Colonel Fremont.--The present electioneering contest in the United States for a President has given a New York paper an opportunity of publishing a very interesting letter.

In the year 1850 the Prussian Government awarded Colonel Fremont the great gold medal for his efforts in the advancement of science, and in transmitting it, Baron Humboldt enhanced its value by sending with it a document, in which he says--"I feel happy in being able once more to give you the assurance of my warm recognition.

In your distant expeditions you displayed a noble fortitude, braved every danger of cold and hunger, enriched every branch of natural science, and opened for us a great region that was previously almost wholly unknown to us. I must especially thank you for the honour you confer upon me by having bestowed the names of myself, as well as of my fellow-explorer and friend Bonpland, on regions that border on those which formed the object of our scientific labours.

California, that has so magnanimously withstood the introduction of slavery, will be worthily represented by a friend to freedom and to the progress of science."