 2.96 | 60 | 10.25 |
| 6 | 3.24 | 70 | 11.07 |
| 7 | 3.49 | 80 | 11.83 |
| 8 | 3.73 | 90 | 12.55 |
| 9 | 3.96 | 100 | 13.23 |
| 10 | 4.18 | 150 | 16.20 |
| 11 | 4.39 | 200 | 18.72 |
| 12 | 4.58 | 300 | 22.91 |
| 13 | 4.77 | 400 | 26.46 |
| 14 | 4.95 | 500 | 29.58 |
| 15 | 5.12 | 1000 | 32.41 |
| 16 | 5.29 | 2000 | 59.20 |
| 17 | 5.45 | 3000 | 72.50 |
| 18 | 5.61 | 4000 | 83.70 |
| 19 | 5.77 | 5000 | 93.50 |
| 20 | 5.92 | 1 Mile | 96.10 |
| 25 | 6.61 |
* 6.99 inches.
The difference in two levels is as the square of the distance. Thus, if the height is required for 2 miles, 1²: 2² :: 6.99 : 27.96 inches; and if for 100 miles, 1² : 100² : : 6.99 : 1.103 + miles.
For Geographical miles, the distance for one mile is 7.962 inches.
Example.-- If a man at the foretop-gallant mast-head of a ship, 100 feet from the water, see another and a large ship (hull to), how far are the ships apart?
A large ship's bulwarks are, say 20 feet from the water.
| Then, by the table, 100 feet | = | 13.23 | |
| , 20 feet | = | 5.92 | |
| Distance | = | 19.15 | miles |
Note. -- 1/13 should be added for horizontal refraction.
From: Engineers' and Mechanics' Pocket-Book (5th edition) by Chas.H.Haswell, Engineer in Chief, U.S.Navy; New York: Harper & Brothers (1848), pages 21-22
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