LoO SUPPOSED PIBATICAL YESSEL. 



On the morning of the 1st of December, the sea slowly 

 calmed, and the breeze became steady from N.E. On the 

 2nd December we descried Cape Beata, in a spot where 

 we had long observed the clouds gathered together. Accord- 

 ing to the observations of Acherner, which I obtained 

 in the night, we were sixty-four miles distant. During the 

 night there was a very curious optical phenomenon, which 

 I shall not undertake to account for. At half-past midnight 

 the wind blew feebly from the east ; the thermometer rose 

 to 23*2, the whalebone hygrometer was at 57. I had 

 remained upon the deck to observe the culmination of some 

 stars. The full-moon was high in the heavens. Suddenly, 

 in the direction of the moon, 45 before its passage over 

 the meridian, a great arch was formed tinged with the pris- 

 matic colours, though not of a bright hue. The arch 

 appeared higher than the moon; this iris-band was near 

 2 broad, and its summit seemed to rise nearly from 80 

 to 85 above the horizon of the sea. The sky was singularly 

 pure ; there was no appearance of rain ; and what struck 

 me most was, that this phenomenon, which perfectly resem- 

 bled a lunar rainbow, was not in the direction opposite to 

 the moon. The arch remained stationary, or at least 

 appeared to do so, during eight or ten minutes ; and at 

 the moment when I tried if it were possible to see it by 

 reflection in the mirror of the sextant, it began to more 

 and descend, crossing successively the Moon and Jupiter. 

 It was 12 b 54 m (mean time) when the summit of the 

 arch sank below the horizon. This movement of an arch, 

 coloured like the rainbow, filled with astonishment the 

 sailors who were on watch on the deck. They alleged, 

 as they do on the appearance of every extraordinary me- 

 teor, that it denoted wind. M. Arago examined the sketch 

 of this arch in my journal ; and he is of opinion that the 

 image of the moon reflected in the waters could not have 

 given a halo of such great dimensions. The rapidity of the 

 movement is no small obstacle in the way of explanation 

 of a phenomenon well worthy of attention. 



On the 3rd of December we felt some uneasiness on account 

 of the proximity of a small vessel supposed to be a pirate, 

 but which, as it drew near, we recognized to be the Balan- 

 dra del Frayle, (the sloop of the Monk). I was at a loss to 



