Riots 4. Wy “Ae a. Reais Witvaatheed vary earl mens Perery a Ws Tt ues . ASD ee teseteis, bee) Es: ee me bie thats ethes pap ve wee Pl ue th be shy rare ve ct ye oye 95 athe an peer ” ite cree! ay Banh ad ty Nera aeage Dre Kis eve va Ra irs wayet ee yn rs . + SAR CS . >) : aad G2) 559 | PROCEEDINGS OF THE American Philosophical Society HELD AT PHILADELPHIA FOR PROMOTING USEFUL KNOWLEDGE VOLUME XLIX 1910 z x tah. 3% | Uddin g PHILADELPHIA THE AMERICAN PHILOSOPHICAL SOCIETY IgIo PROCEEDINGS OF THE AMERICAN PHILOSOPHICAL SOCIETY HELD AT PHILADELPHIA FOR PROMOTING USEFUL KNOWLEDGE VoL. XLIX JANUARY-—JUNE, 1910 No. 194 PHOTOGRAPHIC OBSERVATIONS OF DANIEL’S COMET. (Pirates I-XXV.) By E. E. BARNARD. (Read April 25, 1908.) It is such a long time since one has had the opportunity of seeing a large comet that the sight of this beautiful object sus- pended in the quiet summer morning skies with its slender graceful tail streaming upwards into the night, was something long to be remembered. It was a very impressive picture and those who were. fortunate enough to see it at its best must have been struck with its quiet and majestic beauty. This was specially the case for a few mornings in the middle of August when the moon was absent, and as late as the first week in September when, though very low in the east and visible only for a few minutes before dawn killed it, the tail could be traced for a distance of fifteen degrees or more. | This comet was discovered by Mr. Zaccheus Daniel at Princeton, N. J., on 1907, June 9. Though it proved to be one of the brightest comets that have appeared in the past twenty-five years, it was in some respects a disappointing object—disappointing only, however, in the want of new phenomena. It was visible to the naked eye for two full months. At one time its tail attained a length of twenty-five degrees. Shortly after perihelion passage—when last seen in the + BARNARD—PHOTOGRAPHIC OBSERVATIONS [April 2s, morning sky—the nucleus was as bright as a first magnitude star. Singularly enough, the comet developed its most interesting changes a month or more before perihelion passage. When near perihelion, which occurred September 3, there were few changes in its appear- ance from morning to morning. At that time there seemed to be a uniform unbroken flow of the tail-forming particles, so that what streams there were, were not individually prominent or striking. In the second half of July separate streams of matter were frequent and formed a most interesting feature of the tail. These were specially beautiful on July 17 and 19. On the first of these dates the tail, where it joined the head, was made up of some five broad, diverging streams, which gave it a splendid and symmetrical appearance. This is really the handsomest photograph I have ever seen of a comet. Comparatively few observatories obtained photographs of this comet, which was a great pity, for it was worthy of far more atten- tion from a photographic standpoint than it received. Several, however, succeeded in getting results that are important. Excellent photographs were obtained by Mr. W. A. Cogshall at the Kirkwood Observatory at the State University, Bloomington, Indiana, with a small reflecting telescope made by himself. Though these, from the limitations of the reflector, do not show a great length of tail, they are specially beautiful and valuable for the structural details. A good series was also obtained at Greenwich. Dr. Max Wolf secured some specially valuable photographs with the 30-inch re- flector, whose large scale showed the tail near the head, on several dates, to be made up of a great number of thin rays. An excellent series of photographs of the comet was made by Mr. Duncan at the Lick Observatory. Though the time interval between these last and those of the Yerkes Observatory is roughly only two hours, there are decided changes shown in the tail when these pictures are compared with those made at the Yerkes Observa- tory. Unfortunately the changes in the comet are such that there are no definite markings that can be measured on the photographs to determine the motion of the tail-producing particles, with per- haps one exception—that of July 11. There are twelve dates that 1908.] OF DANIEL’S COMET. 5 are common to the Lick and the Yerkes plates. Several of the Yerkes photographs show very little on account of clouds and thick sky on the dates in question. Another fine series of photographs of the comet was made by M. F. Quénisset of M. Flammarion’s observatory at Juvisy, France. The interval of some six hours makes this series specially valuable for comparison with plates taken in this country. I am greatly indebted to M. Quénisset for enlarged prints from eleven of these pictures. Out of these, there are eight dates which were dupli- cated at the Yerkes Observatory. A comparison of these photo- graphs is of extremely great interest, and though there is but little material from which to accurately determine the amount of motion, progressive outward displacement, especially in the streamers, is strongly shown. A study of these photographs clearly shows how uncertain it is to connect the details of any two dates. Of course a disturbance may extend over several days and the matter from it still be visible, but any particular detail would not probably live through from one date to another. In some of M. Quénisset’s photographs the change has been so great that it is almost impos- sible to be sure of the same features six hours after. What is quite evident, however, in the comparison, is that the structure of the tail (the streamers) has a decided outward motion as a whole; at the same time there is a diffusion effect that constantly tends to destroy the details. Some of these comparisons follow: July 19, Juvisy Plate—There is a principal narrow ray that separates into two rays some distance out. A dark space intervenes between it and a broad streamer south, whose north edge is very definite. There is a very decided change shown in the Yerkes photograph. Two new short rays have appeared on the south side. The north ray has become broad and diffused and irregular. The changes are so striking that one can hardly be sure of the same features, though there is a general resemblance. August rr.—In the Juvisy picture there are four distinct rays. The two middle ones diverge from a point close to the head. These two are clean cut in the Yerkes plate. The south one has become 6 BARNARD—PHOTOGRAPHIC OBSERVATIONS [April 2s, much brighter and more definite. Their junction has bodily moved outward for quite a distance. The north ray of the four has closed in on the one close south of it. A broad light region on the south edge of the northern of the two middle rays has drifted outwards and is less marked. August 14.