clinging to the cable, sometimes in thick groves of red and yellow algæ, slender, transparent, feathery grasses, red, slimy fucoids, and tufts of amethyst moss. We found branching coral plants, upwards of a foot in height, growing on to the cable, the soft skeleton being covered with a fleshy skin, generally of a deep orange colour. Sometimes a sponge was found attached to the roots of these corals, and delicate calcareous structures of varied tints encrusted the stems of all these plants, and served to ornament as well as strengthen them. Parasitic life seems to be as rife under these waters as it is on these shores. Many star-fishes, zoophytes, and curious crabs were likewise pulled in, clinging to the cable. The latter were frequently completely overgrown with the indigenous vegetation of the bottom, or of the colour of the sand there, and so were scarcely distinguishable from it. Others, although not so covered, were found to have the same tints as the vegetation they inhabited, and even in structure resembled the latter somewhat. Others, again, were perfectly or partially transparent; and one most beautiful creature, perhaps new to science, united singularly enough in its person several prevailing colours of the bottom. Its slender limbs (Fig. 1), like jointed filaments of glass, were stained here and there of a deep topaz brown (a). Its pointed snout (6) was of a deep scarlet; its triangular body (c) of a light yellow; its eyes were green, and its tiny hands (d) an amethyst blue.

Another very active crab or water-beetle was also picked up. It was quite transparent, and had bright green highly convex eyes (Fig. 2).

Another creature (Fig. 3) of quite a different description was also picked up. It was more like a water-spider than anything else. Its transparent hair-like limbs were dappled with dull green, and it seemed a mere skeleton

fig. 4

framework made to carry a small white sac containing entrails, which was slung underneath. These three distinguished specimens were entirely free from parasitic weeds, and were the only ones of their kind observed. Many crabs (Fig. 4), generally resembling Fig. I in shape, but altogether ruder in form, were found in plenty, all bearded with moss in the manner shown. While looking at these frail organisms, one was forced to conclude that there must surely be little disturbance in their habitats.

The temperature varied from 79° F. in the deeper water to 83° F. in the shallower. The cable was most thickly encrusted with vegetation in depths of thirty to forty fathoms, and there was a very sensible falling off when the depth reached sixty fathoms, and the water became salter and more free from silt.

The specimens, Figs. 1 and 2, were found in water of thirty and forty fathoms respectively, about lat. 0° 55′ N., long. 48° 8' W., off the coast of Marajo, or Joannes Island.

The specimens, Figs. 3 and 4, were found in water of sixty fathoms, sixty miles off the coast, about lat. 2° 56' N. The few unlucky waifs observed of the many which came up are at least sufficient to hint at the wonderful variety of submarine life there may be in the littoral zones of these regions, which are well worthy of being

examined by naturalists; and picking up cables suggests a novel way of dredging for them.

8. Fishes Bites.-The cause of our picking-up operations is in itself worthy of remark. We found that the cable had been bitten in several places by fishes powerful enough to displace the iron sheathing and pierce the cable to the core with their teeth, pieces of which we found sticking in the bitten places. There is reason to believe that the electric current had given them a shock and caused them to quit their morsel rather hastily. The bites were all located in the cable off the Delta of the Amazon, and had undoubtedly taken place when the cable was freshly laid, and before it was rendered inconspicuous and unattractive by the submarine fauna and flora. J. MUNRO

THE BIRMINGHAM COLLEGE OF SCIENCE

SOME months ago we intimated that Sir Josiah Mason

had set aside a munificent sum of money wherewith to erect and endow a College of Science in Birmingham. On Tuesday last, his eightieth birthday, the donor laid the foundation-stone of the building, in presence of a large gathering, composed of representatives of various public bodies.

