Cygni, that it is not the brightest stars which are always nearest to us ; only one of the latter, Alpha Centauri, having a considerable parallax.

New Comets and Planets.-The second and third comets of 1863, discovered respectively by Klinkerfues and Respighi, were frequently observed during the months of April and May, but both became much fainter during the latter month. The first was a round nebula, which on April 20 was about 4' of arc in diameter; the latter on April 26 was visible to the naked eye, with bright stellar nucleus, and a tail of a degree in length. The 78th planet, discovered by Dr. Luther on March 15 last, has received the name of Diana, and was of the 10th magnitude at that epoch. The planet (77) discovered by Peters in November last appears to have been unfortunate, and will with difficulty be refound, as no further observations have been taken, nor its elements computed. Another somewhat luckless planet (Leukothea) comes into opposition in November next, but will be of the last degree of faintness. M. Schubert, however, requests observers with proper means to pay particular attention to it, as he intends to investigate the mass of Jupiter by it—an important object, which shows the utility of even those little bodies.

Spots on Sun and Zodiacal Light.-Professor Wolf, whose labours in respect to the solar spots are so well known, gives further proofs of their periodicity, their relative numbers in the five years 1858-1862 being respectively 50.9; 96·4; 98′6; 774 and 594. He had previously determined the maximum for 1860-2, and has thence deduced the mean declination variation for Prague and Munich. The connection between the Solar Spots and Northern Lights has been likewise satisfactorily established, the period of the first, which recurs every eleven years, agreeing perfectly with that of the second.

Eta Argus.-This celebrated variable star, which passes between the 4th and 1st magnitude, and at its latter phase being brighter than any of the stars of the southern hemisphere, has likewise been investigated by Professor Wolf. He finds a period of 46 years. In the curve of brightness given by him, it passes from the 4th magnitude to the 14 magnitude, then declines to the 2nd magnitude, after this increases to its greatest brightness in 23 years; six years subsequently falls to the 2nd magnitude; whence in five years time it rises to 1 magnitude, and then decreases to the 4th magnitude.

Jupiter's Satellites and the Pleiades.-It has frequently been argued whether Jupiter's satellites are visible to the naked eye, and equally so as to the number of stars in the Pleiades visible under those circumstances. A member of the Astronomer Royal's family instead of the ordinary six always sees seven, and in favourable weather as many as twelve, and this has been verified by actual mapping. Mr. Mason, on April 15, after gazing with great care at Jupiter, and taking every precaution, detected a luminous point close to the planet which was altogether independent of the radiations, and on looking through his telescope found the satellites clustered at the point which he had previously noticed.

BOTANY.

The Calabar Poison Bean (Physostigma venenosum).—The seed of this plant has lately been much noticed for the medicinal properties which reside in it. The most energetic results are obtained from the kernel. These are chiefly marked upon the spinal cord, producing muscular paralysis. When applied locally to the eyeball or eyelids, destruction of the contractility of muscular fibre, and contraction of the pupil result. This property is advantageously employed by the oculist.

Cultivation of Cinchona Trees in India.-Dr. Anderson, Superintendent of the Calcutta Botanic Garden, is inspecting the introduction of Cinchona into the Sikkim Himalayas. His nursery is reported to be in a most flourishing condition, and he has seven species under cultivation. He states that it promises to be a most successful experiment on those moist hills.

Iron as a Tonic in the Vegetable Creation.—It is alleged that a discovery of a curious kind has been made regarding the influence of iron on vegetation. On chalky soils where there is an absence of iron, vegetation has a sere and blanched appearance. This is entirely removed, it is said, by the application of a solution of sulphate of iron. Haricot beans watered with this substance acquired an additional weight of 60 per cent. It is expected that the salts of iron will be found as beneficial in farming as in horticulture, but the experiments are yet very incomplete. In the cultivation of clover, wonderful advantages are declared to have been gained. The material is cheap and the quantity applied is small.

The Flora of Australia.-Dr. Murray, who accompanied Mr. Howitt's expedition as medical officer, has brought back specimens of timber representing seventeen species of trees, the most peculiar of which have received the name of the cork tree, and the orange tree. The fruit of the latter in outward appearance is not unlike a small orange, but it has a pungent flavour, which renders it disagreeable to Europeans, being something between a water-melon and cayenne pepper. The collection of timber, made with great labour, has been sent to Dr. Müller for examination.

