A7!§^Si 2 2, 1878] 



NATURE 



433 



begin our party took their positions. I was about twenty 

 feet to the south of Prof. Hough, who was in a group 

 consisting of himself, Prof. Colbert, and Prof. Easterday, 

 who used the telescope for observing the corona. To the 

 west was a class of fifteen young ladies from Denver, 

 instructed by Prof. Colbert to sketch the corona. South- 

 east of my position Mr. Thomas was stationed. 



" When arranging my instrument I made the post very 

 low, exciting much comment by my companions. I told 

 them I intended to lie on the ground during the observations, 

 this being a position I had found the easiest in my experi- 

 ence of twenty years' comet-seeking. I spread a carpet on 

 the earth and had a great advantage over the other mem- 

 bers of the party, who were obliged to assume constrained 

 positions, which tended to unsteadiness of vision. Seated 

 by me was Daniel Drummond, with an accurate time- 

 piece, set by the chronometer a few minutes before the 

 first contact. E. D. Smith, an old acquaintance, whom 

 I met in Denver, recorded the time of each event as I 

 called it. Mr. Drummond is an experienced engineer, 

 and counted the seconds with great accuracy. 



"As I arranged my telescope for the first event the 

 wind was blowing in fitful gusts from the south-east, 

 shaking our instruments. To prevent my instrument 

 from swaying I tied a long stick to it, about a foot above 

 the eyepiece, the other end being braced against the 

 ground and free to move only in one direction. This was 

 a blunder to which I owe the discovery of a stranger, 

 which I am inclined to think is Vulcan. As the sun 

 moved the eye end of the telescope moved to the east. 

 The stick would not allow any backward movement, and 

 when I attempted to observe the sky to the east of the 

 sun I could not. This confined my area of vision to a 

 small distance west of the sun. But to return to the 

 observation. My observation of the first contact was 

 foiu" seconds later than the observation of Prof. Colbert. 

 The following is my record of events by Washington 

 time : — 



First contact ... 

 Bailey's beads ... 

 Beginning of totality 

 Corona first seen 

 End of totality 

 End of eclipse 



II 18 



20 22 

 20 38 



23 17 



23 26 



26 35 



" The watch was one second slow of the chronometer 

 at the first contact, two seconds at the end of totality, and 

 four seconds at the end of the eclipse. Before the 

 eclipse began I had made up my mind to observe the 

 general phenomena, the corona, protuberances, and 

 Bailey's beads for about half a minute at the beginning 

 of totality. I designed a minute and a half for a 

 search for Vulcan, and the remainder, some forty odd 

 seconds, to observe the phenomena at the end of totality. 



" About one minute after totality two stars caught my 

 eye about three degrees, by estimation, south-west of the 

 sun. I saw them twice, and attempted a third observa- 

 tion, but a small cloud obscured the locality. The stars 

 were both of the fifth magnitude, and but one is on the 

 chart of the heavens. This star I recognised as Theta in 

 Cancer. The two stars were about eight minutes apart. 

 There is no such configuration of stars in the constella- 

 tion of Cancer. I have no doubt that the unknown star 

 is an intra-Mercurial planet, and am also inclined to 

 beheve that there may be more than one such planet. In 

 1859 the French astronomer Lescarbault claimed that he 

 had seen an intra-Mercurial planet crossing the sun's 

 disc. He related his discovery to Leverrier, who became 

 a firm believer in the existence of such a planet. The 

 perturbations of Mercury's orbit demand such a planet as 

 Leverrier named Vulcan. The star I saw may have been 

 the same that was seen by Prof. Watson, who was located 

 at Rawlings, Wy. T. 



"I possessed a comet eye-piece of very flat and large 



field and distinct to the very edge. It was made in this 

 city, and to it and my blunder in failing to untie my in- 

 strument I owe my success. Prof. Colbert, of our party, 

 also searched for Vulcan, but his field was not large. I 

 saw but two protuberances, and those just at the end of 

 totahty. The advancing moon uncovered them. I had 

 a view for at least two seconds of the sun' s chromosphere 

 at the same time. The chromosphere, by my measure- 

 ment, is 2,000 miles in thickness. It is a layer of red-hot 

 hydrogen surrounding the sun. The protuberances are 

 projected from it. 



" The corona was unusually extensive. It had never 

 been seen so far extended. The greatest prolongation 

 was in the direction of the moon's path across the sun, 

 and as drawn by some of the parties extended on each 

 side of the sun to a distance of more than three million 

 miles. The pencils of light were radial mostly, though 

 some of them were curved. I came away so quickly 

 from Denver that I did not learn of the success of the 

 other parties. In comparing notes with our party, Prof. 

 Hough agreed with me in the measurement of the chro- 

 mosphere. This measurement is made by calculating the 

 time it takes the moon to pass over it. I learned of Prof. 

 Watson's discovery the day after the eclipse. I have not 

 seen him since he made the observation." 



OUR ASTRONOMICAL COLUMN 



Watson's Suspected Planet.— At the instance of 

 M. Mouchez, the director of the Bureau des Calculs of 

 the Observatory at Paris, M. Gaillot, who so long assisted 

 Leverrier in the formation of his planetary tables, has ex- 

 amined how far the 'position of the object seen by 

 Prof. Watson wiU accord with the more probable of the 

 orbits which Leverrier inferred for a hypothetical planet, 

 from the observations of suspicious spots in transit over the 

 sun's disc. It may be remembered that their discussion 

 led to a general formula, which was thus expressed by 

 Leverrier; v being the heliocentric longitude of the 

 planet, k an indeterminate which might have values 

 positive or negative, but necessarily whole numbers, and 

 j the number of days reckoned from the beginning of 

 the year 1750 : — 



V - I39""94 4- 2i4°*i8 k + (io''*9oi2S2 - i<"972472 k)j 

 + (-5°-3 + S^'S-^) cos. V. 



M. Gaillot has found that, of the four possible orbits re- 

 tained by Leverrier, corresponding to /^ = — 2, — i, o, 

 and -f- I, respectively, the first agrees the closest with 

 the observation. With this value of k the diurnal motion 

 is I4°'8462, the semi-axis major o'i64, and the period of 

 revolution 24*25 days — less than the period of the sun's 

 rotation. When the question of eccentricity is intro- 

 duced, it is remarked that in the preferable orbit it is 

 already very considerable, and comparable with that of 

 the orbit of Mercury, and it is easy to demonstrate, to 

 use M. Gaillot' s words, " qu' il peut y avoir identity absolue 

 entre la position observ^e et la position prdvue." In fact, 

 he finds that the agreement will be perfect if the eccentri- 

 city is assumed 0-14, and the longitude of the perihelion 

 74°. With regard to the inclination of the orbit to the 

 ecliptic, M. Gaillot, from further consideration, supposes it 

 may not exceed 7°. He notes that the most serious 

 objection which opposes itself to the identification of 

 the object observed, with a planet moving in the orbit 

 indicated by Leverrier's formula, is that we should 

 see but a very small part of the disc illuminated, 

 and without denying that there is reason in this objec- 

 tion, M. Gaillot adds that Prof. Watson describes "as 

 being of the fourth magnitude, a star the diameter of 

 which may be comparable with that of Mercury, and 

 which, in superior conjunction, may appear of the first 

 magnitude." He further remarks that while it is not 

 possible to decide with certainty upon the identity of 



