In 1861, some M. G. Dupuis and others possibly offered to volunteer for the Union army. What was the offer specifically, and were there other individuals who wished to leave Europe to join the Union?

by cynest

I found a letter from Simon Cameron, then Secretary of War, on page 322 of this:

The War of the Rebellion: A Compilation of the Official Records of the Union and Confederate Armies. Series III, Volume I. Correspondence, Orders, Reports and Returns of the Union Authorities from November 1, 1860 to March 31, 1862. Washington: Government Printing Office. 1899. (Serial 122).

The letter:

War Department

Washington, July 5, 1861.

M.G. Dupuis and others,

Geneva, Switzerland:

SIRS: I very much regret that the Government could not accept the generous offer which you made through the US consul at Geneva. We have already an army composed of more than 300,000 men, a number greater than we need for the actual crisis.

Expressing sincerely my appreciation of the honor conferred by your devotion to the cause of the liberty and sovereignty of our great Republic, I have the honor to be , sirs, your devoted servant.

Simon Cameron

It appears that Cameron is rejecting an offer by some parties to volunteer for service under the Union. Is this correct? Were there other offers of European volunteers at the start of the war?