Page:Mexico, Aztec, Spanish and Republican, Vol 2.djvu/461

 crops yielded by that mode of cultivation. With irrigation a succession of crops may be produced throughout the year."

The peculiarities of the climate of California are so well explained in a letter from the Honorable T. Butler King, that we extract his observations thereon as the most valuable portion of the report made by him to the United States Government in March, 1850.

"The north-east winds, in their progress across the continent, towards the Pacific ocean, pass over the snow-capped ridges of the Rocky Mountains and the Sierra Nevada, and are of course deprived of all the moisture which can be extracted from them by the low temperature of that region of eternal snow; consequently no moisture can be precipitated from them, in the form of dew or rain, in a higher temperature than that to which they have been subjected. They pass therefore over the hills and plains of California, where the temperature is very high in summer, in a very dry state; and so far from being charged with moisture, they absorb, like a sponge, all that the atmosphere and surface of the earth can yield, until both become, apparently, perfectly dry.

"This process commences when the line of the sun's greatest attraction comes north in summer, bringing with it vast atmospheric movements. Their approach produces the dry season in California, which, governed by these laws, continues until some time after the sun repasses the equator in September, when, about the middle of November, the climate being relieved from these north-east currents of air, the south-west winds set in from the ocean, charged with moisture—the rains commence, and continue to fall, not constantly, as some persons have represented, but with sufficient frequency to designate the period of their continuance, as the wet season, from about the middle of November until the middle of May, in the latitude of San Francisco.

"It follows, as a matter of course, that the dry season commences first, and continues longest in the southern portions of the Territory, and that the climate of the northern part is influenced in a much less degree by the causes which I have mentioned than any other section of the country. Consequently, we find that as low down as latitude 39º rains are sufficiently frequent in summer to render irrigation quite unnecessary to the perfect maturity of any crop which is suited to the soil and climate.