Page:Science vol. 5.djvu/337

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��The barometrical observations show atmos- pheric changes whiuh I believe arc common to the region within the- arctic circle, north of America at least. The marlied maximum presBore in April gives way rapidly to the principal minimum in July; to be followed by a secondary maximum in November, and a less marked minimum in January or February.

The hourly bai-ometric observations are of special interest as tending towards a Qnal solu- tion of the question wliether or not the regular diurnal variation observed in lower latitudes also occurs near the poles. Buclian, noting the fact that the i-ange at St. Petersburg and Bosukop is but about .Ol^ofuu inch, remarks, "And in still higher latitudes, at that period of the year when there is no alternation of day and night, the diurnal variation probably does not occur."

The first year's observations at Fort Conger satisfied me liiat such diurnal variation does occur in very high latitudes, and ray opinion was confirmed by Bubacqnent observations. Reductions made several months before the. station was abandoned, from nearly five hundrea"" days' continuous observation, showed a range of .0099 of an inch. The primary maximum occurs at 5 a.m., Wasliington mean lime (which is 53 minutes slower than local time), followed by the primary minimnm at I p.m. The second- ary maximum and minimum took place at 6 p.K. and midnight respectively. To determine whether the presence or absence of the sun affected the fluctuation, I calculated separately the means of the days of continual darkness and continuous sunlight up to May 1. 1883. The diurnal fluctuation was substantially the same, and the critical hours were identical in the arctic night and in the polar day.

The absolute range of the barometer ob-

��served was 2.032 inches, — from 31, April 9, 1882, to 28.968, Feb. 19, 1883. It is interest- ing to note that the minimum pressure for the year 1882-83 at Godthaab and in Spitzbergen occuried respectively one day earlier and three days later than at Fort Conger. The barometer at Godthaab touched the unusually low point of 27.89.

The annual mean temperature (—3.9°) is the lowest on the globe, being 1.4° below that deduced for Van Rensselaer harbor from Kane's observations. It quite disposes of the theories of a warmer climate as the pole is approached. The maximum mean at Fort Conger agrees with that of other arctic stations in general, occurring in July; and the monthly mean gradu- ally declines to the minimum in February. This month, I think, is generally the coldest at arctic stations; and, when the lowest mean has been noted in January (or occasionally in March), I believe a series of years would change it to February. The lowest monthly mean ( — 46,5°) for February, 1882. must give way. however, to that at Werchojansk (on the Lena), from which the following means are rej)orted: December, —50.3°; January, — Sf*"; and February, — fyS". The highest monthly mean was that of July, 1883, 37.2". The ab- solute range of temperature was 115.1"', — from -i;-M% Feb. 3, 1882, to -1-53°, June 30, 1882.

The amount of rain and meUeil snow was 3.95 inches the first, and 3.82 the second year, irregularly distributed throughout the year. This small amount of precipitation may ex- plain the non-glaciation of the adjacent country. I believe the precipitation in the interior to be less than at Fort Conger.

The wind resultants are as follows: first year, S. CI. 4° E. 7594 miles; second year, S. 07.3° E. 6437 miles. The wind was more southerly from 2 to 4 p.m., inclusive, than at other hours •during the first year, and from 11 a.m. to 2 p.m. the second year.

The mean tidal establishment was deter- mined by me at Fort Couger from two years' obseriationa on a fixed gauge, as follows: —

��Complete series of high and low waters for two years, with regular hourly readings of the tide for one year at Fort Conger, have been placed in the hands of Mr, Sehott. These observa- tions, with supplementary simultaneous read- ings at Capes Sumner, Beechy, Craycroft, Lecbi, and at Repulse haibor, added to Bessel's and Nares' observations, will, I trust, enable

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