Voyage To Algeria To Observe The Eclipse
( Originally Published 1897 )
THE opening of the Eclipse Expedition was not propitious. Portsmouth, on the 5th of December 1870, was swathed by a fog, which was intensified by smoke, and traversed by a drizzle of fine rain. At six P.M. I was on board the ' Urgent.' On Tuesday morning the weather was too thick to permit of the ship's being swung and her compasses calibrated. The Admiral of the port, a man of very noble presence, came on board. Under his stimulus the energy which the weather had damped appeared to become more active, and soon after his departure we steamed down to Spithead. Here the fog had so far lightened as to enable the officers to swing the ship.
At three P.M. on Tuesday the 6th of December we got away, gliding successively past Whitecliff Bay, Bembridge, Sandown, Shanklin, Ventnor, and St. Catherine's Lighthouse. On Wednesday morning we sighted the Isle of Ushant, on the French side of the Channel. The northern end of the island has been fretted by the waves into detached tower-like masses of rock of very remarkable appearance. In the Channel the sea was green, and opposite Ushant it was a brighter green. On Wednesday evening we committed ourselves to the Bay of Biscay. The roll of the Atlantic was full, but not violent. There had been scarcely a gleam of sunshine throughout the day, but the cloud-forms were fine, and their apparent solidity impressive. On Thursday morning I rose refreshed, and found the green of the sea displaced by a deep indigo blue. The whole of Thursday we steamed across the bay. We had little blue sky, but the clouds were again grand and varied—cirrus, stratus, cumulus, and nimbus, we had them all. Dusky hairlike trails were sometimes dropped from the distant clouds to the sea. These were falling showers, and they sometimes occupied the whole horizon, while we steamed across the rainless circle which was thus surrounded. Sometimes we plunged into the rain, and once or twice, by slightly changing course, avoided a heavy shower. From time to time perfect rainbows spanned the heavens from side to side. At times a bow would appear in fragments, showing the keystone of the arch midway in air, and its two buttresses on the horizon. In all cases the light of the bow could be quenched by a Nicol's prism, with its long diagonal tangent to the arc. Sometimes gleaming patches of the firmament were seen amid the clouds. When viewed in the proper direction, the gleam could be quenched by a Nicol prism, a dark aperture being thus opened into stellar space.
At sunset on Thursday the denser clouds were fiercely fringed, while through the lighter ones seemed to issue the glow of a conflagration. On Friday morning we sighted Cape Finisterre, the extreme end of the arc which sweeps from Ushant round the Bay of Biscay. Calm spaces of blue, in which floated quietly scraps of cumuli, were behind us, but in front of us was a horizon of portentous darkness. It continued thus threatening throughout the day. Towards evening the wind strengthened to a gale, and at dinner it was difficult to preserve the plates and dishes from destruction. Our thinned company hinted that the rolling had other consequences. It was very wild when we went to bed. I slumbered and slept, but after some time was rendered actively conscious that my body had become a kind of projectile, which had the ship's side for a target. I gripped the edge of my berth to save my-self from being thrown out. Outside, I could hear somebody say that he had been thrown from his berth, and sent spinning to the other side of the saloon. The screw laboured violently amid the lurching ; it incessantly quitted the water, and, twirling in the air, rattled against its bearings, and caused the ship to shudder from stem to stern. At times the waves struck us, not with the soft impact which might be expected from a liquid, but with the sudden solid shock of battering-rams. 'No man knows the force of water,' said one of the officers, ' until he has experienced a storm at sea.' These blows followed each other at quicker intervals, the screw rattling after each of them, until, finally, the delivery of a heavier stroke than ordinary seemed to reduce the saloon to chaos. Furniture crashed, glasses rang, and alarmed enquiries immediately followed. Amid the noises I heard one note of forced laughter ; it sounded very ghastly. Men tramped through the saloon, and busy voices were heard aft, as if something there had gone wrong.