The Receptacles of the Juices of Plants.-M. Lestiboudois endeavours to dispel the doubt respecting the existence and nature of latex and laticiferous vessels. He propounds a series of questions, which he answers as the result of his researches. The coloured juices of plants do not resemble (according to this botanist) a fluid which has to furnish organs with the materials of growth, either in their physical properties, in their composition, or in the situations in which they are found. In some plants the reservoirs of the coloured juices constitute a vascular system, so disposed as to follow the vesication of the leaves, and appertaining more particularly to the cortical structure of the stem. The proper juices are more dense, and of a deeper colour in the lower and older parts of the plant, and usually are nearly absent from the root; but in some instances (as Lactuca sativa) abound there. The vasa propria are, as a rule, distinguishable from neighbouring tissues by the colour of their contents, and by their flexuous, thin, branching, and anastomatic form.

Darnel Grass.-M. Filhol has recently investigated the toxical properties of the Solium temulentum. Numerous experiments have been at different times made on animals with this plant; but they have not hitherto led to anything certain concerning the nature of the poison contained in it. M. Filhol has discovered that it contains a double poison-a poison of the strychnine class, and one of the narcotic kind. He has isolated these two poisons, and experiments on animals have shown their special actions, and explained their contradictory effects. M. Filhol adds, that the presence of Solium in corn may be shown by the shape of its starchy particles, which are different from that of wheat.

Vascular Bundles in Ferns.-Mr. Church, in a paper published by the Linnæan Society, lays great stress upon the arrangement of these bundles, and from several hundred observations, deduces that there is no marked distinction between the genus Polystichum and the genus Loppodium (Lastrea M.) in this particular. Foreign specimens bear out this result. Also that the genus Lastrea (of Moore) contains two British species, and many foreign ones, which possess a totally different arrangement of their vascular tissue, and that this fact, taken in connection with the previously recognized differences of these very same species, almost warrants their removal to another genus. And, lastly, that genera whose outward characteristics are conspicuously distinct, exhibit marked differences in the arrangement of their vascular fasciculi, which closely allied genera do not. Parthenogenesis of Alberia Caffra.-Dr. Anderson, of the Calcutta Botanical Gardens, mentions that this plant, a thorny bush, had been in the gardens some years without producing flowers. It contains pistils only, being diœcious. In March, 1861, it bore a large crop of well-ripened fruit, which was sown, and gave rise to a vigorous stock of young plants. In February, 1862, it flowered again, and the most careful examination led to the detection of no trace of stamens. This tree was unfortunately destroyed a few months ago in a severe gale; but a second specimen artificially propagated from the first still exists in the gardens. It has never flowered.

Sarracenia Purpurea.-This pitcher plant has of late been brought into prominent notice from its supposed virtues in cases of smallpox. Numerous experiments have been made upon its properties, with very various results; some practitioners praising it highly, while others have been disappointed. No doubt that many important discoveries remain to be made in vegetable materia medica; but the utmost caution is necessary, lest a hasty conclusion should retard, instead of advancing, the subject.

MR

CHEMISTRY.

R. MARKHAM, who a few years ago was appointed the superintendent of an expedition for the collection of cinchona plants and seeds, and for their introduction into India, has lately read a paper on this subject before the Society of Arts. Although the difficulties that presented themselves were very great, they have been so effectually met that there are

now growing in the Neilgherry Hills and in other parts of India about 130,000 cinchona plants of the most valuable species, the result of the labour bestowed upon the subject.

The greatness of the work will at once be appreciated if it is remembered that the cinchona plant had not yet been cultivated, that its conditions of growth were unknown, that it is found in forests scarcely ever visited by Europeans, and that great care was required in the selection of the species. Mr. Markham, in the prosecution of this undertaking, pointed out the distinction between mere transplantation and that true cultivation which consists in placing the plant in circumstances favourable to its development, and removing hurtful influences.

The importance of the cultivation of this plant cannot be overlooked when the immense medicinal value of quinine, and its present scarcity and high price, are considered. Already, specimens of the bark from these cultivated cinchonas have been analyzed by Messrs. Howard & Sons, who report that they contain as good a per-centage of quinine as the cinchonas from which they have hitherto been in the habit of extracting that alkaloid.

