356 NOTES OF A NATURALIST. 



extinction owing to competition from species intro- 

 duced by settlers, it may be hoped that the explora- 

 tion of this small but remarkable island will before 

 long be undertaken by a competent naturalist. For 

 that purpose it would be, in the first place, necessary 

 to obtain the permission of the Brazilian Government, 

 and to secure the means of existence during a stay of 

 ten or twelve days on the island. The most effectual 

 means would be through direct personal application 

 to the emperor, who is well known to take a lively 

 interest in all branches of natural science. 



With the thermometer standing about 82°, the 

 passengers naturally preferred the upper deck to the 

 close air of the saloon, and were resting in their ship- 

 chairs between nine and ten p.m., when suddenly there 

 came an outburst of coughing and sneezing, followed 

 by demands for muffling of every kind. There was 

 no sensible movement in the air, but I found that the 

 thermometer had fallen to 79'' Fahr., and there was a 

 feeling of chilliness which was not easily explained 

 by that slight fall of temperature. 



The mystery was explained on consulting the chief 

 officer, who throughout the voyage paid much atten- 

 tion to the temperature of the sea. Since leaving 

 Pernambuco, the thermometer in buckets brought up 

 from the surface had varied only between 82° and 83°. 

 On this evening we had abruptly encountered a 

 relatively cold current, with a temperature somewhat 

 below ^6°, and the effect of being surrounded by a 

 body of cool water when the skin was in the con- 

 dition usual in the tropics was felt by nearly all the 

 passengers. 