—There is one broad widening stream in the Juvisy photograph, with two lesser ones symmetrically placed on each side. In the Yerkes plate there is a general resemblance to the other; though the tail is made up of three broad streamers, they are much further out. It looks as if the three had drifted out and fused together more or less. The whole system of tails has bodily receded from the comet. August 19.—In the Yerkes plate the head has become relatively smaller. The tail has spread out very greatly, especially on the south side. There is less structure than in the Juvisy plate. August 20.—In the Juvisy plate a principal ray divides to the north and joins a dark space behind the head. In the Yerkes plate this ray and dark space have both moved outwards. The head and neck are also narrower. On July 11 (which date we will treat specially) a bright con- densation 14° back from the head is strongly shown on both the Yerkes and Lick plates and can be seen on the Juvisy plate, but it is faint and cannot be located with very great accuracy on this last picture. A plate made at the Lick on July 10 seems to show this same object somewhat nearer to the comet or about } as far out as on the eleventh. It is noticeable on all three photographs of July 11 that this condensation was receding from the comet, at the same time that it was following slowly towards the sun. From the appearance I am inclined to think that it is the same object which is visible on the plate of July 10. If so, then it must have left the comet on or about July 7. Between this condensation and the head of the comet on July 11 the tail is very faint but continuous. In reality this mass is the near end of a bright strip of the tail about 3° long. The object on the Lick plate of July 10 is joined to the head by a bright, strongly defined connection, of which the condensation is only an inconspicuous part. In the interval between July ro and 1908.] OF DANIEL’S COMET. 7 11 the mass (if the same) had increased its distance from the head by about 20’. In the meantime it had drifted sunward 1° 10’—fol- lowing in the direction of the comet’s motion. It is probable that this was due to its original motion when a part of the comet, and that if its existence had been permanent enough, the motion would have become one of recession from the sun, but it rapidly dissipated before other photographs could be made of it. With the aid of the BD charts I have taken off the following positions on the photographs of July 11: Position of the Head 1855.0. Position of the Condensation 1855.0. Juvisy, 1" 48.05 + 8° 12’ 1" 44™.0 + 7° 54° Yerkes, 1" 49™.50 + 8° 10’ 1" 45™.0 + 7° 53° Lick, 1" 50.05 + 8° 18’ 1"45".0+ 7° 54’ The position angles of the mean axis of the tail on this date are: Juvisy, Fi. A. 25r° 5 Yerkes, 251°.5 Lick, 251°.0 If one should take the brighter, long part of the tail, independent of the head, the axis of it would pass a little north of the head. The following positions were taken off by the aid of the BD charts on the plates of July ro. Juvisy.—Position of the head 1855.0 2" 40™.50-+ 11° 29’. Posi- tion angle of the middle long, bright branch of the tail 249°.2. The main or central branch separates at 37’.7 back of the head. The south branch of thetail is 5° less in position angle than the middle one. Yerkes.—Position of head 1855.0 2" 42™.67 + 11° 33’. Position angle of main branch of the tail (n. of 2) 253°.5. The south one was in P.A. 250°, but was irregularly curved. Lick.—Position of head 1855.0 2" 42™.50-+-11° 32’. Position angle of main and largest branch 252°.9. The following are the positions on August 11, derived from the charts. Juvisy.—Position of head 1855.0 6" 4™.70-+- 17° 23’. Position 8 BARNARD—PHOTOGRAPHIC OBSERVATIONS [April 2s, angle of south ray 257°.0. Position angle of north ray 270°.0; not extreme north ray. Yerkes.—Position of head 1855.0 6" 7™.10-++.17° 23’. Position angle of south ray 259°.0; assuming center of head as origin. Po- sition angle of north ray 269°.0; assuming center of head as origin. On a number of mornings I carefully examined the comet with the 40-inch telescope and its 4-inch finder. In the great telescope the view was not satisfactory because of the very small field — 53’ of arc. It showed the nucleus, however, and part of the head very well. The view in the finder was very much more satisfactory, but even this was a disappointment. The nucleus and head and part of the tail were very beautiful. The soft nebulous light of the comet with the bright yellowish star-like nucleus imbedded in the head made a very striking picture. But there were no details visible in either the head or the tail. The streamers which were shown on the photographs at about the same time could not be seen. Viewing the comet thus and then afterwards seeing the photograph of it, impressed one greatly with the value of photography in dealing with these objects. I think most of the phenomena of this comet would have passed away unknown had it not been for the photographic plate. NoTES ON THE APPEARANCE OF THE COMET WITH THE NAKED EYE, WITH THE 5-INCH GUIDING TELESCOPE AND WITH THE 40-INCH AND ITS 4-INCH FINDER. July 15.—The comet was visible to the naked eye as a hazy star of the fourth magnitude. It was decidedly brighter than the An- dromeda nebula, but much smaller. It was $ magnitude brighter than the star 3° east of it, BD+-9° 316 (1855.0 2" 17™ 380 -+-9° 57'.9 5™.7). While guiding it seemed to fade for short intervals— perhaps this was due to thin patches of clouds, though I could not see any clouds. July 17.—Bright to naked eye. It was 3} magnitude. Very much like a considerable hazy star. Could faintly see a very slender tail for 5°-- which passed several faint stars 4° from the head. The comet was } magnitude or more brighter than the fourth mag- 1908.] OF DANIEL’S COMET. 9 nitude star, BD + 7° 388 (1855.0 2" 20™ 27°.7 +-7° 48’.4 4™.5),4°+ south of it. It was brighter than any of the stars near. July 18.—To the naked eye, when best seen—visible only through gaps in clouds—the head was third magnitude. It seemed to be brighter than on the seventeenth. July 19.—I am sure there were frequent fluctuations of the comet’s light to the extent of about one magnitude. To the naked eye the comet was 34 magnitude. At best it was 4 magnitude brighter than the naked eye star, BD + 9° 359 (1855.0 2" 37™ 6%.0 + 9° 29’.9 4".0), 3° s.w. of it. Could see faint suggestions of a tail. Good sky. July 28.