pages of the months, the emersions of Jupiter's first and second satellites, at the head of the columns, containing their eclipses, are stated to be immersions. That these are errors is manifest from an observation on page 153 of the same Almanack. "Before the oppositions, (of Jupiter,) the immersions only of the first satellite are visible; and after the opposition, the emersions only. The same is generally the case with respect to the second satellite." Now Jupiter passed his opposition, in 1814, on the 23d astronomical day of February, and did not reach his conjunction with the sun till the 15th of September. In the intermediate time, therefore, the immersions of his first and second satellites were not visible. For 1816.

In Blunt's Edition.

On the second page preceding the first page of January, five Chronological Cycles, twelve Ember Days, and twelve Moveable Feasts are wrong; answering to 1812, instead of 1816.

In the London Edition. Page 66. June 19th, at noon, the moon's declination is put down, 0° 16' N. It should be 2° 16′ N.

Page 136. In the left hand column, at the bottom, 21 is put where there should be 31; and there is nothing where there should be 21. The geocentric latitude of the Georgian is also omitted on the 21st day.

For 1817.

In Blunt's Edition. Page 109. On the 23d day of October, the sun is said to enter ny, Virgo; which is impossible. It should be in, Scorpio.

In the London Edition. Page 43. April 15th, at midnight, the moon's parallax is put down fifty seconds too small.

For 1818.

In the London Edition. On the second page preceding the first page of January, at the bottom, the mean obliquity of the ecliptic, as determined with extreme precision with the new mural circle, is stated to be 28° 27′ 50". It should be 23° 27' 50."

Page 4. On the 13th day of January, Venus is stated to pass the meridian at 20 hours. It should be 23 hours.

Page 73. In the column headed "Other Phenomena," against the 29th day, it is put down thus ; that is according to the language adopted in the Nautical Almanack, Venus and Conjunction in conjunction. It should be 9; or Venus & Mars in conjunction.

To THE EDITORS OF THE AMERICAN MONTHLY MAGAZINE.

I notice a small error in Dr. Akerly's, valuable communication on the Locust tree. He says it "is a native of the United States, but was not "known north or east of the Potomac before the white settlers brought it from thence."

About 30 miles southeast from Catawissy in Pennsylvania, on the road to Philadelphia, there is a ridge called “the Locust Mountain,” on which this tree appears to be indigenous. The south part of that elevated tract is encumbered by the Pudding Stone, which is very loosely cemented, and to its disintegration ought to be referred the origin of the soil. But nearly all the declivity on the northwest side presents new scenery. A reddish loam, moderately fertile, rests on rocks of Mica-slate, if my recollection is distinct, and from the scrubby oak and pine of the opposite side, we pass into a forest of Locust and Chesnut, which, though not stately, extends to the east and west, as far as the eye can distinguish such objects. This vegetable assumes every ap pearance of having been one of the original possessors of the soil. The fewness of the inhabitants in the valley below, and their characteristic lack of energy, preclude the idea of its being a naturalized stranger, neither have I ever seen it at any of their farms.

Southwest of this place, near the Susquehanna, the frequency of this tree in the fields left no doubt in my mind of its being a native. Near the Schuylkill it is cultivated on land which I should judge equally favourable for its growth, but it is

not scattered over the farms as on the Susquehanna. The inference from this fact is, that the roots of those trees, which once constituted a part of the ancient forest, have remained unsubdued. Indeed I recollect no instance of young plants shooting up in old cleared land without the fostering hand of the nursery

man.

Further, it appears in situations on the hills north of Pittsburgh, which leaves no doubt of its being indigenous; and sixty miles west of that city, in the State of Ohio, whenever the forest is reduced, and the soil burnt, it springs up in abundance. It will be observed that this is considerably north of the Potomac.

It will, doubtless, be a satisfaction to Dr. Akerly to be apprized of these facts, which, though varying from the information he had procured, by no means derogate from his general accuracy. Respectfully, &c.

DAVID THOMAS.

Scipio, 9 mo. 25, 1817.

An account of the cause and symptoms of the disease of neat-cattle, called the footrot or canker, with the best mode of treatment, by JAMES CLEMENT, Veterinary Surgeon, New-York.

The prevalence of a disease attacking the feet of neat-cattle, at this season, and particularly in the vicinity of New-York, induces me, for the benefit of agriculturists, breeders, milkmen, &c. to give a few outlines of the disease, with the best mode of treatment, it being a disease lit tle known or understood in this part of the country.