I rose, and not without difficulty got into my clothes. In the after-cabin, under the superintendence of the able and energetic navigating lieutenant, Mr. Brown, a group of blue jackets were working at the tiller-ropes. These had become loose, and the helm refused to answer the wheel. High moral lessons might be gained on shipboard by observing what steadfast adherence to an object can accomplish, and what large effects are heaped up by the addition of infinitesimals. The tiller-rope, as the blue jackets strained in concert, seemed hardly to move ; still it did move a little, until finally, by timing the pull to the lurching of the ship, the mastery of the rudder was obtained. I had previously gone on deck. Round the saloon-d-or were a few members of the eclipse party, who seemed in no mood for scientific observation. Nor did I ; but I wished to see the storm. I climbed the steps to the poop, exchanged a word with Captain Toynbee, the only member of the party to be seen on the poop, and by his direction made towards a cleat not far from the wheel,' Round it I coiled my arms. With the exception of the men at the wheel, who stood as silent as corpses, I was alone.
I had seen grandeur elsewhere, but this was a new form of grandeur to me. The ' Urgent' is long and narrow, and during our expedition she lacked the steadying influence of sufficient ballast. She was for a time practically rudderless, and lay in the trough of the sea. I could see the long ridges, with some hundreds of feet between 'their crests, rolling upon the ship perfectly parallel to her sides. As they approached they so grew upon the eye as to render the expression ' mountains high' intelligible. At all events, there was no mistaking their mechanical might, as they took the ship upon their shoulders, and swung her like a pendulum. The poop sloped sometimes at an angle which I estimated at over forty-five degrees ; wanting my previous Alpine practice, I should have felt less confidence in my grip of the cleat. Here and there the long rollers were tossed by interference into heaps of greater height. The wind caught their crests, and scattered them over the sea, the whole surface of which was seething white. The aspect of the clouds was a fit accompaniment to the fury of the ocean. The moon was almost full—at times concealed, at times revealed, as the scud flew wildly over it. These things appealed to the eye, while the ear was filled by the whistle and boom of the storm and the groaning of the screw.
Nor was the outward agitation the only object of interest to me. I was at once subject and object to myself, and watched with intense interest the workings of my own mind. The ' Urgent' is an elderly ship. She had been built, I was told, by a contracting firm for some foreign Government, and had been diverted from her first purpose when converted into a troop-ship. She had been for some time out of work, and I had heard that one of her boilers, at least, needed repair. Our scanty but excellent crew, moreover, did not belong to the ' Urgent,' but had been gathered from other ships. Our three lieutenants were also volunteers. All this passed swiftly through my mind as the ship shook under the blows of the waves, and I thought that probably no one on board could say how much of this thumping and straining the ' Urgent' would be able to bear. This uncertainty caused me to look steadily at the worst, and I tried to strengthen myself in the face of it.
But at length the helm laid hold of the water, and the ship was got gradually round to face the waves. The rolling diminished, a certain amount of pitching taking its place. Our speed had fallen from eleven knots to two. I went again to bed. After a space of calm, when we seemed crossing the vortex of a storm, heavy tossing recommenced. I was afraid to allow myself to fall asleep, as my berth was high, and to be pitched out of it might be attended with bruises, if not with fractures. From Friday at noon to Saturday at noon we accomplished sixty-six miles, or an average of less than three miles an hour. I overheard the sailors talking about this storm. The ' Urgent,' according to those that knew her, had never previously experienced anything like it.'
All through Saturday the wind, though somewhat sobered, blew dead against us. The atmospheric effects were exceedingly fine. The cumuli resembled mountains in shape, and their peaked summits shone as white as Alpine snows. At one place this resemblance was greatly strengthened by a vast area of cloud, uniformly illuminated, and lying like a névé below the peaks. From it fell a kind of cloud-river, strikingly like a glacier. The horizon at sunset was remarkable—spaces of brilliant green between clouds of fiery red. Rainbows had been frequent throughout the day, and at night a perfectly continuous lunar bow spanned the heavens from side to side. Its colours were feeble ; but, contrasted with the black ground against which it rested, its luminousness was extraordinary.
Sunday morning found us opposite to Lisbon, and at midnight we rounded Cape St. Vincent, where the lurching seemed disposed to recommence. Through the kindness of Lieutenant Walton, a cot had been slung for me. It hung between a tiller-wheel and a flue, and at one A.M. I was roused by the banging of the cot against its boundaries. But the wind was now behind us, and we went along at a speed of eleven knots. We felt certain of reaching Cadiz by three. But a new lighthouse came in sight, which some affirmed to be Cadiz lighthouse, while the surrounding houses were declared to be Cadiz itself. Out of deference to these statements, the navigating lieutenant changed his course, and steered for the place. A pilot came on board, and he informed us that we were before the mouth of the Guadalquivir, and that the lighthouse was that of Cipiôna. Cadiz was still some eighteen miles distant.
