Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.2): between the years 1826 and 1836 : describing their examination of the southern shores of South America, and the Beagles's circumnavigation of the globe

1830. ' LOSS OF THE THETIS. 71 Presuming that the Thetis was carried out of her supposed position, by the former cause, about twenty-four miles ; surely rather more than a mile an hour is no surprising current during nineteen hours. But if a stream of tide also affected her, in that time she would have had one whole tide either in her favour or against her. There was no reason to suspect the existence of much cur- rent near Cape Frio, when the Thetis was lost, except on such general grounds as those just mentioned, because no pilot, as far as I know, was aware of such a fact. With strong southerly winds ships of large size do not often leave Rio de Janeiro coasting vessels never — therefore few persons could have expe- rienced its effect when sailing from the port; and when approaching Rio in similar weather, vessels sail before a fair wind, steer by sight of the land, and take little notice of the log : besides which, they then employ but three or four hours in passing through that space of sea where the Thetis was detained nineteen. In all probability, such a current as that which drove the Thetis on the rocks is only to be found during southerly winds, and in the summer season of that climate, when the general set of the current is along the coast, towards the south and west. If' a man of war is accidentally lost, a degree of asto- nishment is expressed at the unexpected fate of a fine ship, well found, well manned, and well officered ; and blame is imputed to some one : but before admitting a hastily-formed opinion as fact, much inquiry is necessary. As in the case of the Thetis, an English man-of-war may incur risk in con- sequence of a praiseworthy zeal to avoid delaying in port, as a merchant-ship would probably be obliged to do, from her being unable to beat out against an adverse wind, and, like that frigate, may be the first to prove the existence of an unsuspected danger. Those who never run any risk ; who sail only when the wind is fair ; who heave to when approaching land, though perhaps a day's sail distant ; and who even delay tlie performance of urgent duties until they can be done easily and quite safely ; are.