We have already given some details of Sir Josiah Mason's scheme, which appears to us exceedingly judicious, liberal, and comprehensive. The entire sum to be spent by the wise and generous founder will amount to upwards of 100,000l., of which 65,000l. will be reserved for endowstruction in mathematics, abstract and applied; physics, ment. The plan of education comprises courses of inboth mathematical and experimental; chemistry, theoretical, practical, and applied; the natural sciences, especially geology and mineralogy, with their application to mines and metallurgy; botany and geology, with special application to manufactures; physiology, with special reference to the laws of health; and the English, French, and German languages. The course of study may also, in the discretion of the trustees, include such other subjects of instruction as will conduce to a sound practical knowledge of scientific subjects, excluding mere literary education. It is provided that popular or unsystematic instruction may be given gratuitously or by fees in the discretion of the trustees, and shall be open to all persons without distinction of age, class, creed, race, or sex. Theology and theological or religious subjects are absolutely excluded from the curriculum. Students must be between the ages of fourteen and twentyfive, and must pass such preliminary examination as the trustees may direct. In exceptional cases, students above twenty-five will be admitted; but these must not exceed the proportion of one to ten. The founder has decided that a certain proportion must be selected on grounds which are reasonable and not too narrow. The original trustees are Mr. W. C. Aitken, Mr. J. Thackray Bunce, Dr. Gibbs Blake, Dr. Heslop, Mr. G. J. Johnson, and Mr. George Shaw, and the Town Council of Birmingham is empowered to appoint five additional trustees after the death of the founder. The building, which is in the early pointed style, from designs by Mr. J. A. Cossins, architect, of Birmingham, will occupy an area of about an acre, with frontages on either side of 149 feet and 127 feet respectively, in the immediate vicinity of the Town Hall, the Midland Institute, and the new municipal buildings.

After the ceremony of laying the foundation-stone, a meeting was held in the Queen's Hotel, at which, among others, Mr. John Bright was present, and paid a deserved tribute to the far-seeing liberality of the founder of the College. Sir Josiah Mason himself, in an address marked by moderation and great sagacity, gave a simple account of his own career, in which he has amassed a fortune by patient industry, and spoke with great emphasis of the

difficulties which he and his contemporaries had to encounter in their youth from the want of any means of carrying on their education, especially in science, during the intervals they had to spare from work. The aims which he has in view in founding the College may be gathered from the following extract from his address :"Whatever is necessary for the improvement of scientific industry and for the cultivation of art, especially as applied to manufactures, the trustees will be able to teach; they may also, by a provision subsequent to the original deed, afford facilities for medical instruction; and they are authorised, and indeed enjoined, to revise the scheme of instruction from time to time, so as to adapt it to the requirements of the district in future years, as well as at the present time. It is not my desire to set up an institution in rivalry of any now existing; but to provide the means of carrying further and completing the teaching now given in other scientific institutions and in the evening classes now so numerous in the town and its neighbourhood, and especially in connection with the Midland Institute, which has already conferred so much benefit upon large numbers of students, and which I am glad to see represented here to-day. My wish is, in short, to give all classes in Birmingham, in Kidderminster, and in the district generally, the means of carrying on, in the capital of the Midland district, their scientific studies as completely and thoroughly as they can be prosecuted in the great science schools of this country and the Continent; for I am persuaded that in this way alone-by the acquirement of sound, extensive, and practical scientific knowledge-can England hope to maintain her position as the chief manufacturing centre of the world. I have great and I believe well-founded hope for the future of this foundation. I look forward to its class-rooms and lecture-halls being filled with a succession of earnest and intelligent students, willing to learn not only all that can be taught, but in their turn to communicate their knowledge to others, and to apply it to useful purposes for the benefit of the community."

Thus it will be seen that Sir Joseph Mason's design has been conceived in a spirit of true wisdom; he perceives that the prosperity of Birmingham, like the prosperity of the country at large, depends upon the extent to which every branch of history is founded upon a broad and deep scientific basis. He evidently does not intend that his institution will become a mere "Technical" College. We should think that the trustees will carry out the design and wishes of the founder if they aim to make the Mason College do for Birmingham what the Owens College is doing for Manchester. Moreover, we hope that as in the case of Manchester other endowments will be added to that of the wise and generous founder, and that thus the trustees will be able ultimately to carry out his ideas to their fullest development. Meantime all who have the cause of scientific education at heart, all who wish for the highest prosperity of the country, will feel warm gratitude to and admiration for Sir Joseph Mason, a true benefactor to Birmingham, to England, and to Science.