Mr. Lewis Thompson, M.R.C.S., has been making some experiments on nickel with respect to its preparation in a state of purity. He considers that the large quantity of arsenic employed in the manufacture of nickel, and which is very prejudicial to health, is quite unnecessary; for by first roasting the ore, and then heating it with half its weight of chalk, he succeeded in obtaining a rough metal containing 88 per cent. of pure nickel, the rest being cobalt and iron, with a little sulphur, but no arsenic; this metal being decidedly more pure than the ordinary commercial nickel. He proposes, as a method for the analytical separation of nickel and cobalt from other metals, the addition to the warm solution of the mixed sulphates of nickel, cobalt, manganese, iron, copper, &c., of as much sulphate of ammonia as the liquid will dissolve, and to set the solution aside to cool, when almost every particle of nickel and cobalt will separate as double sulphates of nickel and of cobalt with sulphate of ammonia.

The new metal thallium has attracted considerable notice for some time past. From a lecture given by its discoverer, Mr. Crookes, at the Royal Institution, we gather the following particulars concerning this metal :

The property by which its discovery was effected was that of giving a single brilliant green line when examined by means of the spectroscope. Mr. Crookes was engaged in examining the residue from a manufactory at Tilkerode, in the Hartz, for the purpose of extracting the selenium from it. This was effected in the ordinary way, and the crude selenium was distilled. A considerable residuum was left behind in this operation, in which he suspected the presence of tellurium. Some time afterwards, happening to require some tellurium, he examined this residue more minutely, but without getting definite results; the chemical tests appearing to give contradictory evidence. Recourse was then had to spectrum analysis, when a remarkable green line was observed to cross the field of view. This convinced him that a hitherto unrecognized element was present, and he set himself to the task of isolating it. At first he inclined to the belief that he had a metalloid, or semi-metal, to deal with; but having

obtained an additional supply of material, he was enabled to precipitate the substance from solution, by means of zinc, in the form of a black powder, and to obtain it in distinct metallic crystals by voltaic deposition, which removed all doubt as to its metallic nature. It may be as well to remark, in vindication of Mr. Crookes's claim to the priority in the discovery of this metal, that he obtained these metallic crystals in September,

1861.

To obtain the metal in a coherent form, it is only necessary to squeeze the precipitated mass together, and fuse it under cyanide of potassium, or simply to submit it to powerful pressure, when, from its great softness, it will unite into one mass.

Spectrum analysis furnishing an easy method for the detection of the new metal, Mr. Crookes has discovered its existence in varying proportions in many specimens of pyrites, sulphur, sulphide of cadmium, metallic cadmium, and zinc; also in copper and in bismuth ores. A specimen of native sulphur from Lipari was found to contain so much thallium that it might almost be classed as a new mineral.

Thallium is extracted from pyrites by distilling the sulphur from it, the thallium passing away at the same time; the thalliferous sulphur is then boiled with potash, and the black residue heated with sulphuric acid; the solution is then filtered, and hydrochloric acid added to the filtrate, when the difficultly-soluble protochloride of thallium is precipitated; this is filtered off, washed, and converted into sulphate; the solution of the sulphate is then decomposed by means of the voltaic battery.

The chief characteristics of thallium are as follows: It is a white opaque metal, with a perfect metallic lustre ; its specific gravity is 11.19; it is very malleable, and may be rolled into leaves as thin as tissue-paper; it is not very ductile, and can only with difficulty be drawn into wire, but, by means of pressure, thallium-wire can be made with great ease. The metal also possesses the singular property of compressibility, and it is the softest known heavy metal, being exceeded in this respect only by the metals of the alkalies. Thallium marks paper like plumbago; the mark fades out from oxidation in a short time, but it may be again rendered visible by moistening the paper with a solution of sulphide of ammonium; with the exception of bismuth it is the most diamagnetic metal known. Thallium melts at 550° Fahrenheit; at a full red heat it may be distilled ; it burns in oxygen, and tarnishes very quickly in the air, becoming coated with an oxide which is tolerably soluble in water; the oxide may be rendered anhydrous at the ordinary temperature in a vacuum. The metal dissolves in acids, the proper solvent being nitric acid; it forms at least two basic oxides; the protochloride, like chloride of lead, is slightly soluble in water; bichloride of platinum produces an insoluble double salt with chloride of thallium; sulphuretted hydrogen produces no precipitate in an acid solution; sulphide of ammonium, a black precipitate of sulphide of thallium; on adding ammonia to a solution of the sesquichloride, a brown peroxide is produced, together with protochloride of thallium. In one or two of the properties here alluded to, thallium approaches the metals of the alkalies, but the great majority of its characteristics point out that its true position is by the side of silver and lead.