it

was filled with wet mud and leaves. The labourers followed my level, and dug the trench. On getting into the hollow or pond, I observed that they threw up the body of a swallow. I took it up, muddy as it was, and having washed it in the water, I put it into my pocket. In a few hours I returned to the house of Mr. Stettler, took the swallow and placed upon the wall of the stove, which was just warm. While we were taking some refreshments, we were surprised by the chirping of the bird, which soon afterwards was flying about the room, catching flies, and alighting from time to time upon the furniture. From the time of laying it on the stove, to the moment of its revival, was not more, I think, than about a quarter of an hour. Mr. Stettler kept the s vallow in his house till the weather became warm, and the swallows began generally to appear: he then gave it its liberty.

The stream, which was the object of my business with Mr. Stettler, was dry during the summer; but after a heavy rain during the winter, and often during the summer, it flowed over into the hollow, carrying into it the leaves and mud which I found there, but did not flow through it. It had been a very mild winter;-the swallow was buried perhaps a foot, for the trench was no deeper; but it was certainly buried below the frost. I did not observe in that place any other swallows, the trench was narrow, and was carried near the edge of the pond. I have many times since that period, seen the swallows turned up out of the mud early in the spring; although the particulars of these instances, are not so clearly impressed upon my recollection. I have also often seen swallows, especially martins, creep under the roots of trees on the margin of creeks; 1 have then sought for them without success, and believe that they were retiring for the winter.

FREDERICK ANTES.

No. XIII.

Astronomical observations made at Lancaster, Pennsylvania, chiefly with a view to ascertain the longitude of that borough, and as a test of the accuracy with which the longitude may be found by lunar observation; in a letter from Andrew Ellicott to Robert Patterson.

DEAR SIR,

Read January 21st, 1803.
Lancaster December 16th, 1802.

IF you think the following astronomical observations of sufficient importance, you have my permission to hand them to the Philosophical Society. In making them I had principally two objects in view; first, the determination of the longitude of this borough; and secondly, the correction of the theory of the satellites of Jupiter, by increasing the number of observations on their eclipses.-The latitude of the place of observation is about 40° 2′ 39′′ north.

Nov. 25th, 1801. The observed times, and distances, between the sun and moon's nearest limbs,

27th, The observed times, and distances between the sun and moon's nearest limbs.

28th, The observed times, and distances, between the sun and moon's nearest limbs,

December 11th, The observed times, and distances, between the sun and moon's nearest limbs,

12th, The observed times, and distances, between the sun and moon's nearest limbs.

The observed times, and distances, between the moon's western limb, and Aldebaran (a Tauri,) east of her.

24th, Immersion of the 1st satellite of Jupiter, observed at 12h 34′ 27′′ mean time, or 12" 34′ 13" apparent time.-The planet and satellites well defined:-magnifying power of the telescope 100.

Jan. 5th, 1802. Immersion of the 2d satellite of Jupiter, observed at 10 15' 6" mean time, or 10 9' 10" apparent time. The night fine and clear, the belts and satellites well defined:-magnifying power 100.

25th, Immersion of the 1st satellite of Jupiter, observed at 9" 5' 7" mean time, or 8 52′ 19′′ apparent time.

Emersion of the 4th satellite of Jupiter, observed at 11" 32′ 42′′ mean time, or 11" 19′ 53′′ apparent time. The night was remarkably fine,—the belts and satellites perfectly defined: -magnifying power 100.

February 6th, Immersion of the 2d satellite of Jupiter, observed at 9 51' 46" mean time, or 9 37' 15" apparent time:The night a little hazy:-magnifying power 100.

9th, The moon occulted a number of stars in the northern part of that cluster called the Pleiades: the occultations of the three largest were particularly attended to.-The immersons were all instantaneous; but the emersions could not be observed on account of the houses on the west side of the street. Not having either the places, or characters of the stars observed, I have in Fig. 3d, Plate III, laid down the relative positions of the principal ones in the cluster, as nearly as I could do it without the aid of any other instrument than my telescope, and numbered those that were occulted.

In the diagram, ABCE represents the dark part of the moon's disk, and A E C D the enlightened part. When the enlightened part was kept out of the field of the telescope, the limb of the dark part was sufficiently visible, and well defined; by which I was enabled, without fatiguing my eye, to trace the approach of the moon to the stars, and pay that close attention so very necessary at the instant of the occultation. The star No. 1 is very small, and seldom visible without the aid of a glass. In each case the star appeared for a few seconds well defined on the edge of the moon's disk.Various theories have been devised to account for this singular phenomenon, but I am inclined to believe with La Lande, that it is merely an optical illusion*.

* Il arrive souvent dans les éclipses d'étoiles ou de planettes par la lune, que l'astre éclipsé paroît tout entier pendant quelques secondes sur le disque éclairé de la lune; on a attribué ce phénomene á l'atmosphère de la lune, et M. Euler enterprend de prouver son existence par les éclipses de soleil

17th, About 9' 14' 9" mean time, or 8h 59' 47" apparent time, the 1st satellite of Jupiter disappeared behind the body of the planet: Jupiter being too near the opposition for the eclipse to be visible.-Observations of this kind cannot be made with great accuracy.

March 10th, Emersion of the 2d satellite of Jupiter, observed at 12" 26′ 10′′ mean time, or 12" 15′ 41′′ apparent time: -night remarkably fine, magnifying power of the telescope

100.

16th, Immersion of the 4th satellite of Jupiter, observed at 12" 50′ 1′′ mean time, or 12" 41′ 13′′ apparent time:-the night clear, but the moon was so near to the planet that her superior light rendered the satellites less distinct; on which account I suspect that at least 10" ought to be added to the time of the immersion, and which I have used in deducing the longitude from this observation: magnifying power 100..

21st, Emersion of the 1st satellite of Jupiter, observed at 8h 2′ 53′′ mean time, or 7 55′ 32" apparent time:—the night fine,-magnifying power of the telescope 100.

28th, Emersion of the 2d satellite of Jupiter, observed at 6 57' 57" mean time, or 6h 52′ 45′′ apparent time.

Emersion of the 1st satellite of Jupiter, observed at 9" 57" 21" mean time, or 9h 52′ 12′′ apparent time:-night remarkably fine: magnifying power 100,

April 4th, Emersion of the 2d satellite of Jupiter, observed at 9 34′ 57′′ mean time, or 9" 31′ 56′′ apparent time.

Emersion of the 1st satellite of Jupiter observed at 11" 51′ 36′′ mean time, or 11" 48′ 36" apparent time.-Night uncommonly clear: magnifying power 100.

20th, Emersion of the 1st satellite of Jupiter, observed at 10" 9' 28" mear time, or 10' 10' 40" apparent time:-night a little hazy, belts badly defined, magnifying power 100.

May 6th, Emersion of the 1st satellite of Jupiter, observed at S 27' 56" mean time, or 8" 31′ 33′′ apparent time:-very

(Mém de Berlin 1748 p, 103.) M, de l'Isle l'attribuoit á la diffraction ou á l'inflection des rayons qui rasent les bords de la lune (Mém, pour servir á l'hist. de l'astron 1738, p. 249.) e phenomene, observé par Grimaldi et par Newton (Opt. par.e 3d ) servoit sur-tout a M de l'Isle pour expliquer les anneaux que l'on voit autour du soleil dans les éclipses totales; pour moi, je pense que c'est une simple illusion optique occasionée par l'irradiation ou le débordement de luniere.

Astron. par La Lande Tom. 2d. art. 1991.