22 MEMOIR OF 



of its founder, who was at length constrained to re- 

 linquish it; and the less reluctantly as the approach 

 of age, and the increasing delicacy of his constitution, 

 admonished him of the necessity of seeking a more 

 genial climate. We accordingly find him, in the 

 autumn of 1827, embarking for Mexico in company 

 with his friend Mr. Say. They passed the winter 

 in that delightful country; and employed their time 

 in observing and recording the various new facts in 

 science which there presented themselves; and on 

 the approach of summer they returned to the United 

 States. 



Mr. Maclure was so pleased with the climate of 

 Mexico, and so solicitous to study the social and po- 

 litical institutions of that country, that he determined 

 to return the same year; and with this intent he 

 visited Philadelphia, proceeded thence to New Haven, 

 and presided for the last time at a meeting of the 

 American Geological Society in that city on the 17th 

 of November, 1828. Of this institution he had also 

 long been President, and took an active interest in 

 its prosperity, which was strengthened by his regard 

 for his friend Professor Silliman — a man whom we 

 all esteem for his zealous and successful exertions to 

 advance the interests of Science, as well as for his 

 extensive acquirements and his many virtues. On 

 this occasion Mr. Maclure declared his intention to 



