AND PORTO SANTO. 49 



feeling some confidence in the result of my own observations, 

 although I observe by Captain Sabine's recent article in the Journal 

 of Science, that he'made it only 543S feet above the level of the 

 sea. Baron de Humboldt found the decrease of caloric at Tene- 

 rifFe, to be ninety-four toises for every degree of the centigrade 

 thermometer ; De Saussure, at Etna, ninety-one toises ; my obser- 

 vation gives eighty-nine toises, or five less than De Humboldt's ; 

 but Captain Sabine's gives only sixty toises for a centigrade degree, 

 or thirty-four less than De Humboldt ^ : this would seem to be a 

 further evidence in favour of the greater height of Kuivo, 



My next route was northwards to St. Vicente, which is about 

 twenty-five miles from Funchal, passing first along the brink of 

 the Coural or ravine, into which I had already descended, and then 

 on the very margin of a second, scarcely less bold, but less awful, 

 and much more luxuriant in vegetation. Woods of laurels line 

 the declivities along which the road is formed, and wooden bridge, 

 are thrown over the frequent torrents, near one of which the 

 basalt rock assumes the form and detail of a ruined castle so 

 happily, that it seems to defy the pencil to draw any thing else. 

 Beyond this, the distant sheets of broom look like sloping lawns, 

 occasionally diversified by the mellow brown of decaying ferns. 

 Here I first saw the beautiful fern asplenium palmatum. The 

 fihces form by far the most interesting family in Madeira, verifying 

 Baron de Humboldt's remark, that their maximum may be found 

 in the mountainous parts of small islands : it will be seen that 

 several are new% and all were highly luxuriant, yet I was disap- 



^ Temp, at Ruivo, 36° F., at Funchal, eight feet above the sea, 61.5. Journal of 

 Science, xxix. p. 82. 



" For a more particular list of the ferns I must refer my readers to the Appendix, 

 No. 1. The P. rulgare therein mentioned, I think must be a variety of that species 

 found at Tenewffe by M. Leschenault. The aspidium palmatum I believe to be rare ; 



H 



