Изображения страниц
PDF
EPUB

We learn that Part xi. of "Reliquiæ Aquitanica" is in the ress. This serial work, descriptive of the Caves of Perigord ind their contents, has been interrupted of late by the death of M. E. Lartet and the disturbances in France. The executors and friends of the late Henry Christy are proceeding with the work as expeditiously as possible, but do not expect to produce quite as many parts as originally contemplated.

THE School Board Chronicle tells us that an international college such as appears to have been the ideal of Mr. Stuart Mill has existed for some time in the Canton of Zurich. This is he Institution Breidenstein, in which there are at present as nany as eighty-eight pupils, representing fourteen different nations from the two hemispheres. These scholars speak nine different languages between them.

We have received the last three numbers of the Horological Fournal, and, judging from its contents, it seems well calculated o accomplish one of its chief purposes, to spread a knowledge of the scientific principles upon which the art of watch and clock making is founded. It well deserves the support of all those for whose benefit it is intended.

CONSIDERABLE changes, says the Quarterly Meteorological Journal, are in progress in the meteorological organisations of various countries. In France, M. Jules Simon has reversed the action of the Imperial Government, and placed the entire meteorological system under the Observatory of Paris. The Observatory of Montsouris, which C. Ste.-Claire Deville had established with much care, has been placed under the Observatory, and most of the meteorological work of the latter establishment has been transferred to it. The Bulletin International is now dated from Montsouris, but the series of observations at the Paris Observatory has not been suspended. M. C. Ste.-Claire Deville has been appointed Inspector-General of all the French Meteorological Stations, except those in connection with the telegraphic system. In Denmark, Captain N. Hoffmeyer has been placed at the head of the newly organised Institute. In Sweden, the intention of the Government to establish a central . Institute in Stockholm in the year 1873 is announced, and the Observatory at Upsala is to be the central station. In Berlin arrangements are reported to be in progress for the founding of a more complete meteorological organisation than that now existing, which is of old date, and is in connection with the Statistical Bureau.

Harper's Weekly announces the death, at Reading, Pennsylvania, at the age of fifty-six, of Mr. William M. Baird, a gentleman who was much interested in natural history, and especially in ornithology. Mr. Baird, while residing at Carlisle, Pennsyl vania, commenced in 1838 a collection of the birds of the county, in which he was assisted by his younger brother, Prof. S. F. Baird, of the Smithsonian Institution; and the two carried on their labours in common for many years, during which time they pablished conjointly descriptions of two new species of small fly catchers discovered by them in the vicinity of Carlisle, as also a list of the birds of Cumberland County. Having adopted the profession of the law, Mr. William Baird was obliged to give up his active labours in ornithology, and the work was continued by his brother, who, on receiving an appointment in connection with the Smithsonian Institution at Washington, carried to it the conjoint collection, which formed, in a measure, the basis of the magnificent series of North Ame rican birds in the institution, and which has served as the material for so much research on the part of naturalists in America and other countries.

ON November 26, the first Annual General Meeting of the National Union for improving the Education of Women of all classes was held at the rooms of the Society of Arts, Lord Lyttelton in the chair. The two principal resolutions were that "the

meeting, feeling the inadequacy of the supply of good schools for girls, pledges itself to promote the establishment of such schools, and also to aid all measures for extending to women the means of higher education beyond the school period of life; and that the meeting, feeling the necessity of thorough training for teachers, and of some recognised test of their efficiency, pledges itself to promote measures for the attainment of those objects." The grand principle upon which the Union is founded, is "that the human faculties and intellect have been impartially given, and belong in equal degree to both men and women.

[ocr errors]

WE notice that a new method of lighting gas has been invented by Mr. J. Billington Booth, of Preston, the working of which was shown by him the other night in that town. By this method the whole of the street lamps can be lighted simul. taneously from any distance. The apparatus constituting the invention, the Preston Chronicle tells us, looks like a moderately-sized globular inkstand of glass, surmounted by a tube of the same material, with a metallic top; by screwing off the burner it can be very easily attached to any lamp, chandelier pipe, or ordinary gas-jet. The base or globular portion is filled with a deep red-coloured liquid, so cheap that three pennyworth will serve the lamp for a year. Over the liquid and within the plate of zinc, with a piece of graphite or glass tube there is gas coal, and between these and a thin coiled platinum wire, fixed over the cup of the general vessel, into which a gas-burner is inserted, galvanic communication is obtained. Ignition is thus effected: A pipe is screwed to the top of the gaspipe; pressure on the gas in this pipe causes a simultaneous depression upon the chemical solution which occupies a lower level in two side tubes; the gas occupies the vacuum caused by the displaced liquid, and then ascends to a chamber connected with the burner, while the displaced liquid is pressed into two side-tubes effecting contact with the zinc and graphite, and generating galvanic activity. This is communicated to the platinum wire, and excites its catalytic power; the wire being then exposed to the ascending jet of gas, immediate ignition takes place.

