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These three suppositions, of two currents in the air, and of a downward motion of the cloud, seem to be necessary to any explanation of the appearances of the cloud. But they do not entirely account for the whorls and changes of form described by Miss Colby and others, and so evident in Mr. Gilman's sketches.
The same were quite remarkable at New Haven also, though my sketches were not designed to show them. I only designed to show the place of the body of the cloud, relatively to Jupiter. Mr. Gilman's sketches, which reached me but a day or two after the shower, seemed a remarkably accurate expression of my recollection of the shapes of the cloud.
To account for these whorls and transformations, we may suppose between these two principal currents of air, or traversing them, various other currents. These need not necessarily be horizontal. But at that distance from the disturbing causes upon the earth's surface, it is not probable that there are so many rapid and varied currents in the narrow limits of 10 miles in vertical direction, as the various contortions of the cloud imply. We expect greater simplicity in the aerial movements in these upper regions of the atmosphere.
To attribute these motions of meteor trains to previously existing currents, implies, moreover, that complex currents extend through the whole thickness of the stratum in which the cloudy trains are developed. For in all cases of a persistent cloud, we see the same coiling motions of the line of phosphorescent matter, shortly after the flight of the meteor. Such a system of currents previously existing in the air is not probable.
An alternative seems much more reasonable, which is to assume that the motion of the meteor produced this coiling of the train. As a meteor rushed through the air, it carried before it, and with it, and dragged behind it, a mass of air of considerable dimensions. Thus a large mass of air, containing in it the cloudy line of meteor dust, was thrust down into the lower current, and then swept away to the southward. This column of air, of course, sets in motion vast eddies which cannot be easily reduced to system.
If this is a true explanation, the mass of the meteor must have been sufficient to set in rapid motion the air that fills hundreds of cubic miles of space, as well as to develop light and heat. What kind of matter it is which remains visible in the cold upper air for three-fourths of an hour, until by gradual dissipation the light faded out, I leave for others to say. AM. JOUR. SCI.-SECOND SERIES, VOL. XLVII, No. 141.-MAY, 1869.
Meteor of 116 18m, N. York time,-seen by Mr. Gilman, at Fern Lodge Observatory, Palisades.—A very grand meteor, much larger than Venus, which shot nearly vertically up from the horizon, in Leo Minor. The nucleus was white, and it left a bright blue train of sparks. The figure in plate II, represents it just previous to disappearance. Length of track 15°. It was not observed elsewhere.
Meteor of 116 25m, N. Y. time.-Two meteors were seen at Palisades. One, equal in brilliancy to Venus, white, left a bright blue train, visible eight minutes. The figure plate II represents its appearance, as seen by the naked eye, at 116 26m 30. It was a greyish cloud, 2° or 3o long. In a 4 inch telescope, power 40, diameter of field 43, it presented a double line of bluish-green luminous matter. Not observed elsewhere,
Meteor of 15 53m, N. Y. time.-A white meteor, of the first magnitude, was seen by Mr. Gilman, at the Palisades, to pass through the northern limits of Camelopardus, toward and beyond x and B Cassiopeia. The length of path was 30°. It left a smoky train, of a greenish-white tinge. The train was visible about half a minute, and on turning the telescope upon it, Mr. Gilman saw the double line of smoke represented in the figure plate II. Stars as small as the eighth magnitude were seen through the train. Twists or whorls of clouds appeared as represented in the engraving. The general appearance of the smoky substance was very like that of the nebula of Orion, as seen in a large glass. The same power and field of view were employed as upon the previous train.
I find no observations at other places upon this body.
Meteor of 24 45ın, N. I. time.-Mr. Gilman, at Palisades, saw at this time a meteor disappear at , Leonis ; from the direction of a Leonis ; smoky train remained 8 minutes.
At Stamford, Mr. Fuertes recorded a curved track, of double curvature, beginning at R. A. 150°, N. dec. 7°, and ending at R. A. 1493°, N. dec. 3o. He adds the notes :-Brighter than Venus ; very curved path ; somewhat spiral and short ; left a train which placed itself at right angles with the path, and lasted 650 seconds.
The two paths belong to the same body, but are not quite consistent. The want of conformability of the Palisades track may be due to the curvature of the track. There is indicated, however, a parallax of about 6°, which represents a vertical altitude of 51 miles. The smallness of the base line and of the parallax, makes the result uncertain. If there were two principal currents in the atmosphere, one above from the South, and one below from the North, as seems to be proved by the
1h 12m meteor, this meteor must have reached the surface, dividing the two currents, and its train have been acted upon in the same manner as the train of the earlier meteor.
Meteor of 2h 48m, N. Y. time, at Fern Lodge Observatory, Palisades.-A fine meteor, half-way between Polaris and Ursæ Majoris. No description of the meteor recorded. The view of the train near the point of disappearance, by means of a 4 inch glass, a power of 40, and a field of view of 43' in diameter, is given in plate II. The train was double, (as often observed during the evening,) and terminated in an oval cloud, at right angles to the direction of the meteor's flight.
At Stamford, Conn. (lat. 41° 2' 45", long. 73° 35').-Upon the chart sent by Mr. E. A. Fuertes, who was assisted in his observations by Mr. F. G. Wheeler, is the following position for the track of this meteor :- Beginning, R. A. 136°, Ñ. P. D. 19°; end, R. A. 9°, N. P. D. 7o. The two tracks correspond very well with each other, though the base line is small. The parallax is about 14° for the end, which gives an elevation of 52 miles for the end of the track, and 65 for the beginning, with a length of path of 27 miles.
