302 METEOEOLOGY. 



GENERAL REMARKS. '^ 



a 



The foregoing table for 1856 is the result of three daily observa- 

 tions, made at 7 a. m., 2 p. m., and 9 p. m., with the instruments 

 and instructions recommended by the Smithsonian Institution, The 

 readings of the barometer have been reduced to the temperature of 

 32^ Fahrenheit, but not to sea level. The height of the lower sur- 

 face of the mercury is 41 feet above the mean level of the sea at San 

 Francisco. The rainy days are included in the cloudy and foggy 

 days, and are also put separately to show the number of these days 

 on which rain fell every month. Professor Coffin's psychrometrical 

 table for determining the elastic force of aqueous vapor and the rela- 

 tive humidity of the atmosphere will be used in our register hereafter, 

 and the dew-point column omitted. The following corrections of ' 

 errata are to be applied to our tables for 1853-'54, published in the 

 Smithsonian Report for 1855 : Barometer mean for September, 1853, 

 30.00, and mean mean 30.02 inches ; mean of barometer for January, 

 1854, 30.11 inches. 



MONTHLY REMARKS. 



January. — The means of the barometer and thermometer were above 

 the average of the three preceding years, the former by 0.254 inch, 

 and the latter by 3.59 degrees. The rainy days exceeded the average ■ 

 to the number of seven. There were five days of more or less fog. 

 The quantity of rain was plus the average 1.460 inch. A sprinkle ■ 

 of snow, just enough to be perceptible, occurred on the 8th at 9 a. m. 

 On the 3d frost remained all day unthawed in the shade. 



February, — There was little variation in the atmospheric pressure 

 from that of previous years. The mean temperature was plus the 

 average by 1.14 degree. Spring opened early. On the 7th the wil- 

 low (Salix) flowered. On the 13th the buttercup^ and on the 16th 

 the wild violet were also in blossom. The rain fell short of the 

 average by 1.460 inch. 



March. — The temperature exceeded the average still more this 

 month, being plus 3.12 degrees. Spring progressed rapidly. On the 

 Ist the peach was in full blossom, and on the 10th was leafed out. 

 Although the deficit of rain for the month amounted to 2.560 inches, 

 frequent showers, accompanied on the 29th by lightning and thunder, 

 tempered, in this locality, the effects of the drought which prevailed I 

 generally throughout the State. 



April. — There was very little variation in the readings of the 

 barometer and thermometer from that of previous years. Seasonable 

 rains invigorated vegetation, and although nothing like the deficiency ' 

 was made up, still the Sacramento river remained comparatively high 

 for the season, in consequence of the warm rains melting the snow. 

 Its temperature averaged about 54*^, being four degrees lower than 

 that of well water. The last frost of the season occurred on the 29th. 

 The barn swallow made its first appearance on the 1st, and toward 

 the latter part of the month wild geese were observed wending their 