In demonstrating this subject, I laid before the Lyceum of Natural History, preparations of the foot, so as to convey a more perfect idea of the nature and extent of the malady in question, with the various names under which it has been treated. It has been called the Lowe, the Foul, and the Foot-rot, but would be better denominated Canker. The symptoms in the early stage are extensive swelling of the leg, affecting the action of the animal; great heat and tension; staring of the hair, with a dead appearance; loss of appetite; wasting of the flesh; and in a cow, giving very little milk, so as to affect the profit of the owner, and cause inquiry into her condition. On examining between the cleft of the diseased foot, will be discovered a thin ichorous, foetid discharge, exurling from the superficial blood vessels of the skin; which, from the great vascularity of these parts, heightens the violence of the in

flammatory action, and eventually, if not stopped in its progress, extends itself to the sensitive sole, seating itself in the heel, and producing an extensive ulcer, so much so as to cause a detachment of the horny box from the living parts; which, when effected, is the second stage of the disease. In this second stage, the disease is seated immediately on the heel, inflaming the vascular sole, from which ensues an extensive ulceration, producing a separation of the horn from the sensitive parts. The suppurative process is accompanied with the sprouting of a luxuriant, peculiar fungus, which is with difficulty kept down, even by the skilful, and entirely baffles the well-meant endeavours of those not acquainted with the disease.

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In regard to the treatment, the practice which I would recommend, is to have the cattle removed to a dry healthy pasture, there to be examined. Such as are found to be diseased should be taken to a barn or out-house, and the feet washed clean, particularly between the cleft, with a hard brush and strong suds. In cases of early standing, as before described, let the diseased feet be immersed in strong lye, as warm as the hand can bear, from five to ten minutes, using brisk friction in the cleft: let a poultice, made of bran, or shorts, with hogs-lard, be ready, sufficiently large to envelope the whole foot, which should be changed twice a day till the active inflammation subsides; dress with mild astringents, adding liberal pressure between the phalanges, or divisions of the foot, with lint, or fine tow, so as to prevent their coming into contact. The feet should be wrapped in canvass, and the animal kept on a dry floor. Attention should be paid to the general habits of body: should the inflammation extend up the legs, bleed, and give aperient medicine; when extreme pain exists, anodynes, administered with discretion, will prove beneficial.

In the second stage a different mode of treatment will be necessary. The animal being secured, proceed to remove the horn that surrounds the cankered parts, and follow up with a knife so as thoroughly to separate the offending parts which surround the opening where the fungus arises. Should hemorrhage take place, as it frequently does, it is easily checked by touching the part with the muriate of antimony, sometimes called, among farmers, the butter of antimony. Should the fungus rise higher than the surrounding surface, use the knife, so as to bring it on a level; dress with escha

rotics, adding considerable pressure. The best covering in this case is a compress of oakum, securing the whole with canvass. Cleanliness and an entire exclusion of moisture are indispensably necessary. The feet should be dressed once a day, and in bad cases, twice. When the animal is sufficiently recovered to be turned out, the bottoms of the feet should be coated with tar.

The opinion, that this disease arises from fulness of habit, is without foundation. It attacks fat cattle and lean alike, and is not confined to the fore-feet or the hind-feet. It has been considered epidemic, having made its appearance for successive years; this is an erroneous opinion. Cattle in upland, where the soil is dry, are never known to be effected with it; it is those fed on swampy or springy ground are liable to it. The cause of the discase being thus pointed out, remove the cattle to dry pasture and its ravages will cease.

TO THE EDITORS OF THE AMERICAN MONTHLY MAGAZINE.

Gentlemen,

If the following remarks, (produced by ́ the perusal of Mr. Wood's observations respecting the swallow,) in your 4th No. Vol. 1. p. 292, from a lady in Chambersburgh, Penn. to her correspondent in this city, should appear useful in helping naturalists to describe the habits of this species of the feathered tribe, they are at your service. K.

Many years ago, while setting in my father's garden at Loudon forge, we noticed the chimney-swallows collecting in great numbers in the air, and sweeping in a circuit large and wide, past an old hollow locust tree, whose top had been blown off. This excited our curiosity, and induced us to watch their motions, when we observed them pouring in parcels(funnel shaped) into the tree, and those that missed getting in, flew off in the air, renewing their circuitous route, and gathering as before, lodged themselves in the same manner until there was not one to be seen, before the twilight closed. This was continued year after year, and was an object of great curiosity, which often amused both ourselves and our visiters, until by the burning of some brush-wood, in an adjoining meadow, the tree caught fire and was consumed. Their roosting place afterwards was in a hollow sycamore, on a small island below the house; though we had the pleasure to know they

were near neighbours, yet the curiosity was in a great measure destroyed, as the tree, where they deposited themselves, was at some distance, and our view of it intercepted by other trees.

"In Chambersburgh I have observed the same habits in these birds. They would collect in the evening about sundown, and pour themselves into my neighbour's chimney. I have often sat in my piazza and viewed them with pleasure, until my neighbour was apprized of the fact and closed the chimney. This you may have an opportunity of viewing any summer yourself.

