His revenue chiefly arises from properties confiscated by his own arbitrary judgments, and from tithes in kind upon all articles of produce, the right to levy which is yearly sold by the government to the best bidder in each department; the contractors generally underlet them to others, and they are in consequence rigorously exacted.[56] The principal expenditure is in the maintenance of a large militia force, in which every person capable of bearing arms is enrolled and called upon to do duty in turn. Francia is of course commander-in-chief of the army, as he is the head of the church, the law, and every other branch of the administration. When I arrived in the River Plate, in 1824, I found that many British subjects had been for several years detained in Paraguay by this monster against their will; and it became my duty in consequence to make a representation to him upon the subject, and to apply for their liberation. This I was fortunate enough to obtain, together with the release of many other Europeans, whom, that it should not appear that he was granting any special favour to the English, he allowed at the same time to depart; amongst the rest Messrs. Rengger and Longchamps, two Swiss gentlemen, who have since published a highly-interesting account of their detention, and of the state of the country.[57] He made, however, an exception of M. Bompland, the well-known companion of Baron Humboldt, whom he had some years before caused to be seized and carried off by an armed force, sent across the Paranã for the purpose, whilst engaged in his own inoffensive pursuits in the province of Corrientes. As there was no accredited French agent at Buenos Ayres at the time, I took upon myself to make another application to Francia, specially in favour of an individual in whose fate I could justly say that all the scientific world was interested; and I further offered to guarantee the fulfilment of any promise M. Bompland might himself choose to make, in case of his liberation, to return at once to Europe. I wrote in the same sense to M. Bompland, and enclosed my letter, open, to the Dictator, to forward to its destination if he approved of it. But, instead of doing so, he returned it to me, with a rude intimation that that must close our correspondence.[58] I believe he was disappointed at finding that I could not concur with him in his notion of opening a direct trade between Great Britain and Paraguay, on which it appeared he had long set his heart, the rather as he expected thereby to be able to show to his own subjects his independence of his neighbours, and especially of the Buenos Ayreans.