FRIENDS AND COADJUTORS AT PARIS. 39 



upon mineralogy and geology, which he continued till the 

 year 1821. He also gave instruction in zoology. Humboldt 

 had the highest respect for his scientific acquirements, and as 

 late as 1840 he sent to Paris for his investigation several 

 crustaceous infusoria from Sanssouci. 



Foremost among the mineralogists frequenting the scientific 

 circles in Paris stands Pierre-Louis- Antoine Cordier, born in 

 1777 ; his career closely resembled that of Humboldt, since 

 he was not only a miner by profession, but also an extensive 

 traveller. He had visited the Alps with Dolomieu, and after- 

 wards, in company with him, joined the expedition to Egypt ; 

 later, he travelled through Germany, France, and Spain, and 

 undertook a voyage to Madeira and Teneriffe. The friendship 

 formed between him and Humboldt, drawn together as they 

 were by the similarity of their path in life, was cemented by 

 mutual esteem, and maintained for nearly half a century. 

 Cordier survived his distinguished friend, and died in 1861, at 

 the advanced age of eighty-four. It is certainly remarkable, as 

 we have before observed, that so many of Humboldt's friends 

 should have attained an extraordinary age. A notable instance 

 of this is furnished in the case of another geologist, Jacques- 

 Louis-Marin Defrance, a mutual friend of Cordier and 

 Humboldt, who, born in the year 1758, lived to the extreme 

 age of ninety-three. In his sixty-sixth year he dedicated to 

 Humboldt a work on petrifactions, in acknowledgment of 

 which Humboldt penned the following letter : ] 



< March 1824. 



c Sir, As I had not the pleasure yesterday of expressing to 

 you verbally my deep sense of the honour you have conferred 

 upon me, allow me in this form to offer you my sincere thanks. I 

 am deeply touched by your kind remembrance, and I have not 

 the heart to reproach you for having singled me out for a dis- 

 tinction so marked at a time when the commendation of the 

 public is a cause of irritation to all who are not its recipients. 

 I prefer to confess to you simply how much I feel honoured by 

 the friendship of one who has rendered services of such value 

 both in geology and. natural history, who is distinguished by a 



1 Be la Roquette, vol. i. p. 224 



