without could see the luminous flashing eyes of beasts of prey among the bushes, attracted by the scent of food, but which did not venture upon a nearer approach, and they were soon scared away, and once more all was quiet till daylight.

The morning was splendid, and the day which followed brilliant ; indeed, I may almost say, too brilliant, for we were in a close and sweltering valley in which the November sun had very great power. Our Scheik told us that it was a remarkably cool and pleasant day, and to him probably the heat did not appear intense; but we could only try to picture to ourselves what a hot day must be in these regions if this was to be considered a cool one. We all felt languid and oppressed by the heavy motionless air; and one of our party, the youngest, was so overcome by it that in the middle of the day we had to send him back to camp under an escort, with threatenings of sunstroke. We mounted our horses at eight o'clock for an interesting excursion to the Dead Sea and the Jordan. We first passed through the bush or scrub-irregular ground with clumps of the thorny shrub called nubk. The soil was bored with a great many holes or burrows by a small animal, apparently a species of squirrel, of which we caught glimpses from time to time nimbly scudding to their retreats. We were at this time too far from the banks of the Dead Sea to meet with the curious characteristics of its lifeless shores; but our route was in a rather easterly direction, which brought us, in the course of an hour, to an inhabited village, situated upon a mound, which I have already mentioned as being probably the site of Gilgal. This village is now called Riha, or Eriha, a word bearing a strong similarity to Jericho, in whose immediate neighbourhood it undoubtedly is, though not perhaps absolutely the site of that great city itself. Riha is a small place of a couple of hundred inhabitants, who bear a very bad character, and is, I believe, the only settled inhabited spot hereabout. On the mound in the centre of the village is a medieval ruin, which is usually known as the house of Zacchæus, but with no claim to that distinction beyond the fact that it was as our Lord passed through Jericho that that interesting episode occurred related in Luke xix. 1-6. But if Riha be really Gilgal, it is a place of surpassing interest, as the first foothold of the wandering Israelites on their arrival in the Land of Promise. Gilgal, we read (Josh. iv. 19), was in the east border of Jericho ;" and if Jericho had a border at all, then must this be Gilgal, and not Jericho itself, for which there is plenty of space between this spot and our camp to the westward. For we are here not far from the Jordan, just such a distance

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as we might suppose the Israelites would have marched from their wondrous ford until they should find a suitable resting-place. "The people came up out of Jordan . . . and encamped in Gilgal. . . And those twelve stones which they took out of Jordan did Joshua pitch in Gilgal." (See also Josh. v. 9.)

Jericho itself doubtless stood upon the plain which we have just crossed or skirted, a plain now desolate, barren, given up to wild beasts, but which once was designated "the plain of the valley of Jericho, the city of palm-trees" (Deut. xxxiv. 3). It must in those days have been a splendid cluster of towers, seen amid groves of majestic and useful trees. But palms have long since ceased to be characteristic of this plain, though it is said that one solitary tree remained in 1838. The grapes of Eshcol had taught the spies the fertility of the soil; the walls of the great city of Jericho, of the wealth and power of the people; and the children of Anak who dwelt there must have altogether combined to strike awe into the minds of those who were going up to brave all, with the conviction that they were to dispossess the lords of the soil and to conquer them through the might of Jehovah. What an unparalleled scene was that when the proud and exalted towers of Jericho fell flat before the ark of the Lord and the rams' horns of the priests; when the people shouted and rushed in through the levelled defences and Jericho became the first-fruits of the spoil of Israel !

A curse was uttered against the rebuilders of Jericho: "Cursed be he that riseth up and buildeth this city of Jericho: he shall lay the foundation thereof in his firstborn, and in his youngest son shall he set up the gates of it" (Josh. vi. 26). But notwithstanding this curse, there were found in after times those who were willing to brave it; and in 1 Kings xvi. 34 we read that in the days of wicked Ahab "did Hiel the Beth-elite build Jericho: he laid the foundation thereof in Abiram his firstborn, and set up the gates thereof in his youngest son Segub, according to the word of the Lord, which He spake by Joshua the son of Nun." It was to this restored Jericho, where was a school of prophets, that Elijah and Elisha went from Bethel on their way to cross Jordan when the former was taken up; and in later times Herod the Great adorned the city and resided there, and there he died. We read of it in the New Testament as the last place visited by our Lord, who, passing through Jericho, marked Zacchæus in the sycamore-tree; and from there "ascended up" to Jerusalem, tarrying at Bethany, and making thence His last entry into the Holy City riding upon an ass's colt (Luke xix.).

From Riha (Gilgal) we turned southwards, and now came into the district rendered characteristic by the vicinity of the Dead Sea. Here we took leave of bushes and shrubs; no more vegetation marked the country, but the soil became soft and sandy, honeycombed and cavernous, and arranged in numerous terraces, which seemed to imply that there was a gradual subsidence. Large pit-like depressions extend for a considerable distance, while spots here and there remaining point out the original level from which it had last sunk. It was not difficult to trace three successive terraces, or levels, in some places. The surface of the soil was covered over with a thin white incrustation of salt, and nothing seemed capable of growing out of it, although I noticed one small shrub in our path which appeared to have sprung up, but was now dead. The sea itself looked close at hand when we were yet two hours' distant from it; and as we approached we observed a number of bare, gaunt, whitened branches of trees which had been carried down by the river, and afterwards thrown up on the north-west shore by the wind. No shells strew the sandy beach, nor do any fishes exist in its bitter waters, it is truly a Dead Sea; although it is not an Avernus over which if birds fly they fall dead into its waters, as some would feign. It is also said, on the other hand, with what truth I am not able to state, that madrepores have been found in the Dead Sea. The water was perfectly clear and bright, and to the sight offered no indications of differing from other waters; and yet in its constitutions and geological position this sheet of water is among the most remarkable in the world, though not without parallel.

