spicuous at an epoch preceding only by an hour or so the time of Mr. Baxendell's observation. We ventured in our last to express agreement with Schmidt's view,-considering it highly improbable that so experienced an observer, examining the very constellation in which the strange star appeared (in the search, too, for a variable star), would have overlooked a star brighter than Alphecca, the "brilliant" of the Crown. Mr. Stone has since carefully examined Mr. Barker's claim, and, at a late meeting of the Astronomical Society, he expressed the opinion (fully supported by the evidence adduced) that " Mr. Barker's observations, previous to those of May 14th, are not entitled to the slightest credit."

Mr. J. Norman Lockyer has commenced the spectroscopic observation of sun-spots. His object is to test the rival theories of M. Faye on the one hand, and Messrs. De la Rue, Balfour Stewart, and Löewy on the other. According to M. Faye, the interior of the sun is "a nebulous gaseous mass, of feeble radiating power at a temperature of dissociation,"-a sun-spot is caused by the heating effects of an up-rush from the interior breaking through the less intensely heated photosphere. The English physicists named above refer the appearances connected with sun-spots to the cooling effects of a down-rush from the exterior. Mr. Lockyer has not yet obtained results which he can consider quite satisfactory; but, so far as he has gone, he sees confirmation of the latter view. In the spectrum of light from the spot the absorption bands were visible, as in the spectrum given by the photosphere; they appeared even to be thicker. Further, no bright lines were visible. The observation, if confirmed by the examination of larger spots, would establish the presence of descending currents, but would leave the question of greater or less heat in the neighbourhood and interior of spots undecided. Repeated observations have been afforded of the apparent descent, with diminishing brightness, of a large portion of the photosphere into the interior of a spot, but whether the change indicates a cooling process, or rather a process corresponding to the transformation of clouds into invisible vapour, is a question which observation has not yet enabled us to answer.

It is gratifying to hear that the speculum prepared by Mr. Grubb, of Dublin, for the Melbourne Observatory, is a perfect success. The telescope will, doubtless, soon be at work. Mr. Le Sueur, of Pembroke College, Cambridge (a wrangler of 1863), is entrusted with the charge of the observatory. He has been engaged in studying sidereal astronomy under Professor Adams, at the Cambridge Observatory; and we understand that Mr. Delarue has kindly undertaken to instruct him in the principles and practice of celestial photography.

In the new edition of Lyell's Geology' there are presented the

results of Mr. Stone's calculation of the variations which have taken place in the figure and position of the earth's orbit during one million of years. These results are well worth careful study. They are sufficient to show how far from the truth is the statement so often repeated in works on popular astronomy, that the eccentricity of the orbit varies between definite limits with a definite period of oscillation, the position of the perihelion travelling (meanwhile) continually in one direction. On the contrary, the successive maxima of eccentricity differ considerably inter se, and so of the successive minima; the period of oscillation is variable; and the perihelion not only travels with variable velocity, but sometimes retrogrades for twenty or thirty thousand years together. We must pass over many maxima before we arrive at one approaching Le Verrier's estimate of the absolute maximum (0777). In the whole range of years tabulated by Mr. Stone, the greatest eccentricity is 0 0747;-this was the case 850,000 years ago, and the earth's orbit was then nearly as eccentric as Mars's present orbit. The least eccentricity (within the period tabulated) occurred 900,000 years ago; at this time the eccentricity was 0.0102. The present eccentricity is 0.0168.

The late Dr. Hincks (shortly before his death) effected an elaborate calculation respecting an eclipse recorded in the 'Cuneiform Inscriptions of Western Asia.' The record runs :-"In the month Tisri the moon was eclipsed, and the moon emerged from the shadow while the sun was rising." Such an eclipse admits of identification. Accordingly, Dr. Hincks was able to satisfy himself that it occurred on September 13th, 701 B.C. (at the beginning of Sennacherib's reign). He adds:-" According to Hansen's Tables the moon would be very far-perhaps half a degree-beyond the place which would allow the phenomenon to appear, as recorded, in the latitude of Nineveh." But by adopting values given by Professor Adams, conjoined with a correction ascribed to a retardation of the earth's diurnal rotation, he considers that the circumstances of the eclipse can be satisfactorily accounted for.

PROCEEDINGS OF THE ROYAL ASTRONOMICAL SOCIETY.

Our space will not permit us to notice separately (with whatever brevity) the papers (sixteen in number) which have reference to the November star-shower. We have already summarized the results presented in them.

Messrs. De la Rue, Stewart, and Löewy present a note exhibiting the results of their second series of "Researches on Solar Physics.' Their observations indicate an apparent connection between the behaviour of sun-spots and the longitude of Venus. Jupiter's influence seems also to have been detected. The planets which

should exert the largest influence on the sun (assuming planetary attractions to be the true disturbing agent) are Jupiter, Venus, Saturn, and the Earth. Estimated according to their attractive effects merely, these planets should exert influences represented by the numbers 70, 9, 7, and 5 respectively. But as the influence exerted by Venus depends on the distance of the planet from the sun's equator, a large orbital inclination to this plane appears to be an important element of disturbing influence; so that the other three planets whose inclination to the sun's equator is about twice as great as that of Venus, should exhibit a disturbing power proportionately strengthened. Mercury, on the other hand, whose influence Mr. Dunkin considers should be nearly as great as that of Venus, travels nearly in the plane of the sun's equator; and further, the smallness of Mercury's mass is far from being "compensated by diminished distance."

The observers promise to give early attention to the influence of Jupiter, which should exhibit a period of six years, since the planet's sidereal period is about twelve years. In a later paper they exhibit the close agreement between the observations made at Kew, and those effected by M. Schwabe, at Dessau, during the year 1866.

