The Grand Canyon of the Yellowstone

1. 1

   What is written

   Painted in the studio and completed in 1872, from sketches Moran made at the Lower Falls between the evening of 27 July and the morning of 31 July 1871, with the Hayden survey.

   • July 28. Sketching & photographing about the Falls. July 29 photographing & sketching around the Falls & Canon July 30 still at the Falls.Thomas Moran, diary, 1871 (NPS transcription)
   • I did not wish to realize the scene literally, but to preserve and to convey its true impression.Moran, in G. W. Sheldon, American Painters (1879)
2. 2

   Records of those days

   • J. W. Beaman’s camp logThe survey meteorologist read a barometer and an open-air thermometer two to four times a day at each camp, with wind, cloud and the share of clear sky. Transcribed by Nephos from the printed tables.
   • Boteler’s Ranch base stationThe same survey’s fixed station in the Yellowstone valley, 4,925 feet, four to six readings a day with wet and dry bulbs.
   • Fort Ellis post surgeon’s registerThree readings a day, cloud and rain, 110 km from the falls.
   • Lake Yellowstone and the Canyon snow stationLate-July temperatures today, 1991–2020, 19 km and 1.1 km from the falls.

   Not found or not yet searched

   • No instrument stood at the canyon on 28–30 July: the survey’s camp left Cascade Creek, 2.4 km from the falls, on the morning of the day Moran arrived.
   • No one measured rain; rain appears only in remarks.
   • Captain Barlow’s parallel instrument record was destroyed in the Chicago fire of October 1871.
3. 3

   Each claim tested

   • The painting’s sunlit canyon under a bright sky, as Nephos reads the canvas. On 28–30 July the plateau camps logged about half the sky clear by day (5.6 of 10 on average) and 8 to 10 of 10 in the evenings; the valley station 6.4 of 10 by day. Beyond showers on the night of 27–28 July, no rain was remarked through the 30th; a storm stood in the northeast on the evening of the 29th.
   • “a gale was blowing”, Captain Barlow on the summit of Mount Washburn, 26 July 1871. That afternoon Beaman logged the strongest wind of the week at Cascade Creek below the mountain: south-west, force 4, a stiff breeze on his 0–10 scale.
   • “frosts occur every night”, Barlow on the plateau. Beaman remarked frost once, on the night of 26–27 July at Cascade Creek (42° at 6 a.m.); the next dawns read 42½° to 51°.
   • The day and the sky of the canvas itself. A studio composite; Moran said the relations of the parts “are not always preserved”.
4. 4

   Verdict

   The week Moran sketched the canyon was fair high-plateau summer: frosty dawns in the low 40s, afternoons near 70°, the sky about half clear by day and clearing at dusk, one storm on the horizon and no measured rain. The instruments had moved up-river the day he arrived, so the canyon itself went unmeasured.

   • Partially agreesThe bright sky Fair days on the survey’s logs, 13–20 trail miles from the canyon; nothing measured at the falls.
   • Partially agreesBarlow’s gale on Mount Washburn The windiest reading of the week, below the mountain; the summit was not measured.
   • Partially agrees“frosts occur every night” Frost is remarked on one night of five; the thermometer was read after dawn, not at the coldest hour.
   • UnknownThe day painted A studio composite from several days’ sketches and photographs.

What this cannot tell you. Beaman’s readings are single spot readings at irregular hours, not daily highest and lowest, with unknown exposure. The plateau camps moved every day or two between 7,400 and 7,800 feet; the valley station is 2,500 feet lower and 63 trail miles away. The modern averages are context only: Beaman’s single readings at odd hours from moving camps are not daily highs and lows, so they cannot show that 1871 was like today.