Final answer:
The author compares the way Lewis communicated with the Shoshone chief to a pipeline because it stretched across large distances and was used to deliver information.
Step-by-step explanation:
The author compares the way Lewis communicated with the Shoshone chief to a pipeline because it stretched across large distances and was used to deliver information. Just like a pipeline transports something from one place to another, Lewis used communication to bridge the physical distance between him and the chief, allowing them to exchange information and establish a connection. This comparison highlights the efficiency and importance of communication in their interaction.