AN invention by Mr. J. A. H. Ellis, of Boston, U. S., is describe 1 in the Industrial Monthly, by means of which, it is said, enormous amount of heat wasted in exhaust steam is profitabl utilised. The method consists in passing the exhaust steam from. an ordinary steam-engine through the tube of a boiler filled with the bisulphide of carbon (which boils at 110° Fah.), in the same way that smoke and the products of combustion are passed through a steam-boiler filled with water. The result is, according to our authority, that the bisulphide boiler will be rapidly heated up to 212° Fah., the resulting vapour being able to keep an engine going, and do a large amount of work, if the supply of exhaust steam is sufficient. By this means one large steam-engine might keep not only itself going, but supply the necessary power to a number of neighbouring small ones, the latter being thus able to dispense with fire and all attendance. The Industrial says the method is actually at work at Fitchburg, Massachussetts.

FROM the British Medical Journal we learn that at the last examination in anatomy held at the University of Berlin, two candidates alone, amongst the thirteen who presented themselves, obtained the notice "good." One of these was a Japanese medical student called Sasumi Satoo. The intellectual labour and the amount of perseverance necessary to gain this success will be appreciated when it is known that in November 1869, the time when Sasumi Satoo was sent by his father to Berlin, he did not even know the German characters. The first five months he applied himself exclusively to the study of German, and he acquired in the remaining six months the knowledge of all the subjects, including Latin, which were required for the first examination. The father of Sasumi is the principal physician to the Mikado, and enjoys in Japan great celebrity as an operator.

THE BIRTH OF CHEMISTRY

V.

The Alchemists.-Origin of Alchemy.-Hermes Trismegistus.-rently new dogmas are united with older dogmas in the closest
Greek MSS. on Alchemy.-Their probable authorship and age.
WE speak here of the alchemists almost for the first time, and

we must now turn our attention to the origin and growth of their dogmas, and to their work. We have already seen that the word xnuela is first found in the Lexicon of Suidas, and that he defines it as "the preparation of gold and silver.' He further tells us, under the same heading, that the books on the subject were sought for by Dioclesian and burnt, lest the Egyptians should become rich through their knowledge of the art, and should thus be able to resist the Romans. Now, the people who professed a knowledge of the art of making gold were called alchemists. The word alchemy, as we have previously shown, consists of a Coptic root united with an Arabic prefix, and signifies the hidden or obscure art. Alchemists were those who practised this mysterious art. We can well understand why the professors of such an art should maintain the utmost secrecy; to divulge such magic would be to make all men equally rich; hence it was necessarily a hidden art. Neither did the books on the subject avail much, for they are filled with some of the most incomprehensible nonsense that ever was written. Yet the literature of the subject is enormous. The volumes on alchemy in our large libraries are to be counted by the hundred. In 1602 Zetzner published, in Strasburg, a "Theatrum Chemicum," containing more than a hundred tracts on alchemy, selected from various notable authors. A century later Mangetus published his "Bibliotheca Chemica Curiosa," in two large folios, containing a hundred and twenty-two alchemical treatises. We have previously given the titles of a few Greek MSS. on alchemy. The list has been extended to eighty-three. Arabic and Persian MSS. on the subject are not uncommon. There are treatises in Spanish, Italian, German, Dutch, and English on alchemy, and, more numerous than all, treatises in Latin, in every large library. Let us endeavour to get from the tangled mazes of this hieroglyphical literature, some idea of alchemy, and of its influence upon chemistry.

