Existing comment:
The Mochila:
Pony Express riders carried the mail in four pockets of a saddlebag called a mochila, which fit snugly over the saddle. When a rider switched horses, he grabbed the mochila and swung it onto the saddle of the new horse. The letters were wrapped in oiled silk to protect them from moisture. One of the pockets could be unlocked only by stationmasters. This pocket also held a time card on which the station master recorded the time the rider arrived. |