切手
In 1862, Gault and the American population were faced with a shortage of coins. The government reacted first to this problem by passing a law on July 17, 1862 that allowed postage stamps to be used to pay off debts to the government as long as they were under $5. Stamps were accepted as having value across the US because they were evidence of having paid for postage. This remedial law was only a temporary solution due to the fragile nature of a thin, paper postage stamp. Postage stamps were easily torn and damaged when constantly handled. Gault proposed a solution to this problem in August of that year when he patented his idea of the encased postage stamp. He advertised his invention in the local newspapers as “New Metallic Currency.” His ingenuity was simple and his invention was based on the familiar roundness of coins. As suggested by its name, the encased postage stamp consisted of a postage stamp encased, or sandwiched between two covers made out of brass. Gault constructed the original postage cases out of silver in order for them to more closely resemble real coins. However, Gault found that silver encased postage stamps were too expensive for him to manufacture and the case quickly lost its silver coloring because of continuous handling.