The distance from Palisades to the end of the path is 70 miles. The field of view at that distance had a diameter of seven-eighths of a mile. As the course of the meteor was inclined 80° to the line of vision, the lengths of the portion of the cloud included in the field of view was 0.89 of a mile.
I think the double train of this and the other meteors is due to actual duality in the meteor itself. The same double or multiple character is common among the detonating and stoneproducing meteors.
Meteor of 3h 51m 30°, Portland time.-Prof. Rockwood, of Bowdoin College, saw a meteor of a bright green color pass in a direction parallel to a line joining 8. and a Aurigæ, and about 5° north of those stars. It left a bright train, 5° or 6° in length, which gradually curled up, and floated northward as it faded.
Mr. Tuttle reports the same meteor as seen at Boston ; very bright between and y Ursæ Minoris; train visible 3 minutes. The latitude and longitude of Brunswick, (place of observation,) are 43° 54' 32", and 69' 57' 24" ; and those of Boston, (State House,) are 42 21' 28", and 71° 3' 30".
These observations give a parallax of 53° upon the base line of 121 miles. The altitude of the meteor when it crossed the line joining B and y Ursæ Minoris, as seen from Boston, was 77 miles. This was near the beginning of the path, since the point corresponds upon the Brunswick path to a point 4 or 5° toward the radiant from opposite ß Aurigæ. The cloud must have been ten miles long.
Meteor of 5b6", Portland time. This was a very bright green meteor, seen by Prof. Rockwood to pass directly across o Leonis in the direction toward ( Hydræ. It disappeared after having crossed about two-thirds of the distance between these stars. It became visible about midway between 7 and o Leonis. It left a long train, which assumed the serpentine form before it disappeared.
Mr. Tuttle, at Boston, saw the body near , Ursæ Majoris. The altitude of this meteor at disappearance was about 48 miles. Its first appearance, if Prof. Rockwood's observation be taken literally, was at a height of nearly 150 miles. But the track was so near to the radiant, that a difference of three or four degrees in the apparent length, would reduce the first altitude below 100 miles.
Meteor of 5h 6m 45*, New Haven time.—This meteor passed one degree south of B Geminorum as seen by me at New Haven.
The central part of the train floated north, and the upper part south. The amount of the northward motion was three degrees in three minutes. At first the lower or western end floated south-or at least fell behind the rest, but this part appears soon to have vanished, for in my representations of the shape of the train it is only presented in the earlier diagrams.
At New York City Prof. Twining saw the same meteor, and by a careful reference to the stars in the neighborhood he locates the beginning and end of the track as in R. A., 176o, N. dec., 47°, and R. A., 191°, N. dec., 54'. The train moved a little to the east of north five degrees in three minutes, and continued visible six minutes.
The altitude of the beginning, and end of the visible path of the meteor is, from these observations, 85 and 60 miles, rerespectively. The motions of the train seem to indicate an upper current from the north, above that from the south, which was shown by the motions of the train of the meteor at lh 12m
Meteor of 5h 30m 30s, Boston time.—Mr. Tuttle saw a very bright meteor at this instant which passed above Cor. Caroli, downward to a point below » Ursæ Majoris, leaving a train visible for seven minutes. But for daylight it might have been seen longer. Immediately after the meteor disappeared the train began to shorten and widen, and take a serpentine form. It finally became a cloudy mass, oblong in form, and drifted away northward under n Ursæ Majoris.
From the position of this track and the description, I feel sure that it is the same as the one described by a writer in Fairhaven, Mass., in an article signed D. (Mr. Jabez Delano), in the New Bedford Standard as follows.
At twenty-three minutes past five, a most superb meteor burst from the region of Ursa Major, and went toward Ursa Minor, leaving a bright trail. For two full minutes it remained unchanged. He then drove a stake in a direct line from the top of a tree, to the meteor. At this stage the trail had contracted in length and widened in breadth, presenting a serpentine aspect. It was a pale cloud, nearly circular, and larger than the full moon. It was now waning away, and soon became extinct, having been visible and stationary nearly five minutes. The two stars in Ursa Minor, known as the Guards, pointed directly toward it in a S. E. direction, about 8° distant. In the morning he took the altitude and azimuth of the line from the stake to the tree, and found the direction of the meteor to be N. 38° 30' E., alt. 32° 40' 51". The latitude and longitude of the place is 41° 38' 6'' N. lat., and 70° 53' 51" W. long
One of the young ladies in Miss Mitchell's class at Vassar College gives a diagram of the path of a meteor at 5b 21m 15%. I think it is the same body, notwithstanding a slight discrepancy in the observed times. She places it between Arcturus and Corona Borealis. The reference to the stars in Ursa Minor shows the Fairhaven azimuth to have been the magnetic azimuth. The Poughkeepsie path is not drawn so as to be quite conformable. Changing it as little as is possible to make it conformable, and the three observed paths agree very well with necessary conditions, and indicate an altitude of about 59 miles for the lower part of the cloud. The northward motion of the cloud showed that it did not penetrate through the upper into the lower current, which swept away southward the lower part of the train of the meteor at 11 12m.
ART. XLIII.-A Proposed Arrangement for Observing the
Corona, and Searching for intra-Mercurial Planets during a Total Eclipse of the Sun; by Simon NEWCOMB.
It is a fact of universal observation that, during a total eclipse of the sun, the dark body of the moon is surrounded by a brilliant crown of light, commonly likened to the “glory represented by painters as surrounding the heads of saints. But, of the form and extent of this “corona," nothing definite seems to be certainly known. It is commonly represented as being not uniformly luminous at equal distances from the center, but as radially striated, and extending out into rays in various directions. At least, one observer has gone so far as