Uniform Regulations, 1864
For all officers, to be of navy-blue cloth or white drill, or for "service dress" of navy-blue fine flannel, and to be worn over the boots or shoes.
Within the tropics, white pantaloons are to be worn at all seasons, unless when otherwise authorized by the officer in command.
North of the tropics blue ones are to be worn from the 1st of October to the 15th of May, and white ones from the 15th of May to the 1st of October; and south, of the tropics, vice versa, subject, however, to such exceptions as may be directed or authorized by the senior officer present in command.
For all officers, single-breasted, standing collar, with nine small navy buttons in front.
Source: Uniform for Officers of the United States Navy, As Prescribed in Regulations for the Uniform of the U.S. Navy, Jan. 28, 1864. Tomes, Melvain & Co., 6 Maiden Lane, New York. Entered according to Act of Congress, in the year 1864, BY TOMES, MELVAIN & CO., in the Clerk's Office of the District Court of the United States, in and for the Southern District of New-York. The text is reproduced here exactly as in the original, following the original use of capitalization and italics.