204

isolated, band of light across the zenith, but as soon as it was dark that evening, the zodiacal light was distinctly seen to stretch across the whole sky, forming that faint band of light previously observed; I then began to note its position, but the best observations were made on the night of the 27th, when it was most distinct.

On that night it passed centrally over the planet Venus, and then over the stars 8 Capricorni, y Aquarii, o Piscium, and reached a point between the Pleiades and the Hyades, so that the central portion of the light traced out the course of the Ecliptic with wonderful precision; it was brightest in the central part of the band, and gradually faded off towards the edges; its illumination about Venus was somewhat greater than that of the Milky Way, but became fainter and fainter as the light proceeded along the Ecliptic; it was impossible to trace it beyond the Hyades, where it seemed absolutely to terminate; at midnight, however, a feeble glow could be seen above the eastern horizon in Leo and Cancer, but nothing was certain about this branch.

Returning to the western and brighter branch, at Venus its breadth was about 40°, and as the longitude of the planet was 280° while that of the sun was 246°, its breadth was 40° at a distance of 34° from the sun; at 8 Capricorni its breadth was 20°, at y Aquarii 16°, and at o Piscium 10°, so that we get the following results :

Breadth 40°

20

16

ΙΟ

and its extreme distance from the sun was about 177°, where it was too faint to note anything but its existence. The light seemed perfectly fixed in the heavens, and there was no sign of any displacement such as might be caused by parallax combined with the earth's rotation; and when the brighter part had set and was far below the horizon, the band across the zenith was quite as distinct

as before.

Now these few facts go a long way towards explaining the nature of the zodiacal light, and a few more observations at different times of the year may be all that are necessary to do so satisfactorily; but as the light was so vivid here, it must have been seen in other parts of the world, and a comparison of the different accounts may bring about the desired result; hence these notes, and the following rough explanation.

The zodiacal light has generally been supposed to be a luminous ring, surrounding the Sun, and situated between the orbits of Venus and Mars; the fact that the light has often been seen in both the east and west at the same place and time does not affect the probability of this explanation, as we have only to suppose the earth to be just within the ring; but there are many difficulties to encounter, and the explanation never seemed satisfactory. The instant, however, that I saw the prolonged ray, I felt sure that the zodiacal light was similar in its nature to the rays issued from a comet towards the sun, which, drifting over the nucleus, are then forced backwards and form the tail; and that in the case of the earth, the light is generated in those regions to which the sun is vertical, and passing round the earth, the light is swept back in a direct line from the sun, thus forming a train which always tends towards a point in the heavens 180° from the sun, and which is therefore stationary with regard to the earth's axial rotation.

It is not easy, however, to test the truth of these ideas by means of the notes above, but the following attempt may not prove uninteresting.

If the zodiacal light were a ring, and the earth within it, we could compare the distances of the different parts of the ring by means of their apparent angular breadths, supposing the actual breadth of the ring to be uniform; in order to see whether that prolonged ray was part of a

curve drawn through these points is by no means an arc of a circle, and very fairly represents what we have expressed in words above, so that the rays issuing from E towards S are swept to the right hand and to the left, and passing by the earth they form a train of light stretching out into space.

But to what an astonishing distance must this train proceed, in order to acquire an angular distance of 177° from the sun! It is, however, quite possible that the two branches close together near the point F, following the branches of the spiral of Archimedes, and fairly repredotted curves; these curves are the positive and negative sent our curves for an angular distance of 90° from the MAXWELL HALL

sun.

Jamaica

THE LATE PROFESSOR W. J. MACQUORN RANKINE

THE

He

HE death of Prof. Macquorn Rankine, which we announced a fortnight ago, will excite a pang in the hearts of many persons who had enjoyed actual intercourse with the genial spirit whose early loss we now mourn, and of a still greater number who were only acquainted with him through his published works. died at his residence in Glasgow, on Christmas Eve, in his fifty-third year, the date of his birth being July 5, 1820. For several months he had been labouring under a serious derangement of his eyesight, coupled with heart disease; but it was confidently hoped for a time that his valuable life might be preserved for the benefit of science, pro. vided that he rested himself from all his ordinary labours, Latterly he did take that rest which seemed to be so imperatively demanded by his physical nature, the chief portion of his ordinary work, namely, that of conducting his class in the University of Glasgow, being handed over to Mr. Bamber, C.E., who formerly distinguished himself as a student under the deceased professor; but the bodily system had evidently little power of resisting the ravages of the insidious disease under which it laboured; paralysis set in on Sunday, the 22nd ult., and in forty-eight hours Macquorn Rankine was dead.