The Astronomer Royal calls the attention of observers to the opportunity which will be afforded them in the present year of observing Jupiter without satellites. The phenomenon is very rare, having only been observed twice, one of the observations being that of Mr. W. R. Dawes. On August 21, Jupiter will be without satellites for one hour and three-quarters; and if the weather be favourable, all the four disappearances and the four reappearances may be observed in this country. They occur in the following order: at 8h. 14m., G.M.T. (soon after sunset), the third satellite will enter on Jupiter's face; at 9h. 9m. the second satellite will be eclipsed in Jupiter's shadow; at 9h. 28m. the fourth; and at 10h. 4m. the first satellite will enter on Jupiter's face. All the four satellites will then be invisible. At 11h. 49m. the third satellite will pass from Jupiter's face; at 12h. 13m. the second satellite will reappear from behind the body of Jupiter; at 12h. 23m. the first, and at 13h. 54m. the fourth satellite will pass off the

disk.

In a letter to Mr. Stone, Major Tennant, R.A., calls the attention of astronomers to the total eclipse of August 17, 1868. This will be visible in India; and the certainty (almost) that east of the Ghauts the weather will be fine, renders it the more desirable that such of our observers as may be in India at the time should take part in an observation of so much interest. "Probably," says Major Tennant, "the Council will not think that it would be too much to ask that the Government should, by organizing an observing party

or two, give the business that element of discipline and unity of action which volunteer observers, collected from various parts of a large country, will almost necessarily want."

Mr. Peacock discusses the epoch of a partial eclipse recorded on a brass plate dug up at Calcutta, and described as having occurred "in the month Chaitra, when the sun was entering the northern hemisphere, the moon being in the Nakshatra Aswini." He identifies it with the eclipse observed at Constantinople on the 3rd of April, A.D. 889.

Mr. Wray presents an interesting paper on the correction of the secondary spectrum of object-glasses. After trying "a great number of different kinds of glass," flint and crown, having densities varying from 2.833 to 5-49, he came to the conclusion that by the mere combination of glasses, the secondary spectrum could not be corrected, "with anything like a reasonably shallow system of curves, even where four lenses were used." He finds, however that by a judicious selection of flint and crown glass, separated by an extremely thin meniscus film of highly dispersive cement, it is easy, not only to destroy the irrationality, but even to invert the spectrum. Under high powers he obtains a perfectly achromatic image of the moon and planets, "which are shown in a surprisingly sharp and clean manner on the black ground of the sky, reminding one of a first-class reflector, under its very best behaviour. The Astronomer-Royal has promised to examine a large object-glass for Mr. Wray, who has constructed one for the purpose, having a 7-inch clear aperture and a focal length of 8 feet.

Mr. Knott exhibits in a table the apparent increase of diameter shown by star-discs as the aperture of the telescope is diminished.

Mr. Dawes remarks, with reference to the eye-piece prism suggested by him for correcting errors in double-star measurement, that in all ordinary cases he should not recommend its use; "only in those where the obliquity is such that a slight and not inconvenient inclination of the head was insufficient to bring the stars into an apparently vertical position."

The small companion of Herculis having emerged from its recent conjunction with its primary, Mr. Dawes has succeeded in effecting measurement of it. One set of measures was taken exactly at noon on December 30th, the sky being quite unclouded. Mr. O. Struve, with the great Pulkowa refractor, found the object one of extreme difficulty, and was surprised that Mr. Dawes should have been enabled to see, much more that he should have measured the object with the smaller telescopic powers at his disposal. The measures of Mr. Dawes agree admirably with M. Struve's.

4. BOTANY, VEGETABLE MORPHOLOGY, AND

PHYSIOLOGY.

ENGLAND.-The Structure of the Seed in Solanaceæ, &c.—Mr. Tuffen West, the well-known micrographic artist, has published a paper on this subject, read to the International Botanical Congress held in London last summer. The seeds of the Solanaceæ are remarkable for the rugosity of their surface, being scrobiculated, or deeply pitted. Numerous observations were made by Mr. West, under a binocular of high power, and the structure was observed by making thin slices of the objects, longitudinally and transversely, by a sharp razor. The cancellated prominences seen around each depression form sinuous intersecting bars, and are caused by the extreme thickening of the walls of the cells, owing to the deposition of solid matter upon the inner surface of the original cells. In the Scrophulariaceae the structure of the seeds presents a considerable difference; but in the intermediate family, the Atropaces, formed to embrace the many genera whose corolla have an imbricated æstivation, and which have been separated by Mr. Miers from the Solanaceae so as to render this last family uniformly consistent in the valvate æstivation of the corolla, the structure of the testa, although sufficiently distinct, approaches nearer to the character observed in Solanacea than to that of Scrophulariaceæ. A very large series of observations on the species of various genera of these three families is given by Mr. West.

Effect of Cold on the Growth of Trees.-Professor Caspary, of Königsberg, contributed to the proceedings of the late Botanical Congress the results of some very elaborate observations on the effect of low temperatures in altering the direction of the branches of trees, from which it appeared that different species are, in this respect, acted on in diverse manners, some moving during a frost vertically upwards, and others downward; whilst a lateral movement towards the left is nearly universal.

A Heterogeneous Flora.-At the same meeting Mr. Axel Blytt, of Christiania, read a paper "On the Vegetation of the Sogne Fiord," one of the larger arms of the sea on the coast of Norway. In this singular district, cut off from the rest of Norway by impassable mountains covered with eternal snow, and lying in lat. 61° N., all seasons and climates seem to be mingled and coexistent; whilst an Alpine flora extends down to the very sea-level, and its members grow on the rocks of the shore mixed with maritime species, vines, peaches, nectarines, and walnuts ripen their fruit in