Page:History of merchant shipping and ancient commerce (Volume 2).djvu/587

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                              BIRKENHEAD BASINS.
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   | | | Height | | |
   | Birkenhead Basins. | Width of | of Piers | Water | Lineal |
   | | Entrance. | above | Area. | Quayage. |
   | | | Datum. | | |
   +———————————+—————-+—————+——————+——————+
   | | Ft. In. | Ft. In. | Acres Yds. | Miles Yds. |
   | Low-Water Basin | 300 0 | 26 0 | 14 0 | 0 1360 |
   | North Basin | 500 0 | 31 0 | 4 2843 | 0 689 |
   | +——————+——————+
   | Total Water Area and Quay Space of the } | 18 2843 | 1 269 |
   | Birkenhead Basins } | | |
   | Do. do. do. Docks | 147 722 | 8 609 |
   | +——————+——————+
   | Total | 165 3565 | 9 878 |
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         TOTAL AREA OF THE LIVERPOOL AND BIRKENHEAD DOCKS AND BASINS.
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   | | Acres Yds. | Miles Yds. |
   | Total Water Area and Quay Space of the } | | |
   | Liverpool Docks and Basins } | 259 587 | 18 916 |
   | | | |
   | Total Water Area and Quay Space of the } | | |
   | Birkenhead Docks and Basins } | 165 3565 | 9 878 |
   | | | |
   | Total | 424 4152 | 28 34 |
===+=============================================+============+============+==
                       LEVELS OF TIDES AT LIVERPOOL.

   Derived from the Record of the Self-Registering Gauge at George's Pier
  deduced from Ten Years' Observations, 1854 to 1863. Datum Old Dock Sill.
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                                                      | Ft. In. |
An extraordinary High Tide, as marked on the } | 25 0 | { Above
    Leasowe Lighthouse } | | { Datum.
An extraordinary High Tide, 20 January, 1863 | 23 9 | "
Average High-Water Mark of Equinoctial Spring Tides. | 21 1 | "
Average High Water of Spring Tides, including | |
    Equinoctial Tides | 19 0-1/2 | "
Average High-Water Mark of Ordinary Spring Tides, | |
    excluding the Equinoctial Tides | 18 10 | "
Mean High-Water Level | 15 6 | "
Highest High-Water Mark of Neap Tides | 14 8 | "
Average High-Water Mark of Ordinary Neap Tides | 11 7 | "
Lowest High-Water Mark of Neap Tides | 8 7 | "
Mean Tide Level (Ordnance Datum) | 5 0 | "
Highest Low-Water Mark of Neap Tides | 4 1 | "
Average Low-Water Mark of Ordinary Neap Tides | 1 5 | { Below
                                                      | | { Datum.
Lowest Low-Water Mark of Neap Tides | 3 10 | "
Mean Low-Water Level | 5 6-1/2 | "
Average Low-Water Mark of Ordinary Spring Tides, | |
    exclusive of Equinoctial Tides | 8 8 | "
Average Low-Water Mark of Spring Tides, inclusive of | |
    Equinoctial Tides | 8 10 | "
Lowest Low-Water Mark of Equinoctial Spring Tides | 10 4 | "
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