—15® 45™. The head was conspicuous, like a hazy star, notwithstanding a gibbous moon. In the finder of the 40-inch I could trace the tail faintly across the field (2°). There was a bright stellar nucleus of about the sixth magnitude. In the 40-inch the nucleus was very bright, but not stellar. The head filled the field of view (54’ power 460). There seemed to be a shadow effect behind the nucleus—away from the sun. July 31.—In spite of the presence of a half moon the comet was conspicuous, like a hazy star, 2° west of Aldebaran. I could see it with the naked eye as late as 16" 3”. August 1.—The comet was conspicuous, like a bright hazy star. It was the same brightness as 8' or 8? Tauri. Could not be certain of any tail. In the guiding telescope the nucleus was not so dis- tinct as it was on July 31. August 3.—It was conspicuous like a small 3 or 34 magnitude star. There were faint suggestions of a tail to the naked eye. It was not decidedly brighter [than on the first]. There was, of course, less moonlight than on the other morning. In the 5-inch the nucleus was not definite—only a central condensation. There seemed to be fluctuations in its light with the 5-inch and I think they were verified with the naked eye. August 5—To the naked eye the head of the comet was equal to ¢ Tauri. The tail was about 15° in length and stretched out to within a degree or two of Aldebaran. At times I thought I could see it as far as Aldebaran. It would have passed south of that 10 BARNARD—PHOTOGRAPHIC OBSERVATIONS [April 2s, star and was fairly distinct. The comet was a conspicuous object to the naked eye. August 6.—With the naked eye the head was as bright as § Tauri. Could trace the tail, which was conspicuous but not bright, as far as Aldebaran, where it passed south of that star; it was neither slender nor broad—and seemed to be straight. With the 4o-inch the nucleus was not stellar but was bright and yellowish. It was blurred or ill defined in the direction of the sun—apparently spread out—while on the opposite side (away from the sun) it was quite definite wtih a darker space in the nebulosity. The head was much larger than the field of view. In the finder, the tail stretched away across the field. There was a sixth magnitude yellowish star in it, about 4° back from the head. There was no detail or structure in the comet as seen in the 4-inch finder. The nucleus was about the fifth magnitude and almost stellar. The tail was very slender. The edges were soft and roundish—like a cylindrical or conical body. It was very beautiful in the finder. August 8.—To the naked eye the tail seemed to be almost the same as on the sixth and was not sensibly longer, but the head was brighter. The comet was 4 magnitude brighter than ¢ Tauri and > about equal to 6 Aurige. The sky was good. With the 40-inch the measured diameter of the nucleus at 16" 7™ was 2’.49. This gives a diameter of 2,580 miles. It was slightly yellow. There was a sharp outline several minutes long nearly straight, which passed the preceding edge of the nucleus and which bounded a much denser nebulosity following, in which the nucleus was immersed. The position angle of this definitely bounded nebulosity was 160°.6 (1) at 16" 8™. In the finder the nucleus was stellar and bright. The comet was still faintly visible with the naked eye at 16" 19", but at the limit of vision on the dawn-lit sky. August 9.—Sky not very transparent. The tail was not so con- spicuous as on the eighth; the head seemed brighter, however. It could be faintly traced to a distance as great as that from ¢ Tauri to Aldebaran (16°). The head was somewhat less bright than A Orionis. August 10.—Sky very good. To the naked eye the comet was 1908.] OF DANIEL’S COMET. 11 bright for some 3° or 4° back from the head. The nucleus was visible to the eye as a star of about the third magnitude. The head was midway in brightness between that of § Tauri and A Orionis. The tail could be traced faintly for at least 15°. It was pretty faint but when looked at with averted vision it could be seen fairly well for a distance equal to that from £ Tauri to Aldebaran. The end of the tail just reached to BD+ 15° 732 (1855.0 4" 56™ 18*.0 + 15°12’.3). August 11.—The tail, with the naked eye, could be traced to BD+ 15° 732. The south edge would pass through that star. It was 1° or 14° wide at that point. Though faint, it could be seen quite well. It was straight and somewhat narrow. The nucleus was conspicuous as a star-like body in the head. The head itself was narrow. The tail was bright for 2° or more and then it faded out rapidly towards the end. The head was as bright as » Gemi- norum. In the 40-inch the nucleus was ill defined, and blurred into the brightness following. It was distinct at the preceding edge. August 12.—Sky first-class. With the naked eye the nucleus was bright and stellar. It was about as bright as » Geminorum. The tail was perhaps a little brighter than before but rather feeble except near the head. I could trace it faintly nearly to BD + 15° 732. The head was as conspicuous as y Geminorum, near and to the east, but the nucleus was much less bright than that star. August 13—The sky was very thick, and part of the time at first the comet was behind clouds. August 14.—Clouds at first covered the comet. It then came out and was conspicuous about 2° east of y Geminorum. When the comet and star came out of the clouds they were very much alike, but as they rose higher the stellar condition of the nucleus was much inferior to the star—say I magnitude less bright. The tail was straight and rather slender. For 5° back of the head it was pretty bright, then for the rest of its length it was faint. It could, however, be readily traced to 126 Tauri (Proctor’s chart). August 19.—It was bright to the eye—perhaps brighter than before. The tail could not be traced far—perhaps nearly to y Geminorum. Sky very poor. 12 BARNARD—PHOTOGRAPHIC OBSERVATIONS _ [April 2s, August 20—With the naked eye the comet was a very graceful and beautiful object. The tail could be faintly traced to about y Geminorum. The nucleus was star-like and bright. August 21.—After the nearly full moon set, the sky was still affected by moonlight when dawn began. At 15" 30™ or 15" 40™ the comet was bright. The nucleus was bright to the eye and was perhaps of 2} magnitude. The head was not as conspicuous as y Geminorum—but not much inferior to it. August 22—Full moon. The head and nucleus of the comet were conspicuous in spite of the moonlight. The nucleus was about 2} magnitude. The tail was noticeable or conspicuous for 3° or 4°. In looking in its direction one would have been impressed with its distinctness. August 24.