over Portsdown-hill, the iris as yet incomplete: at 55 minutes past six, the moon shining in a clear space, with an altitude of only 740, a distance of 29° westward of the meridian, and the rain moderately descending, our gratification was completed, at the expense of a wetting, by the appearance of a perfect lunar iris, of a silvery colour in a black passing nimbus or rain-fraught cloud to the N.E. No prismatic colours were distinguishable in any part of the iris, the moon not having come to her first quarter; consequently her light seemed too faint to produce a variety of colours in the bow. The extent of the iris along the plane of the earth's surface was 81° 34'; that is, within 3° of its greatest extent, on the supposition of an observer standing on a plain ground, with the moon in the horizon: and the altitude of its apex above the horizon was upwards of 27°. By comparisons of this measurement with solar rainbows, when the sun has had a similar altitude, we conclude that there is no perceptible difference in the extent of the solar and lunar iris. On the 19th December 1820, we observed a faint lunar iris to the westward, in a thick fog, from 7 till 8 P.M.; but the altitude of the moon being upwards of 30°, the apex of the iris was not more than 10° or 11° above the horizon. On the 15th October 1820, we observed a perfect lunar iris to the N.E., with part of an exterior bow above it, during a shower at 9 P.M., in which some faint prismatic colours were discovered, the moon at that time being almost in the middle of her second quarter. On the 25th of August 1817, we also observed a perfect lunar iris to the N.W. from 30 to 40 minutes past 8 P.M. on a large but slowly passing nimbus, the moon being to the S.E. and nearly full: prismatic colours were distinctly traced in this iris; but they certainly bore no near comparison with those of the solar rainbow that appeared the following afternoon. In all these appearances of the lunar iris, the weather at the respective times was unsettled and stormy for several days together: the phænomenon, however, is not a prognostic, but rather the effect of a series of sudden storms. From these remarks we may conclude, that the best time to look out for such a rare phænomenon is in stormy weather, when the nimbi pass in quick succession over us, and when the moon has a low altitude and is at least five or six days old (12 or 14 or 16 would be better): but the nearer she is to the horizon at either rising or setting, the more beautiful and extensive will the silvery arc appear with its delicate prismatic colours in the front of the rain-cloud, which must come from or near the quarter in which the moon appears. Note on Mr. MURRAY'S Paper on the Relation of Acids and Alkalies to vegetable Colours. IN reference to Mr. Murray's letter which appeared in our last Number, p. 170, it has been suggested to us to refer our readers to vol. v. p. 125; vol. vi. p. 152; vol. xi. p. 402, of the Quarterly Journal of Science, where Mr. Faraday's original remarks on the action of boracic acid and other acids on turmeric paper are stated as they occurred to him some years since::-Also that it may perhaps occur to Mr. M. that, as he had not seen Mr. F.'s previous observations, Mr. F. probably had not seen his when he wrote the additional observation, vol. xiii. p. 315. Page 171, line 17, for Turmeire read turmeric. ELEMENTS LX. Notices respecting New Books. LEMENTS of the Philosophy of Plants. By A. P. Decardolle, and K. Sprengell. Translated from the German. Transactions of the Horticultural Society of London, vol. v. Part I. 4to. 17. 11s. 6d. A System of Mechanics. By the Rev. J. R. Robinson. 8vo. Remarks on the present defective State of the Nautical Almanack. By Francis Baily, F.R.S. and L.S. 8vo. 2s. 6d. Practical Electricity and Galvanism. By John Cuthbertson, 8vo. 12s. Preparing for Publication. In a few days will be published, in one neat pocket volume, a new Edition of Mr. Parkes's Rudiments of Chemistry, carefully corrected, and adapted to the present state of chemical science. This edition is printed on a larger and better paper than heretofore, and the new matter which has been added since the publication of the first impression, has enlarged the volume full one-fourth beyond its original size. A new and copious Index will be appended to the work, and it will be illustrated with several highly-finished Copper-plate Engravings of Chemical Apparatus. ANALYSIS OF PERIODICAL WORKS ON ZOOLOGY AND BOTANY. The Botanical Register. No. 92. Two elegant and beautiful species of Thysanotus (Brown Prod.) commence this month's Number. The plants of this singular genus are all natives of New Holland; and, until very lately, have been strangers to our gardens. Th. isantherus, Pl. 655, is distinguished by bulbous roots; and Th. junceus, which follows, is likewise figured in this month's Number of Curtis's Magazine. Pl. 657. Elæocarpus reticulata. 