State Agricultural Society. 427 



be constructed which have been proposed in connection with a general 

 irrigation system, converting the lake into a reservoir and raising its 

 surface so that its waters can be conducted out over the surface of the 

 soil, the entire volume of water then conducted by the canals will be an 

 addition to the supply available for irrigation and transportation, with- 

 out abstracting any part of that which now flows through the natural 

 drainage courses. The same thing may be true of other irrigation works 

 depending on this matter of underground drainage, as it operates upon 

 the streams and at the poinjt whence their supply is obtained. Thus the 

 effect of the San Joaquin and King's Eiver Canal upon- the volume of 

 water flowing in the San Joaquin, has been tested by the experiment of 

 closing the head-gates so as to exclude all water from the canal. The 

 effect was to raise the water in the river below the head-works exactly 

 one inch! The explanation of this apparent anomaly is, that about this 

 portion of its course the San Joaquin receives an important accession of 

 volume from underground drainage — probably from the Tulare Lake 

 drainage; thus its waters are maintained at a given level, whether one 

 canal full be abstracted or not. It is possible that an amount of water 

 might be taken from the San Joaquin at this point equal to the volume 

 discharged into the lake by King's Eiver, without materially decreasing 

 its volume. Such an amount would require three or four canals of the 

 size of the present one. The fact that one tenth of the visible volume of 

 the river at its lowest stage can be taken froni it with a decrease of volume 

 which is barely appreciable (lowering the surface one inch) is very re- 

 markable, and of a high degree of scientific interest. 



METEOROLOGY. 



Besides the absence of rainfall, explained above, other important 

 features of the meteorology of this region are the winds and dews. 

 Throughout the Summer a fierce wind from the northward, parallel with 

 the main axis of the plains, draws over them from one. end to the other. 

 With some local exceptions, it appears to increase in intensity proceed- 

 ing southward. It is due to the heating of the table lands and deserts 

 lying beyond the Tejon, rarif'ying the atmosphere over their surface, 

 which rises, while a portion of that from the California plains rushes in 

 to fill its place. These gales rise daily soon after sunrise, and continue 

 to blow till towards midnight. It follows that large areas of the plains, 

 fitted by soil, irrigation, and other circumstances for the cultivation of 

 cotton, hops, and such crops of the more valuable sorts, will be unavail- 

 able therefor at present, and until trees — all kinds of which appear to 

 flourish luxuriantly under the stimulus of irrigation — shall have been 

 planted and attained sufficient size to afford protection from this zephyr 

 of truly California type. Where the native trees now grow, the protec- 

 tion is often sufficient, and amid the stately groves of Tulare County 

 every crop can be raised with profusion. The absence of dews through- 

 out all the region north of Tulare Lake must also be noticed. To the 

 east of that lake the dews appear again and are often heavy. What dif- 

 ferences, if any, in the character and growth of some of the more valu- 

 able crops in these several localities may become attributable to this 

 circumstance, experience must be left to determine. 