—Nearly full moon. Sky clear. The comet was con- spicuous. Even in the bright moonlight I could see the tail for a Oris: August 25.—In clouds and haze. August 31.—Sky good and clear. Crescent moon. The comet was fairly noticeable to the naked eye when its place was known. Could feebly trace the tail for 4° or 5°. September 2.—It was conspicuous to the eye with a tail 4° or 5° long even in the strong moonlight. The nucleus was about 2 or 2} magnitude. September 5—The comet was very low but the head was bright. The tail, though not bright, could be traced for 14° as drawn on a star chart. It was long and straight and gradually faded out to the end. The sky was fairly good, but as dawn came up some masses of haze were visible in the east. It was estimated that, to the eye, the head and nucleus were about third magnitude. Very slender crescent moon near horizon. September 8.—To the naked eye the nucleus was as bright as a first magnitude star. The tail could be traced 5° or 6° but partly hidden by clouds. September 11.—The comet was very low. The nucleus was fairly distinct to the naked eye, but there was only a suggestion of a tail. It had faded very much since the eighth [due to its low position?]. Sky lit with dawn. 1908.] OF DANIEL’S COMET. 13 September 12.—I could not see it with the naked eye though I tried hard. Not bright in guiding telescope. Sky not pure. Strong dawn. The photographs taken here of this comet were made with the 10-inch, the 6.2-inch and the 3.4-inch portrait lenses of the Bruce telescope of the Yerkes Observatory. The plates used were Seed 27 Gilt Edge. They were backed with a dark red paste made of burnt sienna and caramels. Much trouble was experienced from cloudy weather and had skies. Every opportunity was taken advantage of, however, to secure photographs of the comet. I am greatly obliged to my friend Dr. S. A. Mitchell, who guided for me on several mornings that work with the large telescope would otherwise have prevented photographs being secured. On a few mornings Dr. Mitchell at- tached his small camera with a Goerz double anistigmat lens of 1}- inch aperture and 6-inch focus .”. a/f = %.g, on to the Bruce mount- ing, and secured some negatives which showed a greater length of tail than was possible with the other lenses. Following is a list of the photographs made with the Bruce telescope: In the column marked “ Lenses,” a is the 10-inch Brashear doub- let, b the 6-inch, c the 3.4-inch and d the 14-inch Goerz lens. In conclusion it would seem that we have to deal with several different kinds of physical phenomena in the study of comets. These are doubtless closely related and are probably the same phe- nomena acting under different conditions. There is the regular production of the tail through the repellent action of the sun’s light. The tail forming particles in this case will be very small. They may go out from the comet as a broad stream or they may produce several streams more or less narrow. The direction of these various rays are dependent, to some extent, on an exciting and directing force in the comet itself, but the general direction will be more or less influenced by light pressure. These streams, or rays, will be more or less uniformly straight or curved— almost always straight or nearly so. They may be broken or abruptly deflected but this will be due to some influence encountered 14 BARNARD—PHOTOGRAPHIC OBSERVATIONS | [April 2s, in their progressive motion in the general direction of the comet’s flight. Such streams will more nearly represent the true emissive velocity of the particles. I have shown in the Astrophysical Journal, Vol. XVIIL., p. 214, in the case of Borrelley’s comet, that the tail of a comet actually moves forward bodily as a whole both outward from the sun and progressively in the direction of the comet’s mo- List OF PHOTOGRAPHS OF DANIEL’S COMET MADE WITH THE Bruce TELESCOPE. APPROXIMATE PosITIoN 1855.0. 2 5 | Cong Sean. | Rraration of | Lenses. h. m. ofa h. m. h, m. June 20 (Oo 18 |+ I 20 14 23 Oo 45 ab July 3 |: 8 [4+ 515 14 6 oe 2 ab II |i 49.5|+ 8 20°| 13 58 2 12 abc 13 |2 1.5\+ 96 14 7 I 55 abc 15 |2 14 |+I100 13 52 2 20 abc 17. |2 27.5|/-+I0 40 13 59 2 10 S08 17 |2 27.5|-+10 40 14 27 re F1 b 18 |2 35 |+11 10 oO I 50 abc 19 |2 42 |+11 32 13 54 2.08 abc 20 |2 50+/+12 O+ abc 29 |4 +15 30 14 41 I 40 abc 31 |4 24 |+16 o 152 Pe t7 abc Aug. I |4 33 |+16 9 14 46 I 45 abc 3 |4 53 |+16 40 14 5 I 40 abe § |5§ tr {+17 § 15 CE abc 6 |5 21 {+17 I0 ie Ia! abc 8 |5 39 |+17 22 15 30 °o 33 abc 9 |5 5° j|+17 20 ee E32 abc 10 |5 58 |+17 25 14 57 I 43 abc mm 16 «7 «|+17 25 14 59 I 42 abcd 12 |6 16 |-+17 25 rs 7 R43 abcd 13 |6 25 |-+17 20 5 8 ae ye abcd 14 |6 34 |+17 20 15 11 2196 abcd 17 17 © |-+16 55 15 10 I 30 abcd Ig |7 16 |-+-16 30 15 40 Oo 40 abed 20 |7 24 |+16 30 15 27 ot abcd 21 |7 33 |+16 30 15 36 © 50 ab d 22 |7 39 (+16 5 15 40 Oo 44 abcd 23 17 47 |+16 0 15 45 ° 40 abed 24 |7 54 |+15 40 | 1548 | © 34 | abed 25 15 23 o. 2 ab 29 15 45 a bed | Few min. only, clouds 30 15 55 abed “ “e “ «e 31 |8 4 -+-14 20 15 59 °o 39 abed Sept. 2 |8 5 +13 10 15 51 o 18 abe H 9 18 [+12 jot) 16 0 ° 37 abe 9 34 |+I1 20 1617+; O 5§+/ ab um 16 19 Oo 24 abc 12 16 25 © 20 abe 1908.] OF DANIEL’S COMET. 15 tion, and that some of the particles must move outward from the sun very much faster than others. of the same stream. This was shown in the formation of the new tail of the above-named comet on July 24. In the tail on that date the later photographs showed that the end of the new tail was increasing its distance from the head much faster than the end of the receding disconnected tail. But in this case the conditions were different; the supply of matter forming the outgoing stream had suddently been stopped and the stream itself continued to move out bodily into space until it was dissipated. The apparent velocity was then the velocity of the stream of particles. In the case of Daniel’s comet a denser mass of particles differing from the general streams that formed the tail was separated from the main body. This would naturally leave the comet slowly and continue to partake of the original motion. Still another case was that of Brook’s comet of 1889 (comet V., 1889) where the masses thrown off were so dense that they traveled with the parent comet for months as individual companions before finally disappearing.t And yet another case, that of Biela’s comet which separated into two masses that remained individually distinct for some years and then entirely