Indians in Dakota, Montana, and Wyoming. These, to the number of about 3,000, under Sitting Bull, Crazy Horse, and other chiefs, had made war on the friendly Indians, and had refused to settle upon a reservation. In March an unsatisfactory expedition was made by General Crook toward Powder River. General Sheridan now ordered three columns to move simultaneously to a common centre, where the Indians were supposed to be, from Montana, from Dakota, and from the Platte. The two former were under command of General Terry, and the latter under General Crook. General Crook started from Fort Fetterman, May 29th, with about 1,000 men. This expedition marched to a point on Goose Creek, which is the head of Tongue River, a tributary of the Yellowstone. On June 17th General Crook was attacked by the Indians on the Rosebud, also a tributary of the Yellowstone. The Indians left 13 dead warriors on the field; General Crook's loss was nine dead and 21 wounded. Meantime, Colonel John Gibbons, with about 450 men, had marched from Fort Ellis, in Montana, down the valley of the Yellowstone, to meet General Terry, who was ascending the same valley. General Terry, with the Seventh Cavalry, under its lieutenant-colonel, Custer, containing about 600 men and horses, and about 400 infantry, had started from Fort Abraham Lincoln on the 17th of May, and reached the Yellowstone, at the mouth of Powder River, June 9th, where he established a supply-camp. Resuming his march along the south bank, he reached the mouth of the Rosebud on the 21st. Near this point he came in communication with Colonel Gibbons, whose command was left at the mouth of the Big Horn, and determined in person to continue to the same place, but to detach the Seventh Cavalry by a circuit to the Upper Rosebud (a tributary of the Big Horn), where all his command, embracing that of Colonel Gibbons, was to meet on a day appointed.

On the 22d General Custer started, with his whole regiment and a strong detachment of scouts and guides, from the mouth of the Rosebud. Proceeding up that river about twenty miles, he struck a heavy Indian trail, which he followed to the Little Big Horn River. Here be found a village of almost unlimited extent, and at once attacked it with that portion of his command which was immediately at hand. Major Reno, with three companies, was sent into the valley of the stream at the point where the trail struck it. General Custer, with five companies, attempted to enter about three miles lower down. Reno forded the river, but was completely overwhelmed by the Indians, and was forced to recross. In a short time he was joined on the bluffs by Captain Benteen with three companies, and by Captain McDougall with one company. Soon after, this united force was nearly surrounded by Indians. The fighting continued from about half-past two o'clock of the 25th till six o'clock of the

26th. General Terry's command arrived on the morning of the 27th, and the Indians withdrew from the valley, taking with them their village.

Of the movements of General Custer, and the five companies under his immediate command, scarcely anything is known. He was killed, and his entire command was obliterated. The remaining seven companies of the Seventh Cavalry were saved by the brave and prudent conduct of Major Reno, and the timely arrival of General Terry. The loss was 12 officers, 247 enlisted men, five civilians, and three Indian scouts killed, and two officers and 51 men wounded. The Indian force was estimated at from 2,500 to 3,000 warriors.

General Terry, after burying the dead and caring for the wounded, regained his position at the mouth of the Big Horn, and called for reënforcements. General Crook also awaited reënforcements at his camp on Goose Creek, and the hostile Indians meantime remained between them, near the base of the Big Horn Mountains. These commands, having been reenforced, effected a junction, August 10th, on the Rosebud, at a point 35 miles above its mouth. The march was now begun in pursuit of the retreating Indians. The followers of Sitting Bull seemed to have retreated north, near or beyond the Yellowstone, and those of Crazy Horse to the south, near Slim Butte and Owl Creek, in the direction of the Black Hills.

In October Colonel Miles received hostages, on the Yellowstone, opposite the mouth of Cabin Creek, for the surrender of about 2,000 Indians.

In his annual report, Lieutenant - General Sheridan says:

The surrender of the Indians from the Missouri River agencies to Colonel Miles, on the 27th of October, numbering, in men, women, and children, at small band to the north, leave now out and hostile least 2,000, and the escape of Sitting Bull with his only the northern Cheyennes and the band of Crazy Horse and his allies from the Red Cloud agency, and it is against these Indians that General Crook is now operating; and when these are killed, captured, or surrendered, the Sioux war will be at an end, and I think all future trouble with them, as it is intended to put most of them on foot, and a Sioux on foot is a Sioux warrior no longer. . . . I recommend that the whole Sioux nation be established on the Missouri River, between Standing Rock and Fort Randall. They can be cheaply fed there, and can be sufficiently isolated to be controlled. To take so many wild Indians to the Indian Territory would be a difficult undertaking at this time, and would, in my opinion, be attended with the worst results to these now there, as well as to the Sioux. They should go gradually, from time to time, and when the Indians there are ready to receive them.

