Графични страници
PDF файл

most favorable time for observation; and not being known by the observer until the actual difference between the motion after the observation was completed. of the two sides of Jupiter's equator be- But Professor Young, at Dartmouth ing nearly 15 miles per second, the effect College, Hanover, N. H., has done much on the light-waves is equivalent to that more than merely obtain evidence by the due to a difference of nearly 30 miles new method that the sun is rotating as per second. Thus the new method may we already knew. He has succeeded so fairly be expected to indicate Jupiter's perfectly in mastering the instrumental motion of rotation. The Greenwich ob- and observational difficulties, as absoservers have succeeded in applying it, lutely to be able to rely on his measurethough Jupiter has not been favorably meni (as distinguished from the mere situated for observation. Only on one recognition) of the sun's motion of rotaoccasion, says Sir G. Airy, was the spec- tion. The manner in which he has extrum of Jupiter “seen fairly well," and tended the powers of ordinary spectroon that occasion “measures were ob- scopic analysis, cannot very readily be tained which gave a result in remarkable described in these pages, simply because agreement with the calculated value." It the principles on which the extension may well be hoped that when in the depends require for their complete decourse of a few years Jupiter returns to scription a reference to mathematical that part of his course where he rises considerations of some complexity. Let high above the horizon, shining more it be simply noted that what is called the brightly and through a less perturbed diffractive spectrum, obtained by using air, the new method will be still more a finely-lined plate, results from the dissuccessfully applied. We may even hope persive action of such a plate, or grating to see it extended to Saturn, not merely as it is technically called, and this disto confirm the measures already made of persive power can be readily combined Saturn's rotation, but to resolve the with that of a spectroscope of the ordidoubts which exist as to the rotation of nary kind. Now Dr. Rutherfurd of New Saturn's ring-system.

York has succeeded in ruling so many Lastly, there remains the rotation of thousand lines on glass within the breadth the sun, a movement much more difficult of a single inch as to produce a grating to detect by the new method, because of high dispersive power. Availing himthe actual rate of motion even at the self of this beautiful extension of specsun's equator amounts only to about i troscopic powers, Professor Young has mile per second.

succeeded in recognizing effects of much In dealing with this very difficult task, smaller motions of recession and apthe hardest which spectroscopists have proach than had before been observable yet attempted, the Greenwich observers by the new method. He has thus been have achieved an undoubted success; able to measure the rotation-rate of the but unfortunately for them, though for- sun's equatorial regions. His result extunately for science, another observatory, ceeds considerably that inferred from far smaller and of much less celebrity, the telescopic observation of the solar has at the critical moment achieved suc- spots. For whereas from the motion of cess still more complete.

the spots a rotation-rate of about 11 The astronomers at our national ob- miles per second has been calculated for servatory have been able to recognize by the sun's equator, Professor Young obthe new method the turning motion of tains from his spectroscopic observations the sun upon his axis. And here we a rate of rather more than it miles, or have not, as in the case of Venus, to re- about 300 yards per second more than cord merely that the observers have seen the telescopic rate. what they expected to see because of the If Young had been measuring the moknown motion of the sun. “Particular tion of the same matter which is obcare was taken,” says Airy,“ to avoid served with the telescope, there could of any bias from previous knowledge of the course be no doubt that the telescope direction in which a displacement" (of was right and the spectroscope wrong. the spectral lines)“ was to be expected," We might add a few yards per second the side of the sun under observation for the probably greater distance of the

