On July 12th, 1804, he wrote to Sir Joseph Banks:—
"Since my imprisonment in this island I have written to you, Sir Joseph, several letters, and by several conveyances. Some of them must no doubt have been received. General de Caen still keeps me closely confined, but he has lately given me the greater part of my books and papers, and, therefore, I shall again be able to proceed in preparing the accounts of our discoveries.
"I have now been kept in prison seven months. The time passes drearily along, and I have yet to remain five months longer before any orders are likely to be received concerning me from the French Government; and then it is uncertain of what nature they may be, since it is not known what statement the General has made of my particular case; and probably the vessels carrying the despatches will be taken, and the letters thrown overboard, in which case it cannot be guessed how long I may be kept. My dependence, therefore, is on the Admiralty demanding me to be given up, by virtue of the French passport, in which, even here it is acknowledged, there has been no infringement on my part further than in intention, which intention has been misconstrued and misunderstood by a man violent against the name of an Englishman, and ignorant of what relates to voyages of discovery.
"This arbitrary man is now doing me the greatest injury without even making a plea for it. His own subjects (for he is a most despotic monarch), Frenchmen, who are acquainted with the circumstances,
condemn him for it; but the generality cannot believe that the commander of a voyage of discovery, whose labour is calculated for the good of all nations, should be kept a prisoner without something greatly wrong on his part; and, since no crime is charged against me, it is currently reported here that I have not the requisite papers to prove my identity.
"I hope, Sir Joseph, that, even from the charts which I have sent home, you will think we did as much as the lateness of the season with which we first came upon the coast, and the early rottenness of the Investigator could well allow; and I think our labours will not lose on a comparison with what was done by the Geographe and Naturaliste. No part of the unfortunate circumstances that have since occurred can, I believe, be attributed to my neglects or mistakes; and therefore I am not without hope that, when the Admiralty know I am suffering an unjust imprisonment, they will think me worthy to be put upon the post-captains' list. My age now exceeds the time at which we judge in the navy a man ought to have taken his station there who is to arrive at anything eminent. It would soften the dark shade with which my reflections in this confinement cannot but be overspread to know that I was promoted to the list where my rank would be progressive. It is to you only, Sir Joseph, that I can address upon this subject. I have had ample testimonies of your power and of the strength of your mind in resisting the malicious insinuations of those who are pleased to be my enemies, nor do I further doubt your willingness to give me assistance than that I fear you do not yet think me worthy of it; but I will be. If I do not prove myself worthy of
your patronage, Sir Joseph, let me be thrown out of the society of all good men. I have too much ambition to rest in the unnoticed middle order of mankind. Since neither birth nor fortune have favoured me, my actions shall speak to the world. In the regular service of the navy there are too many competitors for fame. I have therefore chosen a branch which, though less rewarded by rank and fortune, is yet little less in celebrity. In this the candidates are fewer, and in this, if adverse fortune does not oppose me, I will succeed; and although I cannot rival the immortalized name of Cook, yet if persevering industry, joined to what ability I may possess, can accomplish it, then will I secure the second place, if you, Sir Joseph, as my guardian genius, will but conduct me into the place of probation.
"But this is visionary, for I am so fast in prison that I cannot get forth. The thought is bitterness. When I recollect where and what I am, and compare it with where and how I ought to be employed, it is misery; but when to this the recollection of my family and the present derangement of their affairs from my absence are added, then it is that the bonds enter deep into my soul."
While his money lasted, Flinders spent it in buying fruit and vegetables for his imprisoned crew; when cash ran out, he drew a bill on the Admiralty. The interpreter who undertook to get it cashed was nearly killed by the soldiers for carrying, as they thought, a private letter.
Eventually the Danish consul cashed this bill for the Englishmen, and gave them full value for it, which, considering the state of the times, shows that he was a truly good man.
The Cumberland was taken to the head of the harbour and converted into a hulk, and a document was brought to Flinders to sign in which—in truly French fashion—he was asked to accuse himself of being a spy. He promptly refused the request, which was again and again made, and he always scorned to comply. While his papers were being overhauled, Flinders managed to secure some of them, and among other things the signal-book, which he destroyed.
De Caen's report to his Government shows the view he took of these proceedings. In it he says:—
"Commander Flinders, formerly captain of the corvette Investigator, sent by the English Government for work of discovery in the Pacific Ocean, has altered absolutely the mission for which he had obtained from the French Government the passport signed by the Minister for Marine. In such passport he is certainly not authorized to land at the Isle of France to study the prevailing winds, the port, or the state of the colony, and by this conduct he has violated the neutrality under which he had been permitted to land. It is necessary therefore to order M. Monistrol, chief of the battalion, to board the schooner Cumberland
in the presence of Captain Flinders, break the seals put on his room, and gather certain papers which may be required to complete proofs already in existence of the charge against him. The room is then to be resealed, and Captain Flinders to be taken back to the house where he has already been confined as prisoner. The crew of the schooner are meanwhile to be kept prisoners on the prison-ship."