We are, perhaps, puzzled at the outset to comprehend how any one man, much less thousands of men, could have deluded themselves with the belief in the possibility of transmuting one kind of matter into another :-crude lead, or tin, or mercury, into weighty, lustrous gold. But this was not the greatest wonder of the age. At the time when alchemy arose, and throughout the period during which it most flourished, the belief in theurgy, witchcraft, necromancy, and magic of all kinds was rife among all classes; and surely it was less wonderful to change lead or tin into gold, than to call up the spirit of one's ancestor, or to confer perpetual youth upon a nonagenarian! It is, for wonderment, as compared with the greater magic of the day, as the process for the conversion of benzine into aniline compared with spirit-rapping; or as a demonstration of specific inductive capacity compared with a manifestation of psychic force. Alchemy was considered to be perfectly rational not two centuries ago, and was among the lesser forms of magic, inasmuch as it did not require the influence of supernatural

causes.

The growth of the idea is not difficult to trace. The ancients had persistently asserted the change of one element into another. Thales, as we have seen, evolved the ten thousand forms of nature and kinds of matter, from water, Anaximenes from air, by successive transmutation. Aristotle, whose physical views were accepted without question by the alchemists, had endeavoured to show by clever argument that, if you transfer a quality of water to fire, you obtain air; while if you transfer a quality of earth to air, you get water; and so for fire and earth, and that from these elements all things proceed. This was readily accepted by Middle Age thinkers. The alchemists reasoned, plausibly enough: -if fire becomes air, air water, and water earth, why may not one kind of substance formed from these elements be changed into another kind of substance of somewhat the same nature, and certainly more similar than air and water, or water and earth? Why may not lead, compounded of these elements in certain proportions, be changed into gold, compounded of these elements in certain other proportions? There have been falser modes of reasoning than this in the history of science.

Let the ancient Greek theory of the transmutation of the elements be once literally accepted, and the alchemical belief in

transmutation follows naturally; it is a minor application of the major proposition. There is nothing to wonder at in this; the human mind seldom moves by fits and starts; an essentially new mode of thought and new form of belief is rare, and many appaSuch manner, and are in fact direct emanations from them. was the alchemical idea of transmutation. Admitting the possibility of the process, a man would naturally ask himself "What do I most desire to make? What in this world procures the greatest amount of happiness, and of power?" For what have men slaughtered each other by the thousand in open war, or singly and secretly in the dead of night? For what have kingdoms been sold, great tracts of land ceded, and people been ground into serfdom till they rose and rioted against their oppressors? For what have princes and cardinals been created, emperors and kings destroyed, and the eternal peace of troubled souls promised? In a word, for what will man dare all things, sacrifice all things; for what will he toil during a lifetime; to what will he devote all his intellectual energies? This is surely the thing for the ready acquirement of which we may devote much time and thought, and this thing is gold. This is the key to the prodigious masses of alchemical literature, and to the mysteries and anomalies connected with men who often wasted their whole lives and all they possessed in the endeavour to change baser metals into gold.

If we consult alchemical MSS., no matter the date or author, or language, we find constant mention of Hermes Trismegistus, who was indeed considered, and sometimes designated, the father of alchemy. In a treatise attributed to Albertus Magnus we are told that the tomb of Hermes was discovered by Alexander the Great, in a cave near Hebron. In this was found a slab of emerald which had been taken from the hands of the dead Hermes by Sarah, the wife of Abraham, and which had inscribed upon it in Phoenician characters the precepts of the great master concerning the art of making gold. The inscription consisted of thirteen sentences, and is to be found in numerous alchemical works. It is for the most part quite unintelligible, and in style closely resembles the great mass of Middle Age alchemical litera

ture.

The following is cited as the inscription of the "Smaragdine Table," and is to be found in very early MSS. in various lan guages:

I. I speak not fictitious things, but that which is certain and

most true,

2. What is below is like that which is above, and what is above is like that which is below, to accomplish the miracles of one thing.

3. And as all things were produced by the one word of one Being, so all things were produced from this one thing by adap

tation.

4. Its father is the sun, its mother the moon; the wind carries it in its belly, its nurse is the earth.

5. It is the father of all perfection throughout the world. 6. The power is vigorous if it be changed into earth.

7. Separate the earth from the fire, the subtle from the gross, acting prudently and with judgment.

8. Ascend with the greatest sagacity from the earth to heaven, and then again descend to the earth, and unite together the powers of things superior and things inferior. Thus you will obtain the glory of the whole world, and obscurity will fly far away from you.