The amount of space at our disposal is quite insufficient for the simple mention of the many important facts that

are intimately bound up with the professional and scientific career of Professor Rankine, and therefore our sketch, at the best, can only be of the most cursory sort. In due time, doubtless, a suitable tribute will be paid to his memory and his scientific genius by the hand of one of his literary executors.

Professor Rankine was born in Edinburgh, and received most of his ordinary school education in the Burgh Academy of the town of Ayr, and in the High School of Glasgow ; but he received the most valuable part of his education, doubtless, from his father, who was a retired lieutenant of the Rifle Brigade, during the residence of the family at Edinburgh. At a very early age young Rankine entered himself as a student in the University of Edinburgh, where he enjoyed the invaluable benefit of instruction in chemistry from Dr. D. B. Reid; in natural history (including zoology, geology, and mineralogy) from Prof. Jameson, a man of European reputation as a naturalist; in botany from Prof. Graham; and in natural philosophy from Prof. James D. Forbes. The extraordinary genius which he displayed in after life in pure and applied mathematics seems to have owed little or nothing to any external or adventitious aid in the shape of professional instruction: he was a born mathematician.

The bent of his mind began very early to show itself, for before he was out of his "teens" he had written two essays on purely physical subjects-"The Undulatory Theory of Light," and "Methods of Physical Investigation." When he was about eighteen years of age he betook himself to the profession of civil engineering, and served as a pupil under an eminent master, Sir John Macneil, for three or four years, a large portion of which was spent on engineering works in Ireland. He was afterwards employed for several years on railway and other engineering works in Scotland, and in 1850 or 1851 he settled down in Glasgow to pursue his profession in partnership with Mr. John Thomson, C.E.

Meanwhile, Mr. Rankine had been prosecuting inquiry in reference to several purely scientific subjects, as well as those that more immediately pertained to his profession as a civil engineer; and he did not fail to put on record the results of his investigations, almost all of which he gave to the world through the medium of one of the learned societies. He was elected a Fellow of the Royal Scottish Society of Arts in 1842, an Associate of the Institution of Civil Engineers in 1843, a Fellow of the Royal Society of Edinburgh in 1849, a Member of the Philosophical Society of Glasgow in 1853, and a Fellow of the Royal Society of London in the same year. In the year 1850 he first cast in his lot with the British Association, and at the meeting held in Edinburgh that year he was the Secretary of the Physical and Mathematical Section. He afterwards occupied still more prominent positions both in Section A and Section G, and many of his admirers looked forward with pleasure to an early meeting of the Association being held in Glasgow, when they hoped to see him filling the presidential chair.

In the year 1855 he was appointed by the Crown to the Regius Professorship of Civil Engineering and Mechanics in the University of Glasgow, in succession to Prof. Lewis Gordon, and in that highly honourable position he laboured with unexampled distinction for seventeen years. The spirit in which he conducted his class may be judged of by the following extract from the introductory lecture which he delivered on the occasion of taking possession of his chair; the subject of the lecture was, "The Harmony of Theory and Practice in Mechanics," in the course of which he said: "The objects of instruction in purely scientific mechanics and physics are, first, to produce in the student that improvement of the understanding which results from the cultivation of natural knowledge, and that elevation of mind which flows from the contemplation of the order of the universe;

and, secondly, if possible, to qualify him to become a scientific discoverer. In this branch of study exactness is an essential feature, and mathematical difficulties must not be shrunk from when the nature of the subject leads to them. The ascertainment and illustration of truth are the objects; and structures and machines are looked upon merely as natural bodies are, namely, as furnishing experimental data for the ascertaining of principles and examples for their illustration."