We steered towards the city, hoping to get into the harbour before dark. But the pilot was snapped up by another vessel, and we did not get in. We beat about during the night, and in the morning found ourselves about fifteen miles from Cadiz. The sun rose behind the city, and we steered straight into the light. The three-towered cathedral stood in the midst, round which swarmed apparently a multitude of chimney-stacks. A nearer approach showed the chimneys to be small turrets. A pilot was taken on board ; for there is a dangerous shoal in the harbour. The appearance of the town as the sun shone upon its white and lofty walls was singularly beautiful. We cast anchor ; some officials arrived and demanded a clean bill of health. We had none. They would have nothing to do with us ; so the yellow quarantine flag was hoisted, and we waited for per-mission to land the Cadiz party. After some hours of delay the English consul and vice-consul came on board, and with them a Spanish officer, ablaze with gold lace and decorations. Under slight pressure the requisite permission had been granted. We landed our party, and in the afternoon weighed anchor. Thanks to the kindness of our excellent pay-master, I was here transferred to a roomier berth.
Cadiz soon sank beneath the sea, and we sighted in succession Cape Trafalgar, Tarifa, and the revolving light of Ceuta. The water was very calm, and the moon rose in a quiet heaven. She swung with her convex surface downwards, the common boundary between light and shadow being almost horizontal. A pillar of reflected light shimmered up to us from the slightly rippled sea. I had already noticed the phosphorescence of the water, but to-night it was stronger than usual, especially among the foam at the bows. A bucket let down into the sea brought up a number of the little sparkling organisms which cause the phosphorescence. I caught some of them in my hand. And here an appearance was observed which was new to most of us, and strikingly beautiful to all. Standing at the bow and looking forwards, at a distance of forty or fifty yards from the ship a number of luminous streamers were seen rushing towards us. On nearing the vessel they rapidly turned, like a comet round its perihelion, placed themselves side by side, and, as parallel trails of light, kept up with the ship. One of them placed itself right in front of the bow as a pioneer. These comets of the sea were joined at intervals by others. Sometimes as many as six at a time would rush at us, bend with extraordinary rapidity round a sharp curve, and afterwards keep us company. Leaning over the bow, and scanning the streamers closely, the frontal portion of each revealed the outline of a porpoise. The rush of the creatures through the water had started the phosphorescence, every spark of which was converted by the motion of the retina into a line of light. Each porpoise was thus wrapped in a luminous sheath. The phosphorescence did not cease at the creature's tail, but was carried many porpoise-lengths behind it.
To our right we had the African hills, illuminated by the moon. Gibraltar Rock at length became visible, but the town remained long hidden by a belt of haze. Through this at length the brighter lamps struggled. It was like the gradual resolution of a nebula into stars. As the intervening depth be-came gradually less the mist vanished more and more, and finally all the lamps shone through it. They formed a bright foil to the sombre mass of rock above them. The sea was so calm and the scene so lovely that Mr. Huggins and myself stayed on deck till the ship was moored, near midnight. During our walking to and fro a striking enlargement of the disc of Jupiter was observed whenever the heated air of the funnels came between us and the planet. On passing away from the heated air, the flat dim disc would immediately shrink to a luminous point. The effect was one of retinal persistence. The retinal image of the planet was set quivering in all azimuths by the streams of heated air, describing in quick succession minute lines of light, which summed themselves to a disc of sensible area.