NOTES

WE can only, this week, express our regret—a regret which is universal-at the death of Sir Charles Lyell, Bart., F.R.S., which took place on Monday last. Sir Charles was born on Nov. 14, 1797, so that he was nearly 78 years of age. We hope to give an obituary notice in our next number.

WE regret to announce the death, on Feb. 17, of the celebrated astronomer, Prof. F. W. August Argelander, at Bonn. He was born at Memel on March 22nd, 1790, and began his studies at the University of Königsberg, where he soon became a zealous pupil of Bessel, and in 1820 his official assistant at

the Observatory. Three years later, he followed a call to Abo (Finland), and his principal occupation there was the observation of fixed stars showing large proper motions. These observations were continued at Helsingfors, where he settled in 1832. He succeeded in pointing out nearly 400 fixed stars, which in the time from 1755 until 1830 have moved over more than fifteen seconds in the direction towards the constellation of Hercules. In 1837, when his pamphlet "On the Motion of the Solar System" had appeared, he received an invitation from the University at Bonn, where an observatory was being built, which was completed in 1845. Here he continued his studies most energetically, and particularly investigated the variable stars. In his "Uranometria" he gave excellent determinations of star-magnitudes. His celestial atlas, which was only completed a little while ago, comprises all stars from the first to the tenth magnitude; it is entirely based on his own determinations of position, and decidedly ranks amongst the best works of the kind.

AN important telegram was received by the French Academy of Sciences, at its sittting of the 22nd February, from M. Mouchez, the head of the St. Paul Transit Station. It is said that the observation of internal contacts was perfectly successful. The external contacts were not good, owing to clouds, the weather having been bad for three months. Numerous photographs have been taken. A steamer had left St. Paul for Cherbourg, bringing the detailed results of the observations.

AT the same sitting, M. Dumas announced that the Academy had received, almost at the same moment, two different parcels sent by two different ships, both consisting of documents sent by Capt. Fleuriais, the head of the Pekin Transit Expedition. These parcels, having been sealed, will not be opened for some time to come.

THE following quaint extract from the Gazetteer of May 31, 1769, will no doubt have some interest for our readers at the present time :-"The Transit of Venus over the sun is a phenomenon whereby the astronomers can determine the distance of the sun from the earth, and the dimensions of the whole solar system, more accurately than by any other method. Such a transit will be visible near London on Saturday afternoon, June 3, a little after seven o'clock, if the weather be fair; and never more for this age, nor perhaps for many ages to come, will such a phenomenon be seen in this quarter of the world. The curious, both ladies and gentlemen, who are desirous of being entertained with a sight of this phenomenon, may have the best situation for that purpose, with the assistance of proper persons and telescopes, at Mr. Lightfoot's, at Denmark Hall, on Camberwell Hill, in the road towards Dulwich, where the best of accommodations and wines may be had."

AN official intimation has been received from Dr. Neumayer confirming the announcement, as regards the Deutsche Seewarte at Hamburg, contained in the Times telegram noticed in our last number. It appears that the Government have purchased Herr v. Freeden's interest in the establishment, and that he has no longer any connection with it. It does not yet appear what is the relation of the Hydrographic Office at Berlin, of which Dr. Neumayer is chief, to the Deutsche Seewarte, which is also under him.

A SOCIETY has been formed in Calcutta for obtaining spectroscopic observations of the sun.

WE are much gratified to hear that the Committee of the Chester Society of Natural Science recommend for the consideration of the members that a permanent memorial to the late Canon Kingsley, their founder and president, be established. The memorial proposed and recommended is (1) That a Scholarship (including a medal), to be called "The

Kingsley Memorial," Le founded for the encouragement of Natural Science, to be open to residents and students within the district embraced by the society, subject to such regulations as may be hereafter agreed upon. 2. That if a sufficient fund be raised, a medal may from time to time be given by the Chester Society of Natural Science, for original research within the district of the aforesaid society, and that the medal be called "The Kingsley Memorial Medal."

