All text between the lines following is directly transcribed from the original document.  Any clarifying comments are colored in blue, between brackets, [as an example].

U.S. Infantry and Cavalry School
Light Battery “F”, 2d Artillery
Fort Leavenworth, Kas. August 10, 1883

To the
Chief of Ordnance, U.S.A.
Washington, D.C.

General:
In making the request herein contained, I respectfully state that I have always been of the opinion that our present artillery harness, which proved so satisfactory during the hard service rendered during our late war requires but slight modification to adapt it to what is deemed necessary now.

I have devoted no little attention to this subject particularly since the Light Artillery Board adjourned and have made our changes which, after months of trial, I consider a perfect success viz. the substitution of the hair girth for the leather belly band. Until the present time I have not felt justified in asking for authority for further change, but now I respectfully request authority, to change all of my artillery harness saddles for the McClellan saddles.

Among the principal advantages to be gained by this changes are

1st That the McClellan gives the driver a more secure seat and is easier for man and horse;

2nd That these will be the same saddle all through the battery for near and off horses, and all mounted men;

3rd That cannoneers can be carried on the off horses – a position necessity now that we are to have breech loaders, and the range and precision of modern guns forbid bringing the caissons on the ground with the guns.

I am particularly anxious to make this change as I have machine guns and frequently drill the battery as a six gun horse battery, using these guns, but I cannot drill as a mounted battery, with them, as I have no caissons and in consequence cannot carry the cannoneers.

In case the proposed change is made I can carry a cannoneer on each of the off horses and the other three on the limber and in consequence drill the battery as a mounted battery, when using machine guns.

This request has been deferred because the saddles belonging to my harness, although old, when issued, were in fair condition but now they are considerably worn, on account of continous use.

I would like to have these saddles furnished from the Rock Island Arsenal and moreover I would ask to confer with Col. Flagler [then commanding RIA – th] regarding the modifications as required to adapt the McClellan saddle to the harness.

Finally I respectfully ask that in case my request is granted that authority for the change be given as soon as practicable for the next course of this school commences on the 1st proximo, and being a member of the School Staff, I shall be too busy to attend to this matter for some weeks, after that date.

Very respectfully,
Your obdt. Servt.
(sgd) E. B. Williston
Captain 2nd Artillery
Commanding

[Annotations to back of original letter, in order of chronology:]

[1st annotation]

#390 1883
OO
4226
Fort Leavenworth, Kas.
August 10, 1883

Capt E. B. Williston

Requests authority to change all his artillery harness saddles for the McClellan Saddles, re.

[2nd annotation]

First Endorsement
O.O. Washington, Aug 17/83

Respectfully referred to the Comdg. Officer of Rock Island Arsenal approved.
Confer with Capt. Williston regarding the modifications re., sending to this office a detailed report with drawings of same,
Capt. Williston has been requested to communicate with him.

(sgd.) Jas. M. Whittenson
Acting Chief of Ordnance

[3rd annotation]

Second Endorsement

Rock Island Arsenal, Ills.
September 21, 1883
Respectfully returned to the Chief of Ordnance, U.S. Army
Washington, D.C.

The alterations of the McClellan saddles to adapt them for use with artillery harness has been completed and the saddles were shipped to Capt. Williston on the 18 past.
The detailed report and drawings required are transmitted here with.

(sgd) D. W. Flagler
Lt. Colonel of Ordnance
Commanding

Detailed drawings attached to this document show the modified fittings for attaching trace lines to saddle, and loops to be riveted to the cantle and pommel arches for attaching harness to saddle.



Trace holder attachment for
McClellan saddle – modified M1874 would have had off-side D-ring replaced with round ring.   With hair girth, this would have been essentially an early M1885 saddle.
Collar and breeching assembly loop that was riveted to the pommel and cantle arches.