When the British Association meeting was held in Dublin in 1857 Prof. Rankine had the honorary degree of LL.D. conferred upon him as a mark of the eminence which he had then attained as a physical investigator, although only thirty-seven years of age; and in the same year he was chosen as the first president of the Institution of Engineers in Scotland, an organisation which he materially helped to bring into existence. In November 1861 he also became President of the Philosophical Society of Glasgow, and during his term of office he conducted the business of the society with great tact and superlative ability; he delivered two addresses from the presidential chair and contributed several other papers, all of which were valuable contributions to science. We would only mention his first presidential address, the subject of which was "On the Use of Mechanical Hypotheses in Science, especially in the Theory of Heat." In it he gave a short account of the results which had been derived from that hypothesis which ascribes the mechanical action of heat to the centrifugal force of certain supposed molecular motions, a hypothesis which, like the wave theory of light, the hypothesis of atoms in chemistry, and all other physical hypotheses whatsoever, substitutes a supposed for a real phenomenon, namely, invisible motion for tangible heat; the object being to deduce the laws of the real phenomenon from those of the supposed one. Another of the most remarkable of his Philosophical Society papers was one which he read in January 1867, the subject_being "On the Phrase Potential Energy,' and on the Definitions of Physical Quantities." This was suggested by a paper, entitled "On the Origin of Force," which Sir John Herschel contributed to the Fortnightly Review, and in which he expressed the opinion that the phrase in question was unfortunate, inasmuch as it went to substitute a truism for the announcement of a great dynamical fact.

Prof. Rankine did not content himself with being a "star of the first magnitude" in respect of the science of thermodynamics; he also plunged into, and won distinction in, the science of naval architecture, being impelled in that direction, doubtless, through the intimate friendly intercourse which he had with Mr. James R. Napier, F.R.S., one of the most original-minded naval architects and marine engineers that the Clyde has yet produced.

The deceased professor's writings are exceedingly numerous. He wrote and published, up to and including the year 1863, no fewer than eighty papers which were found to be worthy of mention in the Royal Society's catalogue ; and between that and his death he had probably written as many more, in addition to the various treatises which he wrote upon "Civil Engineering," Civil Engineering," "Applied Mechanics," &c., all of which are of the very highest scientific and practical value. Whatever he wrote he executed with almost matchless perfection, whether we regard the elegance of his diction, the scientific order of his exposition, or the lucid methods of illustration which he adopted. His mind was of the very first order, and his death creates such a profound void in pure physics and scientific engineering that we could easily have afforded to give half-a-dozen of our most eminent practical engineers, civil or mechanical, that he might have been retained among us to pursue his original investigations and mould the minds of the engineers of the future.

JOHN MAYER

IN the last article we discussed the Greek MSS. on Alchemy, and endeavoured to show that, owing to the uncertainty of their age and the obscurity of their authorship, they are less important components of the early history of chemistry than some writers have laboured to prove them.

There exist also many MSS. in Arabic and Persian on alchemy, but in all probability few of them are earlier than the 8th century. The Library of El Escorial is undoubtedly more rich in such MSS. than any existing library; but from the imperfect manner in which its treasures are catalogued, we are unable even to give a list of the more important of these treatises. The British Museum

contains several Arabic MSS. on alchemy, written about the 12th century. Such of these as we have seen are devoid of drawings, and apparently also of symbols.

Early MSS. on alchemy in Latin exist in all large libraries. They contain various recipes for making the philosophers' stone, secrets of art," copies of the inscription of the Smaragdine table, with the interpretation thereof, and an infinite amount of unintelligible nonsense. They differ in no respect from the later printed treatises on alchemy, which we shall presently discuss in detail. The matter of most of the MSS. is to be found in printed works compiled by alchemists of the 15th and 16th centuries.

One of the oldest alchemical MSS. in the British Museum is a transcript of the Speculum Secretorum of Roger Bacon, who died in 1284. It is in the Sloane Collection, and was written towards the end of the 13th century, say between 1290 and 1300. There is no autograph MS. of Roger Bacon either in the British Museum or in the Record Office; the MS. in question was copied by an unknown man. The following woodcut represents a few lines of the commencement of the MS.

The above reads as follows:-"Incipit speculum secretorum alkimiæ. In nomine Domini Nostri Jesu Christi ad instructionem multorum circa hanc artem studere volentium, quibus deficit copia librorum, hic libellus edatur, speculumque secretorum indicatur, idcirco quia in illo, quasi in speculo, totum secretum philosopho rum et operatio eorum in hac arte, nec non et ordo operis, sensibiliter inspiciatur. Et habeant amici nostri posteri ex ejus inspectu sine tedio delectationem, sine obscuritate viam hoc opus aggrediendi, sine difficultate artem operandi." The translation is as follows:-"In the name of our Lord Jesus Christ, for the information of the many who wish to devote themselves to the study of this art, and who lack a supply of books, this small manual is published, and is entitled the ' Mirror of Secrets,' seeing that in it, as in a mirror, the whole secret of philosophers and their working in this art-nay more, the process of their work-may be visibly discerned. And may our friendly descendants obtain from the perusal of it unwearied delight, a clear path for taking this work in hand, and a mode of operation unnampered by obstacles.

