254 , TRANSACTIONS OF THE 



ments of this great current, when taken into consideration, that go'to 

 make it one of the physical constants in tlie formation of climate, 

 seems as yet but partially understood. Its depth, width, velocity, and 

 temperature have not been investigated as have some of the currents 

 of the Atlantic Ocean! Professor Davidson, of San Francisco, seems 

 to have been almost the only one who has given this subject any 

 attention, with the exception of some casual observers, who have here 

 and there made memoranda for their own curiosity. The professor 

 starts with a maximum temperature of the Japan current of 88° Fah- 

 renheit. At Alaska, 50.06°. Six to eight hundred miles west from 

 San Francisco, 60.33°; one hundred miles west, 55.05°. At the tidal 

 station at Fort Point the mean temperature for eight years was 55.66°, 

 that of the air being 54.97°. The mean temperature of the ocean 

 nine hundred miles west of San Francisco for one year was 60.52°, as 

 found by the ocean steamers going and coming from Yokohama to 

 San Francisco. This shows a difference of temperature to be in the 

 water of the ocean current one hundred miles to the west and that at 

 the tidal station on shore to be .61° less; at six to eight hundred miles 

 4.67° greater; at nine hundred miles, 4.86° greater or warmer. 



The great ocean current in flowing from its origin to the coast of 

 California has parted with 32.34° of heat; or, in other words, has lost, 

 from the average temperature of the equatorial waters (78°), 22.34°, 

 and leaves an average surface ocean temperature, to the distance of 

 900 miles west of California, of 57.89°. The temperature of the air 

 along the coast, and the water, hardly ever rises more than two or 

 three degrees, and the above figures show only 2.92° for the average 

 difference in temperature of the water and air over a large area of the 

 ocean contiguous to the Pacific Coast, and gives an explanation of the 

 low temperature at the base of the atmospherical column that rests 

 on the ocean's water. Also the great freedom from rain during the 

 Summer months, when the westerly winds overcast and fogs prevail. 



For the purpose designed by this paper, the above is all the infor- 

 mation that can be obtained bearing upon the temperature of the 

 ocean's water in the vicinity of this coast, with the exception of the 

 counter or eddying current, said to have been discovered by Professor 

 Davidson; who in describing the great stream that flows_ across the 

 ocean, remarks that "a branch of this current continues direct to the 

 Alexandrian Archipelago, and, striking the southern part of the 

 coast, is deflected to the northward and westward," and calls it the 

 warm Alaska current, which causes the high isothermal lines that 

 exist directly on the Alaskan coast. 



The great aerial air current that moves with the ocean stream, is the 

 counter trade wind of the northern hemisphere, and seems to deter- 

 mine the character of the climate, almost wholly, of California. As 

 it strikes this coast it is always the high current, and flowing from a 

 westerly direction changing but very little the point of the compass 

 at the same date of time in each year. 



It oscillates from the south of west at one portion ofthe yeartothe 

 north of west at another, moving from north to south with the declina- 

 tion of the sun, and then back again. During the Summer season it 

 blows nearly from the west, and in the Winter, being acted on by the 

 polar winds, is given a more northwesterly direction. 



Physical geography has so well described the great systems of atmos- 

 pherical currents that it is superfluous to enter into a description of 

 all the winds, and the laws that produce them. Owing to solar heat, 



