Donation to the Cabinet: Twenty-eight mineralogical specimens from Dr. A. B. Stout; mineralogical specimens from Mount Hood, by Col. R. S. Williamson.
The following paper was read:
On the Height of Mt. Hood.
BY R. S. WILLIAMSON.
Having recently formed a party and visited Mt. Hood for the purpose of ascertaining its altitude, and as my determination of its height is much less than previous parties have made it, I think it proper to state somewhat in detail the nature of the observations and the method I have pursued to arrive at the number I adopt as a close approximation to its true height.
By the kindness of Gen. F. Steele, commanding the Department of the Columbia, the necessary transportation was furnished for the party, consisting of twelve persons, of whom my two assistants, Lieut. W. H. Heuer, U. S. Engineers, and Mr. John T. Best, were specially charged with the observations on the summit. We left Portland, Oregon, August 20th, and on the evening of the twenty-second arrived at a place on the slope of the mountain, where we camped, and from which, the next day, the ascent was made; seven of the party attempting to reach, and six reaching, the summit, where they remained from one and a-half to three hours.
From this camp to the summit and back ten hours were occupied, starting at 7:30, A.M. The weather was clear and pleasant, and had been so for several days before, and was so for several days after.
The instruments used at all the stations were made by James Green, of New York, were in perfect order, and most of them new. They consisted of cistern barometers reading to two thousandths of an inch, with attached thermometer, and open air thermometer, (dry and wet) with large divisions, so that they were easily read to tenths of a degree. All the barometers had been adjusted to or compared with the standard, and all agreed with it except the one at Astoria, which required a plus correction of three thousandths of an inch.
The stations used were Astoria, Fort Vancouver, Fort Dalles, camp on slope of Mt. Hood, and summit of Mt. Hood. Observations had been taken for several years at Astoria for me by Louis Wilson, U. S. Tidal Observer, at 7, A.M., 2, P.M., and 9, P.M., of every day, besides hourly observations for ten days or more of each month. The cistern of this barometer is fifty-three feet above mean low tide.
At Fort Vancouver observations of the same character were commenced July 1st of this year, and are still going on. At Fort Dalles similar observations have been made since July 10th.