"The reason for finding dead birds and bones, is obviously from such numbers depositing themselves in the trunk of a tree, where the weak must be pressed, and where want of air produces suffocation. In chimnies the air being communicated both from top and bottom hinders suffocation." S. B. D.

The following hints on the methods of determining the latitude and longitude of places on the land, are respectfully submitted for publication in the American Monthly Magazine.

It will readily be admitted by all who are in any degree acquainted with geography and astronomy, that it is of the utmost importance to the geographer to have the latitude and longitude of several extreme and intermediate points of a country, correctly ascertained, in order to construct a map of the same with precision. And although much has been done in the science of geography, by the aid of astronomical observations, it is well known that the great degree of imperfection which still remains, is more to be attributed to a deficiency of these observations, than to any other cause. Hence we may perceive that it would be a meritorious act in the government of every country, to employ persons of competent skill, and furnish them, at the public expense, with suitable instruments for making correct determinations of the latitude and longitude of every important place therein. These, combined with accurate surveys of the boundaries, would give to this science a degree of perfection hitherto unknown.

The most useful instruments for these purposes are an astronomical quadrant, a circular instrument of reflection, a per

fable transit instrument, a telescope of sufficient magnifying power for observing the immersion and emersion of Jupiter's satellites, and a time-keeper. The quadrant might be of two feet radius; the circular instrument of fifteen inches diameter, a refracting telescope of Dollond's or Tully's construction, about four feet in length, of focal distance, with a triple object glass of three and threefourth inches aperture, would answer very well for the travelling astronomer. His transit instrument might be of moderate dimensions, and a watch of the best kind might serve for his timekeeper. But since these alone would form an expensive apparatus, which presupposes in its use, an accomplished practitioner, acting under liberal patronage, it seems improper to undertake a description of the instruments, or to give directions for using them. A full description of these may be found in Vince's and La Lande's astronomy, and the article Astronomy in the New Edinburgh Encyclopedia. We shall only suppose, that a person of ingenuity, and some previous knowledge of the theory, should become desirous of exercising his talents in this way, and being sufficiently independent in his circumstances to expend a sum of eight hundred dollars in the purchase of instruments, and employ several months in the year in finding the latitude and longitude of a considerable number of places through which he should travel for that purpose. With the above sum he might purchase a patent lever or horizontal watch, a sextant of the best construction, contained in a square mahogany box, which should also contain an artificial horizon, and a case of quicksilver to be used in the same. To these he might add a telescope, of the dimensions already given. The Nautical and Astronomical Ephemeris of the English Board of longitude, Bowditch's Navigator, and Mackay on the longitude, contain a sufficiency of instructions and astronomical tables for his purpose. He should also have with him the best map of the country or territory in which his observations made that can be procured, and a case of mathematical instruments. The map would enable him to find more nearly an estimated latitude and longitude of those places, whose positions would otherwise be too uncertain to be made the basis of his calculations.

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Our intended practitioner, after being Instructed in the use of his instruments, and their adjustments, must, in every

observation for obtaining the longitude, find the error of his watch for apparent time, and its gain or loss of time in 24 hours. The most effectual method of doing this will be, by taking the mean of 5 or 6 altitudes of the sun in the morning, and afternoon of the same day when the sun bears nearly east or west. Or, if the sun cannot be observed in that position, the lowest altitudes that can be taken. The apparent time is used in all astronomical problems except that of determining the longitude by the eclipses of Jupiter's moons. Because the time of their immersions and emersions at Greenwich are given in the tables for mean time, the error of the watch must be found for the same at the meridian of the observer. This method of determining the longitude of a place is one of the most simple, though not the most accurate; but will generally approach so near the truth as to be very useful in geography. In attempting this, the greatest power the telescope will bear, consistent with distinct vision, should be employed. The observer, according to the directions given in the Ephemeris, should be ready with his telescope at a suitable time before the ingress or egress of the satellite into, or out of Jupiter's shadow, takes place. And at the instant it happens, must give notice to his assistant, holding the watch, to note the time shown thereby. Then, making an allowance for its error, the difference of time between his observation and that of the Ephemeris will be the longitude of his meridian, expressed in time.

The simple telescope may also be used, instead of the transit instrument, for determining the longitude, by observing the time at which the moon's eastern or western limb passes the meridian. The manner of doing this, and also of observing when an eclipse of the sun or moon commences or terminates, are fully explained in Mackay's treatise on finding the longitude by sea and land. An eclipse of the sun affords the best means for a correct determination. That of the moon is attended with some uncertainty; but should always be observed with care whenever an opportunity occurs.

The lunar method, which consists in observing the angular distance between the moon and the sun, or a star, measured by the sextant, and noting the apparent time of observation, enables the observer to find the true distance, the true time at Greenwich corresponding thereto, and consequently, the difference