On our way on the railroad as well as through El Cajon valley, we have frequently passed alongside of or under the now famous Cuyamaca flume, carrying water to San Diego and Coronado. This flume is a fine structure, running sometimes in the ground, sometimes again on elevated trestle-work over the ravines, or spanning the gaps between lofty hills. The whole length of the flume is thirty-six miles, and the cost of construction was $112,000. Its size is five feet, ten inches wide, and sixteen inches deep, but by an addition of two more boards the depth of the water can be increased to three feet, ten inches,--a large body of water for this country, where water is comparatively scarce. The flume heads in a magnificent dam at the head of San Diego river, and it would suffice to irrigate quite a large stretch of country if the people were only willing to use the water. But the farmers here have been so repeatedly told that the land absolutely needs no irrigation, and indeed would be ruined by the same, that the most of them now fully believe this to be the case. The water is therefore not diverted anywhere along the route of the flume, and even in El Cajon and other places, where the crop of almost every kind of fruit would be doubled by judicious irrigation, no effort to use the same is made. I could find no one who irrigated, and as a consequence the company that owns the flume have not yet put in the extra boards that would more than double the carrying capacity of the flume. One of the most interesting places in San Diego county is the famous Sweetwater dam. It takes only two and one-half hours to visit it and return, and a trip to it will repay the trouble. We start out southeast and cross to National City, only a few miles from San Diego, and really a suburb of that town. National City is decidedly new, an attempt at something grand, which it will take sometime to finish. The most interesting thing there, in a horticultural sense, is the olive orchards of Kimball Brothers. They are scattered in two or three places, and comprise about fifty acres altogether. The trees are as large as good size apple trees, bushy and silvery, and are heavily laden with fruit. The land around each tree was checked up, each tree having a little square for itself, and a Chinaman with a hoe was busy irrigating. In one corner of the orchard was a large circular reservoir five or six feet high, and perhaps twenty feet across, to facilitate the irrigation. The train starts from here directly in among the hills, following the bed of the Sweetwater river. The bottom land is now being settled up by farmers and gardeners, who were busy taking their first lessons in irrigation. The plantations of course are very young, the irrigation works having been finished quite recently. At Sunnyside there are a few older orchards of oranges and olives, but, as a whole, the country is uncultivated.