Plimsoll, Samuel, “the sailor's friend,” born at Bristol; after experience in a Sheffield brewery entered business in London as a coal-dealer; interesting himself in the condition of the sailor's life in the mercantile marine, he directed public attention to many scandalous abuses practised by unscrupulous owners, the overloading, under-manning, and insufficient equipment of ships and sending unseaworthy vessels out to founder for the sake of insurance money; entering Parliament for Derby in 1868, he secured the passing of the Merchant Shipping Act in 1876 levelled against these abuses; his name has been given to the circle with horizontal line through the centre, now placed by the Board of Trade on the side of every vessel to indicate to what depth she may be loaded in salt water (1824‒1898).
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Pleydell, Mr. Paulus * Plinlimmon