sun resulting from recent transit observa- in its infarcy, and this method is but tions. For of course with an increase in a recent application of spectroscopy. our estimate of the sun's distance there A century or so hence astronomers will comes an increase in our estimate of the smile (though not disdainfully) at these sun's dimensions, and of the velocity of feeble efforts, much as we smile now in the rotational motion of his surface; but contemplating the puny telescopes with only about 12 yards per second could be which Galileo and his contemporaries allowed on this account, the rest would studied the star-depths. And we may have to be regarded as an error due to well believe that largely as the knowledge the difficulties involved in the spectro- gained by telescopists in our own time scopic method. But in reality the tele- surpasses that which Galileo obtained, scopist and the spectroscopist observe so will spectroscopists a few generations difterent things in determining by their hence have gained a far wider and deeprespective methods the sun's motion of er insight into the constitution and rotation. The former observes the mo movements of the stellar universe than tion of the spots, belonging to the sun's the spectroscopists of our own day dare visible surface; the latter observes the even hope to attain. I venture. confimotion of the glowing vapors outside dently to predict that, with that insight, that surface, for it is from these vapors, astronomers will recognize in the uninot from the surface of the sun, that the verse of stars a variety of structure, a dark lines of the spectrum proceed. complexity of arrangement, an abundance Now so confident is Professor Young of of every form of cosmical vitality, such the accuracy of his spectroscopic obser as I have been led by other consideravations, that he is prepared to regard the tions to suggest, not the mere cloven seeming difference of velocity between Jamina of uniformly scattered stars more the atmosphere and surface of the sun as or less resembling our sun, and all in real. He believes that “the solar atmos- nearly the same stage of cosmical develphere really sweeps forward over the opment, which the books of astronomy underlying surface, in the same way that not many years since agreed in describthe equatorial regions outstrip the other ing. The history of astronomical progparts of the sun's surface.”. This infer- ress does not render it probable that the ence, important and interesting in itself, is reasoning already advanced, though in far more important in what it involves. reality demonstrative, will convince the For if we can accept it, it follows that generality of science-students until direct the spectroscopic method of measuring and easily understood observations have the velocity of motions in the line of shown the real nature of the constitution sight is competent, under favorable con- of that part of the universe over which ditions, to obtain results accurate within astronomical survey extends. But the a few hundred yards per second, or 10 evidence already obtained, though its or 12 miles per minute. If this shall thorough analysis may be “caviare to the really prove to be true for the method general,” suffices to show the real nature now, less than nine years after it was of the relations which one day will come first successfully applied, what may we within the direct scope of astronomical not hope from the method in future observation.-Contemporary Review. years ? Spectroscopic analysis itself is




amateur voyage of circumnavigation, I In admitting into the pages of the fear that the Editor runs a risk of deNineteenth Century a narrative of an scending into a sphere too narrow in its With the exception of the introductory

scope to deserve the attention of a large

public. remarks, the following paper is wholly composed of extracts from the author's note-book,

But as he decides to run that risk I written afloat and for the most part at sea. make no further apology, and address

myself at once to the task which I have east trades from Teneriffe to Tarafal been requested to undertake. I com- Bay, and thence pursued our voyage mence with a general outline of the voy- across the Atlantic to Rio. age, and shall subsequently fill in the The 'Sunbeam' again put to sea on details of the picture, which, unless con- the 5th of September, and in six days nected together at the commencement reached Montevideo. On the 8th and by a slight sketch of the whole cruise, 9th a gale blew from the north-east; the would be seen in a disjointed and frag- distances sailed under reefed canvas on mentary aspect.

these two days being 243 and 270 knots The expedition was in some respects respectively. During our stay in the unprecedented; and the most exception- River Plate we spent a fortnight at Bueal feature was the little company of pas- nos Ayres, and made excursions to Rosengers. They included Mrs. Brassey sario and Cordova, and to Azul, on the and our fonr children. The youngest southern frontier; we afterwards visited was less than two years of age, and has Ensenada. returned to England in robust health. The voyage was resumed on the 28th A voyage of circumnavigation is an ordi- of September, and on the 6th of October nary undertaking for a professional sea- we arrived at Sandy Point, in the Straits man; but it was no inconsiderable effort of Magellan. On this passage we resfor a lady to exchange the luxuries of an cued a crew of fifteen hands from the English home for an uneasy residence of barque Monks? Haven,' bound from eleven months on the rolling sea. And Cardiff to Valparaiso with a cargo of what shall be said of the nurses ? True smelting coals. On the end of October daughters of their Scandinavian fore- we encountered a gale from the southfathers, they accepted the unusual and west, but escaped its full effects by clostrying conditions of their sea life with ing with the coast of Patagonia. undaunted spirit, and showed no symp- The voyage was continued through toms either of fear or discontent from the Straits of Magellan and Smyth's the day of their departure to the hour of Channel. It was our happy fortune to their final disembarkation. A circum- see the magnificent mountains of those navigation of 35,400 miles has never be- 'stern and wild 'regions in most auspifore been made in the short period of 46 cious weather. The distance from the weeks, from which must be deducted 112 eastern entrance to the Straits of Mageldays of well-earned repose in harbor. lan to the northern outlet from Smyth's We had, it is true, the advantage of steam, Channel into the Gulf of Penas was 659 without which such a performance would miles. We made the passage under have been an impossibility ; but we trav- steam in seventy-six hours. Aided by elled 20,517 miles under sail alone, and the admirable charts from the surveys the consumption of coal has not exceed- of Captain King, Admiral Fitzroy, and ed 400 tons.

