The following testimonial from a distinguished man and a scholar ought to excite feelings of admiration and regard towards Col. Fremont.

LETTER FROM BARON HUMBOLDT.

"To COL. FREMONT, Senator:--It is very agreable to me, sir, to address you these lines by my excellent friend our minister to the United States, M . de Gerold after having given you, in the new edition of my "Aspects of nature," the public testimony of the admiration which is due to your gigantic labors between St. Louis, of Missouri, and the coasts of the South Sea, I feel happy to offer you, in this little token of my existence (dans ce petit signe de vie), the homage of my warm acknowledgement.

You have displayed a noble courage in distant expeditions, braved all the dangers of cold and famine, enriched all the branches of the natural sciences, illustrated a vast country which was almost entirely unknown to us.

A merit so rare has been acknowledged by a sovereign warmly interested in the progress of physical geography; the king orders me to offer you the grand golden medal destined to those who have labored at scientific progress.

I hope that this mark of the Royal good will, will be agreeable to you at a time when, upon the proposition of the illustrious geographer, Chas.

Ritter, the Geographical Society at Berlin has named you an honorary member.

For myself, I must thank you particularly also for the honor which you have done in attaching my name and that of my fellow-laborer and intimate friend, Mr. Bonpland, to countries neighboring to those which have been the object of our labors.

California, which has so nobly resisted the introduction of Slavery, will be worthily represented by a friend of liberty and of the progress of intelligence.

Accept, I pray you, sir, the expression of my high and affectionate consideration.

Your most humble and most obedient servant,

A. VON HUMBOLDT.

Sans Souci, October 7, On the envelope thus addressed:

To Colonel Fremont, Senator, With the Great Golden Medal For progress in the sciences.

Baron Humboldt.