9. This has more fortitude than fortitude itself; because it conquers every subtle thing and can penetrate every solid. 10. Thus was the world formed.

11. Hence proceed wonders, which are here established. 12. Therefore I am called Hermes Trismegistus, having three parts of the philosophy of the whole world.

13. That which I had to say concerning the operation of the sun is completed.

The story and the inscription, together with all books attri buted to Hermes, are no doubt the production of monks of the Middle Ages, albeit they are attributed to Hermes, who is asserted to have lived about 2000 B.C. In spite of the obvious worthlessness of the inscription of the emerald table, men have not been wanting who have laboured long and lovingly to prove its authenticity, to interpret it, and to show that it is in good sooth a marvellous revelation, full of sublime secrets of considerable import to mankind.

Hermes Trismegistus is generally asserted by the alchemists to have been a priest who lived a little after the time of Moses. According to Clemens Alexandrinus he was the author of forty

two books containing all the learning of the Egyptians; others tell us that he was the author of several thousand volumes. Plato speaks of him in the "Phædrus" as the inventor of numbers and letters. He was in fact the Egyptian god of letters, and as such of course could be described as the author of multitudinous works. He was the deified intellect, and hence has often been confounded with Thoth, "the intellect." Sir Gardner Wilkinson -speaks of Hermes as an emanation of Thoth, and as representing

the abstract quality of the understanding." The woodcut (Fig. 6) representing Hermes, is from a temple at Pselcis, which was erected by Erganum, a contemporary of Ptolemy Philadelphus. It may be well to note the extent of the symbolism associated with the sculpture; in one hand Hermes holds the Crux ansata, the symbol of life, in the other a staff, associated with which are a serpent, a scorpion, a hawk's head, and, above all, a circle surrounded by an asp, each with its special symbolical significance. On the Rosetta stone Hermes is called "the great and great," or twice great; he was called Trismegistus, or thrice great, according to the twelfth aphorism of the emerald table, because he possessed three parts of the wisdom of the

[blocks in formation]

well do.

Perhaps no author is more often quoted by the Alchemists than Hermes, the supposed father of their art. They called themselves hermetic philosophers. Alchemy is often called the Hermetic Art, or simply hermetics. To enclose a substance very securely, as by placing it in a glass tube and fusing, or sealing, the mouth of the tube, was called securing with "Hermes his seal," and the echo of the idea lives amongst us yet; for, in our most modern treatises, the expression "to seal hermetically" may be found. Petrus Hauboldus, of Copenhagen, was surely one of the most enterprising publishers of his day, for he had the temerity to publish a book entitled, Hermetis Ægyptiorum et Chemicorum Sapientia. A book square as to its dimensions, small as to its type, drier than dust as to its contents, of four hundred odd pages, of two centuries of age, writ in Latin, with a sprinkling of contracted Greek, and floridly dedicated to Jean Baptiste Col. bert. A book wherein the author endeavours to prove that alchemy was known before the flood, that Hermes Trismegistus was a real personage, the inventor of all arts, the father of alchemy, and much else besides. We may well imagine that the author of such a treatise was no ordinary man, and our conjecture proves a tolerably correct one. Olaf Borch, whose Latinised name because

the more resounding Olaus Borrichius, was apparently the great mainstay of the University of Copenhagen; at all events, he was simultaneously Professor of Philology, Poetry, Chemistry, and Botany, and we must either imagine that in 1660, professors were difficult to procure in the Kingdom of Denmark, or else that Olaus Borrichius was such an astounding genius that he could readily undertake the duties of four diverse professorships at the same time. We can scarcely imagine three greater antitheses than the philological faculty, the poetical faculty, and the chemical faculty; but here we find them united, or assumed to be united, in one man. Yet more, Borrichius was appointed Court Physician, and Assessor of the Supreme Court of Law. He was the very personification of all learning, if we may judge by the treatment he received from his countrymen. In addition to the work mentioned above, he wrote several on philology, on the quantity of syllables, on the Greek and Latin poets, on medicine, chemistry, and botany. It is strange that a man who, presumably in his capacity of judge, was in the habit of sifting evidence, and of avoiding hasty generalisation, should have endeavoured with much elaborate argument to prove that Hermes Trismegistus was a real personage; that his Smaragdine table was really found by the wife of Abraham, and that it contained matter of the highest import to mankind. We must imagine that in this matter Borrichius allowed the imaginative faculty due to his poetical temperament to exert an undue influence over his more sober judgment. He is equally at pains to assert the authenticity and antiquity of the various Greek MSS. on alchemy in the libraries of Europe. He specially mentions a MS. by Zozimus of Panapolis, on the art of making gold, in the King's Library in Paris; and Scaliger tells us that this same MS. was written in the fifth century. M. Ferdinand Hoefer is apparently penetrated by the Borrichian spirit of faith and imagination, and he unhesitatingly accepts the early date attributed to the Paris MS.