Captain Mayne, C.B., we were enabled The ‘Sunbeam'sailed from Cowes on to navigate these intricate channels at the 6th of July, 1876, put into Torbay on full speed, and find well-sheltered anchorthe following day, resumed her voyage ages every night. on the 8th, and reached Madeira on the Lota was our first port on the coast of 16th of July. Strong winds were expe- Chili, and on the 21st of October we rienced in the Channel, and a fresh gale reached Valparaiso. After a stay of nine from the north-east off Cape Finisterre. days in that busy but ill-protected harSouth of the latitude of Lisbon calms bor, we proceeded on our long and loneprevailed. In this stage of the voyage ly voyage of 12,333 miles across the Pa353 miles were traversed under steam, cific to Yokohama. We touched at Bow and 886 miles under sail.

Island in the Low Archipelago, at MaiLeaving Madeira on the 20th of July, tea and Tahiti in the Society Islands, at we called at Orotava, for the ascent of Hawaii and Honolulu, in the Sandwich the Peak of Teneriffe, and at Tarafal Islands, sighted Assumption, an isolated Bay, in the island of San Antonio, one extinct volcano in the Ladrones, on the of the Cape de Verdes, for provisions, 21st of January, and arrived at Yokohaarriving at Rio de Janeiro' on the 17th ma on the 29th. We had made the pasof August. We sailed before the north- sage from Valparaiso in seventy-two days at sea, and had indulged ourselves in calm, we proceeded under steam until only seventeen days of rest and relaxa- the afternoon of the 22nd, when we ention in harbor. By far the greater countered a strong northerly gale, blowpart of this passage was made in the ing in heavy gusts off the high mountains favored region of the trade winds, no of the Sinaitic peninsula. We worked severe weather having been encountered up to and through the Straits of Zubal until we entered the Kuro Siwo, or warm under steam and sail, and up the Gulf Japan current, a sea not less stormy than of Suez under sail only. the Gulf Stream of the Atlantic, and The importance of the Suez Canal is probably rendered boisterous from sim- abundantly testified to the traveller in ilar causes.

Eastern waters by the frequency with After a short stay at Yokohama we which he meets large steamers carrying proceeded to Kobe, in the Inland Sea, the British flag. While upwards of a and attended the opening of the railway thousand British vessels pass through the to Kioto by the Mikado. From Kobe canal every year, no other nation sends we steamed through the Inland Sea in so many as one hundred; and of the truly winterly weather to Simonoseki, foreign vessels by far the greater number where we found the people much agitated are maintained by liberal subsidies. All by the recent insurrection of the Sat- the French steamers, save one, which suma clan. Bidding farewell to Japan makes an annual voyage to Madagascar, with regret, we steamed to the south- are largely subsidised. It is a significani ward. We issued forth from the Inland circumstance that no vessel of the merSea by the Boungo Channel, through chant service of the United States, and which Admiral Kuper conducted the only two steamers bearing the Belgian combined fleets to the bombardment of flag, have passed through the canal. Simonoseki, but which has since been The Norwegian flag, which is displayed rarely used. Passing between the Lin- so widely in other waters, is scarcely schoten Islands, many of which are ac- ever seen at Suez. tive volcanoes, and the Liukiu group, The ‘Sunbeam.' steamed through the we entered the Formosa Channel on the canal in two days, and reached Alex an24th of February, on which day, aided dria on the 29th of April, after a boisby the current, and running before a terous passage of two days from Port strong north-east monsoon, we made Said. We sailed from Alexandria on good upwards of 300 knots under sail the end of May. For three days the only. This was the best performance of wind was so strong from the west that it the voyage. On the following evening would have been impossible to gain any we arrived off Hongkong.

advantage by the use of our auxiliary We sailed from Hongkong on the 7th steam-power. We accordingly stood to of March, touched at Macao on the same the north-west, close hauled, under reefday, ran down the China Sea before ed canvas, and made the island of Crete pleasant north-east breezes, and reached on the evening of the 5th. Here the Singapore on the 17th of March. After

After wind shifted to the south-east, enabling calling at Johore, Malacca, and Penang, us to press forward under steam and we crossed the Indian Ocean, in calm sail, and reach Malta on the 8th of May. and oppressively hot weather, and ar- We arrived at Gibraltar on the 16th, rived at Galle on the 29th, and Colombo having made the passage, against weston the 30th of March.

