The lower division of the table and the last two columns on the right are to be used for a general summary of the whole investigation. By adding together all the totals of _clear_, _fair_, and _cloudy_ weather observed with all the eight wind directions you obtain the whole number of observations you have made. Enter this in the space marked A, at the right of the table. From this grand total and the total number of observations in each column you may find (in percentages) the relative frequencies of the different wind directions. These should be entered under the totals at the bottom of each column, in the spaces marked _Percentages_ (spaces B, C, etc.). The total number of observations of _clear_, _fair_, _cloud_, and _rain_ or _snow_, noted with all the wind directions, are to be entered in spaces D, F, G, and H, at the right of the table. From these totals, and from the grand total in space A, we can determine the relative frequency (in percentages) of each kind of weather during the month. These results should be entered in spaces J, K, L, and M. Study these results carefully. Formulate them in a brief written statement. Express graphically the following:—— _A._ The percentages of frequency of the different wind directions during the month. _B._ The percentages of the different kinds of weather noted during the whole month for all wind directions. [Illustration: FIG. 51.] A wind rose, indicating the percentages of frequency of different winds during a month, or a year, or several years, may be constructed as shown in Fig. 51. A certain convenient scale is adopted as representing a frequency of 10%, and a circle is drawn with this unit as a radius. A second circle, with a radius twice as long, represents a frequency of 20%, and a third circle, with a radius three times as long, represents a frequency of 30%. Additional circles may be added if necessary. Distances corresponding to the different percentages of frequency of the eight wind directions are then laid off along the eight radii of the circles, and the points thus fixed are joined by a line. The results asked for under question _B_ may be plotted as a weather rose on a diagram similar to that above figured. In this case the percentages of frequency of the different varieties of weather (_clear_, _fair_, _cloudy_, _stormy_) may be indicated on the same figure by using different kinds of lines. Thus, a _solid_ line may be employed to represent _clear_ weather; a _broken_ line for _fair_; a _broken and dotted_ line for _cloudy_; and a _dotted_ line for _stormy_ weather. CHAPTER XVI. CORRELATION OF CYCLONES AND ANTICYCLONES AND THE WEATHER.