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worth and Brown's stations, on the Nevada Desert, on the line of the 

 Central Pacific Railroad, from eighteen hundred and seventy-two to 

 eighteen hundred and seventy-seven, was, for Wadsworth, eighty 

 degrees and thirty-three one-hundredths, and for Brown's, seventy- 

 eight degrees and eight one-hundredths. The summer temperature at 

 Fort Mohave, from a record of six years, was ninety-two degrees and 

 fifty-nine one-hundredths, and at Fort Yuma, from a record of twenty 

 years, ninety-two degrees and seven one-hundredths. Lieutenant 

 Wheeler, in his report of eighteen hundred and seventy-six of the 

 survey west of the one-hundredth meridian, gives the mean tempera- 

 ture of the Mohave Desert for July as ninety-three degrees and six 

 one-hundredths. 



Fort Yuma is about five hundred miles south-southeast from 

 Wadsworth. The country intervening is entirely desert. 



The indraught of westerly winds from the Pacific in summer does 

 not appear to be alone sufficient to satisfy the demands of the heat 

 of these great deserts. Lieutenant Wheeler states that on the Mohave 

 desert " southeast winds are by far the most prevalent in the sum- 

 mer time." He adds: "It is also easily observed that the clouds 

 and summer rains come from that direction." From this it would 

 appear that the deserts create an indraught from the Gulf of Califor- 

 nia as well as from the Pacific Ocean. 



I have shown that we are in the latitude of the southwest return 

 trades, and that their force is augmented by the effects of the radia- 

 tion of heat from the deserts on our eastern borders. The configura- 

 tion of the immediate coast near San Francisco, from Point San 

 Pedro to Point Reyes, and the open Golden Gate, cause an increased 

 quantity of this daily sea breeze to pass by and over this city. This 

 increased wind and accompanying fog, coming directly from over 

 the cool Japan gulf stream, so lowers the summer temperature of 

 this city that, as have been shown by Dr. Gibbons and the records of 

 the Smithsonian Institute, there is no other place in the whole terri- 

 tory of the United States, of the same elevation, that has so low a 

 temperature, the mean summer temperature at the Golden Gate being 

 fifty-six degrees. Another cause affecting the climate of California, 

 to which attention was first called by Guyot, is in the fact that the 

 Sierra Nevada and Cascade Mountains reach the coast of Alaska, and 

 bend like a great arm around its western and southern shore, thus 

 shutting off or deflecting the polar winds that otherwise would flow 

 down over Oregon and California. The cold winds that reach this 

 State are usually from the northwest, and have had their temperature 

 raised by passing over the Japan gulf stream, before that gulf stream 

 has been reduced to the temperature we find it while passing our 

 coast. It has been shown that this northwest wind precipitates its 

 moisture by becoming reduced in temperature where it meets the 

 coast of Alaska, British Columbia, and Washington Territory. It 

 passes inland, following the Cascade Mountains where they leave 

 the coast. As it comes south it is heated by coming into warmer 

 latitudes, its capacity to take up moisture is increased, but it finds 

 none in its course. The Cascades, which are a continuation of the 

 Sierra Nevada, direct it into the Sacramento Valley where it meets 

 still greater heat, which the more increases its capacity for moisture. 

 It, therefore, possesses all the desiccating qualities for which it has 

 become famous, and which are well described by Reverend Mr. Bonte 

 in his article on the subject, to which I have referred. Of course its 



