therefore, if the time of high water at full and change (new moon) is known, and the age of the moon, the time of high water for any particular day can be roughly calculated, about twenty-five minutes being allowed for each tide.
(the time of high water at full and change; is known; ) (the age of the moon; can be roughly calculated; ) (about twenty-five minutes; being allowed; )
the time of high water at full and change the age of the moon about twenty-five minutes
is known can be roughly calculated being allowed