154 TRAVELS AMONOST TEE GREAT ANDES, chap. vii. 



that tlie closing-up process went on with greater activity, and 

 that the vent was sometimes entirely closed, causing the volcano 

 to appear unusually tranquil. 



Steam unquestionably plays a leading part in the operations 

 of Cotopaxi, and sometimes the quantity that issues is enormous. 

 One morning in the following April, when encamped, at the 

 height of 14,760 feet, on Cayambe, at a distance of about sixty 

 miles to the north-north-east, just after daybreak, we saw Coto- 

 paxi pouring out a prodigious volume of steam, which boiled up 

 a few hundred feet above the rim of its crater, and then, being 

 caught by a south-westerly wind, was borne towards the north- 

 east, almost up to Cayambe. The bottom of this cloud was 

 about 5000 feet above us ; it rose at least a mile high, and spread 

 over a width of several miles ; and, as it was travelling a little 

 to the east of us, we had a perfect and unimpeded view of it. 

 I estimate that on this occasion we saw a continuous body of 

 not less than sixty cubic miles of cloud formed from steam. If 

 this vast volume, instead of issuing from a free vent, had found 

 its passage barred, itself imprisoned, Cotopaxi on that morning 

 might have been effaced, and the whole continent might have 

 quivered under an explosion rivalling or surpassing the mighty 

 catastrophe at Krakatoa. 



We were up again before dayliglit on the lOth, and then 

 measured GOO feet on the western side of the crater, and took 

 angles to gtiin an idea of its dimensions. I photographed it,^ 

 and made final observations of the mercurial barometer to deter- 

 mine its altitude. From the mean of the whole, its summit 

 appears to be 19,613 feet above the sea. In 1872-3, Messrs. 

 Keiss and Stiibel (by angles taken from various barometrically 

 measured bases) made its height 19,498 feet ; and, by the same 

 method, La Condamine, in the early part of last century, found 

 that its height was 18,865 feet. As there is not much proba- 



^ Tlie engraving facing p. 147 has been made from this photograph. The whole of 

 the interior of the crater M^as surrounded by cliffs and slopes of the same character. 