The extraordinary characteristics of the Dead Sea, or as it is termed in Scripture," the sea of the plain, even the salt sea" (Josh. iii. 16), are, first, that it lies at the depression of 1292 feet below the level of the Mediterranean, unequalled in this respect by any other known lake. It has positively no outlet, but is cooped up in the heart of the mountains, the nearest body of water, the Gulf of Arabah, being on the same level as the Mediterranean. It receives the waters of the Jordan and some insignificant tributaries from the mountains, but these are not sufficient to overcome other influences and keep the waters of the Dead Sea of the same nature and character as other waters. But its most prominent characteristic is its extraordinary saltness; for the waters of the Dead Sea, instead of being like other inland lakes, or even possessing a saltness of 4 per cent., which is the average of the waters of the ocean, absolutely contain 264 per cent. of salt! The reason of this accumulation appears to be the existence of a mountain of rock salt in

its south-western corner, which impregnates its waters, whose evaporation in the hot, low, confined valley cannot be compensated by the small bodies of fresh water which flow into it from the Jordan and other sources.

Here, then, we were upon the banks of this well-known and singular sea; not the saltest in the world, however, for some Russian lakes near the Volga are said to have a saltness of 29 per cent. Nevertheless, some natural consequences arising from its high degree of salinity we now proceeded to put to the test. We were most of us determined to have a swim in its waters, whose remarkable buoyancy was one of its most curious characters. The hot sun, the dazzling atmosphere, the white salt-incrusted landscape, and the brightness of the waters themselves all invited us to plunge into them. And yet it was necessary to act with caution; and our dragoman warned us against taking a header, or even plunging overhead at all into these clear waters. And this for two reasons: first, because the preternatural saltness of the water would cause intense irritation to the eyes, if any got into them, and the fearful bitterness would equally offend the taste if a mouthful of it were inadvertently swallowed. But a more important reason was, that, owing to its buoyancy, the heaviest part of the body, viz. the head, would inevitably tend to sink, at the expense of the lighter portions, or the legs, and hence it would be difficult to regain one's upright position, and the result would be the danger of being drowned. We soon discovered the truth of this; for while, on the one hand, we could not sink, on the other we were almost equally unable to swim. It was easy to lie in the water perfectly motionless, as upon a couch, the only objection being the tendency presently to roll over and for the head to fall in; but when we attempted to swim we discovered that our legs refused to remain in the water, but persisted in striking out into the air for want of weight-rejected from the water like pieces of wood; neither did it do to splash about, lest the water should get into our eyes and mouth. Altogether the bath caused great amusement as well as interest, though it left our hair and beards incrusted with salt, and our skin not in so soft and pleasant a condition as a Turkish bath would have done. These désagréments, however, we did not mind, because it was our intention, after quitting the banks of the Dead Sea, to proceed to the Jordan, and then, pilgrim-like, dip in its fresh flowing waters and wash off the impurities of the Salt Sea.

(To be continued.)

DISCOURSES FROM NATURE FOR JUNIOR READERS.

IV.

THE subject for our study to-day is closely connected with that which engaged cur attention in our former discourses. The science of sound or acoustics is no less interesting than that of light. The phenomena of each appeal to a special organ of sensation, and hence as presented to the mind, appear to have no relation, yet the radical cause of each is the same. We have previously said that all spaces infinitely great or infinitely small are filled with a subtle, elastic medium so light that no balance can detect it. This medium is called ether, and light is the effect of intensely rapid wave-motion in this ether. Sound is the result also of the movement or vibration, first of some substance or body, and then of a surrounding medium. It is not difficult to prove this. I have here a large glass vessel filled with water. I strike the edge of the vessel a sharp quick blow and you hear a musical sound. That the glass is thrown into rapid motion by the blow is clearly proved by the surface of the water being broken up into beautiful rhythmic forms. On this plate of metal is some fine sand. A fiddle-bow is drawn across an edge of the plate, and the sand begins to dance in a most lively fashion. Nothing can be more evident than that, when sound is drawn from the metal by the bow the plate is in very rapid motion. These two experiments show that vibration of a body is the cause of sound, but they do not tell us how the motion affects the ear. Further evidence is required. Under the receiver of an air-pump we place a carefully-fixed bell. The hammer strikes the sonorous metal and the bell rings out clearly. The air is now pumped out of the glass receiver, and the sound gradually becomes weaker and weaker until at length it ceases altogether. The air is again admitted and the sound revives. If now you were asked what is necessary for the production of sound beside the motion of the particles of a body, you would say without hesitation, atmospheric air. Precisely so. The motion of the sounding body sets the air around in vibration, and sound-waves are produced. These waves are not quite like light-waves, and they do not move so rapidly. As you have before learned that light is a form of motion, so you will understand now that sound is likewise a mode of motion. The nervous network of the eye receives the impact or blow of the light-waves, and the delicate mechanism of the ear takes up the pulses of the soundwaves and conveys them to the brain. We have proved, then, that atmospheric air is necessary for the production of sound, and it may be easily shown that it is essential to life. Air, then, is a thing of the