that a shower was seen in Canada or the United States, where it was supposed there was a more favourable prospect of a noteworthy display being observed. It is just possible that we may still hear of the shower having been seen in the eastern parts of Asia. But we must remember that the presence of the full moon was sufficient in any case to have prevented a large number of shooting-stars from being seen. For it was noticeable in the display of November 14, 1866, that most of the shooting-stars were not brighter than stars of the third magnitude, and as fixed stars of this magnitude can scarcely be seen on a hazy moonlit night, such as that of November 13-14, it seems probable that all the smaller shooting-stars would escape notice altogether. It is to be considered also that Jupiter has now been for several months in a position which brings his attraction to bear very efficiently on that part of the shooting-star system traversed by the earth in November. And as his influence acts now to sway the system outwards, it is far from being unlikely that the earth may have passed inside the ring of meteors, instead of through it as she did last year.

The opinion we have seen expressed, that the absence of a great display ought to throw doubts on the general conclusions of astronomers respecting the November shooting-star system, is wholly erroneous. Even if it were absolutely certain that there had been no shower of falling-stars, all that could be learned from this would be what astronomers have long since inferred, that the band of small bodies forming the system is not continuous.

A careful examination of the observations made upon Jupiter on August 21, when he was (apparently) without satellites, reveals some noteworthy results. The best observers differ as to the

relative dimensions of the shadows of the third and fourth satellites. But it is remarkable that those who used refractors considered that the shadow of the fourth looked larger than that of the third satellite, or, where no comparison is directly instituted between the shadows, that the shadow of the fourth satellite seemed noticeably larger than the satellite itself. On the other hand, the best observers with reflectors, considered that the shadow of the third satellite was larger than that of the fourth. As it is readily demonstrable that the real shadow of the fourth was much smaller than that of the third, and the penumbra much larger, it seems to result that reflectors are less efficient than refractors in exhibiting faint shadows and half-lights. Even refractors, however, did not exhibit the distinction of tint between the penumbra and the true shadow.

The dimness of the fourth satellite was a very noteworthy feature. It looked as dark, says Mr. Dawes, as its shadow, but smaller. One observer suggested even that the fourth satellite suffered eclipse by the third, during a part of the transit, but this certainly did not happen. At the time mentioned by this observer,

the fourth satellite hid a small part of the third satellite's shadow on the disc,—but, of course, an eclipse of one satellite by another would be indicated by the coalescing of the two shadows, which did not and could not happen on August 21st last, since the apparent paths of the shadows across the disc were separated by a considerable interval.

Lastly, a strange dark space divided by a narrow channel of light occupied one-half of the third satellite's disc, and this space resembled one seen in 1860 by the same observer-Mr. Dawesbut was on the opposite side of the disc. This observation seems conclusively to overthrow Sir W. Herschel's theory, that the satellites turn always the same face towards the planet, as our moon towards the earth.

A strange amount of doubt still clings to the supposed discovery of volcanic action within the lunar crater Linné. At a late meeting of the Astronomical Society Captain Noble expressed the opinion that the changes supposed to have taken place in Linné are due entirely to variations in the state of the earth's atmosphere, and of the moon's illumination and libration. Mr. Buckingham, on the contrary, judged from his observations that real changes had taken place. On August 6, he detected a convexity in the white cloud, which after it entered the terminator appeared as an egg-shaped convex disc. On October 19, he saw parts of the whole ring and fragments of a broken ring with his 20-inch refractor. On November 5, he could still see the summit of the small crater, which seemed larger than before. He considers that the crater is considerably larger than at the beginning of the year, and nearer the centre of the cloudy spot. Mr. De la Rue controverted the opinion expressed by Mr. Proctor, that photographs of the Moon afford evidence of change (the photographs referred to being those by Messrs. De la Rue and Buckingham).

At the same meeting the discussion of the circumstances attending the eclipse of the Moon on September 13, elicited from Mr. Buckingham the interesting statement that a portion of the unobscured part of the Moon was absent from the photographs. Mr. De la Rue, who has before observed this peculiarity, expressed its nature by saying that more of the Moon is eclipsed chemically than optically.

It is perhaps hardly necessary that we should make even a passing reference to the so-called Newton and Pascal controversy. Never before, we imagine, has so barefaced an attempt been made to impose upon the scientific world. The chief care of the author of this contemptible affair appears to have been devoted to the concentration of every possible absurdity and blunder within the range allotted to the correspondence he has been at the pains to invent. French scientific men, generally, have acted in this matter in a

manner very creditable to themselves. It is painful to have to note as an exception one eminent mathematician, who having assumed a false position, seems to be ashamed to withdraw from it.

An annular eclipse of the sun will take place on February 23rd. It will be invisible at Greenwich, but the northern line of simple contact will pass very close to England, so that in the northern parts of France the eclipse will be visible as a partial one.

Venus will be well situated for observation during the ensuing months, as an evening star. She will attain her greatest easterly elongation on May 6th.

We have to announce the discovery of two more Asteroids, both detected by Professor Watson, of Ann Arbor (U. S.)-one on the 24th of August, the other on the 6th of September, 1867.

