PILOT KNOB, MO., April 15, 1864.

Brigadier-General EWING:

Will send two howitzers and one caisson to Patterson right off. There are only two howitzers and two 3-pounder guns, smooth-bore. One caisson is being repaired and the boxes belonging to caissons for the Woodruff smooth-bore are being altered to suit the new kind of ammunition, all of which has been ordered to be finished as quickly as possible, and will also be sent to Patterson as soon as practicable. Captain Milks' company at Farmington has been ordered to Saint Genevieve. Will answer your inquiry of last night as soon as advised by Major Wilson at Patterson. Preparatory to my going to Cape Girardeau on court of inquiry, will you please permit me to visit Saint Louis for two days on very important personal business needing my personal attention?

Please answer before train time, 3 p. m. to-day, and oblige,

JOHN N. HERDER,

Lieutenant-Colonel, Commanding Post.

PILOT KNOB, MO., April 15, 1864.

Brigadier-General EWING,

Commanding:

There are some five or six fords between Van Buren and Doniphan, and many places that the river can be forded at low water. All roads crossing Currant River between Van Buren and Doniphan are very bad and scarcely ever traveled. I am not sufficiently well acquainted with the country to give to give you a satisfactory reply in regard to fortifications, but I would suppose that a location might be selected within 1 mile of Doniphan for fortifications. Captain Johns has just returned from Cherokee Bay. He reports guerrillas all gone below to join Kitchen. He did not find one on the trip. There was a mistake in regard to the howitzers. I understand Lieutenant Pope, in charge of them, that [he had] the boxes, or carriages, of guns and one caisson, but I found it not so. The boxes had been taken off some days ago, but the workmen not having the required lumber, a delay was occasioned. at the last issue of ordnance a new kind of cartridge was received not fitting the boxes, being 1 1\2 inches longer than the old ones, projected that far out at the top of the box, making them unserviceable.

Relying on having enough artillery in Battery G, Second Missouri, since ordered to Cape Girardeau, I ordered an alteration in the boxes to suit the ammunition, which has not yet been accomplished; therefore it is impossible for those howitzers to move to-day as promised. In order to do the thing as quickly as possible, I shall, if not countermanded before mail time this noon, send Lieutenant Pope with the boxes to Saint Louis arsenal for suggest to have those two companies, L and K, First Infantry, Missouri State Militia, at present at Benton Barracks, sent down here to re-enforce this post, so that Centreville and Patterson might be sufficiently re-enforced by cavalry from this post, besides some more infantry, there being only one company, one being exclusively used for artillery in Fort Davidson here, and would for garrison duty be far more advantageous, and secure this part of the country against any force that can be brought