might in this case be termed, appeared entirely filled up with light, excepting where the central darkness cut out a large gap in it. Oct. 5, it was doubtful whether or not its outline was defined by a more luminous arc; but now its principal brightness was confined to about a hemisphere, not however symmetrically situated with respect to the general figure of the comet, but inclining a little backwards as though left behind in its movement, so that the faint sector which completed its form round to the central darkness on the antecedent side was considerably larger than the corresponding one in the subsequent direction: this was not very distinctly made out, but such was the prevailing impression. Oct. 11, when the comet had advanced beyond the range of the great telescope, the smaller one showed, though of course less evidently, a similar appearance; but the more luminous hemisphere now seemed to be inclined the other way, or partially to precede the nucleus in its course, its central radius making an angle of about 30° with the axis of the tail, as though there existed a kind of swinging motion, such as was perceived in the last return of the comet of Halley.

3. The Tail. This gave some intimation of its structure even to the naked eye; in the telescope its central darkness was very conspicuous; and as it advanced in its course the sides of the hollow paraboloid became more thin, and the angle included by them increased. Sept. 30, the proportion of the dusky streak to the whole breadth of the tail was estimated at it occupied perhaps on Oct. 11, while it seemed to have become rather more filled up with nebulous light: the clear and broad notch which it cut out of the photosphere, even up to immediate contact with the back of the nucleus, increasing, of course, in breadth in a similar way. Oct. 4, it was traced for a length of 2° or 24° before it was merged in the general brightness. The two streams which formed the tail were for a long time unequal in breadth, but were never observed to change sides so as to indicate rotation: the antecedent branch showed greater fulness and density near its origin even with the small object-glass on Sept. 24. With the large one, on Sept. 30, it was estimated the broader in the ratio of about 4 to 3; on Oct. 4 and 5, as 3 to 2. Oct. 11, they appeared with the small telescope of equal breadth. During the whole time the angle at which they came off from the nucleus underwent a steady increase: the antecedent stream was always far better defined than the other at its exterior edge. These two streams were connected round the sunny side of the envelope or photosphere, by a border of the same material, much narrower and fainter than the envelope. This border, which formed the vertex of the tail considered as a paraboloid, was, on Oct. 4 and 5, suspected to be bounded by a delicately brightened up semicircular edging, as though it were merely a thin shell; but this remained questionable. Beyond this border a considerable extent of very faint haze was visible, melting gradually into the clear sky. During the magnificent transit over Arcturus it was remarkable how distinctly and fully the light of the large object-glass brought out the tail, even close to the dazzling disk of that vivid star.

To the naked eye there was a remarkable irregularity in the curve of the tail, which gave strongly the impression of the exhaustion, beyond a certain distance of the projectile or repulsive force, and of a consequent diffusion and dispersion of the luminous material. This was first noticed on the evening of the transit, when the train extended in a regular curve as far as and Boötis, which were near its centre, but about one-third of the distance between and where the tail attained its greatest width, the convexity began to be a little deflected backwards or flattened off. Oct. 8, this was still more conspicuous; the curve of the antecedent side, which was carried regularly up to a Corona, being subsequently deflected from the direction of d Draconis, to which it had previously tended,

towards a fresh point between and Draconis, about onethird of their distance from the latter star, as far as could be ascertained in making an estimate of so very dim an object; sometimes I thought that Draconis was the point indicated. The fainter branch could not be well made out higher than Boötis; beyond this star it seemed, if anything, to approximate again towards the other branch; and the general impression of this side of the tail was that of spreading out like a feather, as compared with the more definite aspect of the convex edge. The whole length on this evening could not have been less than 45°; the greatest breadth, as measured by a Corone and Boötis, about 7°. Oct. 10, the curvature appeared regular as far as a line joining a Corone and Herculis, or perhaps a little further: thence a fainter ray of considerable breadth was deflected at a large angle, perhaps 60°, as far as the stars of Quadrans Muralis. This portion was very feeble, but certain, and looked quite like a scattered and abandoned vapour. Another observer agreed with me in suspecting that it was less bright at its connexion with the regular tail than a little further off. Oct. 11, the tail has lost all the deflected prolongation, and extends in a simple curve a little above Herculis, perhaps to ; its concave part is much scattered, and it has probably a breadth of 8° or 10°.