In April, 1876, the headquarters of the Army were transferred from St. Louis to Washington. During the year the number of grand military divisions was reduced from four to three, viz., Missouri, Atlantic, and Pacific. The aggregate force of the army is 28,571, including 2,151 officers and 26,420 enlisted men.

8. Mr. Trouvelot has observed spots at least within 10° of the north-pole of the sun.

9. The flocculent objects sometimes seen projected upon the umbra and penumbra of spots are the remaining portion of the granulations composing the chromosphere, more or less dissolved by the forces emanating from the interior of the photosphere. Temperature of the Sun's Surface.-It is well known that eminent authorities have differed very widely in their estimates of the intensity of solar heat. The calculations of Sir John Herschel and Father Secchi give about 10,000,000° as the temperature at the surface; while other physicists, by applying the law of Dulong and Pettit, obtain a degree of heat not greatly superior to that of a blast-furnace. Prof. Langley, of the Allegheny Observatory, who has for several years been devoting special attention to solar physics, read a paper on this subject at the October meeting of the National Academy of Sciences. These recent researches leave little room to doubt the approximate correctness of Herschel's estimate.

The Sun's Atmosphere.-A memoir on the atmospheres of the sun and planets was recently communicated to the American Philosophical Society, at Philadelphia, by Mr. David Trowbridge, of Waterburg, N. Y. Assuming the temperature of the sun's surface to be 9,800,000° Fahr., and that a given volume of the solar atmosphere at 32° becomes doubled at 522°, the analysis of Mr. Trowbridge leads to the conclusion that at the height of about 2,500 miles above the sun's surface its atmosphere has decreased in density to onehalf of what it is at the surface; at a little more than 5,000 miles, to one-fourth, and so on for greater heights. Assuming further that the density of the solar atmosphere at the surface is 855,000,000,000 times what it is at the outer limit, the height of the atmosphere is found to be 121,000 miles, or more than onefourth of the sun's radius. This ratio is less than that which actually exists in the earth's atmosphere. If we now suppose the masses of the terrestrial and solar atmospheres to have the same ratio as the masses of the earth and the sun, the density of the solar atmosphere at the sun's surface will be only of the density of the earth's atmosphere at the earth's surface. The resistance offered to motion in such an atmosphere is much less than it would be in one of low temperature. Were the heat of the sun's surface reduced to 32°, the height of the atmosphere under the conditions above supposed would be only five miles, and at the height of 665 feet the density would be reduced one-half. The pressure on a square inch of surface would be 5 tons, and the density at the surface would be 740 times as great as at the surface of the earth-in other words, about equal to the density of water.

The Late Sun-spot Minimum.-The observations of Prof. R. Wolf, Director of the Zürich Observatory, indicate a minimum of solar spots about the end of the year 1875. The last preceding minimum occurred in 1867, and the

maximum in 1870. The mean period, according to Dr. Wolf, is 11.11 years. The last epoch of least disturbance took place, therefore, nearly two years before the predicted time.

Probable Existence of an Intra-Mercurial Planet. It is well known that dark circular spots have been seen at widely-distant intervals passing rapidly across the solar disk. These phenomena have been regarded by some astronomers as transits of an unknown interior planet. The fact, on the other hand, that no such body has been seen during total eclipses of the sun, is claimed by others as presumptive evidence that the so-called transits have been due to some other cause. But this negative testimony is by no means conclusive. When it is remembered, moreover, that an unexplained motion of Mercury's perihelion has been referred by Leverrier to the disturbing influence either of a planet or a zone of minute asteroids within Mercury's orbit, the question is certainly still open to discussion.

The theory that this outstanding disturbance of Mercury's motion is due, at least in part, to an interior planet, has been recently revived by the distinguished Director of the Paris Observatory. The attention of astronomers was called to the subject by the announcement that on the afternoon of April 4, 1876, Herr Weber, of Peckeloh, had seen a small round sun-spot, which had disappeared before the following morning. It was found, however, that the observers at Madrid and Greenwich had witnessed the same appearance, and that their observations proved it to have been a true sun-spot, not a planet. But Leverrier, who had thus been led to undertake a

discussion of the subject, found sufficient evidence in former observations to render the existence of the planet highly probable. The spots seen at the five following dates are regarded by the French astronomer as transits of the same body:

2,

66 66

26,

66

19,

Decuppis.

"Sidebotham. "Lescarbault. "Lummis.

