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It appears desirable, as a first step to a right theory of the condition of the sun’s surface, that the appearances which it presents should be recorded in some systematic way Photographs will suffice for the distribution of the spots , but careful eye-drawings must be appealed to in evidence of the form, arrangement, and intestine motions of the parts of those spots, and eye-drawings with measures are the only means of recording accurately the dotted, areolar, granular, crested, and other arrangements which under the general title of “porosity” have been recognized over the whole face of the sun Descriptions cannot be complete, but, what is more, they may be, and probably often are, misleading—words which call up right ideas of things often fail very much when required to perform the same function for new objects not well understood.

The return of Mars to his periodical opposition with the sun has enabled me to offer a few observations on this planet, in addition to those which on a former occasion I had the honour to present to the Society. Among the subjects then suggested for consideration was the permanence of the main features of light and shade which had been recognized by many observers. Another question requiring attention referred to the fogginess or seeming cloudiness of the planet, also noticed by many observers, some of whom represented what might be thought effects of currents in the atmosphere round him.

I. Sketch of the Progress of Selenography. ( a ) By Eye-draughts and Micrometry . 1. Beginning with the labours of Hevelius (1647), maps of the moon, embracing the whole, and signalizing special parts, have been repeated by Riccioli (1651), Cassini (1680), Lalande (1787), T. Meyer (1748), Lambert-Schröter (1791), Lohrmann (1824), Beer and Mädler (1836). 2. The degree in which these laborious efforts may be regarded as meeting the wants of “Selenography,” is about equal to that in which the maps of England of the last century satisfy the requirements of physical geography; and in the same proportion as the great one-inch Ordnance Map of 1862 is superior to the old Chart of 1800, so should be the new drawings of the features of the moon to the older delineations.

Frequently, during many years, the peculiarities of the physical aspect of the sun have arrested my attention, and induced me often to sketch and sometimes to measure; but until Mr. Cooke furnished me with the accurate and convenient equatorial which I now employ, there seemed little hope of my being able to draw correctly or observe systematically. During some late occasions I have endeavoured to obtain trustworthy representations not only of some of the darker tracts, denominated “spots,” and the brighter parts which are near them, called “faculæ,” but also of the general uneven groundwork of the sun’s disk.

Notwithstanding the descriptions and drawings of Mars, for which we are indebted to eminent observers, there remains much uncertainty as to the permanent boundaries of the bright and shady parts of the planet, to which respectively, on a first view, we attach, perhaps too readily, the idea of land and seas. The extremely variable aspects under which this planet appears in its excentric orbit, the axis being inclined more than 30° to the ecliptic, the different regions very unequally presented to incident light, and very unequally influenced by vicissitudes of heat and cold, may account for much of the uncertainty. Other difficulties arise when the work of different instruments is compared; for it is established that reflectors will on the whole give the best results for colour, while achromatics of fine quality discover more of detail than instruments of less perfect definition.

My first serious attempts to portray the aspect of the moon were made with the noblest instrument of modern times, the great telescope of Lord Rosse, in 1852. The mirror was not in adjustment, so that the axes of the incident and reflected pencils of light were inclined at a very sensible angle. This being met by a large reduction of the working area of the mirror, the performance was found to be excellent. I have never seen some parts of the moon so well as on that occasion. But when I came to represent what was seen, the difficulty of transferring from the blaze of the picture to the dimly lighted paper, on a high exposed station, with little power of arranging the drawing-apparatus, was found to be insuperable, and the effect was altogether disheartening. It was like setting down things ex memoriâ , to give the rude general meaning, not like an accurate and critical copy. I present as a specimen of this memorial a sketch of the great crater of Gassendi (No. 1). I next mounted, in my garden at York, a small but fine telescope of Cooke only 2·4 inches in the aperture; and, aware of the nature of the difficulty which beset me at Birr Castle, I gave it an equatorial mounting, without, however, a clock movement. The whole was adapted to a large solid stone pillar in the open air. It was not possible, with 1/60 of the light of the Rosse mirror, to see so well; but it was easy to represent far better what one saw, with a conveniently placed board to hold the drawing-paper, a well-arranged light, and no necessity of changing position. I made in this manner the drawing of Gassendi which is marked No. 2.

