 In the beginning, each regiment was made up of six companies of the First Battalion and four of the Second Battalion, but in the latter part of the war, this method of organization was not strictly adhered to.The 18th Regiment, for example, which rendered exceptionally good service in Virginia at Belle Plain, Port Royal, and White House Landing in the spring and early summer of 1864, and in or near Washington DC in the latter part of the summer and through the fall of that year, was made up of only six Second Battalion companies.There were from two to three times as many men in the First Battalion as in the Second, and the soldiers in the First Battalion performed a wide variety of duties.