Among the earlier English MSS. on Alchemy in the British Museum is one which, the Preface informs us, was done "at the instance and prayer of a poure creature, and to the helping of man, I, Malmedis, being at greete uneased in prisone, have thees forseide bokes hidre to itake a hand, and so I shal fynnysshe hit, to God be the laude and preisyng.'

The following woodcut (Fig. 9) represents a portion of this MS. relating to mercury* :

It will be noted that mercury, together with sulphur, and the "rede stoone," is designated the producer of all metals; we also observe an allusion to the Aristotelian theory of the elements (of which an account has been given in the second of these articles) in the assertion that mercury is "hotte and moyste." This MS. is in the Sloane collection, and is well preserved, and written on vellum.

Let us now turn our attention to the dogmas of the alchemists and early chemists, as set forth in the numberless printed books on the subject.

We must bear in mind at the outset that chemistry and alchemy--understanding by the former legitimate inquiry into the nature of different kinds of matter, and by the latter the *We must express our great indebtedness to Mr. Maunde Thompson, of he British Museum, for allowing us ready access to the MSS. department.

futile attempts to make gold-existed side by side in the same age, often in the same person. We cannot agree with M. Hoefer when he says, "La chimie du moyen âge, c'est l'alchimie," because some of the early chemists were not alchemists, and the crude processes of the one often led to the exact processes of the other. Lord Bacon in the "De Augmentis Scientiarum," has some very pertinent remarks regarding alchemy :-" Credulity in arts and opinions," he remarks, "is likewise of two kinds, viz., when men give too much belief to arts themselves, or to certain authors in any art. The sciences that sway the imagination more than the reason are principally three, viz., Astrology, Natural magic, and Alchemy. Alchemy may be com

pared to the man who told his sons that he had left them gold, buried somewhere in his vineyard; where they by digging found no gold, but by turning up the mould about the roots of the vines, procured a plentiful vintage. So the search and endeavours to make gold have brought many useful inventions and instructive experiments to light."

The heritage which the alchemists and early chemists received from the ancients was by no means insignificant; for they possessed all the experience accumulated by the ancients in the various arts and processes which we have before described; and of theoretical matter they possessed, adopted, and prized, the theory of the transmutation of the elements proposed by Aristotle. Of works bearing upon the history of matter they had the writings of Aristotle, Dioscorides, Lucretius, Archimedes, Hero, Vitruvius, and Pliny. Few books are quoted more often in alchemic treatises than the "Natural History" of Pliny; and we sometimes find an almost verbatim transcript of certain portions of this work. The alchemists can therefore scarcely be said to have created a science, for the science of their day is linked with that of the ancients.

When ancient learning had almost died out, and Europe was, intellectually, in a state of complete darkness, the Arabians were the most cultivated people in the world. It is to Arabia that we must look for the origin of several sciences which we are wont to attribute to other nations. The Arabians instituted universities, observatories, public libraries, and museums; they collected together all the remains of ancient learning, and through their medium the greater number of Greek and Latin authors which were read during the Middle Ages were known to Europe. In the eighth century the Arabs had full possession of Spain,

that Geber acquired some of his notions of chemistry from Egypt. Several MSS., purporting to contain the writings of Geber, exist in various libraries in Europe; these were translated into Latin as early as the year 1529, and into English in 1678. We have reason to believe that the Latin translation was faithfully done, if the Arabic text be not corrupt. The work consists of four treatises (a) Of the search for Perfection, (8) Of the Sum of Perfection, (7) Of the Invention of Verity, and (8) Of Furnaces. Geber was acquainted with the seven metals known to the ancients, and he regarded gold, silver, copper, iron, tin, and lead, as compounds of mercury with sulphur in different proportions. Gold and silver are the most perfect metals, and are composed of the purest mercury and sulphur; the other metals consist of less pure mercury and sulphur, but may be converted into gold and silver by purifying their constituents, and uniting them in different proportions. He also describes various chemical substances, among others the following. The carbonates of potash and soda were known to Geber, and were procured from the ashes of plants. Caustic soda was procured from the car. bonate by heating its solution with quicklime, as in the present day. Common salt was purified by ignition, solution, and filtration, and the solution was afterwards evaporated, and the salt crystallised out. Nitrate of potash, or saltpetre, and chloride of ammonium, or sal ammoniac, were apparently common in Geber's time; as also were alum, borax, and green copperas, or protosulphate of iron. Geber procured nitric acid by distilling copperas, saltpetre, and alum, and he used the acid for dissolving silver, and when mixed with sal ammoniac for dissolving gold. He obtained nitrate of silver in the form of crystals, and noticed their fusibility. Various compounds of mercury are described, among others corrosive sublimate or chloride of mercury, cinnabar or sulphide of mercury, and the red oxide of mercury, in which, nearly ten centuries later, oxygen gas was discovered by Dr. Priestley. Geber also obtained sulphuric acid by distilling alum. He appears to have been acquainted with the various processes of distillation, sublimation, calcination, filtration, and many others; indeed, with almost all the processes practised by his successors during the succeeding eight or nine centuries.

