tinual washing of the sea will effectually clear the surface of the wood of any deleterious matter; and although the foremost depredators may perish in making a lodgement in the interior, yet myriads are ready to supply their places, and to maintain the ground already gained, while the continued action of the water will tend to assist them in their efforts: hence I am of opinion that we have not discovered in Kyan's solution a certain remedy against the destruction of wooden erections in any of the estuaries around our island.

Since the publication of my paper the Lords of the Admiralty have ordered the flooring of the south building-slip in this dock-yard to be removed, and replaced with stone.

I have just learned that two arches of the wooden bridge at Teignmouth have fallen down, in consequence of the piers having been destroyed by the Teredo; so that we have here found another locality for that animal.-Edward Moore, M.D.-Plymouth, Sept. 20th, 1838.

Ignes fatui.-The existence of this meteor, which I have endeavoured to confirm in your journal against the doubts of a correspondent, derives additional support from a statement communicated in Poggendorf's 'Annalen,' No. 6, 1838, p. 366, by Prof. Bessel, who made his observations in a perfectly calm and misty December night. The phenomenon consisted in numerous little flames, which originated over ground in many places covered with stagnant water, and disappeared, after having shone forth a short time. The colour of these flames was somewhat bluish, like that of the impure hydrogen generated from iron filings and dilute sulphuric acid.The observation was made on one of the large moors in the Duchy of Bremen, at the distance of a few leagues from the observatory of Lilienthal. On the ground where the ignes fatui were seen, much peat had been dug out, and the surface is consequently uneven. There were hundreds of lights, each of which lasted about a quarter of a minute. They would often remain in the same place, but often also move horizontally; great numbers of them were commonly put into motion together. These movements were, no doubt, effected by currents of air, which were not perceived at the place where Prof. Bessel was. It will be perceived that in every essential particular the observation agrees with that communicated by me.-W. Weissenborn.-Weimar, Jan. 20th, 1839.

Curious capture of a White-headed Eagle.--In the menagery at the Pfaueninsel, near Potsdam, there is a white-headed eagle (Falco albicilla), which was caught in the following curious manner. It was seen to pounce upon a sturgeon in the river Havel, but the fish was too heavy to be lifted into VOL. III.-No. 28. N. s.

X

the air by the bird, though not strong enough to draw the latter, which struggled with its wings, under the water.Thus the fish rushed along on the surface, the two animals looking much like a boat with the sails spread, until both were secured by some people who went after them in a boat. -Id.

Capture of an Eagle at Swaffham.-About the end of December last a large eagle was observed on Beachamwell warren, about three miles from Swaffham, where it made great destruction among the rabbits. The warreners tried every scheme to entrap it, but without success; as it would not come down to a bait. On the 5th instant one of the keepers of John Motteux, Esq., saw it fly into a plantation adjoining the warren, and by sending a person to the farther side, it was frightened towards him, when he got a shot at it and killed it. It proved to be the white-tailed or cinereous eagle (Falco albicilla, Linn.), weighing 102 lbs., and measuring between the tips of the wings 7 ft. 5 inches; it was a male bird, but not in the adult plumage, the general colour being light brown, and the tail feathers not perfectly white. I have preserved it in my collection of British birds, and on skinning it found it a complete mass of fat.

There was a pair of the long-tailed duck (Anas glacialis, Linn.) killed in the beginning of February, in the neighbourhood of Lynn, but I was not fortunate enough to get them. Two pairs of the red-breasted merganser (Mergus serrator, Linn.) were shot about the same time.-Henry Dugmore, Rector of Pensthorp.-Swaffham, March 12th, 1839.

Early appearance of the common Bat.-I have, the last two years, observed an unusually early appearance of the common bat (Vespertilio pipistrellus). On the 6th of March, 1838, at 1 o'clock, P.M., it being a bright, warm, sunny day, I observed one of these animals flitting about in search of food, in a garden at Poole, in Dorsetshire; and although it frequently flew to a considerable distance, it returned again and again to the same locality, and I continued watching it for a considerable period. On the following day a similar circumstance occurred in another garden at Poole. This year I have observed a still earlier appearance of this little animal, viz., on the 23rd of February. I was riding on that day from Brading to Ryde, in the Isle of Wight, at about half-past 5, P.M. The weather was warm and serene, and the light of the moon was succeeding to that of the sun, which had lately set, when I observed a bat hovering about precisely as in a summer evening. Before arriving at Ryde I saw two more of

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these little creatures, but have not observed any since that date.-T. Bell Salter.--Ryde, March 15th, 1839.

Note on the Hirundinide.-On Wednesday, July the 25th, 1838, about a mile from Blackburn, I saw an immense multitude of swifts (Cypselus Apus); there were several hundreds of them the locality was a print-work and a factory, turned by a water-wheel, a large lodge of water, and several streams, close by the river Darwen; this is always a favourite haunt of the whole of the swallow tribe, and they are generally met with there in great numbers, but so large an assemblage of swifts I never saw before, for of late years there have been very few of them. Could they, at that early period be preparing for their annual migration?

On Friday, October 19th, 1838, I saw three swallows hovering in the streets of Blackburn; they were busy hawking for flies, were strong on the wing, and apparently adult birds. -John Skaife.-Blackburn, Oct. 21st, 1838.

Improvements in the Microscope. In the 'Magazine of Natural History' for June, 1838, page 345, was inserted a notice of improvements in the microscope, made by myself. I have now to inform you of an additional improvement for equalizing the light, and of a facility in adjusting the focus, which now scarcely leaves anything to be wished, in the use of this most invaluable instrument of research in its improved

state.

