cost more trouble and expense than it is worth. It is not only artificial oyster-beds which are claimed as private property, but many of those in the open sea, on various parts of our coasts. Oysters of good repute are fished in the neighbourhood of the Channel Islands. There are two oyster-banks, the one off Guernsey and the other off Jersey. The former is of little importance, the latter of considerable value. They belong to the region of oyster-banks which extends along the coasts of Normandy and Brittany. Dr Knapp informs us that the number procured annually from them, for the use of the Channel Islands and English markets, cannot be less than 800,000 tubs, each tub containing two English bushels; and in some years thrice that quantity is believed to be procured from those banks during the season. As many as three hundred cutters have been employed upon them dredging. The oysters on the Jersey bank are of large size, and are sold at from five to seven shillings the tub, or from three to four pence the dozen. Milne-Edwards and Audouin state (in their Histoire Naturelle du Littoral de la France), that, during the year 1828, the total number dredged on the French banks of this region was about 52,000,000, the average price of which was three francs fifty cents for every "miller," i. e., twelve hundred. These French oyster-banks are stated, by the authors quoted, to yield a produce valued at from eight to nine hundred thousand francs a-year. Before the French oyster-fisheries were put under restrictions, the banks were deteriorating through continual fishing. The oyster-fishery of most consequence in Scotland is that of the Frith of Forth, respecting which some valuable information has been communicated to us by Dr Knapp. The oyster-beds there extend about twenty miles, from the island of Mucra to Cockenzie, and are dredged in from four to six or seven fathoms water. The best are procured near Burntisland, on a bed belonging to the Earl of Morton,—on the rocky ground opposite Portobello,-and at Prestonpans. The price varies, wholesale, from two shillings to two shillings and sixpence per hundred ; the retail price from two shillings and sixpence to four shillings and sixpence, or even five shillings. Eight or ten years ago the price was much less; but an individual having taken the ground off Newhaven for a high rent, which he is said never to have paid, so cleared the beds that they have since been comparatively rare.* Natural oyster-beds, of small extent, occur at some distance from land in several places around the Isle of Man. The principal is that off Lascey; but, though the oysters are fine and well flavoured, their abundance is not sufficient to induce a regular fishery. *Note on the Oyster-Fisheries which supply the Edinburgh Market. By Mr George D. Mojjat. Twenty-five boats, working for four months, viz., September, October, March, and April, say sixty-four days (four days per week), dredge at an average 480 oysters per boat per day. Inde, 25 x 64 x 480 = Eight boats, working for four months, viz., November, December, January, and February, say sixty-four days (four days per week) dredge at an average 480 oysters per day per boat. Inde, 8 x 64 x 480 = 768,000 245,760 Number of oysters dredged at an average in the season at 1,013,760 Fisherrow, Prestonpans, and Cockenzie, may be taken in, all at the same ratio. Therefore, doubling the above, makes 2,027,520 oysters, which may be calculated to be dredged in the Forth in the season; only three-fourth parts of which, however, it is believed are sent to Edinburgh, being 1,520,640. From the foregoing average, the quantity dredged per day may be stated as follows: The same number for Fisherrow, Prestonpans, and Cockenzie, makes 31,680, three-fourth parts of which, as before mentioned, come to Edinburgh, being 23,760. With regard to the consumption in Edinburgh, it will be apparent, that out of the season of eight months, only 128 days are stated, these being the men's working days. But the days of the consumption of these molluscs in town, are (excluding Sundays), out of eight months, 207 days. Inde, as before, 1,520,640207 7346 oysters, being the average daily consumed in Edinburgh during the season, from the beginning of September till the end of April. On both sides of Ireland oysters abound in many places, and some of the banks are valuable, producing oysters in abundance, and of good quality. In the west, the most famous are Burton Bindon's oysters, which are highly esteemed in Dublin. They are the Burran oysters, brought from the Burran bank in Galway Bay, where they are laid down artificially, after having been originally dredged chiefly near Achil Head. There are oyster-beds in the Shannon, said, in 1836, to yield a revenue of £1400 annually, and to employ seventy men and sixteen boats. Some small oysterbeds in Clare are private property, and yield various incomes, as do those also in Cork harbour, but none of them are of any extent. Oysters are dredged from natural beds on the coast of Wexford and elsewhere, in order to be laid down on the Beaumaris beds. The most renowned of the Irish oysterfisheries is that of Carlingford. The shell-fish are there dredged by boats, each manned by from three to five men, who take about fifty dozen a-day. The oysters of each boat are deposited within a ring of large stones till sold, the place being marked by a buoy. They are sold to dealers only, at from 8d. to 2s. per ten dozen. A yearly fee of 5s. is paid by each boat to the Marquis of Anglesey. The fishermen earn from 4d. to 1s. 6d. per diem, and are mostly landholders.