Part 10

“These lines,” says Dr. Huggins, “possessed extreme interest, for there was certainly contained within this hieroglyphic writing some new information. A discussion of the position of these new lines showed them to be undoubtedly the same lines which appear in certain compounds of carbon. Not long before, Professors Liveing and Dewar had found from their laboratory experiments that these lines are only present when nitrogen is also present, and that they indicate a nitrogen compound of carbon, namely—cyanogen. Two other bright groups were also seen in the photograph, confirming the presence of hydrogen, carbon, and nitrogen.”

It is worthy of notice that, only a few days later, Dr. H. Draper succeeded in obtaining a photograph of the same comet’s spectrum. It appeared to him to confirm Dr. Huggins’ statements, except only that the dark Fraunhofer lines were not visible—the photograph having probably been taken under less favorable conditions.

So far, then, it seems clear that comets shine in part by reflecting sunlight, partly with light of their own; the part of the cometic substance which certainly shines with its own light is gaseous, and this gas in most comets “contains carbon, hydrogen, and nitrogen, possibly also oxygen, in the form of hydrocarbons, cyanogen, and possibly oxygen compounds of carbon.”

But the latest comet has brought with it fresh news. Its spectrum is not like that given by the comets we have been considering. The bright lines of sodium are seen in it, and also other bright lines and groups of lines, which have not yet been shown to be identical with any belonging to the hydrocarbon groups, but probably are so. Dr. Huggins’ photograph shows, he considers, “that the original light of the comet, which gives a continuous spectrum (he means that portion of the original light which does so), was too strong to allow of the Fraunhofer lines being recognized in the reflected solar light.” We demur to this as being _shown_, it may fairly be said to be _suggested_. The cyanogen groups are not seen.

Such is Dr. Huggins’ account; but it is manifest that this comet underwent important changes, of which—we are surprised to note—Dr. Huggins has taken no account. Thus, in April, Professors Tacchini and Vogel found simply a faint continuous spectrum. In May, Vogel found that the three bands associated with carbon were present, though faint, while there was no trace of the sodium band. On the contrary, on the nights of June 4, 5, and 7, Dr. B. Hasselberg, of the Observatory of Pulkowa, found that the nucleus of the comet gave a very strong and extended continuous spectrum, with an “excessively strong” bright line in the orange yellow, proved by micrometrical measurement to be identical with the D line—the well known double sodium line of the solar spectrum. The observation was confirmed by Dunér, Bredichin, and Vogel. On this Mr. Hind remarks, “It is necessary to conclude that, during the last fortnight of May, the spectrum of Wells’ comet had changed in a manner of which the history of science furnishes no precedent.” It must, however, be remembered that as yet no comets have been examined under sufficiently favorable conditions, to enable us to say whether the change thus observed was really exceptional, or only exceptional in being for the first time noted. Whenever such a comet as Donati’s comes favorably under spectroscopic scrutiny, we shall probably learn something about these changes which will throw more light than anything yet discovered on the physical economy of these mysterious bodies.

What, then, do we know certainly respecting comets? What may we surmise with more or less probability? And in what direction may we look with most hope for future information? We know certainly that, in whatever way they are formed, the sun excites intense disturbance in them as they approach him. Prof. Stokes remarks that these effects, so much greater at a first view than we might fairly expect in the case of many of the comets observed, which have approached the sun no nearer than our own earth does, or not so near, may be accounted for by the circumstance that comets travel in what may be regarded as, to all intents and purposes, a vacuum. From Dr. Crooke’s experiments on very high vacua, we may infer that there is very little loss of heat, except by radiation. Thus the heat received by the meteoric components of a comet would be much greater than might otherwise be expected. Dr. Huggins mentions, in the same connection, the remarkable persistence of the bright trains of meteors in the rare upper air, which sometimes remain visible for three-quarters of an hour before the light fades, as the heat is gradually radiated away. “Our reasoning on these points,” he remarks, in his dry way, “would undergo considerable modification if we accept the views as to the condition of interplanetary space and of the sun’s action which have been recently suggested by Dr. Siemens in his solar theory”—but of course we do not.

Bredichin’s researches, showing that three distinct curvatures in comets’ tails correspond to the winnowing out by solar repulsive action of (1) hydrogen, (2) carbon, and (3) iron, seem worthy of careful study and investigation. It accords well with spectroscopic evidence as to the condition of the matter raised in gaseous form from the nucleus; and if as yet we have had no direct spectroscopic evidence of the existence of iron in comets, we know that meteors are closely connected with comets, and that many meteors contain iron. Moreover, as unexpected spectroscopic evidence of the presence of the substance sodium, common in so many meteors, has been found in the case of one comet, we may fairly hope that under yet more favorable conditions, the presence of iron also may be recognized in the same way.

