Imágenes de páginas
PDF
EPUB

Mr. Glaisher presented the report on Luminous Meteors for 1866–7, in which, amongst much interesting matter with most of which our readers have been acquainted, it is stated that the August meteors which disappointed observers in this country, were seen in countless numbers in America, after midnight of the 10th. Amongst the remarkable meteors, the most curious seems to have been one seen by Prof. Thomson at Aberdeen, on the 14th November last, at 2h. 40.5s., A.M. The nucleus passed over a Tauri and disappeared without noise. Its diameter, 4 of the Moon. Its train was pale yellow, and at first remained as a band of dense nebulous looking light, about half the diameter of the Moon. After two minutes the train wound about in a serpentine form, and aster threa minutes it had collected itself into a nebulous-looking cloud, which remained vividly distinct until four minutes, when it was obscured by a cloud. The same meteor was seen by Prof. Grant at Glasgow, Prof. Piazzi Smith at Edinburgh, and Mr. Barkas at Newcastle. On the 20th November, a large detonating meteor is reported to have been seen at Nashville, Tennessee, which made a tremendous report, rattling windows and shaking the wall. “If,” says the report “it actually took place, it forms an interesting addition to the list.” In the Physiological department, some curious facts were cited by Sir Duncan Gibb, who stated that of 4,600 healthy persons he had examined with the laryngoscope, the epiglottis was pendant instead of vertical. In some cases he found this formation hereditary. It led to a modification of the voice, tending towards a low tone in adult males, and preventing women from reaching the higher notes. In the department of Zoology, Sir John Lubbock read an interesting paper on the anatomy of Thysanura. The long leaps of these insects are taken by means of two long appendages bent under the body and forming a spring held by certain muscles. under a small latch or catch. Directly this is released, the spring jerks back, and the creature is thrown upwards and forwards.

NOTES AND MEMORANDA.

The NEWTON FORGERIES.-M. Chasles holds the extraordinary opinion that the quantity of the alleged Newton correspondence in his possession establishes its claim to authenticity. In opposition to M. Fongere and other French critics, who have detected the character of the letters, he brings forward comparatively trivial criticism on certain details of their objections. The age of Newton, and the date of some of the pretended letters, is quite sufficient to overthrow their claims, and so are the errors in the signature of his mother. M. Chasles declares that he will publish the documents, and that competent judges will do justice, It would surely be wiser first to remove the objections raised by Sir D. Brewster and M. Fougère. The first proves that Newton could not have done what is pretended, and the last brings strong reasons for considering the correspondence inconsistent with known facts concerning Pascal. M. Fougère says of the letters ascribed to different persons, “ They agree together like false witnesses who have combined to stifle truth and obtain credit for falsehood.”

THE EPIORNIS : THE GREAT BIRD OP MADAGASCAR.-M. All. Grandidier writes to the French Academy that his investigations in Madagascar tend to show that the Epiornis is really extinct, and, not as M. Isidor Geoffroy St. Hilaire hoped, still living in unknown parts of the island. Though perfect fossil eggs are rare, fragments are common. The oldest of the Antandrouis never heard of the bird, and they have no traditions of its existence; nevertheless, M. Grandidier does not think it has been extinct for any long period, as its remains are found in the most modern formations, whose development is still going on. “It existed," he says, “ perhaps, at the commencement of our era, and as the country became peopled, it may have been quickly exterminated, like the Moa of New Zealand." M. M. Joly, describing an Epiornis's egg holding more than eight litres, belonging to M. Nau, states that that gentleman, who was for thirteen years a prisoner amongst the Hovas, and who traversed the island in all directions, considers the bird as totally destroyed, and the eggs are very rare. The Malgaches, he says, pretend that the female died after laying a single egg, and they consider the discovery of any remains of the bird to bode misfortune to the finder and to his family.

ACTION OF GREEN LIGHT ON PLANTS.-M. L. Cailletet details experiments on the influence of different coloured rays, and the decomposition of carbonic acid by plants. He observes that green light afforded unexpected results, whether this colour was obtained from a glass, vegetable leaves, or solutions. Under its influence carbonic acid is never decomposed; a fresh quantity of gas seems, on the contrary, to be produced by the leaves. When a glass containing pure air and a leaf was placed in full sunlight, under a green glass shade, after a few hours a quantity of carbonic acid was obtained, scarcely inferior to that which the leaf would have evolved in the dark. This experiment, he thinks, may explain the sickly condition of vegetation under large trees.