disintegrated. The motion of a dense mass thrown off from a comet would not therefore be a criterion for the determination of the velocity in general of the particles of the tail of such a comet. The plate of September 8 is introduced, not from any scientific value it may have, but from an artistic standpoint and from its unique character. So far as I know this is the only comet, or star photograph, on which clouds are actually shown. The exposure was very short, for the comet was visible for only a few minutes in a break. The clouds stand out black and distinct on the dawn-lit sky. To the eye it was a beautiful and striking scene—the comet in pale but clear relief on the dawn-whitening sky, the dark clouds, through a break in which the comet shone, and the solemn stillness of the morning, made it a picture not soon to be forgotten. The photo- graph rather faithfully records the appearance of the comet and clouds and dawn-lit sky, but the reproduction cannot do justice to the *See Astronomische Nachrichten, nos. 2914, 2919, 2988 and 2908. 16 BARNARD—DANIEL’S COMET. [April 25, reality. Quite a number of stars appear upon the original which heighten the artistic effect, but they have disappeared in the repro- duction. The great delay in the appearance of this paper has been due entirely to the difficulty of getting good half-tone reproductions. (E. E. B.) NOTES ON SOME PSEUDOMORPHS, PETRIFACTIONS AND ALTERATIONS. By AUSTIN F. ROGERS, STANFORD UNIVERSITY, CAL. (Read February 4, 1910.) The writer wishes to place on record some interesting cases of pseudomorphs, petrifactions and alterations observed by him in the last few years. Some of these are recorded for the first time, some are American occurrences of minerals known abroad, - while others are good examples of commonly occurring pseudo- morphs. While many examples of such pseudomorphs and altera- tions are of mineralogical interest only, some of them have a possi- ble bearing on the origin of ores. My thanks are due to the gentlemen named in the several items who have kindly furnished me with the specimens which make this paper possible. PSEUDOMORPHS. 1. Copper after Cuprite—Calumet-Arizona Mine, Bisbee, Ari- zona. Collected by Mr. E. W. Rice. Cubes of 4 mm. diameter, modified by faces of the octahedron and dodecahedron occur in cavities of a limonite gangue. The copper consists of dense aggre- gates of small imperfect crystals with smooth cube surfaces. No cuprite was observed in the specimen. 2. Copper after Chalcanthite (?)—Carlisle, Arizona. Collected by Mr. Harry Robertson. The specimen is a coarsely fibrous seam of native copper 2 cm. wide. There are no associated minerals to give a clue as to its origin and the mode of occurrence is unknown, but as copper is practically always a secondary mineral, and as the structure is exactly similar to well-known seams of chalcanthite from Arizona, it is believed to be a pseudomorph after chalcan- thite. PROC, AMER. PHIL. SOC., XLIX. 194 B, PRINTED JUNE II, IQIo. 17 18 ROGERS—NOTES ON PSEUDOMORPHS, [February 4, Pseudomorphs of copper after cuprite from Cornwall have been described by Miers;' copper after azurite from New Mexico by Yeates ;? and copper after aragonite from Bolivia by Forbes.* 3. Chalcedony after Calcite—Guanajuato, Mexico. Obtained from the Foote Mineral Company. An excellent specimen of this pseudomorph consists of pale brown chalcedony in the form of hol- low doubly terminated scalenohedrons (2131) of calcite about 1 cm. in length. 4. Hematite after Marcasite——Lake Co., California. Collected by Mr. H. E. Kramm from the Baker mine, six miles from Lower Lake on the road to Knoxville. The specimen consists of small encrusting crystals giving a red streak. They have the same form as unaltered marcasite crystals from the same mine. 5. Limonite after Chalcopyrite—Granby, Missouri. Small tet- rahedra (2 mm.) of dark brown limonite on a specimen of dolomite, » calamine, and smithsonite have been produced by the alteration of chalcopyrite. The author found similar pseudomorphs at Galena, Kansas, but it is a rare kind of pseudomorph. 6. Limonite after Cerussite—Burke, Idaho. Collected by Mr. H. F. Humphrey at the Bunker Hill mine. At this mine cerussite is a prominent gossan mineral. Several specimens show prismatic crystal aggregates of cerussite with a coating of limonite. Other specimens show limonite of a form exactly similar to the cerussite and are undoubtedly pseudomorphs. 7. Wad after Calcite—Echo Mine near Mojave, California. Collected by Mr. H. W. Young. Cavities in a quartz matrix with the shape of calcite scalenohedrons are occupied by a soft black mineral answering the tests of wad. These are not direct substitu- tion pseudomorphs but probably represent quartz encrustation pseudomorphs after calcite in which the calcite was dissolved out and then the cavities filled with wad. 8. Calcite paramorph after Aragonite——Patterson Pass, east of Livermore, California. A travertine deposit in buff Miocene sand- stone consists of a banded, coarsely fibrous aragonite of an amber * Min, Mag., Vol. I1., p. 266, 1897. > Am, Jour. Sci., Vol. 38, p. 405, 1880. * QOuar. Jour. Geol. Soc., Vol. 17, p. 45, 1861. 1 3 i 1910. ] PETRIFACTIONS AND ALTERATIONS. 19 color, often variegated. The material has been quarried out in large blocks and on the exterior these are often altered to calcite. The aragonite is compact columnar massive, while the calcite is por- ous, though crystalline and shows the cleavage faintly. As the cal- cite retains to some extent the columnar structure of the aragonite the specimens are paramorphs. Occasional calcite crystals are found in cavities. Sicily furnishes excellent specimens of calcite paramorphs after aragonite, but this is the first example found in this country, I believe. 9. Smithsonite after Calcite—Granby, Missouri. This is one of our best known pseudomorphs. Steep rhombohedrons of the —2R form (0221) implanted on dolomite have been replaced by a spongy mass of smithsonite, but the surfaces of the crystals are smooth. 10. Smithsonite after Dolomite——Granby, Missouri. A massive cleavable dolomite specimen 2 cm. thick with warped rhombohedral crystals on one surface have been completely changed to smithsonite of a pale brown color. 11. Cerussite after Calcite—Granby, Missouri. Scalenohedral (2131) calcite crystals of 1 cm. diameter are completely changed to colorless cerussite with adamantine luster. 12. Pyromorphite after Galena——Granby, Missouri. Crystals of % cm. square cross section on chert matrix consist of a little unaltered galena in the center, then cerussite and finally a border of green earthy pyromorphite. 