310 COSMOS. 



the highlands of Quito and Cuenga in the spring of 1743. 

 Fourteen years afterward^vhen he returned from an ascent 

 of Vesuvius (4th of June, 1755), in which he accompanied 

 the. sister of Frederick the Great, the Margravine of Bai- 

 reuth, he had the opportunity of expressing himself warmly, 

 in a meeting of the French Academy, upon the want of true 

 lava streams (laves coulees par torrens de matieres liquejiees) 

 from tlie volcanoes of Quito. The Journal cTun Voyage en 

 Italie^ which was read at the meeting of the 20th of April, 

 1757, only appeared in 1762 in the Alemoires of the Acade- 

 my of Paris, and is of some geognostic iraDortance in the his- 

 tory of the recognition of old extinct vmcanoes in France, 

 because in this journal, La Condamine, with his peculiar 

 acuteness, and without knowing of the certainly earlier ob- 

 servations of Guettard,* expresses himself very decidedly 

 upon the existence of ancient crater lakes and extinct volca- 



kind of blackish crystal, commonly called Piedra de Gallinago in Peru 

 (obsidian), of which I have brought home several fragments, and of 

 which a polished lens of seven or eight inches in diameter may be seen 

 in the cabinet of the Jai-din du Hoi, is nothing but a glass formed by 

 volcanic action. The materials of the stream of fire which flows con- 

 tinually from that of Sangai, in the province of Macas, to the south- 

 east of Quito, are no doubt lava, but we have only seen this mountain 

 from a distance, and I was no longer at Quito at the time of the last 

 eruptions of the volcano of Cotopaxi, when vents opened upon its flanks, 

 from which ignited and liquid matters were seen to issue in streams, 

 which must have been of a similar nature to the lava of Vesuvius" (La 

 Condamine, Journal de Voyage en Italie, in the Mevioires de PA cad. des 

 Sciences, 1757, p. 357, Historie, p. 12). The two examples, especially 

 the first, are not happily chosen. The Sangay was first scientifically 

 examined, in December of the year 1849, by Sebastian Wisse ; what 

 La Condamine, at a distance of 108 miles, took for luminous lava 

 flowing down, and "an effusion of burning sulphur and bitumen," con- 

 sists of red-hot stones and scoriaceous masses, which sometimes, press- 

 ed closely together, slip down on the steep declivities of the cone of 

 ashes {Cosmos, see above, p. 251). On Cotopaxi, as on Tungurahua, 

 Chimborazo, and Pichincha, or on Purace, and Sotara near Popayan, 

 I have seen nothing that could be looked upon as narrow lava streams, 

 which had flowed from these colossal mountains. The incoherent, 

 glowing masses of 5 — 6 feet in diameter, often containing obsidian, 

 which Cotopaxi has scattered abroad during its eruptions, impelled by 

 floods of melting snow and ice, have reached far into the plain, where 

 they form rows partially diverging in a radiate form. La Condamine 

 also says very truly elsewhere {Jom-nal du Voyage a VEquateur, p. 160) : 

 "These fragments of rock, as large as the hut of an Indian, form se- 

 ries of rays,"which start from the volcano as from a common centre." 

 * Guettard's memoir on the extinct volcanoes was read at the Acad- 

 emy in 1 752, consequently three years before La Condamine's journey 

 into Italy; but only printed in 1756, consequently during the Italian 

 travels of the astronomer. 



