cosmos. 



from the seven fragments of trachyte from the same volcano 

 which are contained in my cabinet. It recalls to mind the 

 formation of green slate (schistose augitic-porphyry) which we 



that of Rammelsberg in May, 1854, we shall find that the result 

 obtained by Deville occupies exactly the mean between those of Abich 

 and Rammelsberg. Thus : 



Cliimborazo-rock. 



Silicic acid 65.09 Abich (spec. grav. 2.685) 

 63.19 Deville 

 62.66 do. 

 59.12 Rammelsberg (spec. grav. 2.806)" 



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

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

 named M. Jules Re"my, having succeeded, on the 3rd 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 Haway 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 say, at a height differing by only 40 feet from that 

 given by my trigonometrical measurement at Riobamba Nuevo in the 

 elevated plain of Tapia, in June, 1803, as the height of the summit 

 of Chimborazo, namely, 21,426 feet. This correspondence of a trigo- 

 nometrical measurement of the summit with one founded on the 

 boiling point is the more surprising, as my trigonometrical measure- 

 ment, like all measurements of mountains in the Cordilleras, involves 

 a barometrical portion, and from the want of corresponding observa- 

 tions on the shore of the South Sea, my barometrical determination of 

 the height of the Llano de Tapia, 9484 feet, cannct possess all the 

 exactness that could be desired. (For the details of my trigonometrical 

 measurement, see my Recueil d' Observations Aslron., vol. i, pp. 72 aud 

 74). Professor Poggendorff kindly undertook to ascertain what result 

 under the most probable hypotheses a rational mode of calculation 

 would produce. He found, reckoning under both hypotheses, that 

 the prevailing temperature of the atmosphere at the sea being 81 C .5 F., 

 or 79.7 F., and the barometer marking 29.922 inches, with the ther- 

 mometer at the freezing point, the following result is obtained by 

 Regnault's table : the boiling point at the summit at 171.5 F. answers 

 to 12,677 inches of the barometer at 32 temperature ; the tempera- 

 ture of the air may therefore be taken at 35.3 F. = 34.7 F. 

 According to these data, Oltmanns' tables give, for the height ascended, 

 under the first hypothesis (81.5), = 7328'".2, or 24,043 feet, and under 

 the second (79.7), = 7314 m .5, or 23,998 English feet, showing an 