During the latter half of February and the first half of March, spots of extremely varied character have appeared on the sun, and have been seen with great distinctness, in good observing weather, through the whole or parts of two semi-rotations. On the 13th of February, at 10 h 25 m , four spots were visible on the disk, in the situations marked Z, A, B, C in the diagram No. 1. In that diagram the apparent course of the sun’s equator is marked by the curved line e, and the pole of rotation at P. Thus the four spots indicated for observation being all on the same side of the sun’s equator, and all within the latitude of 10°, constitute a zone of spots. Since that date a fifth spot, D, still in the same zone, has appeared, fol­lowing C. Of these Z was about to disappear; its reappearance was noted, and several remarkable changes in form were observed while it traversed half the disk, till its contraction to a black speck 1000 miles in diameter, after which it was obliterated. The spot B had advanced some distance on the disk, and was followed till the 21st of February, when it approached the edge, with indications of being a shallow concavity. It was not observed to reappear. The spots A and C require longer notice, both on account of their persistence through more than a rotation-period, and because of the remarkable changes which they have undergone. The spot D is now under observation. The spot A, visible from the 4th to the 16th of February, and again reappearing early in March, was solitary, and approximately round, mea­suring, on February 10, about 23,000 miles across the penumbra, and about 8000 across the umbra.

On the 15th of March 1858, occurred an annular eclipse of the sun, whose entral line of shadow passed near the village of Steeple Aston, a few miles orth of Oxford. Ample preparations were made for observing it by resi­dents in Oxford, and they were met on the ground by many persons from distance; Mr. Lasseli being one of the party, there was no lack of telescopic power. The day was unfavourable—cold and cloudy, with some ccasional feeble and delusive gleams, scarcely permitting a sight of the rogress of the eclipse, which, however, was obvious enough by the grow-g and diminishing darkness. Under these circumstances I devoted my trincipal attention to three thermometers, carefully selected and compared forehand—one mercurial with blackened bulb, another mercurial with lear bulb (these were placed in an open space exposed to the sun); the third, minimum- spirit thermometer, tint red, was placed in a shaded situation. The observations began at 11 h 30 m and lasted till 2 h 30 m , thus including he whole period of the eclipse, which began at 11 h 35 m , reached the maxium of obscuration at 0 h 54 m , and ended at 2 h 11 m . The apparent semi-ameters of the sun and moon were so nearly equal that the eclipse was lmost total (997/1000). The observations were recorded as follows:— During the late partial eclipse of the sun on the 6th of March 1867 observations of'the ingress of the moon were favoured at Oxford by brilliant weather; within fire minutes after the moment of maximum obscuration (742/1000) Clouds appeared; and from this time till the end of the eclips they never wholly disappeared, but did not prevent the progress of the moon and the degrees of obscuration from being correctly marked. At the very end it was only just possible to observe the egress by a momentary attenuation of the clouds; the remainder of the day was cold, cloudy, and finally snowy. The observations began at 8 h and ended at 10 h 50 s , thus including the whole period of the eclipse, which began at 8 h 12 m 15 s , reached the greatest obscuration at 9 h 26 m , and ceased at 10 h 45 m 8 s . At the mo­ment of greatest obscuration the light-giving area was reduced to one-third of the solar disk.

Of the few attempts which have been made of late years to prepare drawings, on a large scale, of selected lunar mountains, this contribution from the Roman Observatory appears to be one of the most successful. It is on a scale of magnitude (about 10 geographical miles to one inch) such as only the larger modern telescopes can command, and characterized by such firmness of definition as to do honour alike to the maker of the instrument and to the artist engaged in the delineation. It may assist those who have not attempted, with their own hands, any drawings of this kind, and desire to form a right judgement of the value of this work of P. Secchi, if I send for comparison a drawing of Gassendi, executed from my object-glass of 6¼ inches (Cook), with a focal length of 11 feet. The drawing is on a scale of 20 geographical miles to an inch, and Gassendi thus appears of half the linear dimension of Copernicus, being really almost of the same diameter.

On the 17th of October, 1865, at 2 P. M. the spot referred to had traversed a great portion of its arc, and was approaching the limb. It showed two large unequal umbrse, and in each of them a blacker nucleus. Between them were several small dark dots, partially coalescent.

At my observatory, situated about one third of a mile eastward from the great establishment founded in the name of Dr. Radcliffe, the beginning of the eclipse was obscured by a passing cloud: the end was recorded at 13 h 38' 38" = 1 h 35' 0"·9 Oxford mean time.

Dear Sir,—The favourable position of Jupiter for scrutiny of his physical features may perhaps have already brought to the Royal Society some notice of the aspect of his belts. Whether that be so or not, I think you will readily excuse the desire I feel to lay before the Society a sketch from my equatorial, which shows the colours of several celestial objects more distinctly than I am accustomed to hear is the case with some other instruments of the achromatic class. The sketch shows the usual equatorial bands, or rather bands nearly in the usual latitudes north and south of the equator. These, to the eyes of my friends and to mine, appear not dark grey, or greyish brown, or brown, but nearly of the colour of some ochraceous sands, or the yellower parts of what is called “red” deal. Several friends to whom I have shown the planet have immediately exclaimed, “how red the bands are;” “never saw them so red before.”