Page:Palestine Exploration Fund - Quarterly Statement for 1894.djvu/63

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ON THE FALL OF RAIN AT JERUSALEM.
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mean there were three groups, two of three and one of five years, viz., 1864 to 1866, 1871 to 1875, and 1877 to 1879.
In November above the mean there were two groups of three, viz., 1872 to 1874, and 1890 to 1892; below the mean there were two groups, one of seven and the other of three years, viz., 1865 to 1871, and 1878 to 1880. In December above the mean there were two groups of three, viz., in 1871 to 1873, and 1890 to 1892; below the mean there were three groups, two of three and one of four successive years, viz., 1864 to 1866, 1874 to 1876, and 1881 to 1884.

Therefore, in every month of the rainy season the fall has been above the mean for three or four years in succession; once in March it was above for five years. The fall also has been below the mean for three or four years consecutively; once, both in March and April, it extended to five years, and once, also in March, to six years, and in November there were seven in succession below the mean.

Comparing the yearly falls with the average, viz., 25·23 inches, the first group of three below the mean was in the years 1864, 1865, and 1866. The next is a group of five years, viz., from 1869 to 1873, and besides these there are no two years in succession below the mean.

The first two years in succession above the mean was in 1867 and 1868; the next two years, 1874 and 1875, the next 1882 and 1883; then four years, 1885 to 1888, and three years, 1890, 1891, and 1892.

From the long group of five years of deficient rainfall, ending in 1873, no two dry years have come together, and five years only out of the subsequent 19 have been below the average, and the remaining 14 above, made up of three instances of two successive years of excess, one of four, and one of three. From the five dry years, ending 1873, there has been a gradual increase of rain, and future observations will be looked forward to with very great interest indeed, for it is not possible to infer whether the years ending 1873 were the lowest in a cycle of years, or whether the climate is changing.

From Table III it appears that the number of rainy days has varied—

In January from 3 in 1881 to 19 in 1883 and 1888.
In JanuaryFebruary from 1 in 1870 to 18 in 1868 and 1884.
In JanuaryMarch from 2 in 1892 to 20 in 1874.
In JanuaryApril from 1 in 1861 to 13 in 1868 and 1870.
In JanuaryMay from 0 in several years to 5 in 1867, 1886, and 1892.
In September from none in several years to 2 in 1864 and 1878.
In SeptemberOctober from none in several years to 7 in 1863.
In SeptemberNovember from 1 in several years to 13 in 1888.
In SeptemberDecember from 2 in 1884 to 17 in 1890.

In the months of the rainy season the days of rain have been as few as 1, 2, or 3 in some years, and as many as 17 to 20 in other years.