WE are glad to see from the report of the Syndicate appointed by the Senate of Cambridge University to organise and super.

intend courses of lectures and classes at a limited number of populous centres, that the scheme is working well and is embracing a rapidly widening area. In the first term of 1873-4, the number of towns which took advantage of the scheme was threeNottingham, Derby, and Leicester. This number increased to seven in the following term, and to twelve in the first term of 1874-5. During the present term lectures and classes are being carried on in the following sixteen centres :-Nottingham, Derby, Leicester, Lincoln, Chesterfield, in the Midland district; Leeds, Bradford, Keighley, Halifax, Sheffield, in the Yorkshire district; Stoke-on-Trent, Hanley, Burslem, Newcastle-under-Lyme, in the South Staffordshire district; Liverpool and Birkenhead in the Liverpool district. The subjects on which the lecturers are giving instruction during the present term are Political Economy, English Constitutional History, English Literature, Logic, Physical Geography, Geology, Astronomy, Physical Optics and Spectrum Analysis. A course of lectures is generally concluded in one term, though occasionally it extends over a longer period. The term's course comprises the delivery of twelve weekly lec. tures and the holding of twelve weekly classes. During the present term the number of lecturers employed is thirteen; the total number of pupils attending the courses is about 3,500; and the sum payable to the University for the teaching, examination, and certificates is 1,150. The Syndicate recommend the adoption of a standing Syndicate for the organisation and superintendence of the lectures. A gentleman in Nottingham has offered the sum of 10,000l., to be placed in the hands of trustees, towards the furtherance of this object in that town, provided the Corporation of Nottingham will erect buildings for the accommodation of the University lecturers, to the satisfaction of the Syndicate of the University of Cambridge.

A SERIES of (Davis) Lectures upon zoological subjects will be given in the New Lecture Room, in the Zoological Society's Gardens, Regent's Park, on Thursdays, at 5 P.M., after Easter :April 15, "Monkeys and their Distribution," by Dr. P. L. Sclater, F.R.S.; April 22, Sea-Lions," by J. W. Clark, M.A.; April 29, "Seals and the Walrus," by J. W. Clark, M.A.; May 6, "Deer and their Allies," by Prof. Garrod ; May 13, Sheep, Oxen, and Antelopes," by Prof. Garrod; May 27, "Camels and Llamas," by Prof. Garrod; June 3, "Elephants," by Prof. Flower, F.R.S.; June 10, "Kangaroos," by Prof. Mivart, F.R.S.; June 17, "Pheasants and their Allies," by Dr. P. L. Sclater, F.R.S.; June 24, "The Locomotion of Animals," by Dr. Pye Smith. The lectures will be free to Fellows of the Society and their friends, and to other visitors to the Gardens.

WILLIAM PARKINSON WILSON, Professor of Mathematics at the Melbourne University, died suddenly on Dec. 11. He was Senior Wrangler in 1847, and a Fellow of St. John's, Cambridge, and arrived in the colony in 1855 as a member of the first professorial staff of the University, which he has zealously served ever since. The Professor was everywhere respected. He was, the Times correspondent states, at the head of all scientific movements, devoting himself energetically to anything which promised to promote the intellectual progress of the colony. The selection of his successor at the University is entrusted to Prof. Adams, of Cambridge.

A MUNIFICENT gift has been made to Melbourne University. Mr. Samuel Wilson, of Ercildoun, who recently gave 1, 100%. to the Acclimatisation Society, has sent 30,000l. to the Chancellor, intended for the erection of a hall, but free of conditions, and to be otherwise applied if the authorities think fit.

THE Khedive has instructed Dr. Schweinfurth to organise an African Geographical Society in Egypt.

Scholars' Fund (Cambridge) to Arthur Marshall, B.A., of St. A GRANT of 50%. has been made from the Worts Travelling John's, to enable him to visit Naples for the purpose of using Dr. Dohrn's zoological station and making researches in natural history, with the understanding that he send specimens to the University, accompanied by reports.