13. Calamine after Calcite——Granby, Missouri. Scalenohedral (2131) calcite crystals 1 cm. in diameter on chert matrix have been replaced by calamine. When broken the crystals are found to be hollow and calamine crystals project into the hollow center. 14. Muscovite after Tourmaline-—Pala, California. A speci- men 7 cm. long and 1.5 cm. in diameter represents an original tourmaline crystal, roughly trigonal in cross-section. It is now mostly white scaly muscovite in which is set a number of small black tourmaline crystals in parallel position with the large crystal. 15. Talc after Actinolite—Apperson Creek, southeast of Sunol, Alameda County, California. Gray columnar, subradiating talc is 20 ROGERS—NOTES ON PSEUDOMORPHS, [February 4, probably. pseudomorphous after actinolite as it has the exact struc- ture of the actinolite common in the schists of the Coast Ranges. The mineral has a greasy feel and is scratched by the finger nail. It is practically infusible and gives a little water in the closed tube. Cleavage flakes give a negative biaxial interference figure with a small axial angle. The axial plane is in the direction of the length of the columnar crystals. 16. Chrysocolla after Cuprite—(a) Santa Margarita Mine, - New Almaden, California (b) near Mammoth, Utah (Tintic dis- trict). At both of these localities chrysocolla is pseudomorphous after the chalcotrichite variety of cuprite, a variety that consists of crystal aggregates of elongated cubes crossing and branching at right angles. With polarized light, the chrysocolla exhibits an ag- gregate structure and the outside surface occasionally consists of concentric layers somewhat radiating. At New Almaden the cup- rite occurs in seams in serpentine but it is believed to have its origin in copper-bearing pyrite which occurs in a nearby prospect shaft. 17. Chrysocolla after Calcite—(a) Arlington, N. J. (b) Reward Gold Mine, Inyo County, California. Collected by Mr. C. E. Gilman. (a) At Arlington chalcocite and secondary copper minerals occur at the contact between diabase and triassic sandstone. The pseudo- morphs were found in cavities of the sandstone. They consist of small scalenohedrons (2137) completely replaced by chrysocolla. (b) The Inyo County specimens are large prismatic quartz crys- tals coated with a crust of chrysocolla. Some of the chrysocolla is the form of acute rhombohedrons (—2R or 022r) with rounded edges which represents, no doubt, original calcite. The chrysocolla is made up of concentric layers, the inside ones of which are deeper greenish blue than the outside. Under the microscope the fine aggregate structure is in evidence. Associated cuprite is the source of the copper. PETRIFACTIONS. 18. Sphalerite replacing coral—Galena, Kansas. A _ conical coral, probably a Zaphrentis, 2 cm. in diameter, is replaced by dark granular sphalerite. Most of the fossils from the chert of this 1910.] PETRIFACTIONS AND ALTERATIONS. 21 district are molds or cavities from which the calcareous matter has been dissolved out. The specimen described is a cast probably formed by filling of the mold and not by direct replacement of the organism. 19. Pyrite replacing Aviculopecten—Leavenworth, Kansas. Some excellent pyrite petrifactions were obtained from the Chero- kee shales on coal mine dumps at this‘locality. The pyrite is bright brassy with purplish tarnish. The fossil is Aviculopecten rectila- terarius, which, in Kansas, is limited to this horizon. 20. Limonite replacing gasteropod.—Carnegie, Corral Hollow, California. Fossils of fresh-water gasteropods (probably a new species of Melanea according to Mr. Harold Hannibal) occur in Eocene sandstone exposed along the railroad track near Carnegie, San Joaquin County, California. The sandstone is composed of quartz grains with limonite cement. The shells are completely re- placed by dense limonite .5 mm. thick. 21. Limonite replacing twigs—Bingham, Utah. In Upper Bingham Canyon along the creek bed are found specimens of a por- ous mass of soft, earthy limonite. These evidently represent former plants as hollow, flattened stems are plainly visible. 22. Malachite replacing cedar wood.—Bingham, Utah. At the locality mentioned above, malachite with structure of the cedar wood common at the same place occurs. The mineral is porous and often has a mammillary surface in free spaces. The cell structure of the wood is visible with a hand lens. Selected pieces are com- pletely soluble in hydrochloric acid showing complete replacement but in other cases there is simply a thin green coating of malachite. 23. Barite replacing Productus——Elmont, Kansas. The writer is indebted to Dr. J. W. Beede for this specimen. A specimen of the brachiopod shell, Productus punctatus, has been completely re- placed by pink barite and the surface markings characteristic of this species are preserved. A visit to the locality which is a lime- stone ledge two miles northwest of Elmont, Jackson County, Kansas, revealed a number of fossil pelecypods and gasteropods partially replaced by pink barite, but none so complete as the one described. 22 ROGERS—NOTES ON PSEUDOMORPHS, [February 4, ALTERATIONS. 24. Sulfur from Sphalerite—Galena, Kansas. Specimens of sphalerite and pyrite in chert breccia from the Templar ground, two miles southwest of Galena, Kan., show in an excellent manner the alteration of a sulfid to sulfur. The sphalerite is corroded and covered with pale yellow sulfur while the pyrite is fresh and free from sulfur. Evidently the sphalerite has furnished the sulfur. 25. Strontianite from Celestite—Five miles from Austin, Texas, on the road between Mts. Barker and Bonnell. Collected by Mr. F. L. Hess. Massive cleavable celestite of a pale blue tint is much corroded and the cavities are occupied by tufts of small acicular crystals of strontianite. The crystals are flattened, tapering, six- sided crystals, the forms being a steep rhombic bipyramid (Ahl) and a steep rhombic prism (okl). The crystals are often curved and in consequence give a wavy extinction. The elongation is parallel to the faster ray. The mineral contains some calcium in addition to strontium as the microchemical gypsum test shows. This is the best test for calcium in such a compound. 26. Barite from Witherite—Northumberland, England. Color- less tabular barite crystals (oor, rz0, 102) are found in cavities of massive gray witherite. The barite is evidently a secondary product, formed from the witherite. 