432 COSMOS. 



ruins of Old Riobamba. In the Tunguragua, besides the 



Names of the 

 Volcanoes. 



Structure and Color of the 

 Mass. ** 



Silicic Acid in 

 the whole Mass. 



Chimborazo 



Antisana 



Cotopaxi 



Pichincha 

 Purace 



Guadaloupe 

 Bourbon 



semi-vitrified, brownish gray 



semi-vitreous and black 



crystalline, compact, gray.... 

 gray-black 



vitreous and brownish 



granulated 



bjack, vitreous 



nearly bottle-green .... 



65-09 Abich 

 63-19 Deville 

 62-66 Deville 

 64-26 Abich 

 62-23 Abich 

 69-28 Abich 

 63-98 Abich 

 67-07 Abich 

 68-80 Deville 



58-26 

 58-26 



55-40 



gray, granulated, and cellular 

 crystalline, gray, porous 



57-95 Deville 

 50-90 Deville 



"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/ragments of feldspar similar to those 

 Avhich 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 Hose, " we add to this remarkable synopsis of 

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

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

 obtained by Deville occupies exactly the mean between those of Abich 

 and Kammelsberg. Thus : 



Clihiiborazo Rock. 



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



63-19 Deville 



62-66 do. 



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



In ih^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 Remy, 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 hypsom'etrical 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 