Unfavourable weather precluded any further observations. The envelope or photosphere, and its interruption by the central darkness, were very clearly distinguished by Mr. With at Hereford, with an excellent object-glass by Bardon, of 3 inches aperture.

Observed at Rose Hill, Oxford, by J. Slatter, Esq. Absence from home prevented me from making any observations of the comet before its coming to its perihelion.

The observation on Oct. 11 was made with a portable telescope 2 inches aperture, and a power of about 30, the comet being unable to be seen with the fixed telescope owing to trees. All the other observations were made with the 7-foot equatoreal, 5 inches aperture, and power 117.

Oct. 1, 7 P.M. Nucleus not round, irregular oval; perhaps paraboloidal. Larger diam. 12", smaller 9".

Parabolic Envelope distinct and bright, the shape of its posterior boundary not noticed, but in a rough sketch; it descends a little below the nucleus. Measuring through the nucleus, i. e. if parabolic, the parameter = = 4′′·1.

Oct. 5. Unable to find the comet in daylight. As soon as dark it formed a most splendid sight. The tail more curved, like a bright plume, sweeping upwards with Arcturus enveloped near the head, enclosing y Boötis, central at the widest part, and a Boölis just at its boundary, the tip reaching to the triangle formed by 0, 1, x Boötis. This was the fullest size it attained. The nucleus to the naked eye not so bright as on the 1st, which was fully explained by the telescope.

7 P.M. Nucleus small and bright, and round; diameter 4"8. Envelope very large and bright; the posterior edges greatly prolonged behind the nucleus and opening out at an angle slightly differing from 90° by estimation. Parameter 59′′.

To the naked eye, Arcturus, through the tail, appeared, if anything, to scintillate more than usual; and in the telescope its light appeared white instead of its usual golden colour.

Oct. 8, 7 P.M. Again to the naked eye a perceptible change, the head having become much brighter since the 5th. The tail also apparently more condensed on the brighter side, and much fainter in its upper part above a Coronæ.

Nucleus much larger, irregular in shape, but not sensibly differing from a parabola. Longer diameter 22" (shorter 11" by estimation).

Envelope very large, the posterior angle much more open;

C

25, 26

estimated at 150°. Parameter 83". Inside the nucleus was a yet brighter very small nucleus, estimated at 2" or 3" diameter; in shape round.

Oct. 9, 6 P.M. Nucleus large, paraboloidal, with a brighter core. Diameter of outer nucleus 31"; inner ditto 9".

Envelope had vanished; no trace whatever of any. The tail had greatly diminished in length, not reaching much, if at all, above a Cor. Bor.

Oct. 11, 6 P.M. Nucleus bright; diameter (estimated) 8′′. Envelope. Another now visible, posterior edges open at about an angle of 150°. Parameter 45" about, by measure.

The tail had gradually become more and more curved, and its axis at the head less and less inclined to the earth's equator. The axis of the envelope and nucleus made an angle of 7° or 8°, with the axis of the tail at its origin.

26, 27

while the tail was 8° long, and curved like a scimetar, a characteristic which it preserved during the remainder of its appear

ance.

On October 1st the nucleus had become brighter, but smaller, with projecting wings or jets of light sweeping backwards: while on October 2d a fine dark division in the tail was apparent, reaching from the head for about a degree in length, which subsequently became wider and larger. On October 1st, the tail was 21° in length; on October 5th, 28°; and by the end of the week, on October 9th, fully 36° or 38°, as measured by the declination-circle to the point where the eye estimated its appearance to cease.