ALPHA FIBRE, or Esparto Grass (Machrochloa tenacissima, Kth.), the closely compressed bundles of which are so familiar to us either in stack at wharves or in barges on the Thames, in course of transit to the various paper-mills, has created more than usual interest of late, owing to the report that the supply was becoming exhausted. In contradiction to this it is satisfactory to note, on the authority of Col. Playfair, the ConsulGeneral at Algiers, that enormous tracts of land on the high plateaus in all the provinces of Algeria are covered with the plant. Thus, in the province of Algiers it covers an area of about 2,500,000 acres. In the province of Oran the extent of the Alpha growth is almost unlimited. In the circle of Daïa it is stated to cover a space of about 900,000 acres, while in the subdivision of Mascara there is an immense field for its exploration. In the several divisions of the province of Constantine it is estimated that a total of about 570,000 acres are under growth of this substance. These figures alone show an aggregate of some 3,970,000 acres of Esparto known to exist in Algeria. The difficulty, however, is in the want of proper roads or easy means of transport by which the material could be brought to the sea or availway station. Col. Playfair says that practically there is no limit to the supply of Alpha procurable from Algiers; all that is required is the establishment of railway communication, and the Government of the colony is prepared to sanction the construction of lines, either by French or foreign capitalists, on the most liberal terms.

Several companies have been formed for the purchase and exportation of this fibre, which is becoming more sought for in proportion to the increasing demand for paper. encouraging all such commercial enterprises as may tend to The Algerian authorities are quite alive to the necessity of

develop this important branch of commerce.

IN a communication to the Fharmacist (Chicago) for last month, Mr. H. H. Babcock says he is convinced that Cypripedium spectabile and C. pubescens are capable of producing poisonous effects, on himself at least, similar to those caused by Rhus toxicodendron. He bases this statement upon the fact of his having experienced such symptoms after gathering the plants in question several seasons in succession. It seems scarcely possible that these plants, which have long been in cultivation in this country, possess the noxious properties attributed to them; the general properties of the family to which they belong are so different. However, one direct experiment might settle the question.

DR. ALLEYNE NICHOLSON, Professor of Biology in the College of Physical Science in Newcastle-upon-Tyne, has been offered and accepted the chair of Natural History in the Univer sity of St. Andrew's.

PROF. GABB reports continued progress in his geological and ethnological survey of the Talamanca district in Costa Rica. It may be remembered that Prof. Gabb was invited several years ago, by the Government of Costa Rica, to take charge of an investigation into the resources of the country, and certain reports of his operations from time to time have shown very

satisfactory progress. He has now accomplished the Talamanca survey, and will probably extend his researches into other parts of the country, particularly that bordering upon the Pacific coast, his previous explorations having been confined to the Atlantic slope. With only four assistants besides Indian labourers, Prof. Gabb has surveyed the entire tract, of about 3,000 square miles, from the borders of civilisation on the north to the borders of

Panama, and from the Atlantic to the crest of the Cordilleras; and this he has mapped out more accurately than any other equal area of Costa Rica has been surveyed, not excepting the section where the towns are situated. He also gives reliable information and statistics about an agricultural country sufficiently large, fertile, and healthful to support the entire population of Costa Rica, but which as yet contains only 1,226 Indians and twelve foreigners, of whom only one is white. It is watered by one river, which is navigable throughout the year, and which reaches within thirty miles of the most remote portion of a country valuable for agricultural purposes. In addition to the survey proper, as referred to, information has been gathered in regard to the mineral resources of the region and its animal and vegetable life, immense collections of both, as previously stated, having been sent to the Smithsonian Institution for identification. Among the number are one hundred specimens of monkeys alone, while the other mammals, birds, &c., are in due proportion. The exhaustive inquiries prosecuted into the ethnology of the country have resulted in very rich collections, which have likewise been forwarded to Washington. Numerous vocabularies, with several dialects, have also been obtained, which offer much of promise to the philologist. It is greatly to be hoped that Prof. Gabb's inquiries may be continued, with Costa Rica as a base, until they include the whole of the unknown portions of Central America.

