Domestic parcel post service was adopted in 1913, 25 years after the Post Office had agreed to deliver international parcel post packages pursuant to the Universal Postal Union treaty and various bilateral agreements with other nations. “The establishment of parcel post in 1913 had a tremendously stimulating effect on the national economy; it opened a world of opportunities for both farmers and merchants alike.” Initially, there were no or few postal regulations governing packages mailed by parcel post. E.g., to construct a bank in Vernal, Utah, in 1916, a Salt Lake City company ascertained that the cheapest way to send 40 tons of bricks to the building was by parcel post.