27. Copiapite from Pyrite and Limonite from Copiapite—Five miles n. w. of San Jose, California. Altered pyrite crystals from chlorite-glaucophane schist boulders showed the following cross- section: The interior is hollow with small projecting bits of bright pyrite. The exterior is limonite while between these two is a soft compact yellow material which answers the blowpipe tests for copiapite. Under the microscope the copiapite is seen to consist of minute pseudo-hexagonal crystals. Here the pyrite has evidently altered to copiapite and then the latter to limonite. 28. Hornblende from Hypersthene.—Arroyo Bayo, twelve miles southwest of Livermore, California. These specimens were found in a large outcrop of norite or hypersthene gabbro. Grayish green hypersthene with faint cleavage has been altered around the borders to black hornblende with good cleavage. In fragments the hyper- 1910.] PETRIFACTIONS AND ALTERATIONS. 23 sthene has parallel extinction and characteristic pleochroism from pale reddish to greenish white while the hornblende has has an extinction angle* of about 14° and faint pleochroism from bluish green to yellowish green. The mineral occurs in large anhedra associated with light gray plagioclase. 29. Sericite from Feldspars—New York City. Specimens of orthoclase and oligoclase from the pegmatites and pegmatite lenses of the schists in the upper part of New York City are often ac- companied by secondary muscovite or sericite in the form of thin silvery scales. The scales occupy the cleavage planes but more especially planes of parting parallel to the unit prism faces (1770). *Determined on cleavage fragments. MAGIC OBSERVANCES IN THE HINDU EPIC. By E. WASHBURN HOPKINS. (Read April 21, 1910.) Various works in Hindu literature provide us with a storehouse of magical observances, from the time of Vedic Hymns onward. The Siitras of one sort or another recognize and inculcate magical arts. But in epic literature, what is formally taught elsewhere is found in active operation. There is lacking, of course, any sys- tematic treatment of these magical rites; they must be culled piece- meal from epic narration. Further, the relative importance of magical rites is lost, because to the heroes of the epic some magical observances were much more important than others. Finally, it must be said that at the time of the epic there was no sharp dis- tinction felt between the regular sacrifice and the irregular magical sacrifice. All sacrifice was to win power, often from deities opposed to the sacrificer; but they were constrained to grant his wishes by the (magical) power of the rite. The same is true of the practice of austerities and ascetic observances, which, when persisted in, made the gods uneasy, because by means of such observances the ascetic won power over the gods themselves. Hence the religious devotion of a saint appalled the gods and they tempted him in various ways to fall from his asceticism, not because they disliked him or what he did, but merely as a means of self-defence. On the other hand, magic per se was strictly divided into good and bad magic. The difference lay not in the rite itself so much as in the application of the rite. If one’s adversary was a demon, who naturally employed magic, then a good man himself might use the same means. Injurious magic was justified against an injurer. All the gods as well as the demons use such magic and men may do as the gods do, but with the same restriction, that is, that their magic be Aryan or “noble,” not for base purposes. Hence we are 24 1910.) HOPKINS—MAGIC OBSERVANCES IN HINDU EPIC. 25 told that when a king and his priest perform a magical ceremony involving murder they are sent to hell (see below). A great deal of magical lore lies in the wonder stories of the holy watering-places called Tirthas. We read that at such and such a Tirtha the footprints of the gods are still visible, that “ fishes of gold” are to be found, that animals change their shapes, etc. Primarily, the Tirthas are in the interest of the accepted religious cult and the reward offered for a journey to a Tirtha and a bath in the sacred pool is forgiveness of sins, 3.47.29, etc. But besides this the pilgrim gets “all his wishes ” or more specifically “ regains his youth,” or gets “ beauty and fortune,” as in 3.82.43f., ib. 111f.; 85.32. That diseases are cured in the Tirthas, 3.83.50f., may be due rather to a belief in medicinal waters and is not necessarily a magical trait. But it is a trifle more magical when we read that if one eats once at the Tirtha called Maninaga he will never thereafter be poisoned by snake-bites, 3.84.109f. In the same section it is said that the tracks of the magical cow Kapila “and of her calf” are preserved till now at the Tirtha named for her, ib. 88. The Tirtha is, in short, the place where marvels are to be seen, and these marvels are of more or less magical nature, like the “marvel visible even today at Pindaraka” (in Gujarat), viz., “ im- pressions having the mark of the lotus and lotuses stamped with (Siva’s) trident,” 3.82.66. Like the Tirthas, the trees and mountains show many magical touches, but these require separate treatment. Macic In SACRIFICE. It must be assumed at the outset that all the paraphernalia of the Vedic cult, with its fire sacrifice, havyam and kavyam, 7.59.16, sacrificial sessions, “‘ four-month” sacrifice, the “ five sacrifices,” 5-134.12 (cf. 19); the “six sddyaskas,’ the sarvamedha, the “seven soma-samsthas,” 12,24.7; 29.38, etc., were perfectly well known to the writers of the epic. Thus the horse-sacrifice and human sacrifice are referred to, é. g., 5.29.18, and the countless *Compare my forthcoming paper on “ Mythological Aspects of Woods. and Mountains in the Hindu Epic,” JAOS. toro. 26 HOPKINS—MAGIC OBSERVANCES IN HINDU EPIC. [April 2:, cattle sacrificed by the various kings who are extolled by the poets are the same as in earlier ages, only that the numbers (cf. e. g., the jariithyas, 3.291.70), like the gold employed, 7.61.6, etc., exceed all probability. These need not be described. Indeed the epic does not describe them. It merely mentions them, as it does the “ divine and woodland rule” of performing rajarsiyajiias, 3.240.106. Only in the case of the horse of victory and its subsequent sacrifice do we get a real picture of epic sacrifices of the old sort. It is rather the new features that are instructive, such as the actual presence, in sight of man, of the gods (at sacrifice), 7.67.19; the later insistence on make-believe sacrifices, seeds representing ani- mals, etc., as in 12.338.4 due to the doctrine of non-injury, and the sacrifices not so orthodox as those just mentioned, which smack of magic, though even the regular sacrifices are performed as mere magical rites, by which, for example, India wins the lordship of gods, 12.20.11 (cf. 5.140.14, the girls’ pots and plants in sympathetic magic). One of the most interesting of these is the human sacrifice de- scribed in 3.127.2f.; 128.5. Jantu was the only son of Somaka and his father feared that he would die and leave him childless. He therefore exhorted his domestic chaplain to devise some means by which he might secure more sons. The sinful means devised was the sacrifice of Jantu. The various wives of the king stood about the cauldron where the wretched child was being cooked and sniffed the steam and smoke. This evil sacrifice had two results. The child was reborn as the eldest of a hundred sons conceived by the wives in this process of sniffing; but on the other hand the wicked priest had to go to hell.