How far electricity may be looked to for an explanation of cometic phenomena, is a doubtful point among astronomers and physicists. For my own part, I must confess I share the strong objections which many physicists have expressed against the mere vague suggestion that perhaps _this_ is an electrical phenomenon, perhaps _that other feature_ is electrical too, perhaps _all or most_ of the phenomena of comets depend on electricity. It is so easy to make such suggestions, so difficult to obtain evidence in their favor having the slightest scientific value. Still, I hold the electrical idea to be well worth careful study. Whatever credit may hereafter be given to any electrical theory of comets, will be solely and entirely due to those who may help to establish it upon a basis of sound evidence—none whatever to the mere suggestion, which has been made time and again since it was first advanced by Fontenelle. Dr. Huggins says that he finds there is a rapidly growing feeling among physicists that both the inherent light (which he prefers to call the self-light) of comets and the phenomena of their tails belong to the order of electrical phenomena. An American astronomer recently wrote to him, as to American views of the self-light of comets, “I can not speak with authority for anyone but myself; still I think the prevailing impression amongst us is that this light is due to an electric, or, if I may coin the word, (far better not) an electric-oid action of some kind.” On this Dr. Huggins himself remarks:

“The spectroscopic results fail to give conclusive evidence on this point; still, perhaps, upon the whole, especially if we consider the photographs of last year, the teachings of the spectroscope are in favor of the view that the self-light of comets is due to electric discharges. Those who are disposed to believe that the truth lies in this direction, differ from each other in the precise modes in which they would apply the known laws of electric action to the phenomena of comets. Broadly, the different applications of principles of electricity which have been suggested, group themselves about the common idea, that great electrical disturbances are set up by the sun’s action in connection with the vaporization of some of the matter of the nucleus, and that the tail is probably matter carried away, possibly in connection with electric discharges, under an electrical influence of repulsion exerted by the sun. This view necessitates the supposition that the sun is strongly electrified, either negatively or positively, and further, that in the processes taking place in the comet, either of vaporization or of some other kind, the matter thrown out by the nucleus has become strongly electrified in the same way as the sun—that is, negatively if the sun’s electricity is negative, or positively if the sun’s is positive. The enormous disturbances which the spectroscope shows to be always at work in the sun must be accompanied by electrical changes of equal magnitude, but we know nothing as to how far these are all, or the great majority of them, in one direction, so as to cause the sun to maintain permanently a high electrical state, whether positive or negative.”

Unless some such state of things exist, Sir John Herschel’s statement, “That this force” (the repulsive force forming the tail) “can not be of the nature of electric or magnetic forces,” must be accepted, for, as he points out, “the center of gravity of each particle would not be affected; the attraction on one of its sides would precisely equal the repulsion on the other.” Repulsion of the cometary matter would only take place if this matter, after it has been driven off from the nucleus and the sun, have both high electric potentials of the same kind. Further, it is suggested that luminous jets, streams, halos, and envelopes belong to the same order of phenomena as the aurora, the electrical brush, and the stratified discharges of exhausted tubes.

All this, it will be noticed, is at present merely hypothetical. It is, however, worthy of notice that _outside_ of electricity there is nothing known to physicists which seems to afford even a promise of explanation, so far, at least, as the grander and more striking (also the most mysterious) of cometic phenomena are concerned. It may well be that with our advancing knowledge of meteors and meteor systems, the spectroscopic analysis of the next few comets of the larger and completer types—comets like Donati’s comet, the great comet of 1811, and the comet of 1861—may throw unexpected light on mysteries which still remain among the most profound and unpromising problems presented to modern science.—_The Contemporary Review._

A TOUR ROUND THE WORLD.

By MRS. MARY LOW DICKINSON.

[Continued.]

An early start from Killarney, and a seven-hour journey by rail, ending in delightful quarters at the pleasant Hotel Shelburne, in Dublin, gives a comfortable sense of having passed an agreeable day.

“I would like to have run from Limerick Junction up to Limerick,” says a feminine member of the quartette.

“I don’t think we missed anything in Limerick; I felt like stopping awhile at Kilkenny,” answered her brother.

“But Kilkenny comes to America,” said the first speaker, who had been reading about the enormous annual emigration from that town.

“Well, I fancy one can have all one wants of Limerick at home.”

“Not all I want,” said the little woman, perversely.

“What can you want, who have had your full share of domestic torments, with numberless Bridgets and Norahs?”

There was no answer, but later, in the privacy of her chamber, she said, “I did so want to go to Limerick, to buy some Irish lace. You know they make it there, and send it over to Brussels, and then it is bought back into Ireland for quadruple its cost”—but the air of mild rebuke with which her companion looked up from the diary in which she was describing the beauties of Killarney scenery, seemed to act as a sudden check upon the purely feminine outburst. “Of course I know we can’t stop to buy things,” she added, apologetically.

