sion was visible by my telescope. Dr. Maskelyne seems to be of opinion, that five seconds ought to be allowed for the time elapsed from the first contact until the impression becomes visible in our telescopes. The atmosphere was remarkably fine and serene during the whole time of the eclipse, although the weather was extremely unfavourable for many days both before and after. The limb of the sun was well defined, by a fine circular line, but that of the moon was irregularly indented, more particularly when seen by the reflector with a power of 200. The result is as follows. Visible commencement of the eclipse per clock, at True commencement per clock End of the eclipse per clock. 20h 5′ 59′′ 5 20 5 54 June 18th. Equal altitudes of the sun's lower limb. A. M. h At 8 48 23 50 43 53 5 55 26 Double altitude 57 47 9 0 7 97 98 By these the clock was fast for mean time 28′′ 19, and by a comparison with those of the 12th, the clock loses at the rate of o" 565 per day, which correction being applied to the observed times of the eclipse per clock, the true results will be as follows. By these the clock was fast for mean time 19" 85, and by a comparison with those of the 18th, the clock loses at the rate of 0" 49 per day. M On the evening of the same day the astronomical 5th. with the reflecting telescope, power 100, observed an emersion of Jupiter's 2d satellite at 9 44′ 42′′ per clock; the above correction being applied, we shall have for the moment of the visible emersion, 9" 44′ 22′′ 35, mean time. Clouds were passing and a vapour obscured, in some degree, the disk of the -planet, similar to that of the 11th of June, though rather more dense, and it is thought probable, that the emersion was seen too late by 20 or 30 seconds: the longitude deduced without correction would be 6h 5' 0" west of Greenwich. July 6th, astronomical time, observed with the reflector, power 100, an emersion of Jupiter's first satellite, at 8" 12′ 24′′ per clock, and the correction for the rate of the clock being applied, the visible emersion took place at 8 12′ 4′′ 81, mean time, the longitude deduced would be 6" 5′ 12′′ 19.-Now as the density of the vapour of this evening and that of the 11th of June are supposed to be equal, and that the one observation was an immersion and the other an emersion of the same satellite, the imperfection of vision caused by the vapour or by the great and strong light of the planet, so near to the points of observation, would produce errors in contrary direc tions, the one advancing, the other retarding the moment of visible contact, a mean of the two results will therefore probably be near the truth. Observations of the eclipse of the sun, June 16th, 1806, made at Kinderhook, in the State of New-York, by Jose Joaquin de Ferrer. Read August 15th, 1806. ACCORDING to the latitudes and longitudes of the moon inserted in the French connoissance de temps, the conjunction ought to have happened 4" 29′ 40′′ 8, mean time in Paris, latitude of the moon in conjunction 19′ 19′′ N. = Latitude of Albany 40° 42′ 38′′. Longitude east of NewYork, according to the chronometer, No. 63, in time 58", the maximum of the total obscurity ought to have taken place in latitude 42° 23′ on the bank of the North river.-The following are the results of an approximated calculation. On the 8th of June I embarked in a packet for Kinderhook south landing, which is 15 geographic miles south of Albany on the bank of the river Hudson, to observe the eclipse, taking for that purpose an excellent chronometer of Arnold, No. 63; a circle of reflection; and an achromatic telescope, constructed by Troughton according to particular directions. The circle of reflection is not a multiplier, it is 11 English inches diameter, graduated upon silver, with three indexes, which divide the circle into three equal parts, and sub-divide it to 10"; mounted on a pedestal, and the telescope magnifies 17 times. A complete, or double observation is a compound of two observations, one direct, the other inverse, each observation has three readings, consequently the error of the divisions, in the double observations, is reduced to, the eccentricity destroyed, as also the error of the index, coloured glasses, small speculum, and of almost the whole of the large one. The telescope is 4 feet in length, it has a triple object glass of 2,70 inches aperture, a terrestrial eye glass, and three astronomical ones No. 1, 2, 3, and from the manner in which it is mounted, the zenith may be observed with as much exactness as any other elevation. Rate of going of the chronometer in New-York. On the 10th of June I arrived at Kinderhook south landing, the place where it was intended to observe the eclipse. By observations, of meridian altitudes of the sun and stars, the latitude of the place was ascertained as follows. June 12th. By double altitudes inverse and direct of ursa minor. 14th. By double altitudes direct and inverse, 50′ of time' before and after the meridian. 42 23 11 42 23 18 42 22 54 42 23 00 42 22 53 Rate of going of the chronometer according to mean time, by corresponding altitudes of the sun. Observation of the eclipse, 16th of June, 1806, with the achromatic telescope, 27 English inches aperture, triple obj ect glass No. 1, was used which magnifies 90 times. 91 37′ 33′′, (chronometer.) Beginning 45° from the left inferior vertex, in the very point on which the eye was fixed, the impression was so slight, that 4" elapsed before it was certain that it had commenced. 10 55′ 58′′, (chron.) First interior contact or total obscurity, certain to half a second, 50° from the right superior vertex: 4" or 5" before the total obscurity, the remainder of the disk of the sun was reduced to a very short line, interrupted in many parts.-The darkened glass with which this phenomenon had been observed, was sufficiently clear to distinguish terrestrial objects. After this observation I laid aside the coloured glass, to observe the end of total darkness. I examined the moon during two minutes, without observing one luminous point in her disk. The disk had round it a ring or illuminated atmosphere, which was of a pearl colour, and projected 6' from the limb, the diameter of the ring was estimated at 45'. The darkness was not so great as was expected, and without doubt the light was greater than that of the full moon. From the extremity of the ring, many luminous rays were projected to more than 3 de grees distance. The lunar disk was ill defined, very dark, forming a contrast with the luminous corona; with the telescope I distinguished some very slender columns of smoke, which issued from the western part of the moon. The ring appeared concentric with the sun, but the greatest light was in the very edge of the moon, and terminated confusedly at 6' distance. 11h 00′ 20′′, (chron.) Observed the appearance of a ribbon or border, similar to a very white cloud, concentric with the sun, and which appeared to me to belong to its atmosphere, 90° to the left of the moon. 11h 00′ 28′′, (chron.) Observed the illumination of various points in the disk of the moon on the same side. 11h 00′ 30′′, (chron.) The illumination of the moon was very distinguishable, shewing the irregularities of its disk, the colour of a palish yellow.-In the moment of the sun's re-appearance, the versed sine of the illuminated segment of the moon, was equal to part of the apparent diameter of Jupiter, observed in opposition with the same tube, 11h 00′ 34′′ 8, (chron.) End of total darkness, 90° on the left; the sun appeared as a very bright star of the third magnitude; at the call of the 35", such was the intensity of the light that I abandoned the telescope, having received a violent impression on the eye: from the appearance of the first ray, to the moment when it became insupportable to the eye, was so instantaneous, that I have estimated it at less than of a second. It is to be remarked, that this observation was made without a darkened glass, with tube No. 1, which magnifies 90 times, and is remarkably clear. Oh 21′ 38′′, (chronometer.) End of the eclipse. T During the whole of the eclipse, the sky was very clear, not a single cloud was visible, and there was scarcely any wind. The sun was without a spot. A little dew fell during the darkness; five or six principal stars and planets were visible. Mr. John Garnett (of New-Brunswick, New-Jersey,) who' also observed the eclipse with an excellent telescope of Dolland, with a triple object glass, and 2,7% inches aperture, tube No. 1, of the same power as the one I used, was placed four or |