[ocr errors]

M. Hoefer traces the rise of Alchemy to the fourth century of our era; it was then known as the "sacred art" (ars sacra ; τéxvn Tepa), and one of the chief writers on the subject was the said Zozimus of Panapolis. The principal Greek MSS. attributed to Zozimus, which exist in the Bibliothèque Nationale, have the following titles :-(a) On Furnaces and Chemical Instruments; (B) On the Virtue and Composition of Waters; (7) On the Holy Water; (8) On the Sacred Art of making Gold and Silver. In the latter, Zozimus mentions that if the "soul of copper,' which remains above the water of mercury, be heated, it gives off an aëriform body (σ@μа пνeνμатíkov), and this (says M. Hoefer) was probably oxygen gas, while the soul of copper was oxide of mercury. Á second author of early Greek MSS. was Pelagius, who alludes to two writers named Zozimus-one the "Ancient," the other the "Physician." A third author, Olympiodorus, who calls the "sacred art" chemistry (xnueía), quotes Hermes, Democritus, and Anaximander as alchemists.

Democritus (not to be confounded with the Greek philosopher of that name), in his "Physics and Mystics," informs us how he invoked the shade of his master, Ostane the Mede, and how the spirit appeared and accorded him mystical communings. Synesius, the commentator of Democritus, lived, according to M. Hoefer, about fifty years after Zozimus (say 450 A.D.); but a treatise on the Philosopher's Stone is in existence which claims Synesius as its author, which mentions Geber, who lived at least 400 years later. Mary the Jewess, who is often alluded to by later alchemists, was a contemporary of Democritus, and a writer on alchemy; she also invented various chemical vessels, among others a bath, to gently transmit heat by means of hot sand or cinders, which (according to M. Hoefer) is still called after her, a Bain-Marie.

We cannot assign to the Greek MSS. in the Bibliothèque Nationale the antiquity which M. Hoefer and others so readily accept; and we must still hold to our opinion that they and all other known Greek MSS. on alchemy are the production of later centuries, and are probably the work of Greek monks. In the first place, who was Zozimus? Was it Zozimus the Anti-pope, who succeeded Innocent I., or Zozimus the Sophist of Alexandria, or Zozimus the historian? No one can tell. It cannot be pretended that any of the Paris MSS. are in the actual writing of Zozimus. One of them is entitled "Zozimus the Panapolite, on the Chemical Art, to his Sister Theosebia;" but, according to the "Biographie Universelle," it was Zozimus of Alexandria who dedicated books to his sister Theosebia, and he lived in the third century B. C., while Zozimus of Panopolis lived in the fourth century A.D. Here, then, we

have a discrepancy of 700 years, and a clear confounding of Zozimus of Alexandria with his namesake of Panapolis. Suidas attributes chemical works to the former, but we must remember that the word xnueía does not occur before the eleventh century, A.D. The director of the Bibliothèque Nationale,* in a recent letter for which we have to thank him, writes as follows:"La Bibliothèque Nationale ne renferme aucun manuscrit grec de Zosime de Panapolis qui puisse attribué a une époque antérieure au XIII. Siècle. Le plus ancien de ceux qu'elle possède ne remonte pas plus loin que cette date." Everything tends to prove that the MSS. were not only written, but composed at a period posterior to the fifth century. The fanciful titles of some of them show us that their authors adopted any name they pleased; thus we have "the Epistle of Isis, queen of Egypt, and wife of Osiris on the sacred art, addressed to her son Horus," in which we find a solemn oath dictated to Isis by the angel Amnaël, who swears by Mercury and Anubis, by Tartarus, the Furies, and Cerberus, and by the dragon Kerkouroboros. The whole thing is plainly a blending of eastern and western thought: personages of Egyptian, Greek, and Roman mythology, with angels of the Talmud, and genii of Arabic lore. We are glad to find that M. Hoefer breaks freely away from the too confident Olaus Borrichius, as to the authenticity of Hermes Trismegistus. He admits that the books which bear his name are spurious, and concludes that their author, "vivait probablement à l'époque critique du Christianisme triomphant et du paganisme à l'agonie.' But if we take this as the time of Constantine the Great, we must venture to attach a later date to these writings.