To equalize the light, I have mounted upon the top of my graduating tube, an exceedingly finely greyed plate of glass, and by this means produce the effect, so very desirable, of a cloud. I thus entirely get rid of the unpleasant glare and glitter produced by the use of a candle or lamp. The greying effect was produced on the surface of the glass plate by the employment of emery, which was suspended in water half a minute, and was thus levigated in a very high degree indeed.

The adjustment of the focus, so highly necessary to accompany every change in the position of an object, I now effect as follows. I have before stated that Mr. Andrew Ross had effected the minute adjustment of the focus, by a fine screw with a milled head. Now, this milled head is placed upon the top of the stem of the microscope, and I had only to bring the left hand into use, instead of letting it lie idle as usual, and to employ it to turn the milled screw-head; and I thus at once constantly effected the minute adjustment of the focus with every change in the position of the object.

I hardly need expatiate upon this great advantage in the use of the microscope. The right hand is fully employed in effecting the crossing motions of the stage; and thus both

hands are most usefully engaged: indeed, after fifty years of constant use of the microscope, I can truly say that it is only now that I am perfectly satisfied in the employment of that instrument. Thomas Gill.-125, Strand, March 23rd, 1839. Anomalous Insect found in Spongilla fluviatilis.—At the meeting of the Entomological Society held on the 3rd of December, 1838, Mr. Westwood read the description of a minute and anomalous species of insect recently discovered as the inhabitant of the Spongilla fluviatilis. These little insects are scarcely more than one eighth of an inch long, and of a pale green colour, with six moderately long legs, having, at first sight, much of the appearance of Aphides. They are, however, apterous, and of a very peculiar structure, so that not only is the family doubtful to which they belong, but even the order and class. The antennæ are about half the length of the body and very slender, and the mouth consists of four naked setæ, exceedingly delicate, porrected, and equalling the antenna in length; they arise in pairs at a short distance apart, and are not inclosed in any sheath, like the set of Hemiptera. The body is clothed with numerous long hairs, and each of the abdominal segments is furnished at the sides with a pair of long, flattened, articulated filaments, somewhat like those of the larva of Sialis lutaria, which are evidently organs of respiration, and are kept in constant agitation in their watery abode. Mr. Westwood is doubtful whether, notwithstanding several of their characters, these insects ought not to be regarded as having arrived at their full growth, as they possess certain points of resemblance with the permanently apterous Coccide and Aphide, whilst there is no tribe or family of insects of which they can be regarded as the larvæ, (except perhaps the anomalous genus Acentropus, that has been regarded by Stephens as Neuropterous, Curtis as Trichopterous, and Westwood as Lepidopterous, and of which the larva is unknown).

Mr. Hogg, F.L.S., by whom these insects were discovered, during a series of minute investigations upon the Spongilla, has arrived at the conclusion that the motions of these insects, and the undulations which they produce in the water, have been mistaken by Laurenti and others for movements of the sponge itself, and which they have accordingly regarded as affording proofs of the animality of that substance.

THE MAGAZINE

OF

NATURAL HISTORY.

MAY, 1839.

ART. I.-Extracts from the Proceedings of the Geological Society of London, relating to the supposed Mammiferous Remains of the Stonesfield Oolitic Strata.1

"Nov. 21, 1838.—A paper was first read 'On the jaws of the Thylacotherium Prevostii (Valenciennes) from Stonesfield,' by Richard Owen, Esq., F.G.S., Hunterian Professor, Royal College of Surgeons.

"Doubts having been recently expressed by M. de Blainville, from inspection of casts, respecting the mammiferous nature of the fossil jaws found at Stonesfield, and assigned to the Marsupialia by Baron Cuvier, Mr. Owen brought the paper before the Society to meet the objections, and to give a detailed account of the fossils from a careful inspection of the originals.— In this communication, however, he confined his description chiefly to the jaws of one of the two genera which have been discovered at Stonesfield, and characterised by having eleven molars in each ramus of the lower jaw, reserving to a future occasion an account of the remains of the other genus. "Mr. Owen commences by observing that the scientific world possesses ample experience of the truth and tact with which the illustrious Cuvier formed his judgments of the affinities of an extinct animal from the inspection of a fossil fragment; and that it is only when so distinguished a comparative anatomist as M. de Blainville questions the determinations, that it becomes the duty of those who possess the means, to investigate the nature of the doubts, and reassure the confidence of geologists in their great guide.

"When Cuvier first hastily examined at Oxford, in 1818, one of the jaws described in this paper, in the possession of Dr. Buckland, he decided that it was allied to the Didelphys, (me semblèrent de quelque didelphe2); and when doubts were raised by M. Constant Prevost, in 18243, relative to the age of the Stonesfield slate, Cuvier, from an examination of a drawing made for the express purpose, was confirmed in his former determination; but he added, that the jaw differs from that of all known carnivorous Mammalia, in having ten molars in a series in the lower jaw: "il [the drawing] me confirme dans l'idée que la première inspection m'en avoit donnée.—

1 For other papers upon this subject by M.M. De Blainville and Valenciennes, see 'Mag. Nat. Hist.' vol. ii. n. s., p. 639, and vol. iii. pp. 1 & 49. 2'Ossemens Foss.' tome iii. P. 349.

3'Annales des Sciences Nat.' Avril, 1825; also the papers of Mr. Broderip and Dr. Fitton in the Zoological Journal, 1828, vol. iii. p. 409. VOL. III.-No. 29. N. s.

Y