The surface of Italy is about 90,000 square miles; that of Sicily 10,000 square miles, making together 100,000. A single dust-shower, covering both countries like that of 1803, to the extent of that of Lyons in 1846, would deposit 112,800 cwt. of dust in a single day. With such facts before us, Ehrenberg asks, how many thousand millions of hundredweight of microscopic organisms have reached the earth since the period of Homer, the time of our earliest record of such events? He adds, "I cannot longer doubt, that there are relations according to which living organisms may develope themselves in the atmosphere;" and he speaks of this as a self-development and not a production from introduced He supposes it probable that the atmospheric dustcloud region is of vast extent, and is above a height of 14,000 feet. The facts may seem inexplicable on any other hypothesis; yet much more investigation will be required before an opinion so contrary to received principles can be generally adopted.

ova.

Showers of Blood.

The work proceeds with a historical relation of all showers of dust, blood-rain, red snow, and similar phenomena, from the earliest records to the present time. This history occupies 100 pages of the volume.

The first instance adduced dates about 1500 years before the present era. It is the plague of blood inflicted upon the Egyptians, as related in the Mosaic history, which prevailed. throughout the whole land of Egypt, continuing three days. and three nights.

The second occurred about 1181 B.C., the time of Æneas and Dido, as related by Virgil, Eneid iv., 454:

"Horrendum dictu, latices nigrescere sacros.

Visaque in obscænum se vetere vina cruorem."

The third, about 950 B.C., as described by Homer, Ilias xi., v. 52, 54, and also Ilias xvi., v. 459, 460.

The fourth, about 910 B.C., is the instance of bloody waters mentioned in connection with the victory over the Moabites in 2 Kings iii., v. 21, 22, 23.

Ehrenberg mentions then the rain of blood in the time of

Romulus, as related by Livy, and goes on with other accounts of subsequent date, with regard to which the information is not of as doubtful character as with those just alluded to.

A supplemental chapter contains a notice of meteoric dust showers since 1846. One on the 31st March 1847, in the valley of Gastein, in Salzburg; another in Arabia, January 24, 1848; another in Silesia and Lower Austria, January 31, 1848. The showers afforded similar fresh water and continental forms, with the same South American species before-mentioned, and no characteristic African form. Other showers occurred in 1849. In March there was a reddish dust fell at Catania in Sicily, during a south wind. On the 14th April, during a hail storm in Ireland, there was a black inky deposit, affording numerous microscopic organisms.

The number of showers which Ehrenberg records is in all 340, 81 before Christ and 249 after Christ. Ehrenberg remarks that these showers appear to prevail most within a zone extending from the part of the Atlantic off the west coast of Middle and North Africa, along in the direction of the Mediterranean Sea, reaching a short distance north of this sea, and continued into Asia between the Caspian Sea and the Persian Gulf, perhaps to Turkistan, Kaschgar, and China; and they seldom reach north to Sweden and Russia. This zone, according to the observations of Tuckey, has a breadth of 1800 miles in the north torrid zone. The reddish colour of the dust, as well as the organic forms, shew that the dust is not of African origin. Moreover, the storm winds and sirocco are found to afford the same species of organisms.

Ehrenberg repeats again his opinion that these phenomena are not to be traced to mineral materials from the earth's surface, nor to revolving masses of dust material in space, nor to atmospheric currents simply; but to some general law connected with the earth's atmosphere, according to which there is a self-development within it of living organisms.

The whole number of species of organisms observed is 320. Of marine genera there are only the following: Coscinodiscus, Diploneis, Goniothecium, Grammatophora, and Biddul

phia, besides some Polythalmia and Spongolites. The following are American forms:

A simultaneous occurrence of dust showers and falls of meteoric stones, has been observed in probably eighteen instances before the Christian era. During the Christian era, fourteen coincidences have been observed, making thirtytwo in all.

(Tables and Drawings of Infusoria in a future Number.)

Singing Birds and Sweet Flowers in Jamaica.

