seasons perhaps ten times, as much rain falls at Shasta as in the region of Kern Lake at the southwestern extremity of the valley. This latter section is the driest region in the whole valley, and probably only half the rain falls there that falls about the vicinity of Bakersfield.

On the Coast Range of Mountains snow very rarely falls, and never lies over twenty-four hours; but on the Sierra Nevada it falls to a depth of 60 or 70 feet, (observations at Summit station, 1866-'67,) and lies throughout the winter with an average depth of 14 feet. This snow forms a great natural store-house of water. It supplies the streams throughout the year. If the greater body of it is melted during the winter by warm rains it causes disastrous floods; but in ordinary seasons the main body of it is melted about June and causes the summer-rise in the rivers.

The law of the greater precipitation of rain upon the western flanks of the mountains is well exhibited in the number, size, and volume of the streams which have their sources in these mountain-ranges. The streams of the west, or seaward, flank of the peninsula of San Francisco and of the Coast Range northward are greater than those on the eastern flank; and especially marked is this in the case of the Sierra Nevada, where it may be also noted that the streams of the west flank exceed in aggregate volume those of both flanks of the Coast Range.

The figures to establish this well-known law are not produced in this place, as they will be used in the remarks upon the unequal fall of rain over the country.

C.-The average yearly rain-fall over the basin of the Great Valley is sufficient to insure good crops annually.

This proposition embraces two vital questions:

1st. What amount of rain-fall, if properly distributed, will insure a crop?

2d. What amount of rain-fall is there over the entire basin? Because if the amount of water is insufficient to insure crops over the entire valley, the whole subject of irrigation becomes limited and restricted, and also more complicated in every aspect.

We are satisfied that the proposition is correct.

We can best determine what amount of rain-fall will guarantee a crop by a good practical example, and fortunately that is at hand. During the rainy seasons of 1870-771, 1871-'72, 1872–273, a record of the rain-fall at Visalia, in the southeastern part of the Great Valley, was kept by Dr. James W. Blake, and is so instructive that we introduce the daily rain-fall for the year, upon which good crops were obtained in that section.

In 1870-'71 the total rain-fall was about 6.8 inches; in 1871-72, 10.3 inches; in 1872-73, 7.2 inches. In the first and third of these years the crops were failures; in the second year the harvest was an abundant one. In 1872-73 the distribution of the rain-fall was very equable and adequate to the end of February; after that only one-quarter of an inch of rain fell upon one day in March and one in April, and the crops were virtually lost.

The critical period in the growing crops appears, in this as in other districts, to be about the middle or end of February, when the grain is several inches high, and another rain-fall of one or two inches would give good crops, whilst a cessation of rain leaves them blighted.

Rain-fall at Visalia, 1871-72, when a full crop was secured.

Throughout the southern sections of California crops have been secured when 12 inches of rain have fallen in the wet season; but the precipitation is not so reliably uniform as farther north. Farmers and stockmen claim good crops with 15 inches of rain, if it has fallen somewhat evenly throughout the season. This amount would not be necessary to mature the crops if, at the beginning of the rainy season, the earth had not been parched several feet deep by the excessive dryness and heat of summer.

The laud cannot be plowed until the first rains have moistened the earth to a sufficient depth. During May we experienced a temperature of 1300 in the sun between Bakersfield and San Emedio Cañon, and for months the temperature in the sun ranges over 100°. This great heat, accompanied by excessive dryness of the atmosphere and months of cloudless sky, evaporates every particle of moisture from the ground, and produces conditions which the farmers of the Atlantic States can hardly comprehend. It also demands a larger supply of water for maturing a crop than would be the case if the ground were moist when the proper season of plowing and sowing arrived.

The second question under this proposition now arises, What is the amount of rain-fall over the basin of the Great Valley?

Although the statistics are not as numerous as could be desired, yet they are sufficient to enable us to affirm with certainty that the average yearly rain-fall is not less than 20 inches, and may be much larger. This, it must be understood, is over the whole basin, from the crest of the Sierra Nevada to the crest-line of the Coast Range.