It is probable that some of the processes described by Geber were worked out in the medical schools of Arabia, and were known shortly before his time; yet he was himself a patient worker, and often intersperses his descriptions of substances and processes with remarks on the method of experimenting, and the mode of thought most suitable for the studies which he describes. He has often been called the "Founder of Chemistry;" at least his works are the earliest with which we are acquainted, and he was venerated as Master alike by the alchemists and chemists of the Middle Ages.

Geber appears to have been acquainted with many chemical appliances. In the earliest translations of his works we find figures of various furnaces and forms of distillatory apparatus; one of them, not unlike a still now in use, is represented above. The greater number of vessels described and figured by Baptiste Porta in his treatise De Distillationibus, published in 1609, are to be found in the first Latin translations of the works of Geber. G. F. RODWELL

THE ARCTIC EXPEDITION THE `HE following is the text of the reply of the Government to the deputation which recently had an interview with Mr. Lowe and Mr. Goschen :

"11, Downing Street. "Dear Sir Henry Rawlinson,-Mr. Goschen and I have carefully considered the documents which you have laid before us with regard to the proposed Arctic Expedition. "We do not find in them anything which shows that there is any pressing reason why the expedition should be sent this year.

"We give no opinion as to the expediency of such an expedition at a future time, but we are clearly of opinion that it would not be right to send out a second scientific expedition precisely at the moment when the public revenue has to bear the main burden of the expenses of the operations intrusted to the Challenger.

"I believe it has been erroneously stated that the

It is clear, we take it from this, that it only remains for the men of science to make out their case, and we believe that the Arctic Committee are fully alive to this. The Daily News in a leader has indicated what we had already ventured to suggest as the weak point of the appeal, namely that it was incomplete, and that many men of science knew nothing of the proposed expedition. But in doing this we had no intention to cast a slur upon the Geographical Society; on the contrary we think that that Society's action in this matter is one which the Royal Society could now follow with the greatest advantage to science, and which we hope it will follow,

In 1865 the Geographical Society begged the Royal Society to take the lead in this matter, but the Royal Society Council declined. In 1872 the Geographical Society again entreated the Royal Society to take the matter up, but again received a chilling reply to the effect that the Royal Society Council would be prepared to give advice when applied to by the Government.

The Geographical Society then did the next best thing. It applied to other leading scientific societies, and to some few scientific men for statements of results to be

derived from Arctic exploration. These it received and laid before Government, without giving any undue prominence to purely geographical results.

It is clear, therefore, that it is now the duty of the Royal Society and the other societies at once to add their influence to the movement; let a joint committee be formed to report, if need be, to the various councils. In this way the knowledge posessed by all specialists ought to be made available for the common good, so that a complete statement may be forwarded to

the Government in the summer to enable the officers of the expedition to be appointed in time to avail themselves of special training.

NOTES

THE recent fusion of the Ethnological and Anthropological Societies under the designation of "the Anthropological Institute of Great Britain and Ireland," not only did good service to science but has financially proved thus far so successful that the Report of the Council for 1872, to be presented to the members next Tuesday evening at the annual meeting, announces a handsome surplus income applicable to the reduction of liabilities incurred in former years. In this promising condition of financial prosperity it is all the more to be deplored that a serious dissension has arisen in the Council in reference to the nomination of a successor to Sir John Lubbock, who, to the universal regret of the members, vacates the presidential chair, under the pressure of parliamentary and other engagements. Touching this matter we have received a copy of a printed statement signed by Mr. Harris and seven other members of Council, which alleges that at a Council Meeting, held on the 17th of last month, Dr. Charnock was placed on the House List for 1873, but that at a succeeding Council Meeting of January 7,

this nomination was rescinded and the House List recast with the substitution of Professor Busk as President in the place of Dr. Charnock. This recasting of the List is made a matter of protest, and the members of the Institute, with whom the final decision rests, are appealed to. We need hardly remark that