Humboldt and Fremont.

--To honor him as a pioneer of American discovery, the King of Prussia presented to Col.

John C. Fremont "the great Golden Medal of Progress in the Sciences."

The medal is of fine gold, massive, more than double the size of the American double eagle, and of exquisite workmanship.

On the face is the medallion head of the King, Frederick William the Fourth, surrounded by figures emblematical of religion, jurisprudence, medicine and the arts.

On the reverse, Apollo, in the chariot of the sun, drawn by four high mettled, plunging horses, traversing the zodiac and darting rays of light from his head.

This beautiful tribute to the merit of Col.

Fremont came to him accompanied with a complimentary letter from Baron Humboldt, of which the following is a translation:

To Colonel John C. Fremont:

"It is very agreeable to me, air, to address you these lines by my excellent friend, our minister to the United States, M. de Gerolt.

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 living token (dans ce petit signe da vie) the homage of my warm acknowledgment.

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 entitely 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 scientifie 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, Charles Ritter, the Geographical Society at Berlin has named you as 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 ob't serv't.

A. V. HUMBOLDT.

"Sans Souci, October 7, 1850."

On the envelope thus addressed:

"To Colonel Fremont, Senator, With the great Golden Medal, For progress in the sciences, Baron Humboldt."

The following is the public testimony of the Baron's admiration of the gigantic labors of Fremont, referred to in the letter, as contained in the new or third edition of his "Aspects of Nature," and which, as a reference, becomes a natural appendant to the letter:

Fremont's map and geographical investigations comprehend the extensive region from the junction of the Kansas river with the Missouri, to the falls of the Columbia, and to the missions of the Santa Barbara and Puebla de los Angeles, in New California; or a space of 28 degrees of longitude, and from the 24th to the 43d parallel of latitude.

Four hundred points have been determined hyposometrically by barometric obeervations, and, for the most part, geographically by astronomical observations; so that a district which, with the windings of the route, amounts to 3600 geographical miles, from the mouth of the Kansas, to' Fort Vancouver and the shores of the Pacific, (almost 720 miles more than the distance from Madrid to Tobolsk,) has been represented in profile, showing the relative heights above the level of the sea.

"As I was, I believe, the first person who undertook to represent, in geognostic profile the form of entire countries--such as the Iberian peninsula, the high lands of Mexico, and the Cordilleras of South America, (the semi-perspective projections of a Siberian traveller, the Abbe Chappe, were founded on mere and generally ill-judged estimations of the fall of rivers)--it has given me peculiar pleasure to see the geographical method of representing the form of the earth in a virtual direction, or the elevations of the solid portion of our planet above its watery covering, applied on so grand a scale as has been done in Fremont's map."