THE SMITHSONIAN INSTITUTION. 241 



Atlantic States, from that quarter. In the early spring they sometimes 

 proceed from north of west. As the season advances they depart en- 

 tirel}' from this course, and are almost invariably from south of west. 

 From May to September, a period of five months, the direction of the 

 afternoon sea breeze was north of west on twelve da3?s only ; and even 

 on these occasions it was mostly within one point of west. The pre- 

 vailing direction was west southwest. 



I have reason to believe that the wind off' the coast, at sea, during the 

 period referred to, is more northwardly than on land, and that it is de- 

 flected from that course about the bay of San Francisco. Such, at 

 least, is the account given by the captains of vessels navigating the 

 coast. 



There was a decided sea breeze on 2-3 days in March, 17 days in 

 April, 22 days in May, 24 da3^s in June, every day in July and August, 

 28 da3^s in September, 30 days in October, and 8 in November. 



The number of afternoons that might be described as windy was, in 

 February 8, March 16, April 15, May 18, June 24, July 29, August 

 23, September 19, October 8, November 2. On the 162 days thus 

 noted, the mornings were seldom windy, the wind rising above a mod- 

 erate breeze in the forenoon on 34 da3^s only. In May there were 5 

 days windy at sunrise, and 1 in June ; but not one in the months of 

 April, July, August, September, and October. 



The sea breeze generally rises to its height soon after noon-day, 

 mostly between one and two o'clocic, but sometimes not till three or 

 four. It commonly falls about sunset, or soon after. Sometimes it 

 continues till midnight. In the early part of the season it is apt to set 

 in earher and continue later. There were 8 windy evenings in May, 

 11 in June, 11 in July, 5 in August, and none in September. 



The idea of mist and vapor is commonly associated with these 

 winds ; but the sky is clear, or partially so, more than half the time 

 There were 6 cloudy mornings in May, 11 in June, 16 in July, 21 in 

 August, and 22 in September. About 9 or 10 o'clock, the clouds mostly 

 broke away rapidly, a light breeze springing up at the same time. 

 Several hours of very pleasant weather occurred towards noon, almost 

 every day. The sun shone forth with genial warmth, the mercury 

 rising generall}' from about 50 at sunrise, to 60 or 65 at noon ; but 

 when the sun had reached the zenith, the wind rapidly increased, 

 coming down in gusts from the hills, which separate the city from the 

 ocean, and often bringing with it clouds of mist. But the dampness is 

 never sufficient to prevent the elevation of clouds of dust and sand, 

 which sport through the streets in the most lively manner. The mer- 

 cury falls suddenly, and long before sunset it fixes itself within a few 

 degrees above 50, where it sticks pertinaciously till next morning; 

 often not moving a hair's breadth for twelve hours. Many times I have 

 examined the instrument on suspicion that some defect had fixed the 

 column immovably. The chilUng temperature adds to the effect of 

 sand and dust. Persons who have business out of doors are seen but* 

 toning up their coats or overcoats, and rubbing industriousl}^ at the 

 various apertures about the face as they hurry through the streets, in 

 the worst possible humor. * Such weather, at the summer solstice, with 

 an ahnost vertical sun, is pronounced "perfectly ridiculous." 

 Mis. Doc. 24 16 