The twenty-five inch object-glass, which has been for some time in the hands of Mr. Cooke, the eminent optician, is at length completed. This is the largest refractor 'that has ever been constructed, and we may look for important discoveries through its application to the observation of celestial objects. For it has been shown satisfactorily that the object-glass is optically excellent. On November 5th, 1867, the telescope was directed to the star y Andromedæ, and the small companion was seen distinctly divided, with the spurious discs of the three stars of this triple system perfectly round. "To those who know what a telescope is," says the President of the Astronomical Society, "and how the difficulties of making it are enormously increased with extension of aperture, this statement is enough." He added that in his opinion there were several opticians in London who could make a glass of the same dimensions and optical accuracy, and that therefore it was quite unnecessary to seek out of England—as is frequently done— for any optical instrument whatever.

Mr. Dawes has at length completed the list of double-star observations, which has been one of the results of his long and most valuable labours with the telescope.

PROCEEDINGS OF THE ROYAL ASTRONOMICAL SOCIETY.

Dr. Edmund Weise supplies an important and valuable paper on the total eclipse of August 17th, 1868. He has computed the position of the central line of the eclipse and of the limits of the totality, by Hansen's formula. He finds that the shadow touches the earth near Gondar, in Abyssinia, crosses the Straits of Bab-elMandeb, including Perim, Mokha, and Aden; leaves Arabia by the Cape Râs-Furtak, and enters the peninsula of India between Goa and Rajahpoor. We have already described the path of the shadow across India. The maximum duration of totality occurs in the

Gulf of Siam, when it reaches on the central line no less than 6' 50", the altitude of the sun being 870. On its further progress, the shadow runs through Borneo, Celebes, the Islands Bouru, Amboyna, Ceram, and the Arrou Archipelago; covers completely the southern part of New Guinea, and moves then towards the New Hebrides, where the totality begins at sunset.

What renders this eclipse so important an object of attention to astronomers, is the fact that the totality lasts almost as long as is possible under any circumstances. For at the commencement the Moon will have just passed a perigee of uncommon proximity, and she reaches during the eclipse the ascending node of her orbit. Thus the eclipsed sun rises nearly to the zenith of those countries where the eclipse takes place at noon; and therefore the augmentation of the moon's diameter (due to her altitude) is a maximum, and the rate at which the shadow sweeps over the surface of the earth is a minimum. The result of the coincidence of all these favourable circumstances will be an eclipse without rival in the records of past eclipses. There are to be found only two which may be compared in size with that of August 17, 1868, and none in which the totality lasts so long. The first is the eclipse of Thales (May 28, 585 B.C.), said to have been the first predicted, and to have concluded a fierce engagment between the Medes and Lydians. The second was visible on June 17, 1435, in Scotland, and the time of its occurrence was long remembered by the people of that country as "the black hour."

But besides its enormous size, the eclipse deserves special attention in another respect. In researches on the nature of the red protuberances and other phenomena visible during total solar eclipses, it would certainly be of the highest importance to learn something about the nature of changes to which these appearances may be subject. On a single place upon the shadow's path, the time of visibility is too short to permit of the hope of perceiving processes of physical change in these objects; but it is far from being improbable that observations, obtained at several places along the line of totality, might afford the information we seek on this point. In the present instance the shadow touches a series of accessible regions, as we have seen. It is also very probable that favourable weather will prevail at the time of observation.

It would certainly be well that efforts should speedily be made to take advantage of so favourable an occasion for extending our knowledge of solar physics. Centuries will pass before we have such another opportunity.

Turning to Major Tennant's remarks on the subject of the same eclipse, we find that much has been done in the way of preparation. The Council of the Astronomical Society has decided that there should be provided for photography a silvered-glass reflector,

equatorially mounted and driven by clockwork. The Astronomer Royal also offered to lend Major Tennant two telescopes from the Royal Observatory.

As respects Photography, the conditions as to time rendered it unadvisable to attempt to use a speculum of more than 9 inches diameter. The picture will be taken at the side of the tube, the telescope being a Newtonian one. Provision has been made to obtain a field of more than one degree in diameter, so that, if possible, some traces of the structure of the corona may be obtained in the photograph. The important difference between the position of an equatorial used in such low latitudes as the central parts of India and one used in our latitudes, have rendered new designs necessary for almost every part of the mounting. Hence many unavoidable delays have taken place with respect to this part of the arrangements.

Measures have also been taken to apply tests for the polarization of light from the coloured protuberances and the corona, the following three methods being applicable:

1st. The extinction of the polarized portion of the light by means of a Nicol's prism, reducing the intensity of the image to a minimum.

2nd. Savart's test, where parallel fringes are formed by the interference of the polarized rays, the central one being either dark or light, as its plane is in or perpendicular to the plane of polarization.

3rd. By a double-image prism and analyzing plate, giving images of complementary colours with polarized light.

The first two of these tests can be instantaneously interchanged, and there is no difficulty in using all these tests successively in two minutes.

For spectrum observations, the Astronomer Royal has lent Major Tennant one of the old collimators of the Transit-Circle at Greenwich Observatory. An equatorial mounting is being constructed for this, to follow any object steadily, but without clockwork. The spectroscope will allow of the spectrum being compared with a scale of equal parts, by means of which its peculiarities can be referred to the lines of the solar spectrum.

All the estimates for the expenses of the proposed operations have been duly sanctioned.

Mr. Proctor gives the elements of his new determination of the Rotation-period of the planet Mars. A comparison of pictures taken by Mr. Browning in February of the present year with Hooke's observations in March, 1666-giving a period of nearly two hundred and one years-have enabled Mr. Proctor slightly to correct his former estimate-in obtaining which one or two small errors had crept in. He now gives for Mars' sidereal day the