“Nor can we buy things when we do stop. It’s dreadful of you to begin to want things so early.”

“Yes,” chimed in a masculine voice at the door, “It’s unworthy the spirit of a true Chautauquan. Get on your hats, girls, there’s time enough for a drive, to get what the books recommend—a general view of the town.”

Our hotel fronts Stephen’s Green, whose twenty acres of beautiful grounds form only one of six such ornamented breathing places for that portion of the city which lies on the right bank of the Liffey, beyond the confines of the ancient town. Our coachman knows his business, and halts to point out the equestrian statue of George the Second, showing through the trees in the center of the square. Then we must look at the old Mansion House, and at the site of the great exposition building which stands in twelve acres of garden, and was, if successful, to have been what the Crystal Palace of Sydenham is to London. Financially, it was not a success, and the future use of the building is not yet decided. We halt again to admire the architectural beauty of “the finest building in Dublin, if not in Ireland,” formerly the Irish House of Parliament and now used as the Bank of Ireland. If it were not too late we could go in and see the whole process of printing the bank notes. As it is, we jog slowly on to the eastern end of College Green, which is entirely occupied by the imposing front of Trinity College. The huge Corinthian pile covers an extent of thirty acres. The income is derived largely from landed estates. Its library of one hundred and thirty thousand volumes grows rapidly, for the University is one of the five that has the right to a copy of every volume published in the United Kingdom. The number of students, usually about two thousand, is diminished somewhat by the new Queen’s University, founded by Victoria in 1850, which grants degrees to the graduates from the Queen’s Colleges at Belfast, Galway, and Cork. To a company of learners, nothing could be more interesting than to visit the museums, observatories, botanic gardens, and printing houses of this great institution, which has had such an influence on education in Ireland; but, if we could not see all, we confess to a preference for a day at the Royal Dublin Society, whose professors lecture to the public gratuitously, and whose schools in the fine arts instruct worthy pupils without charge. We want also to see the male and female training schools, under the charge of the Board of Education, the Deaf and Dumb Asylum, and the Drummond Orphanage, owned and supported by a merchant of that name. Other societies for the promotion of science and literature are too numerous to name. No city is more generously provided with the means of education, or produces more learned scholars, yet nowhere is the ignorance of the lowest classes more marked. No place more abounds in charitable institutions. The charity schools number over two hundred, yet the condition of the poor is wretched in the extreme. The city is one of striking contrasts, of grand architectural effects, heightened by the meanness of the dwellings of the poor. The nine bridges over the Liffey add greatly to the picturesqueness of the place, but the water of the stream is as notoriously filthy as ever. Within a few years some efforts have been made to improve the sanitation of the city and the hygienic condition of the poor. Dirty alleys have been widened, model tenements built and drinking fountains supplied. At enormous cost the neighboring streams were turned into a valley, which made a natural reservoir seventeen miles from the city. Thence the water is brought through tunnels to filtering chambers, eight miles from town, from which it is distributed over the city. From the University we went down Dame Street to the Castle, used since the time of Elizabeth as the residence of the Lord Lieutenant. Here there are state apartments to be seen, and music to be heard in the beautiful chapel, but none of this to-day. The sun is setting, and as we whirl on past hospital, postoffice, Custom House, and convents, over the bridge and by the magnificent structure called the Four Courts, because there are held the courts of Queen’s Bench, Common Pleas, Chancery, and Exchequer, there is not time to drive inside the gate of the beautiful Phœnix Park and look at the obelisk that commemorates the victories of Wellington. That must be left for the morrow, as must the old Christ Church and St. Patrick’s Cathedral, whose ancient archepiscopal palace is now used as barracks for the police. In this cathedral are the tombs of Dean Swift and the Stella of his poetry. The structure is the most remarkable instance of complete restoration of our day, Mr. B. L. Guinness, M. P., having spent £150,000 in its restoration. He was knighted for his generosity, and it does not become us to suggest that the sum could have been better spent.

We shall have to divide into two parties to-morrow, and while the artist and teacher go to examine the picture gallery and the schools, the others will get a look at the docks and the harbor, where, by aid of dredging machines, the sand is kept at bay, so that ships can now come up to the quays. Commerce still continues to be important, as Dublin is the avenue of supply for imports for the midland district, but manufacturers of woollen, cotton, silk, etc., are nearly extinct, though the general financial and commercial condition of Ireland is improved within the last twenty years.

