110 



RIO NEGRO. 



worn and weather-beaten sides, that have so 



been invested with 



all the terrors that can beset sailors. Here we first encountered the 

 long swell of the Pacific, but there was scarcely a ripple on its surface. 

 Although the landscape was covered with snow, the lowest tempera- 

 ture we had yet experienced was 40° Fahrenheit. 



The Porpoise, just before night, made signal that she wished to 

 speak us, and sent on board a tub filled with a large medusa, for 

 examination by the naturalists. Its dimensions were nine feet in 

 circumference ; the brachia seven feet long. It proved to be the 

 Acalepha medusa pelagia of Cuvier. 



On the 17th of February, we had 

 an extraordinary degree of mirage 

 or refraction of the Peacock, exhi- 

 biting three images, two of which 

 were upright and one inverted. 

 They were all extremely well 

 defined. The temperature on deck 

 was 54°, that at masthead 62°. A 

 vessel that was not in sight from the 

 Vincennes' decks, became visible, 

 as in the annexed sketch ; the land 



at the same time was much distorted, both vertically and horizontally. 



Barometer stood at 29-62 in. ; hygrometer 10°. 



On board the Peacock, similar appear- 

 ances were observed of the Vincennes and 

 Porpoise. There was, however, a greater 

 difference between the masthead tempe- 



'wwwg!*fy#*>» 



mmmm ra x UT Q anc [ that on deck, the thermometer 

 standing at 62° at masthead, while on 

 deck it was but 50°, being a difference of 

 12°, that on board the Vincennes differed 

 only 8°. The sketches were taken about 

 the same time : that made of the Peacock 

 on board the Vincennes it will be seen was 

 the most elongated. 



We continued beating into the passage 

 between the Hermit Islands and False Cape Horn, and found great 



VINCENNES. 



