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prevails a belt of easterly and northeasterly winds. These winds, 

 coming from the Arctic Ocean, meet the great chain of the Rocky 

 Mountains, are deflected into northwest winds and pass unobstructed 

 along this great stretch of prairie land into the States east of the 

 Rocky Mountains. The conflict between the northwest polar winds 

 and the moisture-laden southwest winds from the Gulf of Mexico, 

 gives all the Atlantic States, north of Florida, their summer rains. 

 As far back as eighteen hundred and fifty, Professor Espy, in his sec- 

 ond report on Meteorology to the Secretary of the Navy, without, at 

 that time, more than suspecting the cause, reported as the result of a 

 long series of observations, that in the northern part of the Atlantic 

 States the winds generally, in great storms, set in from north of east 

 and terminate from north of west, and in the southern part of the 

 Atlantic States they set in from south of east and terminate from 

 south of west. 



The States east of the Rocky Mountains are the great battle ground 

 on this continent of these hot and cold winds. 



It is doubtful if the Atlantic trade winds ever give rain to Califor- 

 nia. That portion which passes the mountains through the valley 

 of the Rio Grande, precipitating its moisture on the White Moun- 

 tains and Black Hills of Arizona, which, by the meteorological 

 records of the Smithsonian Institute, are shown to have an annual 

 -average of twenty inches of rain. 



That these general laws may be applied to California as the cause 

 of our climate, I will assume to follow a given portion of air along 

 well known points on the coast. At midsummer, at noon, the sun 

 would be vertical in Southern California, just north of Cape St. 

 Lucas. In this vicinity this portion of air having been a part of the 

 trade wind would have become heated and saturated with moisture. 

 It would rise until it met colder regions, when it would part with 

 some of its moisture ; a portion would return to the earth within 

 thirty degrees, again to join the trade winds, and another portion pass 

 on towards the north as a part of the great upper current. Under the 

 operation of Professor Henry's law, the greater part must return to 

 the earth between latitude thirty degrees, and, say, latitude thirty- 

 five degrees; the remainder would flow on towards the pole until it 

 met the prevailing polar northwesterly winds ; at these points there 

 would be fogs and summer rains. Wherever the polar wind forced 

 its way south of this it would condense the moisture of these descend- 

 ing return trade winds and give rain. This they would do until 

 they had passed so far south that their temperature would be raised 

 to that of the descending return trades, when, of course, no moisture 

 could be precipitated. It is these polar winds forcing themselves 

 among the descending return trade winds that give British Colum- 

 bia, "Washington Territory, and Northern Oregon their summer 

 showers. Should they force themselves further south, they in their 

 passage have to pass into warmer latitudes; they would, also, meet 

 the heat of our great valleys and deserts, and become as warm as our 

 prevailing summer wind, and therefore could not give 



CALIFORNIA SUMMER RAINS. 



But, from midsummer, the sun is for six months moving south, 

 taking with him the great belts of the winds of the tropical, temper- 

 ate, and polar zones, until, at our midwinter, his rays at noon are 