The following micrometrical measures of the position of the comet with respect to Arcturus were made on the evening of the 5th of October :

Height above sea-level 20:25 feet.

63 43 30 44 20 15

7 42 43

30'4 60'0 57°5

Dubhe Arcturus

30 2 35 29 24 35 30 56 45

27 40

Dubhe Vega Dubhe Vega Dubhe

41 35

62 32 30 54

Vega

Dubhe

Vega

Dubhe

Vega

59 14 45 66 8 30 57 25 70 32 15 57 24 37 79 27 40 58 5 25 43 51 15 62

Observed at Highbury, by T. W. Burr, Esq.

645

The comet was first seen on the 5th Sept. without a telescope. On the 8th the tail was quite half a degree long, of a brushlike form, and the nucleus bright and stellar in appearance. On the 12th the comet had wonderfully increased in brilliancy. The nucleus was more planetary and discoid in character, of a golden tint, and having the coma, or nebulous haze, extending round it on one side, and stretching away to a tail of about 3° of length in the opposite direction. There was a well-marked, comparatively dark, separation between the nucleus and the exterior outline of the head; and the sides of the tail were more brilliant than the central portions, conveying the impression that the bright nucleus was near the extremity of a nebulous tubular envelope with slightly divergent sides, and therefore approximating to a funnel shape. The growth of the tail now became exceedingly rapid; and the brilliancy of the head increased likewise, it being but little inferior to that of the stars composing the tail of Ursa Major. By the 21st September the light of the head exceeded that of any star in Ursa Major, and closely approached that of Procyon;

The observations were made with a telescope of 3 inches aperture, the powers ranging from 20 to 173.

Observed at York, by W. Gray, Esq.

The accompanying sketches of the comet show what particularly impressed me; and though I am unable to draw, they yet may be of use in confirming the observations of better artists. Sept. 30. The second stratum has its crescent prolonged on the following side.

Oct. 3. The first stratum is a sector of 240°, a dark welldefined space between the branches of the tail, a black spot distinct on the preceding side of the glowing nucleus, and on the second area I was under the impression that a similar spot, very faint, existed. (I did not see the latter spot on subsequent evenings, but the spot on the first area was always visible.)

Observed at Spalding, Lincolnshire, by F. Selby, Esq. The observations were made with a six-and-a-half-foot refracting equatoreal, of five inches aperture, by Slater, of London. Owing to the obstruction offered by high buildings, the view of the comet was limited to an interval of time, varying from an hour and a half to half-an-hour each evening.

Sept. 13. A sudden and momentary emanation from the nucleus was remarked. At first it was supposed to be due to atmospheric causes; but from its recurring in precisely the same form, the author felt convinced that it was really attributable to a change in the nucleus.

Appearances of a similar nature continued to be observed during the visibility of the comet. The author arrives at the conclusion that the nucleus is a dense body, emitting igneous or gaseous emanations.

The Great Comets of 1811 and 1858.

The following extract of a letter from Admiral Smyth to the Editor, in reference to the great comets of 1811 and 1858, will be read with interest. It may be mentioned that the comet of 1811 was observed for several months by the gallant admiral while employed on active service in the Mediterranean:

"In re the magnificent comet, I have been closely attending to its fine figure; and am asked on various sides, as I had the advantage of having closely watched both, which I thought the most splendid in appearance, this, or that of 1811? Now, to my memory, which is very distinct, the palm must be given to the latter. As a mere sight-object, the branched tail was of greater interest, the nucleus with its head-veil' was more distinct, and its circumpolarity was a fortunate incident for gazers.

6

"But recollect that in these remarks, I mean nothing disrespectful to the Donati. On the contrary, with those exceptions, it is one of the most beautiful objects I have ever seen in the heavens. The head is certainly not so fully pronounced as in that of 1811; but greatly its physical interest is increased by segments of light and a dark hollow, giving the aspect a resemblance to the gaslight called a bat's-wing.

