VOLCANO POPOCATEPETL AND ITS VICINITY. 65 



Poole, at the Hotel Iturbide. The barometer of Mr. Diaz-Covarrubias stood 

 O mm .20 lower than the instrument I used, and a correction for this has been taken 

 into account in the computation of the observations. Mr. Poole s barometer and 

 my own agreed perfectly. I give his observations, which he kindly communicated 

 to me, in the following pages, together with my own. The observations of Mr. 

 Diaz-Covarrubias I am not able to give at present. 



The direction of the wind is not given, as it is difficult to determine its true 

 course with any accuracy among the mountains, where it follows the direction of 

 the valleys and ravines. Generally the weather is nearly calm in the mornings, 

 and at two o clock P. M. a fresh easterly wind sets in, which continues to blow 

 until seven or eight o clock P. M., when it becomes calm again. The atmosphere 

 during the observations was mostly clear, and is always nearly so from November 

 till May, except when northerly Avinds blow. 



