This may be considered as showing the general conditions of accuracy of the barometrical determinations during the survey inasmuch as all the errors enumerated above have been here considered, and the resulting probable error reduced to feet 56.5 feet may be useful in the comparison with other and similar series. In preparing the following general table of altitudes the principal points occupied are referred to, and in the determinations the probable errors are calculated from the range in the various results. The accuracy of such comparison is doubtful and the formula should be applied to weighted observations, wherein the distance between the stations should enter. Some function indicating the amount of abnormal atmospheric disturbance should also enter, as is plainly indicated in the results of the determination at Camp Supply. As it is, however, the probable errors serve somewhat for comparison of the accuracy of results. The altitude of Dodge City was taken from the report of the Chief Signal Officer of the Army for 1876. The mean of the barometric observations at that point for the period in question gives a slightly different result. The column of No. of observations used, sometimes includes the mean of two barometers and at others of three. The profile of Tule Creek and of the Palo Duro and Tierra Blanca were obtained by using one barometer on the road, and comparing its record with that of one left at one of the camps occupied for a longer period. Dates when observations were made. Station. TABLE GIVING ALTITUDES AND BAROMETRICAL READINGS AT POINTS OCCUPIED IN THE SURVEY OF THE SOURCES OF RED RIVER, TEXAS. May 13. Big Springs, North Fork May 14.. Level of Staked Plains, between North Fork and McClellan Creek. The line of profile here given crossed that of Lieutenant Whipple, Topographical Engineers, on his survey of the thirty-fifth parallel in 1853-254, near his camp No. 36, on the Canadian River. His camp was higher up than my crossing, and was on the south side of the river, mine being on the north. The two camps were probably only a few miles apart in distance. Lieutenant Whipple's altitude of his camp No. 36 is given at The crossing of the Canadian given in my table is Difference..... Feet. 2, 162.6 2, 402. O 239. 4 The line run to the Canadian River from my permanent camp on Red River touched Lieutenant Whipple's line again near his camp No. 43, and the altitudes are as follows: Lieutenant Whipple's altitude of his camp No. 43. Difference Feet. 3,264.6 3, 234. O 30.6 The barometrical readings given in the report of Marcy and McClellan on the survey of the Red River of Texas in 1852 are not at all similar to mine, and, as his altitudes are not calculated, I am unable to suggest the possible reasons for this difference. BOTANY. The following list of plants collected during the survey is necessarily an imperfect catalogue of the flora of the country. The collection was made by persons unfamiliar with botany, and generally at the close of a hard day's work, when the leisure hours of camp were utilized in part by gathering specimens of plants at that time in bloom. Besides the numbers of individuals not yet in bloom, and therefore not reported, there were of necessity thus omitted in the list the names of all trees, ferns, and all non-flowering plants. The list is therefore submitted merely for what it is worth of itself. Upon reaching Fort Leavenworth, Kansas, the collection was placed in the hands of Dr. T. E. Wilcox, Assistant Surgeon, U. S. A., who kindly offered his services. The classification has been prepared by him, and through the kind assistance of Professor Wood, to whom all specimens not recognized were submitted, the list was completed, and Professor Wood's name will be found as the authority in these cases. The list may be considered as almost exclusively one of the flora of the Staked Plains of Northern Texas. CATALOGUE OF PLANTS COLLECTED IN NORTHWEST TEXAS, NEAR THE HEADWATERS OF RED RIVER, BY FIRST LIEUT. E. H. RUFFNER, U. S. ENGINEERS. RANUNCULACEE. Anemone Caroliniana, Watt; Torr. and Gr., Fl. 1, p. 12. PAPAVERACEÆ. Argemone Mexicana, Linn.; Torr. and Gr., Fl. 1, p. 61. |