trine. phlogistic doc. I mention them merely as they offer a contrast to Mr. Mur ray's. The instances of these two gentlemen show the nature of hypothetical reasoning, and its tendency, when followed, to draw the ablest philosophers into difficulties. I am, Sir, with great respect, Your very humble servant, London, Feb. 9, 1811. JOHN DAVY. Account of VI. An Estimate of the Height, Velocity, and Magnitude of the Meteor, that exploded over Weston, in Connecticut, December the 14th, 1807: with Methods of calculating Observations made on such Bodies. By NATHANIEL BOWDITCH, 4. M. A. A. S. and Member of the Philosophical Society held at Philadelphia. (Concluded from p. 97.) Observations at Wenham, Weston, and Rutland. SOME time after the appearance of the meteor, I went with the appearance Mr. Pickering to Mrs. Gardner's house in Wenham, where at Wenham. she had observed the phenomenon. She informed us, that of the meteor on the morning of the fourteenth of December, 1807, when she rose, she went toward the window of her chamber, which looks to the westward, for the purpose of observing the weather, according to her invariable practice for many years past. The sky was clear, except a few thin clouds in the west. It was past day-break, and by estimation about half an hour before sunrise, or seven o'clock. The meteor was immediately observed just over the southern part of the barn in her farm yard, nearly in front of the window; its disc was well defined, and it resembled the moon so much, that, unprepared as Mrs. Gardner's mind was for a phenomenon of that nature, she was not at first aware, that it was not the moon, till she perceived it in motion, when her first reflection (to use her own words) was--where is the moon going to? The reflection however was hardly made, when she corrected herself, and with 'her eye followed the body with the closest attention throughout its whole course. It moved in a direction nearly parallel to the horizon, and disappeared behind a cloud to the northward of the house of Samuel Blanchard, Esq. The true azimuth of the Azimuths of the points of south part of the barn from the place of observation is comparison. N. 107° 59′ W. its altitude 3° 25'. The top part of the building is horizontal. The azimuth of Mr. Blanchard's house is N. 148° 22′ W. These buildings were useful in determining nearly the limits of the azimuths of the meteor. the meteor The azimuths were obtained by observing with an excel- Method of ob lent theodolite the difference of the azimuths of the sun taining them. and object, and finding the sun's azimuth by his observed altitude. The same method was made use of in obtaining the azimuths of the meteor. The angular elevation of the Elevation and meteor above the horizon appeared always greater than that azimuths of of the barn 3° 25', and less than that of a tree in front of from these ob the window, along the branches of which the meteor ranged; servations. the altitude of the top of this tree was 7° 10′. These fixed objects served to determine the altitude of the meteor, which is the most important element in the calculation, to a considerable degree of accuracy. After the theodolite was carefully adjusted, Mrs. Gardner directed the telescope attached to the instrument towards that part of the heavens where she first saw the meteor; the true azimuth was N 106° 54′ 54′′ W. Altitude 5° 50′ 40′′. The azimuth of a second place where it was seen was N 117° 35′ 54′′ W. Altitude as before. The azimuth of a third place was N 132° 15' 54" W. Altitude 5° 29′ 40′′. The azimuth of the place of disappearance was N 144° 33' 54" W. Altitude 4° 1' 40"*. All these azimuths fall within the limits mentioned above, but the two last are undoubtedly too great. For a great circle passing through Wenham and Weston is inclined to the meridian of Wenham by an angle equal to 125° 18′ 38′′, and as the two last azimuths exceed that quantity, they fall to the southward of Weston, which cannot be correct, because the meteor disappeared before it arrived at the zenith of Weston, as was observed by Judge Wheeler. It happens fortunately in the present * In the following calculations the allowances made for refraction in the above observations, were '50", 8′ 50′′, 9 and 10' 10" making the altitudes respectively 5° 41′ 50′′, 5° 41′ 50′′, 5° 20′ 40′′, and 3a 51′ 90". instance, instance, that the other places of observation at Weston and Rutland are so situate with respect to Wenham, that a considerable errour in the azimuths at Wenham would not materially affect the result of the calculation made for determining the height or direction of the meteor, as will appear in the following calculations. Mis. Gardner supposed the meteor to have been visible about half a minute. How long vi- In its progress it was occasionally obscured by thin broken clouds, which intercepted the view of it several times. No train of light was observed to accompany it. Its velocity did not appear to be so great as that of shooting stars. Its colour was more vivid than that of the moon. The place of observation at Wenham is in the latitude of 42° 40′ 15′′ N, and in the longitude of 70° 50′ 15′′ W from Greenwich. sible. Velocity. Weston. Appearance of By the observations of Judge Wheeler at Weston, pubthe meteor at lished in the interesting memoir of Professors Silliman and Kingsley, in the sixth volume of the Transactions of the American Philosophical Society held at Philadelphia, it appears, that on the fourteenth of December, 1807, at about 6h. 30', A. M., "numerous spots of unclouded sky were "visible, and along the northern part of the horizon a space "of ten or fifteen degrees was perfectly clear. The atten"tion of Judge Wheeler was first drawn by a sudden flash of light, which illuminated every object. Looking up "he discovered in the north a globe of fire, just then pass ing behind the cloud, which obscured though it did not "entirely hide the meteor. In this situation its appear "ance was distinct, and well defined, like that of the sun "seen through a mist. It rose from the north, and pro"ceeded in a direction nearly perpendicular to the hori zon, but inclining, by a very small angle, to the west, "and deviating a little from the plane of a great circle, "but in pretty large curves, sometimes on one side of the plane, and sometimes on the other, but never making an angle with it of more than four or five degrees. Its apparent diameter was about one half or two thirds the ap"parent diameter of the full moon. Its progress was not so rapid as that of common meteors and shooting stars. "When it passed behind the thinner clouds, it appeared • brighter 66 66 66 "brighter than before; and when it passed the spots of "clear sky, it flashed with a vivid light, yet not so intense 66 as the lightning of a thunder-storm. Where it was not "too much obscured by thick clouds, a waving conical "train of paler light was seen to attend it, in length about "10 or 12 diameters of the body. In the clear sky a brisk "scintillation was observed about the body of the meteor, "like that of a burning fire-brand carried against the "wind. It disappeared about 15 degrees short of the ze"nith, and about the same number of degrees west of the "meridian. It did not vanish instantaneously, but grew, "pretty rapidly, fainter and fainter, as a red-hot cannon "ball would do, if cooling in the dark, only with much "more rapidity.-The whole period between its first ap66 pearance and total extinction was estimated at about 30 "seconds. About 30 or 40 seconds after this, three loud "and distinct reports, like those of a four-pounder near "at hand, were heard. Then followed a rapid succession "of reports less loud-so as to produce a continued "rumbling. This noise continued about as long as the "body was in rising, and died away apparently in the di"rection from which the meteor came."-Mr. Staples observed, "that when the meteor disappeared, there were apparently three successive efforts or leaps of the fire ball, which grew more dim at every throe, and disap❝peared with the last. From the various accounts which "we have received of the appearance of the body at differ"ent places, we are inclined to believe, that the time be"tween the disappearance and report, as estimated by "Judge Wheeler, is too little, and that a minute is the "least time that could have intervened." The latitude of Weston is about 41° 15′ N, longitude 73° 27 W from Greenwich, but there is a little uncertainty in both these quantities, though not enough to affect materially the result of the calculation. the meteor at Rutland. The observations made at Rutland were procured by the Appearance of kind offices of Professor Hall, of Middlebury College, Vermont, to whom Mr. Page communicated his valuable observations in a paper, expressed in the following terms. "I was at the west door of my house on Monday mornYOL. XXVIII.-MARCH, 1811. P ing, "ing, the fourteenth of December, 1807, about day-light; "and perceiving the sky suddenly illuminated, I raised my eyes, and beheld a meteor of a circular form, in the "southwesterly part of the heavens, rapidly descending to "the south, leaving behind it a vivid sparkling train of light. The atmosphere near the south part of the horizon "was very hazy, but the passage of the meteor behind the "clouds was visible, until it descended below the moun"tains, about twenty miles south of this place. There were "white fleecy clouds scattered about the sky, but none so "dense as to obscure the tract of the meteor. I now la"ment that I did not make more particular observations at "the time, and I should probably until this day have con"sidered it to be what is commonly called a falling star,' "had I not read in the New York papers an account of the "explosion of a meteor, and the falling of some meteoric *stones near New Haven, Connecticut, which, by recur"ing to circumstances, then fresh in my recollection, I found to be on the same morning that I observed the "meteor at Rutland. I am indebted to my learned friend, "Dr. Samuel Williams, for his aid and directions in ascer taining the situation of the meteor, when I first observed * it, and its course, and also for the order of my observa"tions. Form, circular. Magnitude, less than a quarter "of the diameter of the moon. Colour, red vivid light, "Tail, or train of light, about eight times the length of its "diameter at the least, projected opposite to its course. "Azimuth when first observed, about 9° 30' west of the "meridian. Altitude when first observed, about 18° 30' *. "Descent to the south part of the horizon, west of the me"ridian, by estimation 7 or 8 degrees. Motion, very rapid, 66 probably thirty seconds in sight. Place of observation, "Rutland, county of Rutland, and state of Vermont, la❝titude 43° 36′ N, as ascertained by Dr. Williams; longi"tude west from Greenwich [72° 58′ 15′′] as ascertained by "Mr. Bowditch, by calculations made upon observation "of the solar eclipse of June 16, 1806." In a letter, which accompanied the preceding paper, Mr. Page ob In making use of this altitude, 3' for refraction was subtracted, making it 18° 27'. served, |