We recently had an opportunity of examining the MS. in the Bibliothèque Nationale, attributed to Zozimus and to the fifth century; a MS. which, from its frequent mention in both ancient and modern works on the history of chemistry, possesses special interest. It is entitled "Zozimus on Chemical Instruments and furnaces, and on the Holy Water” (Ζωσίμου περὶ ὀρχάνων καὶ Kaμlvæv Kal Teрl Tov telov datos), and it is a well-preserved MS. of the thirteenth century, written on vellum. The few drawings which it contains are asserted to have been taken by the author

[ocr errors][merged small][merged small]

from a temple at Memphis. The Alembic ( in the accompanying woodcut, Fig. 7) is copied from this MS., in which also the line of symbols (a) is found. These symbols occurred in almost every Greek MS. on alchemy which we examined, but we could find no clue to the curious porcupine-like animal. The symbol c is clearly of astronomical origin, and is not often met with in later works. The MSS. are for the most part devoid of figures, and not so full of symbols as later alchemical treatises.

We have endeavoured to prove (a) that no reliable date can be assigned to existing Greek MSS. on alchemy, and (8) that the accepted date is too early. Even if we could prove that a man named Zozimus, living in the fourth century, wrote treatises on alchemy, we could not use the existing MSS. for any exact purpose connected with the history of science with safety; for, since we have no such MS. earlier than the tenth or eleventh centuries, it would be quite impossible to determine whether

*This library has so often changed its name of late, that we think it necessary to mention that we mean the library in the Rue Richelieu, which is called by old writers the Bibliothèque du Roi sometimes the Bibliothèque Royale, lately the Bibliothèque Impériale, still more lately the Bibliothèque Communale, now the Bibliothèque Nationale.. Juncker in his Conspectus Chemia, in speaking of various writers on alchemy cites "Zozimus Panapolites celeberrimus et magni cognomen adeptus, cujus varia scripta exstant in Bibliotheca Regia Parisiensi."

The facts are

additions had been made during transcription. simply these :-There exist in various parts of the world Greek MSS. on alchemy, none of which are older than the tenth century. Many of these bear the names of mythical personages of Egyptian mythology, some of ancient Greek philosophers, some of people who are supposed to have lived in the fourth or fifth century, A. D. When we remember that no ancient writer makes mention of alchemy or chemistry, that the word xnuela is first used in the eleventh century, and when we further bear in mind the condition of the intellectual world in the fourth and fifth centuries, we think we may well admit that further evidence is necessary before we can assert that alchemy arose in the fourth century. Indeed we are of opinion that, in spite of all that has been written on the subject, there is no good evidence to prove that alchemy and chemistry did not originate in Arabia not long prior to the eighth century, A.D. G. F. RODWELL

ON THE ECLIPSE EXPEDITION, 1871*

II.

MUST now state very briefly some of the results of our work; and first, the certain results.

We were able to make out the structure of the corona. We know all about the corona so far as the structure of its lower brighter strata, that portion, viz., which I referred to in my lecture last year as being visible both before and after totality, is concerned. You may define it as consisting of cool prominences; that is to say, if you examine a prominence any day without waiting for an eclipse, and then go to an eclipse and examine the lower portion of the corona, you will find the same phenomena, minus the brightness. You find the delicate thread-like filaments which you are now all so familiar with in prominencesfilaments which were first thrown on a screen in this theatre; the cloudy light masses, the mottling, the nebulous structure, are all absolutely produced in the corona, as far as I could see it with a telescope with an aperture of 6 inches; and I may add that the portion some five minutes round the sun reminded me forcibly in parts of the nebula of Orion, and of that surrounding Argus, as depicted by Sir John Herschel in his Cape observations.

We have shown that the idea that we did not get hydrogen above 10 seconds above the sun is erroneous; for we obtained evidence that hydrogen exists to a height of 8 or 10 minutes at least above the sun; and I need not tell you the extreme im portance of this determination. One of the proofs we have of that lies in this diagram, showing the observations made by Prof Respighi, armed with an instrument the principle of which I hope you are now familiar with.

