• It's a commission appointing John T. McNaught as Captain in the 20th Regiment of Infantry, U.S. Army
• His rank is dated to take effect October 5, 1867
• The commission itself was signed and given at Washington on January 4, 1870 ("the ninety-fourth year of the Independence of the United States")
• It bears the printed signature/text of the President and is countersigned "By the President" with William W. Belknap as Secretary of War (Belknap served in that role 1869–1876)
• The blue embossed seal in the upper left is the official seal affixed to the document
• Marginal notes on the left indicate it was recorded and forwarded through the Adjutant General's Office

Design elements:

• Engraved eagle clutching arrows amid clouds, with a banner reading "E PLURIBUS UNUM"
• Bottom vignette of stacked cannonballs, crossed flags (including a 34–35 star U.S. flag), weapons, a drum, and a knight's helmet — decorative motifs common on Civil War–era military commissions
• Ornate calligraphic lettering typical of engraved government documents of the period