1802, October 10, observed by Fritsch. 1839, 1849, March 12, 1859, 1862, These dates are approximately satisfied by a period of 334 0h. 32m. 24, corresponding to a mean distance of 0.201. It is remarked, however, by a writer in Nature (November 2, 1876), that a period of 27 23h. 8m. 10. not only represents the observations selected by Leverrier, but also that of Stark, October 9, 1819, one of the most definite on record. The question is one of much interest, and as another transit may not occur for several years, diligent search will be made for the body along its calculated path. If a planet of the size indicated by the supposed transits really exist, it ought certainly to be visible off the sun's disk.

New Minor Planets.-The number of known asteroids at the close of 1875 was 157. Eleven

more were detected in 1876, making the present number 168. Coronis, No. 158, was discovered by Dr. Knorre, of the Berlin Observatory, on the 5th of January. Its distance from the sun is 2.99, and it shines with the light of a star of the 11th or 12th magnitude. No. 159, Æmilia, was detected by Paul Henry, of the Paris Observatory, January 26th. Una, the 160th of the group, was found by Dr. Peters, of Hamilton College, Clinton, N. Y., February 20th. It is of the 11th magnitude. No. 161 was first seen on the 19th of April, by Prof. Watson, of Ann Arbor, Mich. The 162d was discovered on the 22d of April, by Prof. Henry, of Paris. M. Perrotin, of Toulouse, detected No. 163 on the 26th of April. Its light is not greater than that of a star of the 12th magnitude. The 164th of the cluster was discovered by M. Paul Henry, at Paris, July 12th. It is of the 12th or 13th magnitude. Nos. 165, 166, and 167, which have received the names of Loreley, Rhodope, and Urda, were discovered on the 9th, 15th, and 28th of August, by Dr. Peters, of Clinton, N. Y. The first two are of the 11th magnitude; the last, of the 12th. Urda is the 26th member of the group first seen by the Director of the Clinton Observatory. No. 168 was discovered by Prof. Watson, at Ann Arbor, Mich., on the 28th of September. This planet is of the 11th magnitude, and is the 19th detected by Prof. Watson. The supposed discovery of another member of the group on the 28th of September by Prof. Henry, of Paris, proved to be a rediscovery of Maia, No. 66, which had been wholly lost sight of for several years.

The name of No. 139, discovered by Prof. Watson while at Peking, was erroneously given in a former volume. The Chinese name selected by the discoverer is Juewa. Most members of the group discovered in 1875 are of the 11th or 12th magnitude, and belong to the exterior portion of the ring. No. 153, detected by Palisa, November 2, 1875, and which was named Hilda by Dr. Oppolzer, has a much longer period than any other yet discovered. Its mean daily motion, according to Dr. Schmidt, is 452", which corresponds to a period of 2,865 days, or seven years and ten months. This is more than double the period of many asteroids in the inner portion of the zone. The mean distance that of the earth being unity—is 3.95. The eccentricity of the orbit being 0.1487, and the inclination 7° 45', the least distance between Jupiter and Hilda will be less than one-fifth of Hilda's greatest distance from the sun. At times, therefore, the motion of the asteroid must be greatly disturbed.

The elements of several recently-discovered members of the group have not yet been computed. The mean distance, eccentricity, inclination, and longitude of perihelion, of those detected since October 1, 1875, are given, so far as known, in the following table:

Saturn and his Rings.-The American Journal of Science for June, 1876, contains an interesting paper by L. Trouvelot on some physical observations of the planet Saturn. The observations of Mr. Trouvelot were continued through several years, and were made with the fifteen-inch refractor of the Harvard College Observatory, the twenty-six-inch refractor of the Washington Observatory, and the six-inch refractor of his own observatory at Cambridge. The ring exterior to the principal division has been always seen under favorable circumstances to be divided into two sections by a narrow, grayish line, called "the pencil-line." The dusky ring, discovered by Bond, does not appear to be separated from the old interior ring by any break or chasm. Designating the annulus exterior to the pencil line by A, that between the pencil line and the principal division by B, and the outer portion of the interior ring by C, Mr. Trouvelot's observations show

the outer border of the principal division, has shown, 1. That the inner margin of the ring B, limiting on the ansæ, some singular dark angular forms, which may be attributed to an irregular and jagged conformation of the inner border of the ring B, either permanent or temporary.

shown a mottled or clouded appearance on the ansæ 2. That the surface of the rings A, B, and C, has during the last four years.

3. That the thickness of the system of rings is increasing from the inner margin of the dusky ring to the outer border of the ring C, as proved by the form of the shadow of the planet thrown upon the rings.

4. That the cloud-forms seen near the outer border of the ring C attain different heights, and change their relative position, either by the rotation indicated by the rapid changes in the indentation of of the rings upon an axis, or by some local cause, as the shadow of the planet.

5. That the inner portion of the dusky ring disappears in the light of the planet at that part which is projected upon its disk.

than in the more central parts, the light diminishing 6. That the planet is less luminous near its limb gradually in approaching the border.