"In tropical countries, where brilliant and varied colours have been granted to the birds and flowers, song has been denied to the one and fragrance to the other." This is one of those flippant generalisations which people are fond of repeating, originally made without investigation, and perpetuated without inquiry. In Jamaica it is certainly very far from truth; and I suspect would be found as groundless everywhere else. The groves and fields of this sunny isle ring with the melody of birds, to a degree fully equal, in my judgment, to that of Europe. In the lone forests of the mountain heights the Glass-eye Merle (Merula Jamaicensis) pours forth a rich and continued song; and that mysterious harmonist, the Solitaire (Ptilogonys armillatus), utters his sweet but solemn thrills, long-drawn and slow, like broken notes of a psalm, so perfectly in keeping with the deep solitude. In the woods that cover, as with an ever verdant crown, the lower hills, the Black Shrike (Tityra leuconotus), and the Cotton-tree Sparrow (Pyrrhula violacea), enunciate their clear musical calls, so much alike as scarcely to be distinguished; four or five notes running up the scale so rapidly, as to be fused as it were together, and suddenly falling at the end. There, too, sits the Hopping Dick (Merula leucogenys), and whistles, by the hour together, a rich and mellow

succession of wild notes, clear and flute-like, like his European cousin, the Blackbird. The constantly reiterated call of the Red-eyed Flycatcher (Vireosylva olivacea), "John to whip! John to whip!" heard at different distances from all parts of the woods, makes their green glades lively; and the loud varied voice of the White-eyed Flycatcher Vireo Noveboracensis), sometimes soft and subdued, sometimes shrill and piercing, is always heard with pleasure.

But birds are particularly social animals: and it is chiefly in the neighbourhood of the presence of man that their melodious voices are heard, as if to cheer him in his toil; the fields, and pastures, and meadows, the hedges, and hedgerow trees, that border and map out his domains; the orchards and groves that surround and embosom his dwellings, affording grateful fruit and shadow from the heat :-these are the situations in every inhabited country that most resound with the voices of feathered songsters. The beautiful park-like estates of the southern slopes of Jamaica, present scenes peculiarly inviting and suitable for the winged orchestra to exercise its vocal talent; and the notes of melodious joy are pouring forth in them from earliest dawn to sunset; aye, long before dawn, and long after the veil of night has been outspread. The swallows (Hirundo paciloma) that shoot along in their arrowy traverses over the plains, now darting across the placid stream, now coursing far up in the thin air, almost lost in the glaring sun-beam, twitter sweetly as they pass, and now and then one and another sitting on the summit of a low tree, commence a stammering song by no means deficient in music. The Blue Martins (Progne Dominicensis), too, sit side by side in close rows on the dead frond of some tall palm, or on the roof-ridge of the dwelling house and utter a shrill but not unmelodious chant. From the green tussocks of the Guinea-grass fields comes the singular hollow cry of the Tichicro (Coturniculus tixierus), and now and again he runs to the summit of a stone, or jumps upon a wall, and warbles a sweet low song. The clear whistle of the Banana bird (Icterus leucopteryx) like the tones of a clarionet, resound from the fruit trees, among whose deep green foliage his gay hues, rich yellow, white, and black, glance fitfully as he shoots to and fro; and his companions, the little Blue

Quits (Euphonia Jamaica), equally devoted admirers of a ripe sour sop or custard-apple, accompany his loud notes with strains of their own, full of soft warbling music. And the most minute of birds, the tiny Vervain Humming bird (Mellisuga humilis), not larger than a school-boy's thumb, utters a song so sweet, but of sound so alternated withal, that you wonder who the musician can be, and are ready to think it the voice of an invisible fairy; when presently you see the atom of a performer perched on the very topmost twig of a mango or orange tree, his slender beak open and his spangled throat quivering, as if he would expire his little soul in the effort.-P. U. Gosse, Jamaica.

(To be continued in our next Number.)

I. Coral Reefs and Islands.

II. The Structure, Growth, and Habits of Coral Zoophytes. By JAMES D. DANA, Esq., Naturalist to the American Exploratory Expedition.

1. General Features of Coral Reefs and Islands.

THE general features of reefs and coral islands have often been delineated by travellers, and are probably almost as familiar to the reader as the scenes of the land around us. Yet a few brief remarks on this subject will not be out of place here as preliminary to our observations on the structure, growth, and habits of coral zoophytes.

Coral Reefs. A wide platform of rock covered with the sea, except at low tide, borders most of the high islands of the Pacific. It is a vast accumulation of coral, based upon the bottom in the shallow waters of the shores. This bank or table of coral rock, is of varying width, from a few hundred feet to a mile or more; and, although the surface is usually nearly flat, it is often intersected by irregular boat-channels, or occasionally encloses large bays, affording harbour protection to scores of ships. In very many instances the reef stands at a distance from the shores like an artificial mole, leaving a wide and deep channel between it and the land; and within this channel are other coral reefs, some in scattered patches, and others attached to the shore. The inner reef in these cases, is distinguished as the fringing reef, and the outer as the barrier reef. The sea rolls in heavy surges against the outer margin of the barrier; but the still waters VOL. LII. NO. CIII.-JANUARY 1852.

C