METEOROLOGY. 297 



according to the course and force of the wind and the stage of the 

 river. If the wind blows strongly from the north this fall is still 

 greater, especially during spring tides. The stage of the water is 

 also aftected by the temperature, as well as by the fall of rain. The 

 months of November, December, January, February, March, and 

 April constitute the "rainy season," although more or less rain 

 generally falls during October and May. The first and generally the 

 greatest rise in the river occurs about the 1st of January, after the 

 early rains. The warmer these rains are the less snow falls in the 

 mountains, and consequently the more sudden is the rise of the river. 

 From the middle of January to the middle of February there is gene- 

 rally a marked abatement, and sometimes a complete suspension of 

 rain, and the river declines correspondingly. From the middle of 

 February to the last of April the latter or warmer rains set in, and 

 cause a second or spring rise, which is kept up in accordance with the 

 prevailing temperature. If the spring and early summer have been 

 cold, the spring freshet soon passes off, and the river maintains a 

 high level, as it did in 1857, in consequence of the gradual melting 

 of the snow at its sources ; and the converse obtaining if the hot 

 weather sets in early. Recurring to the hydrographic scale, we would 

 observe that the figures to the left indicate, when applied to the river, 

 the number of feet from zero or extreme low-water mark at spring 

 tide to the highest point the Siicramento has yet been known to rise, 

 viz : nearly 22 feet, in January, 1852. The curves for all the years 

 are not complete,, our notes not being full and regular. The same 

 scale of feet, if read for inches, when applied to the perpendicular 

 lines, will denote at a glance, and which is most important in this 

 connexion, the monthly quantity of rain that fell at Sacramento during 

 the last five years — the rain for 1853-'54 being placed in the first 

 column of each month, of 1855 in the second, and of 1856-'57 in the 

 third. The scale to the right represents inches, and is intended to 

 show the comparative annual fall of rain since the year 1852. As 

 will readily be seen, the rains during 1856-'57 have been so much 

 below the average that they should be regarded as exceptional. 

 Averaging the rains of 1852-'53-'54-'55, we find an annual fall 

 of 21,352 inches ; whereas the average of the last five years gives only 

 17.113 inches. In the rain chart of the Army Meteorological Regis- 

 ter, Sacramento is included with San Francisco in the area of 22 inches 

 of rain ; and Dr. Gibbons puts down the mean annual rain of the 

 latter place at 21.17 inches. This corresponds with our estimate of 

 the amount for Sacramento, and rather strengthens the opinion just 

 expressed, that the years 1856-'57 should be regarded as exceptional. 

 Although the river is, of course, but slightly affected by the amount 

 of rain that falls in this immediate vicinity, nevertheless the con- 

 nexion here preserved is of much interest, inasmuch as experience 

 shows that the amount of rain that falls at Sacramento bears a quan- 

 titative proportion to that which is precipitated in the higher parts of 

 the valley, as well as in the mc untains. Certainly, the river never has 

 attained a high stage when there has occurred a deficit of rain at 

 Sacramento. To substantiate these assertions the following facts, 

 condensed from our publications in the California State Medical 



