John Charles Melliss (1835 to 1911) was a surveyor on the British island of St. Helena. He pursued his interest in the area, where he had been born and raised while his father was posted there, by writing the book: St. Helena: A Physical, Historical, and Topographical Description of the Island, Including Its Geology, Fauna, Flora, and Meteorology (1875). His wife did the illustrations. There are no cats in the illustrations, but they do figure in the text.
Mellis writes first:
There is perhaps no other spot in the whole world which geographically presents so great an interest to the naturalist as St. Helena. A small Island, distinctly of volcanic origin, bearing no trace , whatever of any continental land having existed nearer to it than a thousand miles or more, and yet possessing plants and insects that , have not been found elsewhere in the world, at once suggests the... inquiry, How did these things get there?
In pursuit of this he has a paragraph on cats.
F. domestica, Linn.—The domestic cat is as plentiful as in other parts of the world; it also assumes wild habits, existing abundantly on the rocky outskirts of the Island in holes and caves, where, amongst the eggs and young of partridges and other birds, it commits such havoc that sportsmen never lose an opportunity of killing it. Cats abound at a place called Cat Hole, where they live chiefly upon pigeons. There is no record of their introduction.
There is no record of their introduction, but he does not also mention, there is no mystery about it either. St. Helena was a major stopping point on long sea voyages since 1502. The mystery is why there is no mention of cats consuming the many mice and rats also inhabiting the island. One does have to wonder if Melliss is part of that party which villifies cat predation on birds and ignores the part they play in balancing wildlife.
No mystery either on how the most famous inhabitant got there: Napoleon spent the last few years of his life in exile there. Napoleon Bonoparte arrived on St. Helena on October 15, 1815. He despised cats, and who knows, perhaps they learned to avoid settled places to avoid him. Leaving the human habitat to rats.