THE Kolnische Zeitung of Feb. 10 gives an account of Prof. Böhm's (Dorpat) researches on revival after cases of poisoning. He succeeded in reviving cats which had been poisoned by injection of potash salts into their veins, after forty minutes' duration of a state which was in no way different from actual death, the action of the heart and respiration having completely ceased. He obtained these results by artificial respiration and simultaneous compression of the breast in the vicinity of the heart. The professor points out the importance of the latter point, which he deems as essential as the action of the lungs. In any case his researches are of high interest for the relation they bear upon the revival of poisoned persons.

THE Bohemia reports extremely heavy snowstorms which took place in a part of Moravia and Bohemia on Feb. 5, and caused great damage to railways, several trains being thrown off the lines, luckily without much injury to passengers. At Znaim (Moravia) the storm was so violent at noon that it was impos. sible to see more than three yards ahead.

THE Oberschlesische Volkszeitung of Feb. I reports the discovery of some colossal remains of the Mammoth (Elephas primigenius) near Ober Glogau (Silesia).

THE Neue Freie Presse announces that Herr R. Falb, of Vienna, discovered a new variable star, near Orionis, on the night of Jan. 31. The discovery was confirmed on the same night by Prof. Oppolzer at his private observatory, and on subsequent nights by the astronomers at the Imperial Observatory of Vienna. The star is visible with the naked eye.

PROF. ASA GRAY, in a paper in the February number of Silliman's Journal, on the question, "Do Varieties wear out, or tend to wear out?" comes to the conclusion that from the scientific point of view, sexually propagated varieties, or races, although liable to disappear through change, need not be expected to wear out, and there is no proof that they do; but non-sexually propagated

varieties, though not liable to change, may theoretically be expected to wear out, but to be a very long time about it.

We are glad to see that the Watford Natural History Society is now completely organised and fairly set a-going. At a recent meeting officers were elected, and a conversazione was afterwards held. The president chosen is Mr. John Evans, F.R.S., and Mr. J. Gwyn Jeffreys, F. R.S., is one of the vicepresidents. The first regular meeting is to be held on March 11, when Mr. J. L. Lobley, F.G. S., one of the members of the Council, will read a paper on "The Cretaceous Rocks of England."

ON the 10th inst., at six o'clock in the evening, a large aerolite was observed at Paris, in the department of the Marne, at Orleans, and at Belleisle en Mer. No noise was heard, but the display of light was magnificent. The track was visible for a time varying from a quarter to half an hour.

place on the Danish island of Möen, on a chalky rock named SEVERAL large landslips are reported as having taken "Möensklint;" from another one, called "Jetterbrinken," a piece of several million cubic yards has fallen down. These occurrences are ascribed to enormous changes in the temperature which have lately taken place in that locality.

THE Royal Geological Society of Ireland have just published Part I. vol. iv., new series, of their journal. It contains: On a new genus of fossil fish of the order Dipnoi, by Dr. Traquair; On the microscopic structure of Irish granites and of the Lambay porphyrite, by Prof. Hull; On a bed of fossiliferous "kunkur," by J. E. Gore; On the Leinster coal-field, by J. McC. Meadows; On a raised estuarine beach at Tramore Bay, by E. Hardman; On the elevated shell-bearing gravels near Dublin, by the Rev. Maxwell Close; and Remarks on the genera Palachinus and Archæocidaris, by W. H. Baily.

Society of Ireland has just been published. THE Forty-third Annual Report of the Royal Zoological The number of visitors to the gardens of the Society during 1874 was 109,923, of visitors would appear to have been the smallest during the and the receipts from the same, 1,442. 145. 4d. The number last ten years, but owing to an increase of the admission fees the income is scarcely below that of the best of the ten years. The plan of those so well known in the London Gardens," the total Council propose to construct "an Elephant Compound on the

cost of which will amount to 150%.