* There are natural oyster-beds in Belfast Bay, on banks at a depth of from 12 to 25 fathoms. Mr W. Thomson informs us that, in March 1848, he had the four largest oysters selected from about five hundred taken on these beds, and by weighing them before their being opened, found two to be each one pound and a-half, the third one pound and threequarters, and the fourth two pounds imperial weight. "The two largest oysters," he states, "on being taken from their shells, weighed each an ounce and a-half, and the others somewhat less. The oysters from which these were selected were sold at the rate of sixteen shillings for the one hundred and twenty-four. The shells were in length from 5 to 61 inches; in breadth, from 5 inches to 5; and in depth, with the valves closed, 2 inches." There are oyster-beds partly * Report on Irish Fisheries for 1836. private, and increased by planting in Loch Swilly. Irish oyster-dredgers have a notion that the more the banks are dredged, the more the oysters breed.* Comets Great Number of Recorded Comets-The Number of those unrecorded probably much greater-General Description of a Comet-Comets without Tails, or with more than one-Their extreme Tenuity-Their probable StructureMotions conformable to the Law of Gravity-Actual Dimensions of Comets-Great Interest at present attached to Cometary Astronomy, and its Reasons-Remarks on Cometary Orbits in general. In the admirable Outlines of Astronomy, by Sir John F. W. Herschel, just published, where all is excellent, we were deeply interested with the account of those wonderful members of our system-the Comets. From this masterpiece of thought and writing, we now lay before our readers the following extracts:† The extraordinary aspect of comets, their rapid and seemingly irregular motions, the unexpected manner in which they often burst upon us, and the imposing magnitudes which they occasionally assume, have, in all ages, rendered them objects of astonishment, not unmixed with superstitious dread to the uninstructed, and an enigma to those most conversant with the wonders of creation, and the operations of natural causes. Even now, that we have ceased to regard their movements as irregular, or as governed by other laws than those which retain the planets in their orbits, their intimate nature, and the offices they perform in the economy of our *The above observations are from Part XX. of Messrs Forbes and Stanley's valuable History of British Mollusca. To those interested in the natural and œconomic history of the common oyster, we recommend the perusal of a paper on the Danish Oyster-Beds, by M. H. Kroyer, at page 28 of vol. xxix. of this Journal. † Outlines of Astronomy. By Sir John F. W. Herschel, Bart., &c. &c. &c. 1 vol. 8vo, pp. 661. London: Longman, Brown, Green, and Longmans; and J. Taylor. 1849. No distinct and sa system, are as much unknown as ever. tisfactory account has yet been rendered of those immensely voluminous appendages which they bear about with them, and which are known by the name of their tails (though improperly, since they often precede them in their motions), any more than of several other singularities which they present. The number of comets which have been astronomically observed, or of which notices have been recorded in history, is very great, amounting to several hundreds; and when we consider that, in the earlier ages of astronomy, and indeed in more recent times, before the invention of the telescope, only large and conspicuous ones were noticed, and that, since due attention has been paid to the subject, scarcely a year has passed without the observation of one or two of these bodies, and that sometimes two, and even three, have appeared at once,-it will be easily supposed that their actual number must be at least many thousands. Multitudes, indeed, must escape all observation, by reason of their paths traversing only that part of the heavens which is above the horizon in the day-time. Comets so circumstanced can only become visible by the rare coincidence of a total eclipse of the sun,—a coincidence which happened, as related by Seneca, sixty-two years before Christ, when a large comet was actually observed very near the sun. Several, however, stand on record as having been bright enough to be seen with the naked eye in the day-time, even at noon and in bright sunshine. Such were the comets of 1402, 1532, and 1843, and that of 43 B.C. which appeared during the games celebrated by Augustus in honour of Venus shortly after the death of Cæsar, and which the flattery of poets declared to be the soul of that hero taking its place among the divinities. That feelings of awe and astonishment should be excited by the sudden and unexpected appearance of a great comet, is no way surprising; being, in fact, according to the accounts we have of such events, one of the most imposing of all natural phenomena. Comets consist for the most part of a large and more or less splendid, but ill-defined nebulous mass of light, called the head, which is usually much brighter towards its centre, and offers the appearance of a |