ON ITS EXTEEIOK. VOLCANOES. 265 



ing the Papagayos for more than two entire days (9 

 11 March 1803) in all their strength and peculiarity, 

 but a little more to the south, viz. in less than 9 13' N. 

 The waves were higher than any that I had ever seen ; 

 and the constant visibility of the sun in the clearest 

 blue sky made it possible to measure their height by 

 altitudes of the sun taken on the crest of the wave, and 

 in the trough of the sea, by a method which had not 

 then been previously tried. All Spanish, English ( 389 ), 

 and American navigators ascribe these storms in the 

 Pacific to the north-east trade in the Atlantic. 



In a new work ( 39 ) prepared with much pains, partly 

 from already published, and partly from manuscript 

 materials, on the " Reihen-Vulkane " of Central Ame- 

 rica, I have enumerated twenty-nine volcanoes whose 

 former, or present, greater or less degree of activity 

 may be safely affirmed. The natives give a number 

 more than one third greater, adducing, in so doing, 

 several ancient basins of eruption which may have been 

 only lateral eruptions on the declivity of one and the 

 same volcano. Among the isolated conical and bell- 

 shaped mountains which are there called volcanoes, 

 there may indeed be many which consist of trachyte 

 or dolerite, but which have always remained "un- 

 opened" and have never shown any igneous activity 

 since their upheaval. Eighteen may now be regarded 

 as " burning ; " of those which hav sent forth flames, 

 scoriae, and lava in the present century (1825, 1835, 

 1848, and 1850), seven; and in the latter part of the 

 last century (1775 and 1799), two. ( 391 ) The absence 

 of streams of lava in the great volcanoes of Quito has in 

 modern times repeatedly given occasion to statements 