Commencing at the northward, we gather the following statistics from the Smithsonian publication already noticed, and from other

Sources:

At Fort Crook, on the Upper Sacramento River, elevation 3,390 feet, in eight years, from January, 1858, to October, 1867, an average of 23.7 inches of rain-fall.

At Fort Reading, on the Sacramento River, near Redding, in three and three quarter years, from April, 1852, to March, 1856, 29.1 inches

At Clear Lake, head of Cache Creek, in six years, from 1867 to 1873, 34.4 inches.

At Sacramento, in twenty-four years, from September, 1849, to August, 1872, 19.6 inches.

At Benicia, in thirteen and a half years, from November, 1849, to December, 1864, 15.1 inches.

At Stockton, in three and one-half years, from January, 1854, to December, 1857, 13.7 inches.

At Millerton, on the Sau Joaquin River, in six and three-quarter years, from July, 1851, to June, 1858, 19.0 inches.

Thence, through the broadest part of the valley to Fort Tejon, we have no observations except those at Visalia during the three dry winters of 1870-'71-'72-73, as already detailed, and averaging 8.1 inches. At Fort Tejon, 3,240 feet above the sea and 3,000 feet above the valley, in four and two-third years, from March, 1855, to August, 1864, 19.5 inches.

From the mouth of the Sacramento southward along the west side of the valley, to its extremity, there are no records by which we can approximate the rain-fall.

The averages of the foregoing results, giving them weights proportionate to the number of years of observations, give the following

results:

Average yearly rain fall in the valley, or foot-hills of the Valley of California, north of the mouth of the Sacramento River, equals 23 inches; average in the valley south of the Sacramento River, 16 inches.

In the southern part of the valley, the average rain-fall over the valley proper is barely sufficient for maturing a crop if we consider that at Fort Tejon, in the mountains, the rain-fall is heavier than in the valley, and therefore that the derived average of 16 inches, which was obtained for a short period and few stations, is too great.

This is confirmed by the experience of the country where the usual estimate is that one crop in three years or two crops in five years is all that can be raised.

But both in the northern and southern parts of the valley, the flanks of the mountains, where, as we have shown, the largest rain-fall takes place, have a greater area than the plains of the valley, and therefore throughout the northern and southern parts of the basin there falls, on the average, a superabundance of water for all the purposes of maturing

crops.

D.-The rain-fall in different years is very variable, and seasons of drought and of great floods occur, and in any one season it is very unequally distributed in different sections.

A glance at the annexed charts of rain-fall will show to what a narrow belt of coast the rain fall upon the Pacific slope is restricted, in fact, embracing but the State of California, part of Oregon, and Washington Territory, while the region for which irrigation is required embraces but a fraction of California.

Hence it is very evident that any slight modification in the immediate causes which occasion the precipitation of rain along the coast will lead to large variations in the rain-fall of different localities and of different seasons.

A deflection of the oceanic current which bathes the western coast of the United States, or the decrease of the temperature of this stream by a few degrees, and the absence of the vapor-laden air which hangs over it, or the absence or moderate character of the "southeasters" during the winter months, or all combined, will be accompanied by months of

beautifully clear skies, mild weather, and a very small amount of rainfall.

But no matter what the causes are, we have to deal with the facts as we find them, and can best illustrate our proposition by some examples in California from the Smithsonian tables collated to 1867.

Table showing the extremes of rain-fall at various localities in California.

These results* do not, however, fairly represent the ranges, because the yearly averages of the tables are computed from January 1 to December 31 of each year, as is done in the Atlantic States, but they are the best available.

From other sources we have the following results reckoned by wet

seasons.

At Clear Lake, (1,300 feet elevation, 6 years,) range.
At Visalia, (3 years,) range

At San Francisco, (22 years,) range
At Pillarcitos, (9 years,) range

At Sacramento, (24 years,) range

At San Diego, (22 years,) range.
At Modesto, (1870-'71).

