200 tons; Pittsburg, 88 boats - average, 200 tons. At least three-fourths of these boats are in port and can be made ready for service - say 150 boats, average, 225 tons, and able to carry 50,000 men. These are on the upper Ohio. At Louisville, New Albany, Saint Louis, &c., there are at least 100 more of larger size. My estimate, therefore, was under rather than over the mark. I have no doubt that 80,000 men might be transported at once by the boats above Cairo, on the Ohio and Mississippi. If it be necessary to use them, the Quartermaster's Department should use some tact and caution in contracting, for I have no doubt the boatmen and shippers will be ready to ask the full value.

We have had a good deal of trouble in Ohio in getting uniforms and clothing material, &c., in time. This and an occasional bad choice of officers has made some dissatisfaction, but the three years' men will be more than made up. The total number of volunteers in Ohio amounts to over ninety regiments, and, as they are generally full, it amounts to 90,000 men. Of the eleven regiments in Camp Dennison, three or four will prove first rate; the residue not above an average, unless they improve fast. They are very good material, but extremely raw, we having had no military training for several years. There is one German regiment, mostly composed of Prussian soldiers; there is another composed of Germans and Irish. Five of our regiments are, I believe, in Western Virginia. The changing from three-months' to three-years' men has made some commotion and difficulty here, but is now nearly over. Over 50,000 able-bodied men can be spared from Ohio without in the least impairing industry; 100,000 can be spared for one or two campaigns.

Crops will, I think, be very good this year, except that wheat will not be a heavy crop. Fruit is very abundant. Corn of the old crop so abundant that it brings but 28 cents in Cincinnati market, and I should not be surprised to find the martket entirely next autumn with corn.

The State loan of Ohio was entirely taken up at home at par. This State has immense resources in men, money, and food. It is really very rich. Indiana and Illinois are fertile in men and food, but not nearly so rich. The interruption of Southern commerce affects business in Cincinnati very much, but failures are few, and generally few people in want. From these facts you can gather an idea of the strength of the Central West, which is enough to overwhelm the Gulf States, if it must be done.

Yours,

EDWD. D. MANSFIELD.

[Indorsement.]

ENGINEER DEPARTMENT, June 13, 1861.

Respectfully forwarded for information at headquarters.

JOS. G. TOTTEN,

Brevet Brigadier-General, U. S. Army.

[4.]

NEW YORK, June 9, 1861.

Honorable WILLIAM H. SEWARD:

DEAR SIR: I do myself the honor to inclose herewith, for your inspection and that of the President, a letter which I have just received from