THE additions to the Zoological Society's Gardens during the last week include two Feline Douracoulis (Nyctipithecus felinus) and two Squirrel Monkeys (Saimaris sciurea) from Brazil; a Saffron Cock of the Rock (Rupicola crocea) from Demerara; a eighteen Basse (Labrax lupus), all British, deposited and pur. Grey Mullet (Mugil capito), twelve Cottus (Cottus bubalis), and

chased.

PRELIMINARY INQUIRY INTO THE EXISTENCE OF ELEMENTS IN THE SUN NOT PREVIOUSLY TRACED *

IN a paper communicated to the Royal Society on December 12, 1872 (Phil. Trans. 1873, p. 253), I have shown that the test formerly relied on to decide the presence or absence of a metal in the sun, namely, the presence or absence of the brightest and strongest lines of the metal in question in the average solar spectrum, was not a final one, and that the true test was the presence or absence of the longest lines of the metal: this longest line being that which remains longest in the spectrum when the pressure of the vapour is reduced.

Of the test in question I have said in the paper already mentioned, "It is one, doubtless, which will shortly enable us to

Extract from a memoir presented to the Royal Scci ty in November 2`731 which has just been printed in the Philosophical Transactions."

determine the presence of new materials in the solar atmosphere, and it is seen at once that to the last published table of solar elements-that of Thalén-must be added zinc, aluminium, and possibly strontium, as a result of the new method."

In order to pursue the inquiry under the best conditions, complete maps of the long and short lines of all the elements are necessary. It is, however, not absolutely necessary for the purposes of a preliminary inquiry to wait for such a complete set of maps, for the lists of lines given by the various observers may be made to serve as a means of differentiating between the longest and shortest lines, because I have also shown that the lines given at a low temperature, by a feeble percentage composition, or by a chemical combination of the vapour to be observed, are precisely those lines which appear longest when the complete spectrum of the pure dense vapour is studied.

Now with regard to the various lists and maps published by various observers, it is known (1) that very different temperatures were employed to produce the spectra, some investigators using the electric arc with great battery power, others the induction spark with and without the jar ; (2) that some observers employed in certain cases the chlorides of the metals the spectra of which they were investigating, others used specimens of the metals themselves.

It is obvious, then, that these differences of method could not fail to produce differences of result; and accordingly, in referring to various maps and tables of spectra, we find that some include large numbers of lines omitted by others. A reference to these tables in connection with the methods employed shows at once that the large lists are those of observers using great battery power or metallic electrodes, the small ones those of observers using small battery power, or the chlorides. If the lists of the latter class of observers be taken, we shall have only the longest lines, while those omitted by them and given by the former class will be the shortest lines.

In cases therefore in which I had not mapped the spectrum by the new method of observation referred to in my paper, I have taken the longest lines as thus approximately determined; for it seemed desirable, in view of the very large number of unnamed lines, to search at once for the longest elemental lines in the solar spectrum without waiting for a complete set of maps.

A preliminary search having been determined on, I endeavoured to get some guidance by seeing if there was any quality which differentiated the elements already traced in the sun from those not traced; and to this end I requested my assistant, Mr. R. J. Friswell, to prepare two lists showing broadly the chief chemical characteristics of the elements traced and not traced. This was done by taking a number of the best known compounds of each element (such, for instance, as those formed with oxygen, sulphur, chlorine, bromine, or hydrogen), stating after each whether the compounds in question were unstable or stable. Where any compound was known not to exist, that fact was indicated.

Two tables were thus prepared, one containing the solar, the other the more important non-solar elements (according to our knowledge at the time).

These tables gave me, as the differentiation sought, the fact that in the main the known solar elements formed stable oxygen-compounds.

I have said in the main, because the differentiation was not absolute, but it was sufficiently strong to make me commence operations by searching for the outstanding strong oxide-forming

elements in the sun.

The result up to the present time has been that strontium, cadmium, lead, copper, cerium, and uranium,* in addition to those elements in Thalens' last list, would seem with considerable probability to exist in the solar reversing layer. Should the presence of cerium and uranium be subsequently confirmed, most of the iron group of metals will thus have been found in the sun.

