blowing in the direction ; and the mean representative of the velocity for that hour will be deduced from the equation V√200 P. The values of 0, expressed in degrees, are given in Table XII; and the values of the representatives of the bi-horary velocities for the different hours of each month, are given in Table XIII. Table XIV gives the actual mean velocities for the bi-horary intervals in each month; together with the means for the year, and the interpolation equation representing the mean yearly result for any hour of the day. The equation for relative velocities is preferable to that giving absolute velocities, as the value of the scale of velocities seems still uncertain. Table XV gives the General Changes of the Wind for the year, and it has been formed with great facility from the two-hourly registers of direction on the anemographic sheets, by noting the times when conspicuous changes have occurred from direct to retrograde, or the contrary, and then finding what have been the whole changes during those intervals of time in which the wind has been turning on the whole in one direction, retrograde or direct. The Table gives the monthly amounts of changes in both directions, and the whole annual change. Table XVI, giving the relations of Pressure and Temperature of the Air under different Winds, is formed precisely in the same manner as in the preceding year. Thus, all the elements being taken from the "Daily Results of Observations," they have been grouped so as to reduce the whole number of directions to eight, by combining the number of days under the principal point with those under the points immediately preceding and following, allotting to each a weight proportional to the number of observations. Under the North point are included therefore the Barometer and Thermometer Readings, corresponding to North, N. N. W., and N. N. E., and so on for all the rest. The separate columns of the Table require little explanation, excepting that the numbers in Column 6 are taken from the first Table on p. [xxvii] of the volume for 1857, and those in Column 8 from the Table on p. [83] of the same volume, by subtracting the normal temperatures given in that Table from 48° 6, the normal mean annual temperature. Table XVII gives the amount of Rain collected in the four Gauges, one placed on the ground, and the others at elevations of 22, 24, and 112 feet. (See p. 5.) Table XVIII, which gives the relations of the Quantities of Rain which fell during the year 1862 under different winds, has been formed on precisely the same principles as those applied in Table XVI, namely, [ c ] RADCLIFFE OBSERVATIONS, 1862. by forming groups for each principal point, including the half-points immediately preceding and following, and taking the corresponding quantities of rain-fall from the " Daily Results." The observations of a single year necessarily give a very imperfect result, but the combination of several years will give results of considerable importance, so as to make it desirable to continue the calculations from year to year. Table XIX gives the indications of Schönbein's Ozonometer during the year, applying numerically his scale of colours in the usual way. January 9, 1865. ROBERT MAIN. DAILY RESULTS OF METEOROLOGICAL OBSERVATIONS MADE AT THE RADCLIFFE OBSERVATORY, OXFORD, IN THE YEAR 1862. |