While Dublin has declined, especially in manufactures of linen and flax, Belfast, the metropolis of the north of Ireland, has steadily grown in both. It lies on our route to the north, five hours from London. It offers nothing in the common lines of interest, such as churches, museums, public buildings, and parks that would induce a stay; but its immense manufactories are well worth any loss of time a visit may involve. We were shown all through the largest steam-mill, which employs nearly three thousand men; and through the immense establishment at Ardoyne, where the finest linen—that intended for the noblest houses, whose coats of arms are woven in the web—is made by hand. It was interesting indeed, to see, as in the former mill, the process from the beginning with the raw flax to the beautiful completed fabric, and more interesting to watch the workers, many of them women, young girls and little children, who live their lives out day after day in the dust and din of machinery. Their pinched and haggard faces, their dull, spiritless eyes, and the constant monotonous motion of their hands made them seem a part of the machines, and brought to mind with great force Mrs. Browning’s “Cry of the Children.”

Belfast is a great, comfortable, well-to-do looking city, with wide, well-paved streets, many attractive public buildings and substantial homes. We stopped but a night, taking train to Portrush, _via_ the cozy little town of Coleraine. It is a journey of about seventy miles, leaving daylight enough to direct to the picturesque castle of Dunluce, which stands on an isolated rock a hundred feet above the sea. The bridge from the mainland is so narrow as to incline all four of us, like children, “to take hold of hands.” It is a wild spot, with many romantic associations, if the head did not swim, gazing down into the boiling waves that have worn great caves under the walls, so that we could not stay to hear. We creep back, cautiously as we came, to our car, a regular bouncing, swaying, Irish jaunting car, and are whirled on four or five miles further, to see the one thing for which we are up here on this wild Irish shore—the famous Giant’s Causeway. This great natural curiosity has been so often described, that it is already familiar. Its prismatic columns of stone, rising a thousand feet from the sea, make a promontory of pillars, each fitted so perfectly to its neighbor that we can not at first recognize the structure as a freak of nature. As we look over the whole field, it is strangely impressive, and reminds one of the towers, tombs, spires, and strange shapes taken at Vesuvius by the fields of lava, and the mind takes kindly to the wild legends, and does not disturb itself with the various scientific theories concerning the formation. The legends say that the giant was Fin M’Coul, who built the causeway quite across the channel to Scotland, in order to meet in fair fight a boasting Caledonian giant. The giant well whipped, and the causeway, no longer needed, Fin allowed it to fall into the sea. It is a pity to hasten here, for the wild picturesqueness of the spot grows with every hour of wandering upon the rocks, but we must back to Coleraine, and thence to Londonderry, where, tired and sleepy, we hide ourselves away in our cabins on the little steamer, and are carried in our sleep over the channel to Scotland, breakfasting cozily in McLean’s old-fashioned, quiet hotel in Glasgow.

And now we are in another world. Here is no lack of pure water, for Loch Katrine, thirty miles away, pours into the city no less than twenty-four millions of gallons a day. Here is thrift, for around us is a city whose trade so increased that its import duties multiplied a thousand times in sixty years. Here is the beautiful Clyde, literally lined with ships, old and new, ships going and coming, ships in every stage from hulk and beams to paint. Here is a city alive with honest work, with staunch and loyal principles, with churches and schools of the best. Her cathedral ranks next in the kingdom to Westminster Abbey. Among her philanthropies, one of the latest is specially worthy of mention. It is an immense depot, with many branches, for furnishing food to the working classes. They can have a good substantial breakfast for six cents; a dinner of soup, meat, potatoes and pudding, for about nine cents. The originator of this work is Mr. Thomas Corbett, who should find imitators in every city in the world. Is not this a better work than to scrape a cathedral inch by inch from base to tower?

With so much that is living and practical to interest, strange that we hurry away to that which is a matter of poetic sentiment and association with the dead. Yet there are, even in our quartette, those who cheerfully turn from the living pictures of Scotch prosperity, to go and dream for a day on the bridges and in the shadow of the old Wallace tower of Ayr. They want to stroll out to the cottage where Robbie Burns was born, to visit the “auld kirk-yard,” to grow sentimental, perhaps, over his snuff-box, and to touch the Bible he gave his Highland Mary. Well, if they will go, we might as well go along, for, leaving out the poetry and the poet, what can be lovelier than to be out of doors in this early September weather in one of the most picturesque parts of Scotland! The excursion takes only one day from Glasgow, and when we are safely back, we are only two hours by rail from Edinburgh.

And here, as we throw wide open the shutters of front rooms in the old Hotel Royal, and look out upon the deep ravine that divides the city, and across to the castle-crowned hills, and down upon the monument of Walter Scott, just over the way, our cool and quiet ones become eagerly enthusiastic, and the enthusiasts grow wild. We are sure we want to stay here a month; we want to fly out to the nearest circulating library and get all of Scott’s novels at once; we want to hurry our dinner, that we may go and explore this wonderful and picturesque old place.