The hum of comment deepened into surprise, that half stopped and then intensified the giggle.
I was puzzled for a minute, and then the direction of their glances, and their remarks explained it all.

At the rear of the lower part of the cavalry jacket, about where the upper ornamental buttons are on the tail of a frock coat, are two funny tabs, about the size of small pin-cushions.

They are fastened by the edge, and stick out straight behind.

Their use is to support the heavy belt in the rear, as the buttons do in front.

When the belt is off it would puzzle the Seven Wise Men to guess what they are for.