Input (grade 13): On the afternoon of September 18, 1870, members of the Washburn-Langford-Doane Expedition traveled down the Firehole River from the Kepler Cascades and entered the Upper Geyser Basin.
Output (grade 12): The video probes were lowered to a maximum depth of 42 feet (13 m) to observe the conduit formation and the processes that took place in the conduit.