Our author visited several of the most important "diggings," and his account of their location, productiveness, &c., does not materially differ from the descriptions which have become familiar to all our readers. It is evident from his statements, that with good health and perseverance, any reasonable expectation of wealth on the part of the miners may be realized, in a few months or years, according to the richness of the "diggings," or the ease with which they may be worked. What, however, has interested us more than the gold-product of California, is the confirmation which our traveler gives to the statements of Fremont and King, relative to the richness of its soil, and its great agricultural capacities. The valleys of the Sacramento and San Joaquim alone are capable of supporting a population of two millions, if carefully cultivated. The deep, black, porous soil produces the important cereal grains, although on the seaboard the air is too cool for the ripening of Indian corn. Enormous crops of wheat may be obtained by irrigation, such as was successfully practiced by the great Jesuit missions; and, without it, from forty to fifty bushels to the bushel of seed have been raised. Oats of the kind grown on the Atlantic grow luxuriantly and wild, self-sown on all the hills of the coast, furnishing abundant supplies for horses. Irish potatoes grow to a great size, and all edible roots cultivated in the States are produced in perfection, without irrigation. The climate of San Francisco is unquestionably disagreeable; the cold, fierce winds which sweep over the bay, and they alternating with extreme heats, are prejudicial to health and comfort. Inland, however, in the beautiful valleys of San Jose and Los Angelos, the climate is all that can be desired. The heat during the summer months is indeed great, but its dryness renders it more endurable than the damp sultriness of an Atlantic August. At Los Angelos, latitude 34° 7', long. W. 118°, and forty miles from the ocean, the mean monthly temperature of ten months was as follows: June 73 deg., July 74, August 75, September 75, October 69, November 59, December 60. Our author describes with a poet's enthusiasm the atmospheric effects of the Californian sunsets. Fresh from his travels in Italy, and with the dust of that Pincian hill still on his sandals from whence Claude sketched his sunsets, he declares that his memory of that classic atmosphere seems cold and pale, when he thinks of the splendor of evening on the bay and mountains of San Francisco.