432 



COSxMOS. 



ruins of Old Kiobamba. In the Tunguragua, besides the 



Names of the 

 Volcanoes. 



Chimborazo 



Antisana 



Cotopaxi 



Eichincha 

 Purace 



Guadaloupe 

 Bourbon 



Structure and Color of the 

 Mass. 



semi-vitrified, brownish gray 



semi-vitreous and black 



crystalline, compact, gray.... 

 gray-black 



j vitreous and brownish 

 I granulated 



black, vitreous 



nearly bottle-green 



gray, granulated, and cellular 

 crystalline, gray, porous 



Silicic Acid in 

 the whole Mass. 



65-09 

 63-19 

 62-66 

 61-26 

 62-23 

 69-28 

 63-98 

 67-07 

 68-80 



Abich 



Deville 



Deville 



Abich 



Abich 



Abich 



Abich 



Abich 



Deville 



57-95 Deville 

 50-90 Deville 



m T i— ' O 

 *^ r-i O 

 « 05 "3 



CD £ w 



58-26 



58-26 



55-40 



54:25 



49-06 



" These differences, as far as regards the relative richness in silica 

 of the ground mass (and the feldspar)," continues Charles Deville, 

 " will appear still more striking when it is considered that, in analyz- 

 ing a rock en masse, there are included in the analysis, along with the 

 basis properly so called, not only fragments of feldspar similar to those 

 which have been extracted, but even such minerals as amphibole, pyr- 

 oxene, and especially peridote, which are less rich in silica than the 

 feldspar. This excess of silica manifests itself sometimes by the pres- 

 ence of isolated grains of quartz, which M. Abich has detected in the 

 trachytes of the Drachenfels (Siebengebirge, near Bonn), and which I 

 have myself observed with some surprise in the trachytic dolerite of 

 Guadaloupe." 



" If," observes Gustav Eose, " we add to this remarkable synopsis of 

 the silicic acid contained in Chimborazo the result of the latest anal- 

 ysis, that of Bammelsberg in May, 1854, we shall find that the result 

 obtained by Deville occupies exactly the mean between those of Abich 

 and Kammelsberg. Thus : 



Chimborazo Rock. 



Silicic acid 65-09 Abich (specific gravity, 2*685) 



63-19 Deville 



62-66 do. 



59-12 Rammelsberg (specific gravity, 2-806)." 



In the Echo du Pacifique, of the 5th of January, 1857, published at 

 San Francisco, in California, an account is given of a French travel- 

 er, named M. Jules Bemy, having succeeded, on the 3d of November, 

 1856, in company with an Englishman, Mr. Brencklay, in reaching the 

 summit of Chimborazo, which was, "however, enveloped in a cloud, so 

 that we ascended without perceiving it." He observed, it is stated, the 

 boiling point of water at 171°-5 F., with the temperature of the air at 

 31°9 F. On calculating, upon these data, the height he had attained, 

 by a hypsometrical rule tested by him in repeated journeys in the Ha- 

 way Archipelago, he was astonished at the result brought out. He 

 found, in fact, that he was at an elevation of 21,467 feet; that is to 



