Εικόνες σελίδας
PDF
Ηλεκτρ. έκδοση

from eighteen to twenty-seven gallons, was once
common in the country.

СНАР.

V.

1

About three miles beyond Cana, we passed the village of Turan. Near to this place they Turan. pretend to shew the field where the Disciples of Jesus Christ plucked the ears of corn upon the Sabbath-day? The Italian Catholics have named it the field “ degli Setti Spini ;” and they gather the bearded wheat, which is annually growing there, as a part of the collection of relics to be conveyed to their own country. The heat of this day was greater than any to which we had yet been exposed in the Levant ; nor did we afterwards encounter anything so powerful. Captain Culverhouse had the misfortune to break his umbrella -- a frivolous event in milder latitudes, but here of so much importance, that all hopes of continuing our journey depended upon its being repaired. Fortunately beneath some rocks, over which we were then passing, there were caverns“, Caverns. excavated by primæval shepherds, as a shelter

[ocr errors][ocr errors][ocr errors]

(3) Luke vi. 1. Matth. xii. ). Mark ii. 23.

(4) Small reservoirs for containing water, of great antiquity, some in the form of basons, appeared in these caverns.

V.

Intense
Heat.

CHAP. from scorching beams capable of baking bread,

and actually of dressing meat’: into these caves we crept, not only for the purpose of restoring the umbrella, but also to profit by the opportunity thus offered of unpacking our ther. mometers, and of ascertaining the temperature of the atmosphere. It was now twelve o'clock. The mercury, in a subterraneous recess, perfectly shaded, the scale being placed so as not to touch the rock, remained at one hundred degrees of Fahrenheit. As to making any observation in the sun's rays, it was impossible ; no one of the party had courage to wait with the thermometer a single instant in such a situation.

Basaltic Pheno-. mepa.

Along this route, particularly between Cana and Turan, we observed basaltic phænomena. The extremities of columns, prismatically formed, penetrated the surface of the soil, so as to ren

der our journey rough and unpleasant. These Origin ex- marks of regular or of irregular crystallization, plained.

generally denote the vicinity of a bed of water lying beneath their level. The traveller, passing

Their

(1) We afterwards ate bread which had been thus baked, in a camp of Djezzar's troops, in the Plain of Esdraelon; and the first Lieutenant of the Romulus frigate ate bacon so dressed, in Aboukir.

[ocr errors]

V.

the ur la

series of successive plains, resembling, CHAP. in their gradation, the order of a staircase, observes as he descends to the inferior stratum upon which the water rests, that where rocks are disclosed, the appearance of crystallization has taken place; and then the prismatic configuration is vulgarly denominated basaltic. When this series of depressed surfaces occurs very frequently, and the prismatic form is very evident, the Swedes, from the resemblance such rocks have to an artificial flight of steps, call them Trap; a word signifying, in their language, a staircase. In this state Science remains at present, concerning an appearance in Nature which exhibits nothing more than the common process of crystallization, upon a larger scale than has hitherto excited attention. Nothing is more

[ocr errors][ocr errors][ocr errors][ocr errors]

(2) See the observations which occur in pp. 420, 421, vol. II. of the 8vo. edition of these Travels. It was in consequence of a journey upon the Rhine, in the year 1793, that the author first applied the theory of crystallization towards explaining the formation of what are vulgarly called basaltic pillars; an appearance common to a variety of different mineral substances, imbedded in which are found Ammo nites, vegetable impressions, fossil wood, crystals of feldspar, masses of chalcedony, zeolite, and sparry carbonate of lime. He has seen the prismatic configuration, to which the term basaltic is usually applied, in common compact limestone. Werner, according to Professor Jameson, (Syst. of Min. vol. I. p. 372), confines basalt to “ the floetz Trap formation," and (p. 369, ibid.) to the concretionary structure ;

alluding

V.

CHAP. frequent in the vicinity of very antient lakes,

in the bed of considerable rivers, or by the
borders of the ocean. Such an appearance
therefore, in the approach to the Lake of Tiberias,
is only a parallel to similar phænomena exhibited
by rocks near the lakes of Locarno and Bolsenna
in Italy; by those of the Wenner Lake in Sweden;
by the bed of the Rhine, near Cologne in
Germany'; by the Valley of Ronca, in the
territory of Verona”; by the Giant's Causeway
of the Pont du Bridon, in the state of Venice',
and by numerous other examples in the same
country; not to enumerate instances which
occur over all the islands between the north

[merged small][ocr errors]

alluding to a particular substance under that appellation. Count Bournon
(see Note 3. p. 421. vol. 11. of this edition)considers the basaltic form as the
result of a retreat. This is coming very near to the theory maintained
by the author: in furtherance of which, he will only urge, as a more
general remark, that“ all crystals are concretionary, and all columnar
minerals crystals, more or less regular, the consequences of a retreat."

(1) The town gates of Cologne are constructed of stones having
the form commonly called basaltic; and similar substances may be
observed in the walls.

(2) See the account published by the Abate Fortis, “ Della Valle di Ronca nel Territorio Veronese," printed at Venice in 1778.

(3) See“ Memoria de' Monti Colonnari di S. E. il Signor Cavaliere Giovanni Strange," printed at Milan in 1778, for a beautiful representation of this Causeway; engraved by Fessard, from a drawing by De Veyrenc. Also the representations given in the LXIst volume of the Philosophical Transactions of the Royal Society of London, Tab. 19, p. 583, &c.

[ocr errors]
[ocr errors][ocr errors][merged small][merged small]

CHAP.

V.

[ocr errors]

coast of Ireland and Iceland, as well as in
Spain, Portugal, Arabia, and India“. When these
crystals have attained a regularity of structure,
the form is often hexagonal, like that of Cannon
Spar, or of the Asiatic and American emeralds.
It is worthy of remark, that Patrin, during his
visit to the mountain Odon Tchelon, in the deserts
of Oriental Tahtary, discovered, in breaking the
former kind of emerald, when fresh taken from

[ocr errors][ocr errors]

() See the numerous other instances mentioned by Professor JAMESON, (Syst. of Min. vol. I. p. 372. Edin. 1804,) in stating the geographical situation of basalt; a vague term, as he properly expresses it, which ought to be banished from mineralogy: it is in fact applied to any substance which exhibits the phænomena of crystallization upon a large scale, whenever the prisms are large enough to be considered as columns.

(5) Commonly called Siberian Beryl, and Peruvian Emerald. HaïY,
Patrin, and others, have shewn the impropriety of separating these
varieties of the emerald. Some consider the colouring principle as suf-
ficient to distinguish them, which is oxide of iron in the Asiatic emerald,
and of chromium in the American. But it should be observed, that the
emerald of Peru does not always contain chromium ; neither is it yet
known that it does not contain iron. The author has specimens of
the Peruvian emerald, white and limpid as the purest rock crystal.
What then becomes of a distinction founded upon colour ? PATRIN
preserves the names of emerald, chrysolite, and aigue marine, as all
applicable to the Siberian mineral ; but he says, “ Ces gemmes ont la
meme forme cristalline, la meme pesanteur spécifique, la meme dureté
que l'émeraude du Perou ; elles contiennent la meme quantité de glucine;
elles ont encore la double refraction de l'émeraude. Elles n'en différent
donc que par la couleur ; et l'on a ru, par l'exemple du rubis d'Orient,
combien la couleur est nulle aux yeux du naturaliste." Hist. Nat. des
Min. tom. II. p. 23. Paris, An 9.
VOL. IV.

o

[ocr errors]
« ΠροηγούμενηΣυνέχεια »