7. That the dusky ring is not transparent throughout, contrary to all the observations made hitherto; planet, so that, at about the middle of its width, and that it grows more dense as it recedes from the the limb of the planet ceases entirely to be seen through it.

8. And, finally, that the matter composing the dusky ring is agglomerated here and there into small masses, which almost totally prevent the light of the planet from reaching the eye of the observer.

Comets. It is remarkable that no new telescopic comet has been discovered since 1874. This is the longest barren interval in the last forty years. Some interesting researches, how

De Vico's comet of short period has not been seen since 1844. This body is regarded by Leverrier as identical with the comet discovered by Lahire in 1678. It is situated most favorably for observation when the perihelion passage occurs about September 4th, and it is remarkable that those of 1678 and 1844 took place within a few days of the most favorable date. A possible reason for the non-recovery of the comet at any recent return was given in Nature for July 27, 1876. The orbit of De Vico's comet approaches very near to the orbit of Mars at two points falling near 42° and 287° heliocentric longitude. At the former point the distance between the two orbits is about 2,000,000 miles, and at the latter somewhat less than 1,000,000; "and it is to be borne in mind that these distances, small as they are, may have been diminished very sensibly by the effect of accumulated perturbation since 1855, beyond which we have no calculation of the effects of planetary attraction. If the mean diurnal motion in 1855 were as large as 652.05", a value considerably within Brünnow's suggested limits, the comet might have come into extremely close proximity to Mars at the end of August, 1866, in about 42.3° heliocentric longitude."

Meteors.-Between ten and twelve o'clock on the night of April 18, 1876, meteors were seen in unusual numbers near Ellettsville, Ind. A large majority of those whose tracks were well observed were conformable to the radiant in Lyra. Several were remarkably brilliant, apparently equal to stars of the first or second magnitude. The meteors of this epoch are supposed to be derived from the first comet of 1861, and to move in the same orbit.

Watch was kept for meteors at York, England, on the nights of August 10th, 11th, 12th, and 14th. Several nights preceding the 10th were cloudy, and the 11th was very hazy. The brightness of the moonlight also interfered with the observations, except on the 14th, which may be regarded as the close of the August epoch. The hourly numbers radiating from Perseus, seen by a single observer,

on the four nights were 18, 6, 9, 7. There was, therefore, a regular decrease from the 10th, the apparent exception on the 11th being due to the haze. Making all allowance for unfavorable circumstances, Prof. Herschel thinks the shower of 1876 indicates a minimum.

On the evening of October 18, 1876, from about half-past seven to nine o'clock, meteors were seen in greater numbers than usual at Bloomington, Ind. The maximum number for one observer was eleven per hour. They all diverged from the vicinity of a point between Taurus and Auriga. Most of the meteors were small, though two were seen of extraordinary magnitude. At Newburyport, Mass., on the same night, at two o'clock A. M., a bolide was observed to start from the same part of the heavens.

It was half the apparent size of the moon, which it rivaled in brightness, the smallest objects being visible in the intense white light of about two seconds' duration. It left a train 10° long and visible over a quarter of an hour. one-fourth of a degree wide, which remained While the train

was being observed a large number of smaller meteors passed, as often as one a minute, over the same field, one or two of them leaving a slight

train.

The meteors of November 14th move in the orbit of Tempel's comet (1866), and are the débris resulting from its disintegration. The comet, together with the principal swarm of meteors which immediately follow it, is now approaching its aphelion near the orbit of Uranus. As the existence, however, of more than one cluster in the same orbit has been clearly indicated, a yearly watch will be necessary, while passing the node, in order to discover the law of meteoric distribution. "On the morning of November 14th" (according to Prof. Newton), "between twelve and one o'clock, the sky at New Haven was partly clear. Out of about twelve meteors seen, three might be called conformable to the radiant in Leo. Shortly after one o'clock the sky became wholly overcast."

Aerolites and Meteoric Fire-balls.--In the American Journal of Science for June, 1876, Prof. J. Lawrence Smith, of Louisville, Ky., describes a fire-ball seen by himself and many other observers to pass Louisville on the evening of January 31st, at half-past five o'clock. The meteor was first seen about 60° above the horizon: its direction was from northwest to southeast; duration of flight, two or three seconds; apparent size, one-sixteenth that of the moon's disk. The bolide exploded about 10° above the horizon, when all the fragments disappeared, except the largest, which continued its course very nearly to the horizon.

A fall of aërolites took place near Ställdalen, in Sweden, June 28, 1876, between the hours of eleven and twelve A. M. The fall of the stones was accompanied by a brilliant light, though the day was cloudless. Two or three loud detonations were heard, after which the