74 



TRAVELS AMONGST THE GREAT ANDES, chap. hi. 



opinion seemed to prevail that the two mountains act as safety- 

 valves to eacli other. 



Upon the few occasions that we saw it (though scarcely any 

 smoke issued from the crater), there were outrushes of steam 

 at intervals of twenty to thirty minutes^ which shot up with 



.'--^ .K, 



'"^lih 



^J&JS&^^ 



immense rapidity five or six thousand feet above the top of the 

 mountain. They then spread out into mushroom-like clouds, 

 which were drifted by the wind towards the south. The annexed 

 diagram shews three phases (A, B, C) of these eruptions. In A. 

 the nearly invisible jet is being projected. In B, the eruption has 



1 Similar ejections of steam, on a smaller scale, were also observed upon Cotopaxi. 

 See Chapter VII. 



