In reponse to missbaxter's cross-over ephemera.
A letter, addressed to Dr Stephen Maturin, Surgeon, of His Majesty's Frigate Surprise, wrapped in oiled silk and deposited with the Resident at Valetta, Malta, to await that ship's imminent arrival.
County of Middlesex
Sir: This letter will reach you, should it ever reach you, by courtesy of that same John Smith whom you encountered in such extraordinary circumstances. I have sent it to him with a covering note, asking him to leave it at the Admiralty in a reasonably appropriate year and with instructions to ensure that it is forwarded to you through a suitable port. It is possible that on seeing your name, he will recall your company and your conversations — he certainly has fond memories of your curiosity about natural philosophy; and that he will act on the recollection, rejoin you at some point and explain himself. However, Mr Smith — who is usually simply called "Doctor", however eccentric that may sound — leads a disorderly life, or more exactly, a life out of order — and he may be unavailable, or might arrive at the wrong time. So I will attempt a brief explanation of the events, while respecting the reticence that the Doctor generally prefers. Please forgive any awkwardness in my communication. We speak dialects of English separated by distance, and it may be easier if I try to approximate your language.
You should know that Mr Smith is not a terrestrial being, although he is in no way supernatural: no nightmare invention of the Germanic imagination, but a living creature whose anatomy, including the brain, overlaps on the human without precisely duplicating it. He has two hearts, and a breathing system more resilient than ours; he can in limited circumstances regrow amputated limbs, or regrow his body from those limbs; and he is immortal, or rather he has sequential mortality, metamorphosing his corporeal form, though not his essential selfhood, on death. (I have known him well in three guises; he always retained the same soul and memories.) He comes from a world elsewhere in the firmament, its sun one of the distant stars in our heavens, and besides having the technical command to travel over celestial distances, he can also move in time, both backwards and forwards. All that seems a progression to us, within the narrow parameters of our understanding, is in flux to him. The knowledge that this bestows upon him isolates him, and so his character resembles certain of Herr Goethe's protagonists: he is gifted, careless of privilege, rank and forms of society, rebellious, secretive, and sometimes, alas, arrogant. Besides, he is the last of his vanished race. He is also Harlequin tumbled from the moon in the French commedia, an old child full of amazement and delight. The blue chest is his craft, its small size an illusion of perspective projected on to human optical nerves (a scientific Phantasmagoria); as with its captain, its internal dimensions and complexities far surpass its external show. The Doctor claims a protective attachment to the Earth, although he is not always conveniently adjacent when creatures from other worlds threaten its safety. The seamonster you described — with its Surrey Theatre aspects of appearance — was one such, an antediluvian relic of an ancient chaos; it seems to have sought sanctuary in deep waters. I do not know if the Doctor was actively pursuing it or whether he wanted to ship aboard the Surprise, and the behemoth or leviathan — I like those words — surged up by coincidence. It happens. It has happened more often than I have time to recount.
Although I should not in any way infringe the privileges of our mutual acquaintanceship with the Doctor, can I be permitted to encourage any notion you might consider of publishing your observations of the natural world, particularly those regarding physical changes within species, related to unusual or remote habitats, and the evolution of fossil forms in geological strata? These matters of the past may be important to the construction of the future, far more so even than the war upon the oceans.
Might I send my profound respects to Captain Aubrey, to all the Surprisers, and to yourself.
Sarah Jane Smith