* That a domestic priest has occult power over the king is gen- erally admitted. He is able “ to sacrifice the strength of the king” * The artificial “sacrifice” of life (5.141.20f.) in battle is taken seri- ously by the epic poets. Compare 5.58.12 (to Yama): Siva “ sacrificed himself in the sarvayajfia, and so became god of gods,” 12.2012. “In battle a warrior makes a sacrifice (as if making an oblation into fire, Autvda) of his body,” 3.300.36; so 12.24.27, etc., Sibi sacrificed himself, in a pretty tale, by cutting off his limbs to save a fugitive; but the demon Ravana cut off his own heads and offered them in fire, which pleased Brahma so that he let them grow again, 3.275.20. 1910.) HOPKINS—MAGIC OBSERVANCES IN HINDU EPIC. 27 or of the enemy, “on the sacrificial fire”’ medhagni, that is, it is a magical fire-ceremony, 5.126.2; 9.41.12. In the horse-sacrifice, the head is cut off and set on the fire-altar, 7.143.71, that the chief part of the rivals may be destroyed. Even the demons fade away when the domestic priest of the gods “ puts meat on the fire with a view to their abolition,” 9.41.30. The sacrifice of a hundred conquered and captured kings to Siva (Rudra) intended by the victor, king Jarasandha, calls forth the remark in 2.22.11 that “no one ever saw the slaughter of men”; but the entirely casual statement that “there is just as much merit in going to the holy well of Nandini as there is in sacrificing human beings,” 3.84.155, seems to show (since the speaker’s object is merely to exploit this Tirtha) that human sacri- fice was regarded as something actual, and rarely beneficial. In 10.7.56 a man “ sacrifices himself as an offering,” and being accepted by the:god comes out alive with divine power. Many of the sacrifices made by the epic heroes, however, are simple offerings of “words, water, and fruit,” 3.36.45; 41.47. Sacrifice is a means of purification: “ By various sacrifices cleansing off the sin committed let us go to heaven” (pdpam avadhiiya), 3.52.20. The usual sacrifices offered by those dwelling in the woods are isti, pitrydni, and kriyds, 3.25.3. A royal list may be illustrated by those offered by Yudhisthira, to wit, “ vdisvadeva, isti, pasubandhu, kamyandimittika, pakayajia, asvamedha, rajasiya, and gosavas,” 3.30.14f.* There is also a quasi sacrifice of feeding a white bull till it can eat no more, by making offerings to it as to Something sacred, anaduhe sadhave sddhuvahine . . . sduhityadanat (to satiety), 3.35.34. Only a king may offer a royal sacrifice, but there is another “just as good” (as efficacious) which an ambitious prince may offer. Its present interest lies in the fact that it is something quite new. “You cannot have the Rajasitya while the king lives,” says the priest to the ambitious prince, “ but there is another great sacrificial °In 7.68.10, ukthyas, afvamedha, agnistoma, atiratra, visvajit vajapeya; ib, 66.7, darsapiirnamasdu, dgrayana, caturmdasyas, etc. Compare also 7.63.1 f. which adds pundarikas, and remarks that the king gave “all the property of those not Brahmans to the Brahmanas.” 28 HOPKINS —MAGIC OBSERVANCES IN HINDU EPIC. [April 21, session equal to the Rajasitya.” Out of the gold collected as tribute is made a golden plough and with it is ploughed the earth for the altar, yajfavatasya bhiimih, and a great ceremony called Vaisnava, “very well prepared,” susamskrta, is performed, rivalling the Rajasiiya. No one except Visnu ever performed this sacrifice, and the priest says it seems to him even better than the Rajasitya: etena ne’stavan kaScid rte Visnum puratanam, rajasiiyam kratusrestham spardhaty esa mahakratuh; asmakam rocate cai ’va Sreyas ca tava, etc., 3.255.13-21. This rite closes with scattering corn and anoint- ing with sandal-paste ; but “ some said it was not equal to one six- teenth of the other” (the Rajasiiya).* SACRIFICE. “ Sacrifice arose in the eastern country,” says the epic, 5.108.5 and 9g. This is more important as showing that the eastern country (district) was no longer as of old regarded as foreign. Like other things, sacrifice is personified. The Great Father lives in the north with Sacrifice, 5.111.15. The Great Father, by the way, brings a sacrifice, as much as do the other gods, istikrtam nama (satram varsasahasrikam), 3.129.1. “A sacrifice without gifts (to the priest) is dead,” is another saying of the epic, mrto yajnas tv adaksinah, 3.313.84. Cf. 5.106.22, etc. The merit of a sacrifice pertains to the giver; but he may give that merit away to another, 5.122.13, etc. Most of the gods sacrifice as they accept sacrifice. They are “perfectors of the sacrifice,” svistakrtah, 5.42.40 (rare epithet of gods in general; usually of the Fire-god alone). The gods are established through sacrifices, and sacrifices are produced through *This is a standing expression of depreciation, as in 3.34.22; 30.23; 174-33 254.27; (above) 257.4; 4.30.14; 5.49.34; 7.36.7; 111.30 (31, na’lam Parthasya!); 7.197.17; 8.15.28. Compare 12.174.46=177.51==277.6. The fraction is scarcely used otherwise save in the late geographical section of Bhigma, where it is said that Kubera gives to man only one sixteenth of the quarter of Meru’s wealth, which (quarter) he in turn receives (from Siva), 66.23. In 10.12.17, “one hundredth part” and in 12.155.6, “one eighteenth part” are used in the same way as one sixteenth. But “one and one-half times” (better) is found in 7.72.34 and 11.20.1, 1910.1] HOPKINS—MAGIC OBSERVANCES IN HINDU EPIC. 29 the Vedas, 3.150.28. Gods who “ steal the sacrifice” are begotten by Tapas, and are fifteen in number (3 X 5), one group having Mitra-names, 3.220.10f. (Subhima, Atibhima, Bhima, Bhimabala, Abala; Sumitra, Mitravat, °jfia, °vardhana, °dharman; Surapravira, Vira, Surega, Suvarcas, Surahantar).°