"This dark line, or space down the centre of the brilliant phenomenon, not only had the direct tendency to strengthen the luminosity of the jets of light, in the manner observable in the burning of a wax taper, but also, on a fuller scrutiny of this singular characteristic, to recall its striking resemblance to the similar feature seen in water-spouts, and in the pillars raised in sand-storms which I have witnessed in North Africa."

is seen passing over ę, 5, 4, λ, %, 4, and Bootis, extending a little beyond the three last-mentioned stars. At its greatest breadth it extends from a Bootis to a small star, h 2, in the same constellation. The tail, roughly speaking, extends from 20° to 56° of north declination, measuring about 36° on the hour-circle passing through Arcturus.

This drawing was executed by Mr. De La Rue before proceeding to Russia, whence he intends shortly forwarding the results of his observations.

"When the comet had entered well within the margin of the tail a dark notch was formed cutting out a portion of the tail round the star; and as the star got further in, this became a dark areola surrounding the star, and in diameter equal to about one-tenth of the line of transit. This continued until the star reached the middle; at this part there is a broad dark line which extends from the nucleus to a distance considerably above the point where the star crossed. When Arcturus arrived here, this dark space was perfect up to the star, but on the other side the white light of the tail appeared to come quite up to the star; in short, as the bright part of the tail had been darkened in the vicinity of the star, the dark part was brightened, at least so much of it as was on the side furthest from the nucleus.

"I saw the notch again on the opposite side previous to emersion, and then lost it by clouds.

"The effects I have described are, doubtless, optical, and the notch and areola evidently due to the bright light of this star: the effect on the dark central part is not so easy to explain."

Admiral Smyth has forwarded a series of interesting drawings of the comet by Baron De Forester, representing its appearance as seen to the naked eye at Oporto on various evenings included between September 26 and October 15. The drawings are carefully executed upon a dark ground; and as the stars in the vicinity of the comet are laid down, they serve to give a good idea of the varying apparent dimensions, and curvature of the tail.

Thoughts on the Formation of the Tail of a Comet.
By J. J. Waterston, Esq.

Any attempt to account for the formation of the tail of a comet upon exact physical principles would be assisted, if, in the drawings of the telescopic appearances of the nucleus and adjacent coma-which are sometimes provided when circumstances are favourable-we were presented with the projection on the plane of vision of the radius vector, and of the tangent to the orbit. In some cases it might be possible to take such observations as would fix the actual curve of the exterior line of the tail, referred to the radius vector, passing through the centre of the nucleus; i.e. supposing the central axis of the tail to be in the plane of the orbit. This line is very marked in the front side of Donati's comet, and might probably be easily fixed by the equatoreal.

If we view the tail as composed of molecules as free from the force of cohesion as the molecules of an uncondensable gas, and raised from the nucleus by the heat of the sun; and that that heat as it strikes upon each molecule is converted into a force centrifugal, that not only effectually counteracts the force centripetal of the sun's gravity, but that greatly exceeds it; such molecules will be quickly removed from the feeble attraction of the nucleus, and assume the motion of bodies entirely free from its influence. This hypothesis is suggested by the mechanical theory as a possibility.

If we inquire as to the centrifugal power of the sun's rays, we may, with the data afforded by modern research, easily compute the accelerative force it is capable of engendering on a single chemical molecule, if their whole heating power were converted into such a force. This is surpassingly great-no less than 800 miles per second! The data are, value of sun's radiation in a solar day equal to 1.8 ft. thickness of ice melted; the mechanical equivalent of which is about 13 lb. raised 1 foot high per second by the heat impinging on a square foot. If