658. Papaver bracteatum. This plant has been already so well figured (only a few months back) in Mr. Lindley's elegant elegant work, that we see no reason why it is repeated in this publication, particularly as Mr. Lindley's description is copied : moreover, it occupies the space of two plates, which could have been devoted, with much more advantage, to some other of the increasing number of unrecorded plants abounding in the London gardens. Pl. 659. Aneilema sinica, a new plant from China, thus defined: A. caule ramoso diffuso; foliis ligulatis, acuminatis, racemulis alternis subsenis supernè in paniculâ positis: staminibus tribus barbatis quorum uno castrato; sterilibus tribus nudis. Pl. 660. Passiflora pallida, an interesting plant of this elegant genus. Pl. 661, Argyreia cuneata, is a genus distinguished from Convolvulus and Ipomea, "principally by an indehiscent seed-vessel with one-seeded cells.", Curtis's Botanical Magazine. No. 429. To prevent a constant repetition of numbers, we shall in future notice the plates in their regular series, merely giving the number of the first plate, which is 2350, and represents Arthropodium cirratum Willd. beautifully figured on a double plate. Thysanotus junceus, the same plant, unluckily, as we have noticed above in the Register: from a comparison of the two plates, it appears this has been made from a dwarf specimen. The dissections, however, in this are an advantage the other does not possess. Crinum aquaticum, a plant, brought from Southern Africa by Mr. Burchell, which Mr. Herbert has here described. Like Amaryllis revoluta and insignis, it is not, probably, a distinct species from Am. ornata, but Mr. H. is obliged, by the principles he has laid down in defining the genera of Amaryllideæ, to propose it as a genus possibly distinct from any other. Some botanists will consider this as an additional proof that he is wrong in what he' has done in his proposed reformation of the Order; and will question whe ther his new species of Crinum and Amaryllis be any more distinct than the gardeners' varieties of Tulipa, Geranium, &c. Instead of a concise specific character (after the excellent example of Linnæus) we have a detailed description too long for us to copy. Alstroemeria pulchella, Linn., from China. Passiflora lunata; we strongly suspect the leaf represented in outline, as a variety, is, in fact, a very distinct species; as, from native specimens in our Herbarium, the flowers are stated to be very large and white. Crinum arenarium; given as another new addition to this genus, but we doubt whether it be specifically different from Cr. asiaticum: we must protest against the novel mode Mr. Herbert has here introduced of making descriptions and even specific characters of plants from measurement; because until all the plants of one species can be made to grow of one size, such measurements will only suit the individual sample from which they have been taken. Mr. Herbert is a botanist of ability, and we hope he will give this subject further consideration. Swainson's Zoological Illustrations. No. 25. This number commences the third volume of this beautifully executed work. Plate 120 represents Ampullaria corrugata, and the figures and descriptions sufficiently point it out as distinct from A. globosa, figured on the plate of the 2d volume; it is thus defined :-A. testâ globosâ, corrugatâ, olivaceâ; spiræ prominentes, acutæ, anfractibus ventricosis; apertura margine crasso, fulvo, sulcato; umbilico parvo, juxta labii interioris mediam posito; operculo testaceo. Mr. S. observes, that Mr. B. Sowerby has mis taken this shell for the Amp, rugosa of Lam., which has a thin, and not a thick and reflected, margin round the aperture.--Plate 121: This is the most beautiful plate yet given in the work, and represents a new and superbly coloured Creeper, belonging to the African genus Cinnyris, but erroneously placed by Dr. Horsfield among the Nectarinia, which, Mr. S. remarks, are all American birds. C. Javanica, supra nitidè purpureo-ærata, subtus subtus olivaceo-crocea; scapulis, uropygio, strigaque laterali a rostro ad pectus descendente nitidè violaceis; jugulo castaneo; cauda nigra. Plates 122 and 123 contain four uncommon varieties of the true A. virginea (Bulla virginea, Lin.), under which name so many shells have been placed. Mr. Swainson's definition of the characters which belong to this variable species, is as follows:-A. virginea, testâ elongatâ, fasciis numerosis nigris viridibus et flavis ornatâ ; anfractus basalis latitudine altitudinem superante; aperturâ rotundatâ labio exteriore integro; basi profundè emarginatâ.