AND CONSTRUCTION OF RAIN-FALL CHARTS OF THE UNITED STATES. igi 



cipitation in. California and Nevada and barely 6 inches in the northwestern part of 

 Washington Territory. We also find on this chart a remarkable development of a 

 new rain area of 14 inches, extending from eastern Kansas and western Missouri 

 through Iowa and part of Minnesota into Wisconsin. During this season the trade 

 winds blow across Florida with great steadiness from the southeast; they enter 

 Texas in about the same- direction, but as they recede from the coast the winds tend 

 more from the south, and are felt in Kansas, western Missouri, and Iowa, where, and 

 beyond, they become gradually southwest winds. The development of this new area 

 of rain shown by the chart is, therefore, directly traceable to the increased violence 

 and persistency of the southeasterly winds thrown across the coast of Texas and 

 deflected, farther north, more nearly into a meridional direction ; by them the Gulf 

 vapor is directl}'- carried as far north as Lake Superior, and the smaller area of rain 

 development (also of 14 inches) just south of Lake Michigan is at once seen to be 

 only a detached part of it taken hold of by the general westerly currents. The 

 development in northern Alabama or western part of North Carolina, shown on the 

 chart, except that for the autumn, is evidently due to the eifect of the elevated ground 

 interrupting the moisture thrown against its slope. At this season the Atlantic 

 coast rains extend barely beyond the limit of North Carolina. The distribution of 

 the rain during this season in the eastern j^art of the United States is more equable 

 than in any other season, as is shown by reference to the charts. On the Pacific coast 

 the winds at this season are generally northwesterly, or nearly parallel with the coast 

 of California, and this evidently has some effect in lessening the amount of moisture, 

 especially on the more northern coast, where the direction of the winds at other 

 seasons is more nearly from the westward. This whole coast is of comparatively low 

 temperature, near 60° Fahrenheit on the average during summer, and south of Point 

 Conception increasing to about 70° Fahrenheit. 



CHART SHOWING THE DISTRIBUTION OF RAIN DURING THE WINTER. 



The curves of equal amount of rain and melted snoAv are given for every second 

 inch from 2 to 36 inches. Compared with the preceding chart the most striking 

 feature is the heavy rain-fall developed along the northern coast of California, of 

 Oregon, and of Washington Territory, retiching 36 inches in the latter locality, and 

 constituting for that coast a regular rainy season, spreading its influence over a part 

 of Idaho and into western Montana. On the other hand, Florida enjoys a compara- 

 tively dry season, the precipitation there being less then than in the State of Maine. 

 The maximum rain-fall in the eastern section, in parts of Louisiana, Mississippi, 

 Alabama, and northern Georgia, is but 16 inches. If we now examine the average 

 direction of the wind during this season, we find, correspondingly, great changes as 

 compared with the summer season ; the trade winds have retreated southward, giving 