30, 31

this heat impinges on a superficial foot of gold-leaf, one molecule thick (about one 200-millionth of an inch, as deduced from the relation of capillarity to latent heat, both being the measure of liquid cohesion, the first that of the superficial stratum of molecules, the second that of a cubic mass of molecules), and is converted into an impulsive force in one direction, it would in one second communicate a velocity of 800 miles a second; and in about four minutes a velocity equal to light itself. It is, of course, an extreme case to suppose the whole heat absorbed and converted; but it seems right to have in view the quantitative elements of the question. While the earth's atmosphere absorbs heat from the sun's rays, we have reason to suppose that heatvibrations are converted into rectilineal velocity of gaseous molecules; but there is no reason to suppose that the impulse is in the specific direction from the sun, but equally from and to, as in vibratory impulses generally. It may be shown that the mechanical equivalent of the solar heat that impinges on the earth amounts to one-hundredth of its gravity towards the sun; so that, if any part of it acted centrifugally, the orbit would be disturbed. The same remark applies to a comet; but it cannot be denied that the phenomena of the tail, more especially as it turns sharp round in the perihelion passage, are such as require for their explanation a very active exhibition of such a centrifugal force as might be engendered by the conversion of heat acting upon single and free molecules. Oct. 7, 1858.

This Report, which has been forwarded to the Society through the Hon. William Stuart, Her Majesty's Chargé d'Affaires at the Court of Brazil, is a translation in the French language from the original. It extends to 44 pages of folio MSS. divided into sections, as follows:

1st section, historical and introductory.

2. Observations of times of contact, exterior and interior. 3. Notes on the passage of the moon over the spots and faculæ on the sun.

4. Notes on the visibility of the moon beyond the edge of the sun.

5. On the colours of the sky, the sea, and of terrestrial objects, during the obscuration.

6. On the state of the limb of the moon, and on Baily's beads.

7. On the intensity of the light of the sun near the limb. 8. On the intensity of the atmospheric light during the totality.

9. On the corona.

10. On the protuberances.

11. Photographic observations.

12. Measures of the distances of the cusps.

13. Meteorological observations.

14. Effect of the eclipse on men and animals.

The commission was appointed by the Emperor of Brazil, at the instance of M. de Mello, director of the observatory at Rio, and was ordered to repair to Paranagua as a central station. The party consisted of M. Oliveira, M. de Mello, director of the observatory, M. Liais, sent out specially by the French Government, and four naval officers on the staff of the observatory, and had a steam-corvette, the Pedro II., placed at their service. This expedition left Rio about seventeen days before the day of the eclipse, and soon after its arrival at its destination, was increased in force by several

31, 32

officers of the corvette who were detached for the special service. Four stations were selected, a chief central one at the country-house of Dr. Reichsteiner, the Swiss Consul, on the sea-shore near Paranagua, a second on board the corvette at sea, and two others inland at the distances of 12 and 8 leagues, situated the one near the south boundary and the other near the north boundary of the shadow.

The weather seems to have been very unpromising, and rain to have been so frequent previously to the 7th of September, that little hope was entertained of success; but in the event, the excellent arrangements made were not frustrated by this cause.

The position of the shore station was found to be 29° 30′ 33" 2 south latitude, by 48° 26′ 59′′ west of Greenwich. At this station there remained M. de Mello with the telescope of the equatoreal of the observatory of Rio mounted parallactically; M. Oliveira provided with an equatoreally mounted cometseeker; M. Liais, with four parallel telescopes on an equatoreal mounting common to them all, and several other observers with instruments of various kinds. The dimensions of the telescopes employed are, however, not specified with as much fulness and particularity as is desirable.

2. The first exterior contact having been lost by the intervention of cloud at the central station, and the second interior contact having been also lost by the observers being taken by surprise, the remaining contacts noted are passed over here and left for future publication.

