_Subirrigation._--Subirrigation may be either artificial or natural. The artificial subirrigation has, as far as I know, only been used in a few vineyards in Yolo and Solano counties, the report, shortly after it had been established, being very flattering as regards its success. But of late years we have heard nothing about this kind of irrigation, and it is likely that some practical difficulty was encountered which could not be fully overcome. The artificial subirrigation consists in laying larger and smaller cement pipes between the rows of the vines. These pipes are perforated in various places, and, when filled with water under pressure, the water runs through the perforated holes and keeps the ground outside the pipes constantly moist, without causing the surface of the soil to get wet and weedy, and herein consist the principal advantages of the system, as well as in the fact that rolling ground can be irrigated thus without being previously leveled and without being cut up with open ditches. The difficulty of keeping the holes open and of preventing the roots of the vines from entering the pipes is, I understand, very great and probably impossible to overcome. Both irrigation water and liquid manures could by this system be supplied to the roots of the vines directly without any waste, and, in cases of diseases or attacks by underground pests, medicines or insecticides could be brought to the soil with the least possible cost. The natural subirrigation is caused either by the whole soil filling up with water from the natural and original water level to the very top or to the roots of the vines, or from an impervious hardpan or clay, as subsoil, up towards the surface. As an example of the former we might cite the country around the irrigated plains of the San Joaquin valley, especially around Fresno and in Mussel Slough. Before irrigation was begun there in 1872, the surface water was from sixty to seventy feet from the top east of the railroad, and from forty to fifty feet west of the railroad, lower down in the valley. After five years of irrigation it began to be noticed that the soil required less water. The water in the wells began to rise, and the following year the water stood in many places near or on the top of the surface. Now the whole irrigated district around Fresno has filled up with water to such an extent that drainage ditches have become necessary in some places in order to lower the water in the wet season some four or five feet from the surface. Many more drainage ditches will be required, as in wet winters the surface water in places is not only very near the top, but actually forms ponds or swamps where formerly the ground was entirely dry.