Climate : Kaitna and Flora. — For many years past, meteorological observations have been taken at various points in Palestine, and have been tAbulateil and commented on annually by Glaisher. There are three di.stinctive climates in Palestine: (1) that of the seashore, which corre- sponils toother Mediterranean climates in similar liitil\ide; (•_') that of the hill-country, which is iiuire hot and oppre.ssive than the hill country in otlier parta of tlie Mediterramun, owing to the vicinity of the Arabian Desert on south and en.«t; and |3| that of the valley of the Jordan and Sail Sea.
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JORDAN
JORDAN
Tlie climate of the hill-country, Jerusalem for example, is pleasant in the winter, but hot and trj-ing for six months in the summer. During the heat of summer in a liouse in Jerusalem the temperature day after day will for two or three hours reach 104° F., and it sometimes does not go below 80° F. all night. The published returns, how- ever, give much lower readings in the air, with a mean temperature for August of 75° F. In the Jordan Valley in summer-time the heat is in- tense, the temperature being 110° F. after sunset, and scarcely falling daring the night when in the vicinity of rocks with a southern aspect. During the first two months of the year the temperature in the Jordan Valley is very pleasant, hot in the daytime and cool at night, often going down to 40 F. except close to the Salt Sea. Sluch depends, however, upon the direction of the wind. In the month of March there is often snow on the hills. The climate of the Jordan Valley is tropical ; that of the region of the Salt Sea is equatorial, prob- ably the most heated in the world, owing to the de- pressed character of the plain, hemmed in east and west by high mountains. There is a differ- ence of elevation between the summit of Mount Hemion and the level of the Salt Sea of over 10,000 ft., and the ditl'erence of temperature and of climate allows of a great variety of animal life. That on the seashore generally is Mediterranean, while that in the Jordan Valley, especially in the lower parts, is principally Ethic i[iian or Indian, though these parts are cut oil from each other by the deserts of Arabia.
The follo^^^ng observations concerning life in the Jordan Valley are extracted principally from SJVP, Fauna and Flora (Tristram). Here is a patch of tropical character, containing southern forms so peculiar and unique that their presence cannot be connected with any existing causes or other transporting influences. As it has been found by Humboldt that zones of elevation on mountains correspond to parallels of latitude, so here we find a zone of depression, the only one known to us, producing similar phenomena, and exhibiting in generic correspondence the fauna and flora of much lower latitudes : an Ethiopian flora identical with that now existing in Ethiopian regions in the midst of a Mediterranean district.
Tristram considers that the whole of Syria and Arabia Petra?a must have emerged from the Mio- cene ocean while the coast of the Mediterranean was the bed of a Miocene sea, and that during this period Palestine was connected with Ethiopia ; that during the Miocene and Pliocene periods the Jordan basin fonued the northernmost of a long system of fresh-water lakes, extending from north to south, of which, perhaps in the earlier part of the epoch, the Red Sea and Nile basin, Nyanza, Nyassa, and Tanganyika lakes were members.
During that warm period, fluviatUe ichthyologi- cal fauna were developed suitable to its then condi- tions, consisting of representative and perhaps frequently identical species, throughout tne area under consideration. The advent of the Glacial period was, like its close, gradual, and, while many species may have perished, the hardiest would have survived, and have gradually modified to meet the changed conditions. But however severe the climate may have been, that of the Lebanon with its glaciers probably corresponding to the Alps at a proportional elevation (due re- card being had to latitude), the fissure of the Jordan lay, as we know, as much depressed as at present, and there must have been an exceptionally warm temperature in its waters in Avhich the existing ichttiyological fauna could survive.
According to Slater's definition of boundary lines laid before the Linneean Society in 1858, Palestine
forms an extreme southern province of the Palaj- arctic region. An analysis of each class of it» fauna and of its phanerogamic flora shows that while an overwhelming majority of its species in all cases belong to the Pala'arctic region, there is in each class a group of exceptions and peculiar forms which cannot be referred to that region, and the presence of many of which cannot be explained merely by the fact of the l'ala;arctic infringing on the Etliiopian region, and not very distantly on the Indian, but can be satisfactorily accounted for only by reference to the geological history of the country. These species are almost all strictly con- fined to the area of the Jordan Valley and Dead Sea basin.
Of the mammalia, 55 are Palsearctic, 34 Ethio- pian, 16 Indian, and 13 peculiar out of 118. The Indian include 9 which are also Ethiopian, and the Ethiopian 9 which are equally Indian. Of the 13 peculiar forms, 3 are modifications of Patearctic types and 6 are Ethiopian in their character. One species, Lcpus judmcs, the hare of the Dead Sea basin, differs from either the European or Syrian species in the form of its skull. The Uyrax syriacus belongs to a strictly Ethiopian genus, and no theorj' of immigration or di.spersion can account for its presence. Fish of small size abound in the Jordan and its tributaries down to the entrance to the Salt Sea ; the}- bear a strong aflSnity to many of the species of the Nile, though with far less admixture of species than is found in other rivers of the Eastern Mediterranean. Out of 35 species, 2 are Nilotic, 1 Mediterranean, 7 common to the Tigris and Euphrates, 10 common to Syria and the Damascus lakes, and 16 peculiar to the Jordan. There is a great affinity between these fish and those of the rivers and lakes of tropical Africa. These fishes probably date from the earliest times after the elevation of the country above the Eocene ocean, and they form a group more distinct and divergent from that of the surrounding region than can be found in any other class of existing life. The affinity is very close to the forms of the rivers and fresh-water laKes of east Africa, even as far south as the Zambesi ; but while the genera are the same, the species are rather representative than identical. The solution lies in the theory of the Jordan basin having been one of a system of fresh- water lakes, extending from north to south as already proposed. There are no fish in the Salt Sea.