most delightful recognition took place in my mind of an old European guest called snow. All the strange stories we had so often heard about the gold and silver mountain Kilima dja aro, in Jagga, supposed to be inaccessible on account of evil spirits, which had killed a great many of those who had attempted to ascend it, were now at once rendered intelligible to me, as, of course, the extreme cold, to which the poor natives are perfect strangers, would soon chill and kill the half-naked visitors."

Further on this gentleman, Mr. Rebmann, writes," May 12, at about five o'clock, P.M., we had to ford another river, called Gona, which was considerably larger than the Lōōmi, its breadth being from thirty to forty feet, and its depth three feet, with a most rapid stream. Its water was cold enough to prove its source, which evidently is nothing else than the eternal snow of the Kilima dja āro." Mr. Rebmann adds to these remarks some particulars respecting a large exploring party sent by the late king of the country to "examine into the nature of that strange white guest in the neighbouring mountain, when only one man was spared, though with his hands and feet destroyed by excessive cold, to tell his despotic sovereign the sad tidings of all his companions having perished in the expedition."

Although loosely stated, the account of this

BLUENESS OF THE AIR.

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mountain is considered by many to be accurate, and if so, it undoubtedly forms one of the most remarkable exceptions to the general rule, with regard to the temperature of high air in the tropics. It is but right to add, that it has been much disputed whether the white cloud on the mountain really was snow. The white and glistening appearance has been supposed to have been caused by something else, because by ordinary calculations a mountain in East Africa to be covered with perpetual snow must approach 16,000 feet in height; and it is by no means clear that Kilima dja āro approaches this degree of altitude. The mean height of the line of perpetual snow is at the equator 15,200 feet.*

We say that the air is transparent,† and without colour; why then, it may be asked, as we gaze upwards, do our eyes rest in every direction upon a vault of so intense and beautiful a blue? The truth is, the air is not perfectly transparent when seen in bulk; and the

Since the above was written, intelligence of a more definite character as to the nature of this mountain has reached England. It now appears to be without a doubt that its summit is capped with perpetual snow.

+ Mr. Darwin says that while ascending the Bell mountain in Central Chile," the evening was fine, and the atmosphere so clear that the masts of the vessels at anchor in the bay of Valparaiso,although no less than twenty-six geographical miles distant, could be distinguished clearly as little black streaks."

cause of the blue colour is the reflection of the rays of light from its particles, and from those of the watery vapour it contains. As we

ascend, the colour deepens in intensity, in consequence of the dark space beyond our atmosphere being seen through it more distinctly, and at the great elevations which have been attained by means of the balloon it almost approaches a black. On the summit of high mountains it is often seen to be of an intense Prussian blue. M. de Saussure made some singular observations upon this subject, and formed a scale of the shades of colour as we ascend. In Coleridge's sublime lines, entitled the Alpine Hymn, this fact is alluded to in speaking of the "Sovran Blanc."

Around thee and above

Deep is the air, and dark, substantial, black,
An ebon mass. Methinks thou piercest it
As with a wedge."

Sometimes, apparently in consequence of the presence of a large quantity of water in the air, the blueness becomes very remarkable. The following letter describes a most curious example of the occurrence of this phenomenon at Bermuda: "On the 10th of August, 1831, the weather," observes the writer, "was remarkably fair; but as evening drew near, a change took place. The sky began to lower, and put on an awful and gloomy appearance. The

clouds collected voluminously, and very heavily, in every direction over the island, indicating a prodigious fall of rain. At this time I do not recollect any threatening of a storm of wind, save a moderately-hollow sound of the sea dashing against the shore, but by no means equalling that which we frequently witness at this season of the year, when a storm is impending, or has passed by us. Thunder and lightning began to be severe, and the weather more threatening. Next morning, the 11th, I rose early for the purpose of writing, and soon discovered the light was so dim that I could not proceed. I removed to another room, and finding my situation not improved, I said, in the presence of one of my family, I apprehended a sudden failure of sight. I was then asked if I had not observed a very peculiar appearance of the sun's rays the day before. I had not; but had perceived the floor of the room to look blue, especially where the sun shone on it: indeed, every object in the room appeared of a sickly blue colour. The next day, the 12th, a mail-boat was put under weigh, for the first time, with a party on board. The day was so mild and tranquil, we could only reach a few miles: the sails, which were new and pure white, nevertheless appeared to be stained of a bluish colour, and the sea was