THE SMITHSONIAN INSTITUTION. 251 



deficient most frequently in the rainy season, but present almost daily 

 in the dry season. The upper cloud was most wanting in the dry 

 season, especially in July. 



The higher currents of the atmosphere, as indicated by the clouds, 

 pursue the same general course as in the Atlantic States. They show 

 the prevalence of an almost constant stream from the tropical regions, 

 traceable to the action of the sun, which heats and rarefies the air 

 within the tropics, and causes it to ascend and pour over towards the 

 poles. Starting northward, the current comes over portions of the 

 earth having a slower rotary motion, and is thus deflected from a due 

 north course, becoming a southwesterl}^ instead of a south current. 



No. 6.- REVIEW OF THE WEATHER FOR THE YEAR 1853. 



The first part of January was cloudy and rainy, but after the 11th 

 the weather was mostly clear and charming, only one rain occurring 

 in the last two weeks. The lowest temperature was 41, and the 

 highest 62. The mean at sunrise was 47i and at noon 56|^. The 

 prevailing winds were very light from north and northwest. There 

 were nine days entirely clear and lour days entirely cloudy. January, 

 1852, was colder, having five mornings below 41 ; January, 1851, was 

 much colder, having thirteen mornings below that point. Both these 

 months were dry, scarcely any rain falling. But the first two weeks 

 of January, 1852, were rainy ; the remainder of the month dry. 

 Sacramento city was drowned on the first of the month. In January, 

 1851, there was three-quarters inch of rain ; 1852, half inch ; and 1853, 

 four inches. 



February, for the first three weeks, the weather was superb. Up 

 to the 21st there were no less than seventeen days entirely clear. In 

 the last week there were four rainy days, but in the whole month only 

 one day was entirely cloudy. The temperature was delightful, the 

 means at sunrise and noon being 48 and 60. The coldest morning 

 42, and the warmest noon 67. The prevailing winds were from north, 

 northwest and west, and most light. The hills were covered with 

 flowers. In February, 1852, there were lour mornings colder than in 

 this month, and in 1851, thirteen colder mornings. February appears 

 to be always a dry month. In 1851 there was one-third inch of rain ; 

 in 1852, half inch ; in 1853, one inch. 



March was mostly a pleasant month, with several moderate rains 

 towards the middle, and three days of heavy rain in the last week. 

 The prevailing winds were from west, northwest, and north, with an 

 increasing tendency to west, and increasing force. The minimum 

 temperature was 41, and the maximum 77 ; mean at sunrise 49 J, and 

 at noon 62. The first week of the month was very warm. On the 

 15th, Mount Diablo was covered with snow, as mostly happens 

 towards the end of March. There is commonly considerable rain in 

 this month. In the dry winter of 1851 there was two inches ; in 1852, 

 six and a half inches ; in 1853, five inches. 



April was a pleasant month, with winds generally from west and 