As another test, certain of those elements which form unstable compounds with oxygen were also sought for, gold, silver, mer. cury being examples. None of these were found.

The same result occurred when the lines due to the jar-spark taken in chlorine, bromine, iodine, and those of some of the other non-metals were sought, these being distinguishable as a group by formation of compounds with hydrogen.

Now other researches, not yet completely ready for publication, have led me to the following conclusions:

I. The absorption of some elementary and compound gases is limited to the most refrangible part of the spectrum when the

• Potassium has since been added.

II. Both the general and selective absorption of the photospheric light are greater (and therefore the temperature of the photosphere of the sun is higher) than has been supposed.

III. The lines of compounds of a metal and iodine, bromine, &c., are observed generally in the red end of the spectrum, and this holds good for absorption in the case of aqueous vapour. Such spectra, like those of the metalloids, are separated spectroscopically from those of the metallic elements by their columnar or banded structure.

IV. There are in all probability no compounds ordinarily present in the sun's reversing layer.

V. When a metallic compound vapour, such as is referred to in III., is dissociated by the spark, the band spectrum dies out, and the elemental lines come in, according to the degree of temperature employed.

Again, although our knowledge of the spectra of stars is lamentably incomplete, I gather the following facts from the work already accomplished with marvellous skill and industry by Secchi of Rome.

VI. The sun, so far as the spectrum goes, may be regarded as a representative of class (8) intermediate between stars (a) with much simpler spectra of the same kind, and stars (7) with much more complex spectra of a different kind.

VII. Sirius, as a type of a, is (1) the brightest (and therefore hottest?) star in our northern sky; (2) the blue end of its spectrum is open; it is only certainly known to contain hydrogen, the other metallic lines being exceedingly thin, thus indicating a small proportion of metallic vapours; while (3) the hydrogen lines in this star are enormously distended, showing that the chro mosphere is largely composed of that element.

There are other bright stars of this class.

VIII. As types of the red stars may be quoted, the spectra of which are composed of channelled spaces and bands. Hence the reversing layers of these stars probably contain metalloids, or compounds, or both, in great quantity; and in their spectra not only is hydrogen absent, but the metallic lines are reduced in thickness and intensity, which in the light of V., ante, may indicate that the metallic vapours are being associated. It is fair to assume that these stars are of a lower temperature than our sun.

I have asked myself whether all the above facts cannot be grouped together in a working hypothesis which assumes that in the reversing layers of the sun and stars various degrees of "celestial dissociation" are at work, which dissociation prevents the coming together of the atoms which, at the temperature of the earth and at all artificial temperatures yet attained here, compose the metals, the metalloids, and compounds.

On this working hypothesis, the so-called elements not present in the reversing layer of a star will be in course of formation in the coronal atmosphere and in course of destruction as their vapourdensities carry them down; and their absorption will not only be small in consequence of the reduced pressure of that region, but what absorption there is will probably be limited wholly or in great part to the invisible violet end of the spectrum in the case of such bodies as the pure gases and their combinations, and chlorine. (See I. ante.)

The spectroscopic evidence as to what may be called the plasticity of the molecules of the metalloids, including of course oxygen and nitrogen, but excluding hydrogen, is so overwhelming, that even the absorption of iodine, although generally it is transparent to violet light, may (as I have found in a repetition of Dr. Andrews' experiments on the dichroism of iodine, in which I observed the spectrum) in part be driven into the violet end of the spectrum, for iodine in a solution in water or alcohol at once gives up its ordinary absorption properties, and stops violet light."

A preliminary comparison of the ordinary absorption spectrum of a stratum of 6 ft. of chlorine renders it not improbable that chlorine at a low temperature is the cause of some of the Fraunhofer lines in the violet, although, as said before, I have not yet obtained certain evidence as to the reversal of the bright lines of chlorine seen in the jar-spark.

There is also an apparent coincidence between some of the faint Frauenhofer lines and some of the lines of the low temperature absorption-spectrum of iodine.

Should subsequent researches strengthen the probability of this

⚫ I have since obtained the same result Ly observing the absorption of I vapour in a white-hot tube.