Just after the sun disappeared Prof. Respighi employed this prism to determine the materials of which the prominences which were then being eclipsed were composed; and he got the promi nences shaped out in red, yellow, in blue, and in violet light; background of impure spectrum filling the field, and then as the moon swept over the prominences these images become invisible; he saw the impure spectrum and the yellow and violet rings gradually die out, and then three bright and broad rings painted in red, green, and blue, gradually form in the field of view of his instrument; and as long as the more brilliant prominences were invisible on both sides of the sun he saw these magnificent rings, which threw him in a state of ecstacy. And well they might.

These rings were formed by C and F, which shows us that hydrogen extends at least 7 minutes high, for had we not been dealing with hydrogen we should have got a yellow ring as well, because the substance which underlies the hydrogen is more brilliant than the hydrogen itself, and in addition to the red ring and the blue ring, which indicate the spectrum of hydrogen, he saw a bright green ring, much more brilliant than the others, built up by the unknown substance which gives us the Kirchhoff line, 1474

Now at the time that Prof. Respighi was observing these beautiful rings by means of a single prism and a telescope of some four inches aperture, some 300 miles away from him-be was at Poodocottah and I was at Bekul-I had arranged the train of prisms which you see here so that the light of the sun should enter the first prism, and after leaving the last one should

* A Lecture delivered at the Royal Institution of Great Britain, Monday, March 22, 1872, by J. Norman Lockyer, F.R.S. (concluded from p. 58)

enter my eye. And what I saw is shown, side by side with Respighi's observations, in this diagram, in which I have separated the rings somewhat, so that there should be less confusion that in the actual observation. Here is Prof. Respighi's irst observation. He gets indications of C, D, F, and the hydrogen line near G. He was observing the very lowest, rightest region of all, and therefore 1474 was obliterated by the brightness of the continuous spectrum; but as the eclipse went on D3 was entirely obliterated, and afterwards he got C and F building up rings together with 1474, which was not represented n the lower regions of the prominence-not because it was not here, but because, as I have already insisted, of the extreme orilliancy of the background. Now my observation was made ntermediately as it were between the two observations of Prof. Respighi's. Let me show the observations together. F G Prominences at beginning of eclipse.

Respighi C D3

Lockyer

[ocr errors]

...

C 1474 F G Corona at 80 seconds from

commencement.

Respighi C 1474 F Corona at mid eclipse. Note that I had no object-glass to collect light, but that I had more prisms to disperse it; so that with me the rings were not so high as those observed by Respighi, because I had not so much light to work with: but such as they were I saw them better because the continuous spectrum was more dispersed, and because, with my dispersion, the rings-the images of the corona -therefore did not so much overlap. Hence doubtless Respighi missed the violet ring which I saw, so faint, however, that both that and 1474 were almost invisible, while C shot out with marvellous brilliancy, and D was absent.

These observations thus tend to show, therefore, that instead of the element-the line of which corresponds with 1474-existing alone just above the prominences, the hydrogen accompanies it to what may be termed a great height above the more intensely heated lower levels of the chromosphere, including the prominences in which the lower vapours are thrown a greater height. With a spectroscope of small dispersion attached to the largest mirror of smallest focus which I could obtain in England, the gaseous nature of the spectrum, as indicated by its structure, that is, bands of light and darker intervals as distinguished from a continuous spectrum properly so called, was also rendered evident.

While both in the prism and the 6 inch equatorial the corona seemed to form pretty regular rings round the dark moon, of different heights, according to the amount of light utilised by the instrument, on the photographic plates, the corona, which, as I have before stated, exceeds the limits actually seen in the instrument I have named, has a very irregular, somewhat stellate outline, most marked breaks or rifts (ignored by the spectroscope), occurring near the sun's poles, a fact perhaps connected with the other fact that the most active and most brilliant prominences rarely occur there.

From the photographs in which the corona is depicted actinically we pass to the drawings in which it is depicted visually. I would first call attention to two drawings made by Mr. Holiday, who formed part of the expedition, and in whose eye every one who knows him will have every confidence. totality, and then a drawing made at the end. There is a wonFirst there is a drawing made at the commencement of the derful difference between the drawings; the corona is in them very much more extensive than is represented actinically on our plates.

