Page images
PDF

authority of joint resolutions of Congress passed at the late session; and consisted of the following gentlemen, viz: Prof. Stephen Alexander, of the College of New Jersey, Prest. F. A. P. Barnard, of the University of Mississippi, Lieut. E. D. Ashe, R. N., director of the Quebec Observatory, Prof. C. S. Venable, of the College of S. Carolina, and Prof. A. W. Smith, of the U. S. Naval Academy at Annapolis. With these were associated the Commander of the Coast Survey steamer Bibb, conveying the expedition, Lt. Alexander Murray, U. S. N. Messrs. P. C. Duchochois, of New York, and J. P. Thompson, of the Coast Survey service, accompanied the corps for the purpose of taking photographic impressions of the eclipse; and Mr. W. A. Henry, of Washington City, attended as assistant to the chief of the corps. In addition to the purely astronomical objects of the expedition, advantage was taken of the opportunity it presented, to secure determinations of the important magnetic elements at the observing station, as well as meteorological and other observations continued throughout the entire period of absence. The thermometrical and barometrical observations were kept up hourly from the time of sailing until the morning of the day on which the Bibb entered the harbor of Newport. On the day of the eclipse the intervals were reduced to a half hour. Frequent record was made of the surface and deep sea temperature of the Water. The magnetic observations were placed under the charge of Messrs. Edward Goodfellow and Samuel Walker, of the Coast Survey. The meteorological, under that of Prof. Venable, of the astronomical corps, assisted by Oscar M. Lieber, Esq., of South Carolina. Mr. Lieber also undertook such observations of the geology of the coast as the opportunities afforded would permit. The history of the expedition and its results have been communicated by Prof. Alexander, the chief of the corps, to the Supt. of the Coast Survey, and will probably be, at a suitable time, presented to the public in full. The present memorandum is furnished by request, and with the permission of the Superintendent, with the view of presenting in concise form the facts of most immediate interest to the scientific public. The track of the central eclipse left the eastern coast of Labrador in lat. 59° 51%'. On the evening of the 13th July, the expedition had reached this parallel; and was, for several hours, engaged in the endeavor to penetrate the seemingly unbroken and gloomily frowning barrier of precipitous cliffs which marked this rock-bound shore. The navigation at this point was of the most hazardous character. It was necessary to feel every foot of progress with the lead, and the successive soundings, which gave everywhere, a rocky bottom, showed the most singular and sudden variations of depth. One cast, for instance, would give ten fathoms, the next, no bottom with nineteen, and the next again, seven or eight fathoms. On every hand were seen rocky islets, rocks nearly submerged, or reefs and breakers. Through such a sea, for five or six hours, from six o'clock till nearly 12 at night, the Bibb was engaged in cautiously seeking out for herself a harbor of refuge; and just about at the moment when the sun was passing his lower culmination, though a bright twilight still filled the atmosphere, she dropped her anchor in the inlet which divides Aulezavick Island from the main land of Labrador. This was the point which had been previously assumed to be fittest for the purposes of the expedition; but so imperfect and even erroneous had all the charts of the coast been found to be, that even the existence of the island was regarded as doubtful; and the identity of the inlet was not fully recognized until further celestial observation and some hydrographic exploration and survey had established it. During Saturday, July 14, a location was fixed on for the encampment, and some progress was made in the shore arrangements. The harbor, once entered, proved to be commodious and secure; and it was found practicable to moor the Bibb so near to the land as to enable a portion of the party to sleep on board of her, and thus to avoid some of the discomforts of camp life, which, in a region so bleak and dismal, are by no means trifling. Others, including the meteorologists, the magnetic observers, and the members of the astronomical corps in charge of the transit instrument, were compelled to make a larger sacrifice of their ease. What that amounted to may be appreciated, when it is mentioned that several of the tents were blown down almost immediately after their erection; and that a wind as disagreeable for its piercing chilliness as for its force prevailed with little intermission during the entire stay of the expedition, amounting to eleven days. The tents when reërected, were secured, or anchored, by piling rocks upon the margin of the canvass. The exact latitude of the observing station was a few seconds short of 59° 48'; the longitude, by chronometer, 4h 16m 53° west from Greenwich. Hardly had the landing been effected when there commenced a storm of wind and rain which rendered any attempt to use the transit instrument impossible for two or three days. Even up to the Tuesday night preceding the eclipse, the clouds had been so persistent as almost wholly to prevent the observation of the stars. On that evening the sunset seemed to hold out better promise for the coming night and the ensuing day. But on Wednesday morning the prospect for the day was more than doubtful. Fleecy cumulus clouds made their appearance in numbers constantly increasing; and at the moment when the eclipse began, the sky was more than half covered. The sun was, however, totally unobscured at the beginning and for a large portion of the time during the progress of the eclipse. Clouds were, however, continually drifting over it, concealing it for brief intervals entirely from view. At the very close, the alternations of sun and shade were so rapid, that it became a question of doubt whether the final contact would be secured, and a flutter of excitement prevailed throughout the observing corps: but the last four or five seconds presented the sun's eastern limb entirely unobscured; and the desired point was satisfactorily gained. Just previously to the time of the sun's total immersion, a thin veil of cloud intervened between it and the observers, not dense enough to intercept the direct rays of the luminary, but too dense to allow the corona surrounding the dark moon during total obscuration to be visible. Lt. Ashe was fortunate enough, however, to catch one point of brightness and to fix its position in this corona; and this may serve a useful purpose hereafter, in corroborating observations elsewhere made,