THE ABSORPTION OF OBSCURE HEAT.-M. Desains states (Comptes Rendus) that chloride of carbon is more easily traversed by obscure heat than sulphide of carbon, chloroform somewhat less, while benzine and glycerine, with a thickness of Om. 01, almost entirely stops the heat radiated from a blackened sheet of copper, heated to 400° (C.)

BICHROMATE OF POTASH AND ALBUMEN. POLARISCOPE OBJECT.-Mr. Thos. D. Smeaton sends us the following note from Robe, S. Australia. The action of albumen in modifying crystallization and making polariscopes is well known, but the particular plan adopted by Mr. Smeaton will interest our microscopic readers :-“In trying some photographic experiments I had occasion to coat a glass plate with the solution used in the carbon process (bichromate of potash, gelatine, and white of egg); this was left to dry slowly, when it presented a beautiful crystalline appearance. From the edges of the plate, fine arborescent shoots spread towards the centre, ending in larger twigs, enclosing ovoid loops.

These were sometimes filled in with a clear yellow, sometimes with a dark orange, "and occasionally with a feather of crystals so delicate as to challenge microscopic examination. The evenness of the ramifications, the wonderful manner in which they avoid crossing each other, and the varied colouring, tend to make the experiment well worthy of repetition. The solution (being solid at ordinary temperatures) must be floated on warm; and as it is already on glass, all that is needed for the preservation of the specimen is to place it face downwards on a piece of paper rather larger than the glass, to turn the edges over, and to gum them down.

Poisonous FISHES.—The Annals Nat. Hist. has a translation of a paper on this subject by M. Duméril, containing some curious particulars. Risso ascribes the unwholesomeness of the Courpata found at Nice to its feeding on a highly irritating species of the jelly-fish, Stephenomia. Many species of fish are poisonous at certain seasons, the Conger is said to occasion dysentery if eaten at the time of depositing its eggs, and the eggs of pike and barbel are eflicient purgatives. The “ yellow-bill sprat” of the Antilles, in some instances, has caused death, with frightful convulsions, in the space of half an hour; another Meletta (venenosa), is almost equally formidable. A Tetraodon found at the Cape is very dangerous, and others of the same family are poisonous ; and an Anchovy found in the Indian seas (Eugrantis balama) will prove fatal when caten, if the precaution has not been taken of removing the head and intestines before cooking.

[graphic][ocr errors][merged small]

THE INTELLECTUAL OBSERVER.

NOVEMBER, 1867.

BARBETS, AND THEIR DISTRIBUTION.

BY P. I. SCLATER, M.A., PH.D., F.R.S.,

Secretary to the Zoological Society of London.

(With a Coloured Plate.)

In my notice of the Bell-bird and its allies,* I spoke of the difficulties hitherto experienced in the introduction of living representatives of the great fruit-eating families of birds of the tropics into this country, which, however, we had recently succeeded in overcoming in several instances. A case in point is that of the Barbets-a tolerably numerous and well-defined group of zygodactyle birds inhabiting the tropics of both hemispheres, of which, as far as I am aware, no living example had ever been imported into Europe prior to the arrival of the specimen figured in the accompanying illustration. This bird, although not by any means one of the largest or finest of the “Bucconidæ,” as the family to which it belongs is termed, is of interest as representing a form hitherto unknown in our aviaries, and as being endowed with special modifications of structure to adapt it to a peculiar mode of life. First, therefore, I will state what is known of the life history of the present species, and its immediate allies. Then I will endeavour to point out some of the principles which are exemplified by the geographical distribution of the group to which it belongs.

The Blue-cheoked Barbet was first described by the veteran ornithologist Latham in the latter end of the last century, and provided with the not very specially appropriate name Asiatica. Latham regarded it as a kind of Trogon, and, as Trogons were in those days supposed to belong to America exclusively, called it the "Asiatic Trogon, Trogon Asiaticus.This specific name, however, being the first given, we are compelled, in compliance with the general usage of natural

* INTELL. Obs., vol. x , p. 401. VOL. XII.-NO. IV.

« AnteriorContinuar »