Waitt, Ernest Linden, History of the Nineteenth regiment, Massachusetts volunteer infantry , 1861-1865

The signals were cylindrical in shape, an inch or more in diameter, with a wooden projection at the bottom to fit the barrel of the pistol. The quick match protruded from the end of this wooden projection. These cartridges were covered with colored paper, indicating the color that would show when they were lighted. The pistols were fitted with a percussion lock, the signal would be inserted in the barrel as far as the wood plug, leaving the cartridge sticking up outside and the quick match extending down the inside of the barrel. A percussion cap would then be placed on the nipple, and, when snapped by pulling the trigger, the spark would ignite the quickmatch and the signal would be fired like a bengola light.

The first signal issued to the Nineteenth regiment is now in the possession of Capt. Reynolds. These signals were in vogue before the organization of the signal corps, which afterward became a separate, distinct and efficient branch of the service and has been ever since.

There was a ‘countersign’ for the quarter or regimental guard at night, a ‘parole’ for the picket guard, and signals as described for distant signalling. The countersign was a distinct matter in itself and was changed, together with the ‘challenge’ and ‘reply’ of day or night, every 24 hours. It was written on a piece of paper, which was then folded into a triangular shape, like a ‘cocked hat,’ three inches long, sealed with wax at the corners, addressed to the commander of the regiment, marked ‘O. B.,’ which meant ‘Official Business,’ and further marked ‘Confidential.’ Woe to the officer or man who, with out authority broke one of the little seals. The Regulations provided for summary punishment in such a case, but this never occurred in the Nineteenth Massachusetts. One of the countersigns which has been preserved reads, ‘Kansas,’ the parole ‘Missouri.’ The day challenge is ‘22,’ the reply ‘112,’ made by motions of the flag. The night challenge is ‘Red-White,’ the reply being ‘White.’ （¹) These colors