The Sorata and Illimani were first measured by the distinguished geologist, Pentland, in the years 1827 and 1838; and since the publication of his large map of the basin of the Laguna de Titicaca, in June, 1848, we learn that the above elevations given for the Sorata and Illimani are 3960 feet and 2851 feet too high. His map gives only 21,286 feet for the Sorata, and 21,149 feet for the Illimani. A more exact calculation of the trigonometrical operations of 1838 led Mr. Pentland to these new results. He ascribes an elevation of from 21,700 to 22,350 feet to four summits of the western Cordilleras; and, according to his data, the Peak of Sahama would thus be 926 feet higher than the Chimborazo, but 850 feet lower than the Peak of Aconcagua.
[6]. p. 2—“The desert near the basaltic mountains of Harudsch.”
Near the Egyptian Natron Lakes, which in Strabo’s time had not yet been divided into the six reservoirs by which they are now characterized, there rises abruptly to the north a chain of hills, running from east to west past Fezzan, where it at length appears to form one connected range with the Atlas chain. It divides in north-eastern, as Mount Atlas does in north-western Africa the Lybia, described by Herodotus as inhabited and situated near the sea, from the land of the Berbirs, or Biledulgerid, famed for the abundance of its wild animals. On the borders of Middle Egypt the whole region, south of the 30th degree of latitude, is an ocean of sand, studded here and there with islands or oases abounding in springs and rich in vegetation. Owing to the discoveries of recent travellers, a vast addition has been made to the number of the Oases formerly known, and which the ancients limited to three, compared by Strabo to spots upon a panther’s skin. The third Oasis of the ancients, now called Siwah, was the nomos of Ammon, a hierarchical seat and a resting-place for the caravans, which inclosed within its precincts the temple of the horned Ammon and the spring of the Sun, whose waters were supposed to become cool at certain periods. The ruins of Ummibida (Omm-Beydah) incontestably belong to the fortified caravanserai at the Temple of Ammon, and therefore constitute one of the most ancient monuments which have come down to us from the dawn of human civilization.[[AG]]
The word Oasis is Egyptian, and is synonymous with Auasis and Hyasis.[[AH]] Abulfeda calls the Oases el-Wah. In the latter time of the Cæsars, malefactors were sent to the Oases, being banished to these islands in the sandy ocean, as the Spaniards and English transported their malefactors to the Falkland islands and New Holland. The ocean affords almost a better chance of escape than the desert surrounding the Oases; which, moreover, diminish in fruitfulness in proportion to the greater quantity of sand incorporated in the soil.
The small mountain range of Harudsch (Harudje[[AI]]) consists of grotesquely-shaped basaltic hills. It is the Mons Ater of Pliny, and its western extremity, known as the Soudah mountain, has been recently explored by my unfortunate friend, the enterprising traveller Ritchie. These basaltic eruptions in the tertiary limestone, and rows of hills rising abruptly from fissures, appear to be analogous to the basaltic eruptions in the Vicentine territory.
Nature repeats the same phenomena in the most distant regions of the earth. Hornemann found an immense quantity of petrified fishes’ heads in the limestone formations of the White Harudsch (Harudje el-Abiad), belonging probably to the old chalk. Ritchie and Lyon remarked that the basalt of the Soudah mountain was in many places intimately mingled with carbonate of lime, as is the case in Monte Berico; a phenomenon that is probably connected with eruptions through limestone strata. Lyon’s chart even indicates dolomite in the neighbourhood. Modern mineralogists have found syenite and greenstone, but not basalt, in Egypt. Is it possible that the true basalt, from which many of the ancient vases found in various parts of the country were made, can have been derived from a mountain lying so far to the west? Can the obsidius lapis have come from there, or are we to seek basalt and obsidian on the coast of the Red Sea? The strip of the volcanic eruptions of Harudsch, on the borders of the African desert, moreover reminds the geologist of augitic vesicular amygdaloid, phonolite, and greenstone porphyry, which are only found on the northern and western limits of the steppes of Venezuela and of the plains of the Arkansas, and therefore, as it were, on the ancient coast chains.[[AJ]]
[7]. p. 3—“When suddenly deserted by the tropical east wind, and the sea is covered with weeds.”
It is a remarkable phenomenon, although one generally known to mariners, that in the neighbourhood of the African coast, (between the Canaries and the Cape de Verde islands, and more especially between Cape Bojador and the mouth of the Senegal,) a westerly wind often prevails instead of the usual east or trade wind of the tropics. The cause of this phenomenon is to be ascribed to the far-extending desert of Zahara, and arises from the rarefaction, and consequent vertical ascent of the air over the heated sandy surface. To fill up the vacuum thus occasioned, the cool sea-air rushes in, producing a westerly breeze, adverse to vessels sailing to America; and the mariner, long before he perceives any continent, is made sensible of the effects of its heat-radiating sands. As is well known, a similar cause produces that alternation of sea and land breezes, which prevails at certain hours of the day and night on all sea-coasts.
The accumulation of sea-weed in the neighbourhood of the western coasts of Africa has been often referred to by ancient writers. The local position of this accumulation is a problem which is intimately connected with the conjectures regarding the extent of Phœnician navigation. The Periplus, which has been ascribed to Scylax of Caryanda, and which, according to the investigations of Niebuhr and Letronne, was very probably compiled in the time of Philip of Macedon, contains a description of a kind of fucus sea, Mar de Sargasso, beyond Cerne; but the locality indicated appears to me very different from that assigned to it in the work “De Mirabilibus Auscultationibus,” which for a long time, but incorrectly, bore the great name of Aristotle.[[AK]] “Driven by the east wind,” says the pseudo-Aristotle, “Phœnician mariners came in a four days’ voyage from Gades to a place where the sea was found covered with rushes and sea-weed (θρύον καὶ φῦκος). The sea-weed is uncovered at ebb, and overflowed at flood tide.” Does he not here refer to a shoal lying between the 34th and 36th degrees of latitude? Has a shoal disappeared there in consequence of volcanic revolution? Vobonne refers to rocks north of Madeira.[[AL]] In Scylax it is stated that “the sea beyond Cerne ceases to be navigable in consequence of its great shallowness, its muddiness, and its sea-grass. The sea-grass lies a span thick, and it is pointed at its upper extremity, so that it pricks.” The sea-weed which is found between Cerne (the Phœnician station for merchant vessels, Gaulea; or, according to Gosselin, the small estuary of Fedallah, on the north-west coast of Mauritania,) and Cape Verde, at the present time by no means forms a great meadow or connected group, “mare herbidum,” such as exists on the other side of the Azores. Moreover, in the poetic description of the coast given by Festus Avienus,[[AM]] in which, as Avienus himself very distinctly acknowledges, he availed himself of the journals of Phœnician ships, the impediments presented by the sea-weed are described with great minuteness; but Avienus places the site of this obstacle much further north, towards Ierne, the Holy Isle.
Sic nulla late flabra propellunt ratem,