STATE AGRICULTURAL SOCIETY. 165 



from the mean maxima and mean minima, are given, whilst the diifer- 

 ence of the mean temperature of the regions specified are contrasted. 

 To facilitate the comparative estimate, the latitude, longitude, altitude, 

 and mean annual amount of rain, are also inserted. Tiatse contrasted 

 summaries show how irregularly isothermal localities in the State are 

 distributed, and also how widely the nearest approximated points are 

 thermally separated from each other. It is also seen that while there 

 are but few places in which the precipitation of aqueous vapor is approx- 

 imately the same, there are many in which the difference is remarkably 

 striking. These anomalies of temperature and rain distribution, while 

 putting to fault the general law that in temperate latitudes the atmos- 

 pheric temperature is reduced one degree for every three hundred and 

 thirty-three feet of elevation above the sea, and that the quantity of rain 

 diminishes in advancing from the equator to the poles, can by no means 

 be construed into any manifestation of uniformity or correspondence 

 between the ranges of temperature and quantities of rain at different 

 elevations. As is well known, the proper adaptation of agricultural oper- 

 ations to the seasons — the periodical rains — contributes more to the suc- 

 cess of the farmer in California than any other, we might say, every other 

 circumstance. For this reason the rain tables are particularly worthy 

 the study of the natural economist. They are arranged according to 

 the seasons, commencing with September and ending with August. In 

 them will be found the quantity of rain that falls in each month, the 

 total for each year, and the mean monthly and annual supply. 



Our climate is thus seen to have seven months in which it always 

 rains more or less, viz: From November to May, inclusive, with only 

 one single exception ; and five in which it seldom rains, and then for the 

 most part vevy lightl3^ June, July, and August are the driest as well 

 as the hottest months. The heavy rain in July, eighteen hundred and 

 sixty, when over half an inch fell at Sacramento, and the third of an inch 

 on the same da}'' at San Francisco, is a rare exception to the general 

 rule. September and October may be regarded as intermediate between 

 the dry and hot and rainy and cold months. In September, eighteen 

 hundred and fiftj^-one, one inch of rain fell; and the mean monthly rain 

 for the last sixteen 3^ears, amounting to .084 inches, shows the tendency 

 in this month to aqueous precipitation. In October, eighteen hundred 

 and fifty-eight, three inches fell, and the mean monthly rain is about half 

 an inch. December furnishes more than any other month; January 

 next; then February, March, November, April, and May, in the order 

 named. The rain of September, eighteen hundred and fifty-one, and 

 July, eighteen hundi-ed and sixty, present the greatest deviation from 

 the rule. The greatest amount of water that ever fell in any one month 

 was in January, eighteen hundred and sixty-two, and the next greatest 

 in December, eighteen hundred and fifty-two. One half of the supply 

 for the season falls before the last of January, and the other half after 

 that date. There is generally an interim of dry weather, between these 

 dates, of four to eight weeks' duration. The spring rains are quite as 

 constant as those of the previous period, observing generally the same 

 tendency'. If they fall sparingly in the earlier half of the season, they 

 will continue to do so in the latter half Front these results it is evident 

 that, to secure good crops, the seed must be sown at such time and the 

 ground must be prepared in such manner as to secure the full benefit of 

 such rains. This is the view taken and the point insisted upon in the 

 metereological report published in the transactions of this society in 

 eighteen hundred and sixty-three, and time only strengthens the posi- 