Here is another drawing, made by Capt. Tupman, in which again we have something absolutely different from the photographs and from Mr. Holiday's sketches, inasmuch as we get an infinite number of dark lines extending down to the moon, and a greater extension than in the photographs, though in radial places the shape of the actinic corona and some of its details are shown.

Now the corona, as it appeared to me with the naked eye, was nothing but an assemblage of bright and dark lines, it lacked all the structure of the photographs, and apppeared larger; and I have asked myself whether these lines do not in some way depend on the size of the telescope, or the absence of a telescope. It seems as if observations of the corona with the naked eye, or with a telescope of small power, may give us such lines; but that when we use a telescope of large power, it will give, close to the moon, the structure to which I have referred, and abolish the exterior structure altogether, leaving a ring round the dark body of the moon such as Prof. Respighi and myself saw in our prisms, and in the 6-inch telescope, in which the light was reduced by high magnification so as to bring the corona to a definite ring some five minutes high, while Prof. Respighi, using a 4-inch telescope and less magnifying power, brought the corona down to a ring something like 7 minutes high.

And here we have an important connection between spectro

These are results of the highest importance, which alone are worth all the anxiety and labour connected with the expedi-scopic and telescopic work. If we employ a telescope in which tion.

But there is more behind.

The photographic operations (part of the expense of which was borne by Lord Lindsay) were most satisfactory, and the solar corona was photographed to a greater height than it was observed by the spectroscope, and with details which were not observed in the spectroscope.

Mr. Davis was fortunate enough to take an admirable series of five photographs at Bekul, and Captain Hogg also obtained some at Jaffna; but I am sorry to say the latter lack somewhat in detail.

I have prepared two lamps, because I am anxious to exhibit the photographs two at a time, that you may compare one with the other. [This was done.] You see that so far as the camera goes-and mark this well-the corona was almost changeless during the whole period of totality; this is true, not only for one place, but for all the places at which it was photographed.

I now exhibit two other photographs-one taken at Jaffna and the other at Ootacamund. Actinically the corona was the same and practically changeless at all the stations. You see that, though not so obvious as in the other case, there is the same similarity.

Before I leave the actinic corona, I am anxious to show you an image of it, taken during the American eclipse of 1869 in a camera exposed to the sun during the whole of the totality; to a certain extent in our recent photographs we have reproduced what was photographed in 1869.

The solar nature of most, if not all, of the corona recorded on the plates is established by the fact that the plates, taken in different places, and both at the beginning and end of totality, closely resemble each other, and much of the exterior detailed structure is a continuation of that observed in the inner portion independently determined by the spectroscope to belong to the

[ocr errors]

the light is small or is reduced by high magnification, we bring the corona to a definite ring, and perhaps here we have the origin of the "ring-formed" coronas.

Many instances of changing rays, like those seen by Plantamour in 1860, were recorded by observers in whom I have every confidence. One observer noted that the rays revolved and dis appeared over the rifts.

We have next to deal with the polariscopic observations.

Mr. Lewis, in sweeping round the corona at a distance of 6' or 7 from the sun's limb, using a pair of compensating quartz wedges as an analyser, which remained parallel to itself while the telescope swept round, observed the bands gradually change in intensity, then disappear, bands of a complementary character afterwards appearing, thereby indicating radial polarisation.

Dr. Thomson at Bekul saw strong traces of atmospheric, but none of radial polarisation, with a Savart. With the same class of instrument the result obtained by myself was precisely similar; while on turning in the Biquartz, at the top and bottom of the image of the corona, i.e., near the sun's equator, faint traces of radial polarisation were perceptible for a short distance from the moon's limb. Captain Tupman, who observed with the polariscope after totality, announces strong radial polarisation extending to a very considerable distance from the dark moon.

Leaving the extreme outside of the corona as a question to be determined at some future time-and it can well wait-let us come to the base of the corona, and deal with the region to which I have already referred, close to the sun.

What was the general conclusion at which we arrived on this important point? Before I state it, let me tell you the instrumental conditions of the inquiry. We can use such a spectroscope as the one with which you are all familiar, and so arrange matters that the slit shall be carried by a clock, so that it may follow accurately the edge of the moon; but if the least variation in the rate of motion takes place, the observation is rendered almost valueless. But if we employ a spectroscope, in

« ПредыдущаяПродолжить »