- Licinia crisia, Sw.: the male and female of this insect differ in a remarkable manner, and had not observations been made on the living insects, we should almost have doubted their connexion. Greville's Scottish Cryptogamic Flora. Mr. Greville's last No. (4) contains the curious Echinella fasciculata, which by many would be considered of animal origin; but which, as neglected by the zoologist, we are happy to see (whatever may be its real nature) taken up by the botanist: Puccinia Buxi: Amanita nivalis, a delicate new species which well merits the name, whether we consider the snowy whiteness of its hue, or its truly alpine situation among the snow of the highest of the Grampian Hills: Uredo effusa (the U. Spirea of Sowerby); and a new species of Namaspora, N. Rosarum. Under this last individual we have an observation, "that the Genus Namaspora may be found eventually to border too closely upon many species of the old Genus Sphæria.” The justness of this remark will be apparent to those who will trouble them selves to compare the excellent magnified section of the Nam. Rosarum with those of Cryptosphæria Taxi, (Sphæria Taxi of Sowerby,) figured in Mr. Greville's 3d Number. It is by such admirable analyses of the parts of fructification of these obscure plants, that we may expect much new light to be thrown upon the subject. LXI. Intelligence and Miscellaneous Articles. LAW OF CALORIC STATED BY M. LAPLACE. IN an inquiry on the attraction of spherical bodies and the repulsion of elastic fluids, M. Laplace unfolds in the Annales de Chimie, xviii. 185 seq., the following remarkable law agreeing with experiment : "The quantity of heat which is disengaged from a bulk of gas passing under a determined pressure from a higher into a lower temperature, is proportional to the square root of this pressure." This accounts, among other things, for the great advantage of high pressure steam-engines; the pressure which the steam exerts being proportional to the caloric contained in a given space, which may be considered as an unity; the pressure or tension of the steam increases in a much greater ratio than the quantity of caloric, that is to say, fourfold, while the caloric is doubled. DISTRIBUTION OF TEMPERATURE IN METALS BY MECHANICAL CONCUSSION. It is well known that carters are in the habit of well hammering the axles of their waggons, before they put them in motion in a hard frost, in order by this means to guard the iron which has become brittle against breaking. The utility of this practice in great and sudden changes of temperature in a metal becomes obvious, if we recollect that in Laplace's and Lavoisier's experiments on the expansion of metallic rods, these rods would only take. an uniform temperature in their whole length when they had been subjected to percussion. Ann. de Chim. xviii. 35. Vol. 60. No. 294. Oct. 1822. S s OBSER OBSERVATIONS OF THE PRESENT COMET, BY PROFESSOR HARDING OF GETTINGEN. From observations of August 21, 27, and Sept. 2, Professor Harding derived the following parabolical elements: Time of Perihelium, 1822, October 23, Inclination of orbit Long. of 2h. 45' 1" 272° 28′ 31′′ 92 24 50 52 28 46 The comet was discovered by Pons at Marlia, July 13, and by Gambard at Marseilles, July 20. In Germany it was first found on the 20th August: when it was nearly visible by the naked eye. Mr. Enke at Seeberg has clearly convinced himself, by comparing earlier observations made at Marseilles with those of August and September, that its orbit is elliptical, and he has found the following elements. Time of passage through the Pe- October 24 ·99374, Mean Time of rihelium } Motion retrograde. 270°31'30'7 0.96617805 Sceberg. These elements agree with the arc described during two months to 0'5. Mr. Enke is now engaged in further correcting them by later observations, which, however, must soon be closed, as the comet will become invisible in the twilight. ADIPOCIRE OF CORPSES. The adipocire or fatwax of putrified carcases, which is quite different from cetine and cholesterine, consists, according to Mr. Chevreul (Ann. de Chim. xviii. 65), of margarine acid, sebacic acid, and an orange yellow principle, and is formed, according to experiments, by the action of the carbonate of ammonia, which is disengaged by putrefaction upon animal sub stances. RETURN |