238 



SCIENCE. 



[Vol. II., No. 20. 



(April 21 to May 9), ten petty officers and men of the 

 ilartford remained, and rendered very intelligent 

 assistance. 



In all, the party on the island consisted of twenty- 

 two persons. 



After giving details of the proceedings of the 

 expedition, its arrival, and the preparations for the 

 eclipse, Mr. Holden states, as to the event itself, that 

 the following atmospheric conditions prevailed: The 

 sky proved clear at fii'st contact, cloudy at inter- 

 vals till near totality, olear during totality except 

 a slight haze in its first minutes, cloudy a few 

 minutes after third contact, and finally clear at fourth 

 contact. 



Tlie meteorological observations (for which due 

 credit is given to tlie members of the party that had 

 them in charge) are noteworthy. In two weeks, 

 April 25 to May 9, twenty showers were recorded; 

 hut the rainfall in each was very small, the total in 

 the two weeks being about 8 inches. Half of this 

 fell during the only considerable disturbance of the 

 weather, which took place May 4, when it rained 

 from midnight to 9.50 A.M. 



The barometer was notably uniform. Its diurnal 

 movements were plainly marked ; the maxima being 

 at 9 A.M. and p.m., the minima at 3 a.m. and p.m. 

 The indications of the thermometer were very con- 

 stant. The daily range was 9.3°, the highest reading 

 89.3°, the lowest 72.4°, the daily maximum at noon, 

 the minimum at 6 A.M. The relative humidity 

 ranged from 70 per cent at midday to 84 in eai'ly 

 morning, and at no time fell below 61. The island 

 lies in the region of the south-east trades, but the 

 wind (which was very steady) blew constantly be- 

 tween north and east. The average velocity of the 

 wind was 6.05 miles; the largest during twenty-four 

 hours was 212 miles, the least 59 miles; the highest 

 velocity, registered in a squall, was 16 miles per 

 hour. 



The botanical and zoological observations are not 

 yet ready for publication. During the voyage a series 

 of observations was made by Mr. Upton on southern 

 variable stars. Dr. Hastings and Mr. Holden, 

 while on the island, discovered twenty-three new 

 double stars, a list of which has appeared in 

 Science. 



In preparing for the eclipse' Mr. Holden assigned 

 to each observer a single duty, not requiring him to 

 move from one instrument to another. The excel- 

 lent photographic apparatus, prepared under the di- 

 rection of Prof. W. Harkness of the IT. S. naval 

 observatory, was not used: the entire field of pho- 

 tography was left to the English party accompanying 

 our own, and to the French party under M. Jan- 

 ssen, who were very successful in photographing the 

 corona. 



The combination of polariscope and telescope was 

 used, but not with successful results, the apparatus 

 proving unsuitable. Dr. W. S. Dixon, who attended 

 to a telescopic examination of the details of the inner 

 corona, will report on the same separately, giving a 

 drawing of the corona. With the spectroscope, the ■ 

 chief point of observation was as to the relative 



lengths of the line 1474 east and west of the sun. 

 At second contact, this line was 12' longitude east and 

 3' west. The length of 1474 east diminished, while 

 1474 west increased. At mid-totality these were 

 equal. Before the third contact, the appearances 

 were reversed: 1474 west was longer and brighter 

 than 1474 east. 



At the beginning of totality, the lines C, D^, F, 

 and (near G) were seen brilliant but very short. At 

 mid-eclipse the spectrum was deliberately examined. 

 On a continuous spectrum, two lines only were seen: 

 1474 bright, and the D line dark. C, E, h, F, were 

 certainly wanting. Near the end of totality, C, D3, 

 and F appeared again, very short. Five seconds 

 after second contact, four curved lines were seen, — 

 C, Z>3, 1474, F, A light cloud passed over the sun; 

 and on its disappearance the spectrum showed a 

 small line, of about one-third the height of the 

 others, between 1474 and F. One hundred seconds 

 after second contact, three coronal rings took the 

 place of the lines: they were red, yellowish-green, 

 and green, and are supposed to be C, I)^, and 1474. 

 Two hundred seconds after second contact, the red 

 ring was decidedly the brightest, and it continued to 

 increase in brightness during sixty seconds. Two 

 hundred and ninety seconds after second contact, 

 the four curved lines, C, Dj, 1474, F, appeared. The 

 reversal of the bright lines at third contact was 

 observed. The change was instantaneous, or nearly 

 so. The reversal of the Fraunhofer lines was not 

 seen. The only bright line seen for the first 190 

 seconds was 1474. A dark line was seen, which was 

 probably I). 



Ml'. Rockwell, using a Rutherford grating and 

 a narrow slip tangential to the limb, reported 

 that 1474 K was not seen until a minute and a 

 half had passed. It was followed 4' or 5' west of 

 the limb, twice; and it was seen only on the west- 

 ern side of the. moon. Two green lines were also 

 seen, each brighter and broader than 1474, but much 

 shorter. 



Due credit is given by Mr. Holden to each of the 

 observers of the party. His own observations were 

 confined to a search for the planet Vulcan, reported 

 to exist by Professors Watson and Sw'ift. Mr. Hol- 

 den's search continued during the whole of totality 

 (five minutes and twenty-five seconds), with a six- 

 inch telescope with a power of 44 and field of 57' in 

 declination. He saw every star on the map which he 

 had previously published in Science (Feb. 23, 1883), 

 down to the sixth magnitude, inclusive, except the 

 thirty-sixth magnitude stars nearest to the sun; and 

 he saw only these stars. One of the stars of the map 

 was of the same magnitude as Watson's 'Vulcan.' 

 This was a conspicuous object. No star half so 

 bright as this could possibly have escaped observa- 

 tion. Mr. Holden is therefore confident that Vulcan 

 did not exist within the limits swept over. Mr. Hol- 

 den also determined the direction of the motion of 

 the diffraction bands before and after totality. This 

 was an observation which he could not make suc- 

 cessfully in Colorado in 1878, and which he believes 

 has not been before made. 



