Select a file of daily weather maps for some month. Commencing with the first map in the set, observe the weather and the direction of the wind at a considerable number of stations in the same general region (as, _e.g._, the Lake region, the lower Mississippi Valley, the Pacific Coast, etc.). Enter each case in a table, similar to Table IV below, by making a check in the column under the appropriate wind direction and on a line with the appropriate type of weather. TABLE IV.——CORRELATION OF THE DIRECTION OF THE WIND AND THE WEATHER. At ________ during the Month of ________. +-------------+----+-----+----+-----+----+-----+----+-----+------+-----------+ | | N. | NE. | E. | SE. | S. | SW. | W. | NW. |TOTALS|PERCENTAGES| +-------------+----+-----+----+-----+----+-----+----+-----+------+-----------+ |Clear | | | | | | | | | D | J | +-------------+----+-----+----+-----+----+-----+----+-----+------+-----------+ |Fair | | | | | | | | | F | K | +-------------+----+-----+----+-----+----+-----+----+-----+------+-----------+ |Cloudy | | | | | | | | | G | L | +-------------+----+-----+----+-----+----+-----+----+-----+------+-----------+ |Rain and Snow| | | | | | | | | H | M | +-------------+----+-----+----+-----+----+-----+----+-----+------+-----------+ |Totals | | | | | | | | | A | | +-------------+----+-----+----+-----+----+-----+----+-----+------+-----------+ |Percentages | B | C |etc.| | | | | | | | +-------------+----+-----+----+-----+----+-----+----+-----+------+-----------+ Count every observation of _rain_ or _snow also as cloudy_, for it usually rains or snows only when the sky is cloudy. Continue your observations on all the maps for the month you have chosen. Then count up the whole number of cases of _clear_ weather you have found with north winds, and write down this sum in the first space, in the column reserved for N. winds. Do the same with _fair_ and _cloudy_ weather. Add up and enter at the bottom of the column in the space marked _Totals_ the whole number of observations of _clear_, _fair_, and _cloudy_ weather you have observed with N. winds. Then find what percentage of the weather with N. winds was _clear_, and enter this percentage next to the sum of _clear_ weather observations, in the first division in the column headed N. Do the same for _fair_, _cloudy_, and _rainy_ or _snowy_ weather, deriving the percentages of rain or snow from the total of _clear_ and _fair_ and _cloudy_. Repeat this process of summarizing in every column. Your results will then show the percentages of the different kinds of weather noted with the different wind directions.