3. The solar spots were observed and sketched at Rio on several days preceding the eclipse; but the results are not given in the report. Much change of form and number is alone remarked. In this section the principal point noticed is that by M. Liais, who as the moon advanced over a considerable spot, noticed with a power of 300, a slight flattening of the spot in the direction parallel to the moon's limb, which appears to correspond closely with the effect noticed lately in this country during an occultation of Jupiter.

4. In the early stage of the eclipse, both M. de Mello and M. Liais were able to trace the contour of the moon to the distance of from 4' to 8' beyond the sun's limb; but the following are far more curious remarks under Section 4. With one of M. Liais's telescopes having an aperture of 3 inches, the image was observed by projection on a plate of ground glass, and the image of the moon was thus seen very distinctly, and remarked to be whiter than the neighbouring region of the sky, an appearance which lasted for some time, then became less marked, and at last not distinguishable. Some photographs of this appearance were obtained by M. Liais by the dry process on glass collodionised and albumenised, in which the effect was distinctly traced, while the plates were still wet on coming out of the gallic acid bath. M. Liais adds some remarks in explanation of the curious circumstance that both in the photographic negatives and in the projected positive image, the same effect was witnessed. The reader must, however, be referred to the original accounts for this and other matter of value which here follows.

6. M. de Mello and M. Liais were unable to perceive any mountainous irregularities in the last remaining portion of the moon's limb, or on the part which first appeared on the sun after the greatest phase, yet M. de Mello states that in spite of this circumstance, and every care in adjusting for distinct vision of the sun's limb, the phenomenon of Baily's beads presented itself to him on both the disappearance and reappearance of the sun. His telescope had 4 inches aperture and magnified 72 times. M. Liais observed these occurrences by projection, and detected no beads or irregularities.

8. At Paranagua Venus, Mercury, Saturn, Sirius, Canopus, and three other stars, supposed to be a and B Centauri and a Crucis, were seen during the totality; but M. de Mello could

not trace Regulus on the meridian, although previously provided with its position. Numerical results by Rumford's photometer of the degrees of obscurity are added.

9. The corona appears by the accounts of all the observers to have presented on this occasion an unusually complicated appearance; and improbable as the details of the sketch which was sent with the account appeared at first sight, they appear to be well made out and established by the concurrent evidence of several individuals. More than three independent observers agree in testifying to the appearance of 5 distinct brushes of light reaching to an average distance of about 13' from the moon's limb, of the form of a cone with convex sides, the base equal to two-thirds the height, resting on the moon. Of these four were in their general directions normal to the moon, two on each side the vertical, and the fifth oblique, bent upwards and having its base nearly coincident with the lower normal cone on the east or apparent right-hand side. In addition to these were two brushes of white light in a strictly radial direction, one on the right, the other on the left of the vertical, and both starting out below the horizontal diameter of the moon, with a thread-like texture; and on the east or apparent righthand side of the moon an emanation of feebler light of the general outline of a parabola with its apex in contact with the dark limb. Description cannot entirely stand in the place of a figure, and the reader must necessarily be referred to a more detailed account which may probably be published hereafter. The light of the corona forming the ground on which these brighter portions were seen projected was remarked to be exceedingly unequal and patchy, and in many places to present the appearance of coarse rays crossing and intersecting in all directions, and in no part offering any exterior boundary sufficiently defined to have its termination submitted to measurement. An observation was made by M. Liais bearing on the relation of the conical brushes of light to the sun, which must be given nearly in his own words-" 7 or 8 seconds after the commencement of the total obscuration, I fixed my attention on the east side on the bundle of rays forming the apparent lower edge of the oblique cone turned upwards, and which set out from the limb of the moon nearly tangentially. My attention was directed during from 15 to 203 to this bundle of rays, and on a white protuberance having a black border very near to which it passed. One of the rays in particular touched the extremity of this protuberance, and continued backwards arrived at the edge of the moon at a distance of about 2 degrees. I witnessed this distance diminish little by little, the ray all the while remaining in contact with the extremity of the protuberance and contrasting by its brilliancy with the black border of the latter. I watched the bright (white) portion of the protuberance gradually disappear behind the moon till there remained only a minute black point which vanished about 3 seconds later. The point of intersection of the ray in question with the moon was at that instant exactly coincident with the point at which the apex of the protuberance, which had then the appearance of the summit of a lunar mountain, disappeared." simple figure may assist this description. AR PR being the dark edge of the moon 7 or 8s after commencement of totality, Pp the protuberance with a white centre and black outline, R pr the welldefined tangential ray of the corona, the moon's edge was seen to intersect the ray at all points between R and p, as it advanced from the position ARB to a pb, when the protuberance was finally covered up, and the