At Stockton, (1870-'71)
At Marysville, (1870-'71)

These minima clearly indicate that there must exist years of drought when the crops cannot mature, and we have shown that a few inches more of water from rain-fall or from irrigation would have saved the produce of large areas of land.

In some seasons the greater volume of rain falls early in the season, and if the seed is sown before that the crops seem assured; but a following dry spring, as in 1873, cuts off one-half the crop throughout the moister parts of the valley, and totally destroys the crops in the southern part, except those isolated places blessed with the waters of irrigation, which we visited at localities on the east and west sides of the southern part of the valley.

The rain-fall of the years 1868-69, 1869-'70, 1870-'71, was marked as not only below the average over the whole extent of the country, but throughout the southern section south of Monterey, and in the southern part of the Great Valley the rain-fall was so limited that neither grain nor grass grew. Hundreds of farms were abandoned, and stock-men were compelled to drive their cattle, horses, and sheep to the gulches of the mountains not only for food but for water.

Smithsonian Contributions to Knowledge No. 222, already cited.

+ At Shasta it is reported that 94 inches of rain fell in 1870-71, which was a dry winter over the rest of the State, and 32 inches in 1872-73, which was a wet winter with moderately dry spring.

In February, 1870, not a blade of grass was to be seen over the extensive valley of the Santa Clara; and the broad plains of Los Angeles, covering over one million of acres of arable land, were nearly desolate even to the borders of the streams. From Tulare Lake to San Diego, the country was nearly desolate; and in March, 1871, the usual season when the crops should be luxuriant, not a blade of grass was to be seen over the great plains and through the valleys, which are richly covered after favorable rains. Hundreds of thousands of sheep, horses, and cattle were lost by starvation.

The practical deduction of the farmers in the southern part of the Great Valley is that they can secure about two crops in five seasons; but this is still reduced in the extreme southern section, where we traversed ten and twenty miles at a time without a cabin to indicate a claim, yet where the land was remarkably good. The great drought of the seasons 1862-'63, 1863-64, when only 13.6 and 10.1 inches of rain fell at San Francisco, was not so severely felt by the State, because the population was much smaller, and grain-crops were not then so largely cultivated; but a recurrence of such years at the present time or in the future would be accompanied by the most disastrous results to the prosperity of the country, unless artificial means be adopted to secure the use of the waters from the streams.

In 1850 only 7.0 inches of rain fell at San Francisco; such a season now without irrigation would produce a famine.

E---With a proper system of controlling the waters of precipitation and delivering them to cultivated lands when needed, annual ́crops may be assured.

The statistics of rain-fall which we have presented and our personal knowledge of the country satisfy us that the average rain-fall is sufficient to secure an annual crop if the water be properly distributed; but a still more important question arises, whether in seasons of insufficient rainfall enough water can be gathered from the streams draining the flanks of the mountain-range and applied to the cultivated lands, in addition to the rain-fall, to mature the crop. The statistics of rain-fall and crops at Visalia, already given, though limited, are valuable in this connection; but the experience last spring of the farmers on and beyond the line of the San Joaquin and King's River Canal is particularly interesting.

In this section we examined about twenty thousand acres of nearly matured crops at the end of May, and received from the farmers themselves their statement of the effects of irrigation.

Up to the time when the rains ceased, in February, the prospects of the farmers were particularly bright, and they would not take the waters of irrigation.

The grain was about six inches high, and very strong; but the dry weather, clear skies, and north winds soon parched up the earth, and the wheat began to grow yellow and sickly.

About the beginning of March every exertion was made to use the waters of the canal for irrigation; secondary ditches were hurriedly cut, and the water conveyed to the lands in a very crude manner.

One good flooding was given to saturate the soil; the grain revived, the crop was saved, and when we visited it the farmers claimed from thirty to as high as fifty-five bushels of wheat per acre.

They were earnest and enthusiastic in their praise of irrigation, as well they might be, for it was simply the difference of a total loss of their year's labor and grain that would yield them $1.20 per bushel.