under more favorable circumstances, in regard to the features of this beautiful and rare phenomenon. The bright point observed by Lt. Ashe was white and not ruddy. The expedition are unhappily unable to bear any testimony in regard to the roseate clouds which have been so often seen during total eclipses upon the moon's border. This has been a subject of great regret, the more so because the corona which was lost to the astronomical party, was not lost to such of the ship's company as remained on board of the Bibb. From the description given of it by these, the chief of the corps has prepared a drawing, in which there appear four principal radiant beams extending outward beyond the general limit of the coronal luminosity, in positions sufficiently well fixed to admit of comparison with observations made elsewhere. But as this class of observers were not furnished with instruments, they gave no testimony as to the positions, or even as to the presence of rosy clouds. The whole astronomical corps observed the breaking up of the last line of solar light lingering before total obscuration, into the fragments commonly called “Baily's Beads,” from Francis Baily, President of the Royal Astronomical Society, by whom they were described in the Mem. Astr. Soc. for 1837, as observed by him in the annular eclipse of 1836. These fragments were very evanescent, and were not preceded by those longer dark filaments or ligaments noticed by Mr. Baily on the same occasion, and more or less perfectly by others since. At the emergence of the Sun, the beads were not noticed, owing probably to the veil of clouds. Only two of the observers attempted, in fact, to fix the exact second of emergence. The darkness which prevailed during total obscuration was not as remarkable as had been anticipated by most of the observers. The present writer, for instance, found no difficulty in making pencil notes at this time, or in reading lines written in pencil in other parts of his note book. It was not necessary to bring the book nearer to the eye than usual. The pallor or ghastly appearance which has been remarked at such moments in the human countenance by former observers, did not strike the members of this party, though it was looked for. There was something indeed about the character of the gloom which was unusual and impressive, but it scarcely effected the tints of objects or rendered the face of nature very different from what it appears during early twilight. Clouds covered at the time almost nine-tenths of the heavens; and in the intervals of the clouds the blue of the sky was intensely deep and dark. On one side only was the horizon unobscured. This was on the north where the harbor opened out to the sea; and in this direction a beautiful rose and orange flush presented itself. It would be easy to extend this notice to much larger dimensions, if space in the present number of the Journal was available. The instruments employed in the astronomical observations, were a thirty-inch transit by Fitz, a fifty-one inch Fraunhöfer achromatic belonging to Princeton College, a forty-two inch by the same maker belonging to Columbia College, one of similar dimensions belonging to Lt. Ashe, a thirty-inch equatorial belonging to the Naval Academy at Annapolis, a three foot alt. and azimuth, belonging to the College of South Carolina, and a mammoth comet-seeker, of 7% inches aperture, by Fitz. An equatorial belonging to Mr. Rutherford of New York city, a gentleman well known for his disinterested zeal and efficient labors in the cause of astronomical advancement, served the photographers of the expedition to fix from time to time the successive phases of the eclipse. Another comet-seeker was fitted up for the purpose of furnishing an image of the sun upon a white ground in a darkened chamber. Fifteen auroras were observed during the absence of the expedition. In nearly every instance a corona was repeatedly formed, though many of the auroral clouds were exceedingly filmy and thin. Atmospheric electricity was . or absolutely nil during the entire stay of the expedition at the observing station. The passing of the shadow seemed to produce no change in this respect. The diurnal magnetic variation was very large, varying from two to five degrees. During the eclipse the needle was more quiet than before or after. The surface temperature of the sea was very low from the Straits of Belle Isle northward. It was frequently down to 38° or 39°. But the lowest surface temperature at any time observed, was in the Straits themselves, on the return passage; when the thermometer marked, in the surface water, 32°. In the harbor at the observing station, ice formed in the shoals near the beach on the 13th of July. On Sunday, July 22, there occurred a storm of snow and sleet, which covered the deck of the steamer, and wrapped the whole surrounding country so far as visible, in a mantle of white. On the return passage, this snow was observed still enveloping the mountains far down the coast. Scarcely any quarter of the world presents, perhaps, more difficult or dangerous navigation than the coast of Labrador. The islands, islets, submerged rocks and reefs are absolutely innumerable, and icebergs swarm where these more fixed dangers are wanting. The month of July was pronounced by the hardy mariners engaged in the Labrador fisheries, to have been one of the most tempestuous ever known in those seas, and most prolific of disaster to their fishing vessels. It will therefore occasion no surprise to state that the Bibb has been repeatedly in positions of hazard, requiring all the resources of her officers to meet successfully. The members of the corps cannot but feel that the hand of a protecting Providence has been more than once distinctly visible in preserving them amid dangers, and delivering them from situations, to which they can hardly look back with tranquillity. F. A. P. B. 2. Evtract of a letter from the Superintendent of the Coast Survey to the Editors in relation to observations made on the Western coast of the United States, for the Coast Survey, by Lieut. J. M. GILLISS, U.S. N.— Lieut. Gilliss arrived at the station selected by him for observing the eclipse, and which is near Steilacoom, Washington Territory, on the 9th of July. Here he encamped and made his preparations for observations of time, latitude, etc. These are not yet definitely worked up and hence I do not give the position of the station or the times of the different phenomena in detail at present. The following particulars from Lieut. Gilliss's report will be found of interest in anticipation of the time and longitude results:

[graphic]
[graphic]

“For the first time after our arrival at the station, the sun rose clear on the morning of the 17th, nor was there at any time during that day more than two-tenths of the sky obscured by clouds. Yet, although the evening was absolutely cloudless, and the stars were shining with remarkable lustre after midnight, so fickle had been the climate during the preceding three weeks, that when we closed the tent, three hours before the eclipse would begin, I had no confidence that the next morning would be favorable for observâtion.

By 3% A. M. we were up and had removed the meteorological instruments from camp to the knoll. At that time it was sufficiently light to write without artificial aid. Mt. Rainier was distinctly visible and sharply cut against the southeastern sky. Beyond it and towards the point at which the sun would rise, there was a stratum of vapor whose upper line was slightly inclined from mid height of Rainier towards the northern horizon. At that time the barometer stood at 29.698; att, thermometer 44°5, the temp. of the air 45° 2, and there was only a very slight air from the southward. At (0h 17m, sid. chron.) the mist striae became dense to the N. and E., and were more evidently in rays diverging from the point of sunrise to an elevation of some 25°. The air was so cool and so loaded with moisture that although the telescope had been out all night the object glasses were densely covered with dew immediately after the caps were removed. By (0h 30m) a part of the vapor in the N. and E. had condensed into little cumuli beyond the Cascade range each more light and feathery with distance from diverging point, though none of this series extended as far as Mt. Rainier, and it was only towards the north that a dense volume of vapor could be seen coming in towards the lower lands bordering on Puget's Sound. Two minutes later and the edges of the little flocculi were tipped with pink and golden hues increasing in brilliancy of color as the sun approached the horizon.

The eclipse had far advanced when the first cusp appeared above the horizon at (0h 39m 38%). It was seen through a red screen glass and was sharp and without tremor. Indeed the atmosphere was so still that the rise of the second cusp over the distant ground line at (0h 40m 585) was observed almost with the precision of a transit of a limb over the wires of a telescope. But it was at once perceived that there was great disturbance of the lune, the lower half being flattened by the unequal refraction.

At this time I was again obliged to wipe the heavy drops of dew from the object glass of the telescope, and whilst so doing my attention was directed to the vapor near us. The whole northeastern portion of the prairie had apparently been converted into a placid lake with here and there a knoll projecting through and forming a minature isle, the illusion being enhanced by rapidly diminishing intensity of the light. At (0h 54m) distant objects could not be recognized more distinctly than during midsummer twilight at 8%. P. M.

At (0° 55*) the southern cusp had become rounded off and rugged as though the moon's edge was serrated. But had such been the case this portion of the lune would have broken into beads of light before the total obseuration took place, and that did not occur, the moon's disc equally and uniformly interposing between us and the sun until the last glimmer of light disappeared.

« PreviousContinue »