A

B

ray was seen to intersect the limb at the point p. M. Liais

argues that previous observations having connected the protuberances with the sun, and this observation indicating that the corona ray remained consistently stationary as referred to the protuberance, we may conclude that the cone of corona light of which this ray formed a part, also was an appendage to the sun and not to the moon, and by parity of reason may conclude the same for the rest.

10. Several protuberances were also seen during the totality, but they are described as having been of a white colour, and only in one instance tinged with pink. At the commencement of totality three protuberances were found on the sun's east limb, the angles of position of which counted from the lowest point (query nadir) were found by M. Liais with an equatoreal having a divided interior position circle, to be 45°, 105°, and 135° respectively. The two first were vividly white, with a black outline. On the west limb measuring, as before, from the lowest point of the disk, there were seen two others, at the angles 110° and 170°, in which a pink tint was noticeable. In a short time the protuberances on the east side were covered over, and a third one emerged on the west side (making six in all), at the angle 60°. The height of the principal protuberance on the west limb (the one situated at 110°) was twice measured by M. Liais by comparison with a fixed scale provided in the field of this telescope and estimated to be 58" at about 8 seconds after totality commenced, and 1' 18" towards the end, but these values, though probably approximate, are but estimations without the strictly corresponding times. At one of the inland stations, at Campinas, the protuberances at the angles 110° and 60° were seen to be connected by a low dentelated bank of pink light, which was not uncovered to the observers at the central station. These two protuberances with the connecting fringe appear to agree with those in the naval account from Payta on the west coast, with some discrepancy in the angular situation. There appears to be a disagreement between the indications of the letters N ESO on the sketch from Brazil, and the statement in this section that M. Liais's angles were reckoned from the lowest point of the disk. It would appear on examination that though the observers at the central station had three equatoreally mounted telescopes, the only angles read off were referred in reality to the vertical, and that the point marked north on the drawing must be taken for the true nadir point. On applying the correction 24° for the angle between the south pole and the zenith at the sun's centre, we then, from M. Liais's statement, derive the following position-angles for the 6 protuberances seen at Paranagua; 69°, 129°, 159°, 214°, 274°, and 324°, reckoned from N. round by E., the low band of pink light connecting the two last. Similarly correcting the angles read off from the sketch given in M. Le Verrier's bulletin of October 21, by the angle 82°, there result the position-angles 77°, 92°, 2570, and 342°, for the protuberances seen on the west coast, the two latter being connected by a bank of pink matter. Comparing these with the former, the 77° answers to the 69°, and the continuous bank from 257° to 342° with elevated terminations corresponds to M. Liais's bank from 274° to 324° similarly characterised. The angles of M. Liais are probably somewhat more exact than those observed on board the French vessel on the west coast, but they do not encourage one to enter upon any nice comparison with the angles of position of the solar spots and faculæ. Taking them as they here stand, there would appear to be no sort of connexion, which is also M. Liais's conclusion in the Report.

11. The next section is given to an account of the means used for obtaining photographs of the disk, and of the results deduced. The length to which this abstract has already extended precludes the statement of more than that 15 photographs were taken, 9 before the totality and 6 after, of which one failed to develope, and two others were spoiled by the instrument's slipping. The positions of the cusps exhibited in