CLIMATE. 23 



Dr. H. Gibbons, speaking of the mists and fogs at San Fran- 

 cisco, says : 



" It is carious to observe the conflict between the absorbing 

 power of the air and the supplying power of the ocean, in re- 

 gard to moisture. Toward noon, when the wind rises, huge 

 columns of mist may be seen piled along the coast, three or 

 four miles west of the city, and pouring in hke a deluge upon 

 the land. But the air of the land, which is always thirsty, 

 drinks it up with astonishing avidity ; so that the impending 

 wave, though in a current moving from thirty to fifty miles an 

 liour, makes slow progress. By the middle of the afternoon 

 it is within a mile or two of the city; and there it stands, like 

 a solid mass of water several hundred feet in depth, rolling and 

 tumbling toward you (not without grandeur and majesty), and 

 threatening to overwhelm you in a few seconds. You await 

 its coming, but it comes not ; it even recedes, to return and 

 recede again. Xot until the sun has lost his calorific power 

 does the atmosphere reach the point of saturation ; and then, 

 tow^ard sunset or later, every thing is submerged by the va- 

 pory flood. In the course of the evening the wind falls. Dur- 

 ing the night the mist is gradually dissolved and disappears 

 from the lower stratum of air, while it forms a heavy cloud 

 above. About the middle of the forenoon the cloud is dis- 

 persed by the rays of the sun. The dispersion is rapid, the 

 sky often becoming entirely clear in less than half an hour. 



"If it be possible to distinguish between fog and mist — re- 

 garding the former as impalpable, and the latter as composed 

 of palpable particles of moisture — I may remark that mist be- 

 loni^s onlvto the summer and foo; to the winter climate of San 

 Francisco. There is no mist in winter, and no fog in summer. 

 At all seasons the drying tendency of the atmosphere is ob- 

 servable. You notice none of those phenomena which in other 

 climates depend on an excess of water in the air, and on sud- 

 den changes of temperature. The moisture does not condense 

 on your window^s, nor on the plastered w^alls ; salt does not 

 liquify, nor even exhibit the shghtest dampness ; and the house- 