erly winds of varying force, in six days. On the 5th of April we were 'once After a stay of sixteen hours only, we more upon the waters,' and on the 15th, weighed anchor at 8 P.m., and proceeded having steamed the whole distance of under sail, before a strong easterly wind, 2,100 miles, we reached Aden. Here through the Straits of Gibraltar. The we remained a few hours only, and, after next day the wind subsided, and at 7 coaling, resumed our voyage under sail, P.M. we were under steam. with a fresh breeze from the south-east On the coast of Portugal we encounin our favor, which carried us through tered such strong head winds that we the Straits of Bab-el-Mandeb and up the put into Lisbon for two days for shelter ; Red Sea for a distance of 350 miles and off Cape Finisterre we were hove to from Aden. The wind subsiding to a for two days under reefed canvas. Even

157 feet

when the weather moderated, the winds Good Hope and Cape Horn have been continued unfavorable, and we complet- avoided in the inland passages of the ed the voyage under steam, arriving off Straits of Magellan and the Suez Canal. Cowes on the 26th, and finally landing We have met with no continuous stormy at Hastings on the following day. weather, except during the four days

Before entering upon other matters, preceding our arrival at Yokohama. In the little vessel which has carried us so one of these squalls the jib-boom and rapidly and safely over 36,000 miles of topgallant-mast were carried away. No ocean claims a brief description. She other spars were lost during the voyage. was designed by Mr. St. Clare Byrne, of We have suffered discomfort from heat, Liverpool, and may be technically de- and detention in calms; but storms have fined as a composite three-masted top- disturbed us seldom, and they have not sail-yard screw schooner. The engines, lasted long. by Messrs. Laird, are of 70 nominal or The navigation presented few difficul350 indicated horse-power, and devel- ties. All the coasts that we have visited oped a speed of 10'13 knots on the meas- have been surveyed. In this important ured mile. The bunkers contain 80 work the officers of the British Survey tons of coal. The average daily con- have taken a prominent part, and they sumption is 4 tons, and the speed 8 knots deserve the highest praise for their care in fine weather. The principal dimen- and accuracy. sions of the hull are

Lighthouses are no longer confined to Length for tonnage.....

European waters. In China and Japan Beam extreme.......

276 inches. the sinuosities of the coast are defined at Displacement tonnage.

531 tons

night by a complete and methodical illuArea of midship section....

202 square


mination. With an addition of twenty feet to the The perfection to which the manufaclength, and more engine power, the ture of chronometers has been brought Sunbeam' presents a type which might is a very valuable help to the navigator. be found very efficient for naval services Lunar observations, the only really diffiin distant waters where good sailing cult work in ocean navigation, are now qualities are essential, and large ships no longer necessary. Not being lunariare not required. A heavy gun could be ans, we are much beholden to our chrocarried amidships, which should be pro- nometers by Brockbank and Atkins, vided with gear for lowering into the which kept their time most admirably, hold in stormy weather.

and enabled us invariably to make a Our voyage has been abundant in good landfall. illustrations of the advantages of steam- The uniform excellence of the Admipower, of weatherliness under sail, buoy- ralty sailing directions makes it the more ancy in a short confused sea-indeed, to be regretted that none have as yet of all the qualities which go to make a been prepared for some extensive and perfect cruiser. How hard a problem it much-frequented seas. The Admiralty is to the advanced science of the present have published no complete manual for day to unite in any single model these the Pacific, and, what is still more revarious elements!

markable, they have wholly neglected It is not pretended that the Sum- the Mediterranean. beam' was without faults; yet, even in The wind charts and sailing directions the production of so small a vessel-her published by the Admiralty are not less hull, engines, and equipments—what a deserving of mention. The information combination there is of mental skill, they contain for the Atlantic, the China manual effort, experience, and experi- seas, and the Indian Ocean is most amment!

ple. With the aid of these publications, On looking back and contrasting the the inexperienced navigator may confianticipated difficulties with the practical dently select the best point for crossing experiences of the voyage, the ease and the line at any season of the year. He certainty with which every passage has will form a very fair idea of the weather been made are truly surprising. Our he will probably experience, and can lay track has been for the most part within down his track for distant voyages, so as the tropics. The storms off the Cape of -to use the prevailing winds to the best NEW SERIES.- Vol. XXVI., No. 3


« ПредишнаНапред »