At six o'clock next morning the gun at the signal station on the summit of the rock boomed. At eight the band on board the ' Trafalgar' training-ship, which was in the harbour, struck up the national anthem ; and immediately afterwards a crowd of mite-like cadets swarmed up the rigging After the removal of the apparatus belonging to the Gibraltar party we went on shore. Winter was in England when we left, but here we had the warmth of summer. The vegetation was luxuriant—palmtrees, cactuses, and aloes, all ablaze with scarlet flowers. A visit to the Governor was proposed, as an act of necessary courtesy, and I accompanied Admiral Ommaney and Mr. Huggins to the Convent, or Government House. We sent in our cards, waited for a time, and were then conducted by an orderly to his Excellency. He is a fine old man, over six foot high, and of frank military bearing. He received us and conversed with us in a very genial manner. He took us to see his garden, his palms, his shaded promenades, and his orange-trees loaded with fruit, in all of which he took manifest de-light. Evidently 'the hero of Kars' had fallen upon quarters after his own heart. He appeared full of good nature, and engaged us on the spot to dine with him that day.
We sought the town-major for a pass to visit the lines. While awaiting his arrival I purchased a stock of white glass bottles, with a view to experiments on the colour of the sea. Mr. Huggins and myself, who wished to see the rock, were taken by Captain Salmond to the library, where a model of Gibraltar is kept, and whore we had a capital preliminary lesson. At the library we met Colonel Maberly, a courteous and kindly man, who gave us good advice regarding our excursion. He sent an orderly with us to the entrance of the lines. The orderly handed us over to an intelligent Irishman, who was directed to show us everything that we desired to see, and to hide nothing from us. We took the ' upper lines,' traversed the galleries hewn through the limestone, looked through the embrasures, which opened like doors in the precipice, over the hills of Spain, reached St. George's Hall, and went still higher, emerging on the summit of one of the noblest cliffs I have ever seen.
Beyond were the Spanish lines, marked by a line of white sentry-boxes ; nearer were the English lines, less conspicuously marked out ; and between both was the neutral ground. Behind the Spanish lines was the conical hill called the Queen of Spain's Chair. The general aspect of Spain from the rock is bold and rugged. Doubling back from the galleries, we struck upwards towards the crest, reached the signal station, where we indulged in shandy-gaff and bread and cheese. Thence to O'Hara's Tower, the highest point of the rock. It was built by a fermer Governor, who, forgetful of the laws of terrestrial curvature, thought he might look from the tower into the port of Cadiz. The tower is riven, and may be climbed along the edges of the crack. We got to the top of it ; thence descended the curious Mediterranean Stair—a zigzag, mostly of steps down a steeply falling slope, amid palmetto brush, aloes, and prickly pear.
Passing over the Windmill Hill, we were joined at the ' Governor's Cottage' by a car, and drove after-wards to the lighthouse at Europa Point. The tower was built, I believe, by Queen Adelaide, and it contains a fine dioptrie apparatus of the first order, constructed by the Messrs. Chance of Birmingham. At. the appointed hour we were at the Convent. During dinner the same genial traits which appeared in the morning were still more conspicuous. The freshness of the Governor's nature showed itself best when he spoke of his old antagonist in arms, Mouravieff. Chivalry in war is consistent with its stern prosecution. These two men were chivalrous, and after striking the last blow became friends for ever. Our kind and courteous reception at Gibraltar is a thing to be remembered with pleasure.
On the 15th of December we committed our selves to the Mediterranean. The views of Gibraltar with which we are most acquainted represent it as a huge ridge ; but its aspect, end on, both from the Spanish lines' and from the other side, is truly noble. There is a sloping bank of sand at the back of the rock, which I was disposed to regard simply as the débris of the limestone. I wished to let myself down upon it, but had not the time. My friend Mr. Busk, however, assures me that it is silica, and that the same sand constitutes the adjacent neutral ground. There are theories afloat as to its having been blown from Sahara. The Mediterranean throughout this first day, and indeed throughout the entire voyage to Oran, was of less deep a blue than the Atlantic. Possibly the quantity of organisms may have modified the colour. At night the phosphorescence was delicious, breaking with the suddenness of a snapped spring along the crests of the waves formed by the port and starboard bows. Its strength was not uniform. Having flashed brilliantly for a time, it would in part subside, and afterwards regain its vigour. Several large phosphorescent masses of wierd appearance also floated past.
On the morning of the 16th we sighted the fort and lighthouse of Marsa el Kibir, and beyond them the white walls of Oran lying in the bight of a bay, sheltered by dominant hills. The sun was shining brightly; during our whole voyage we had not had so fine a day. The wisdom which had led us to choose Oran as our place of observation seemed demonstrated. A rather excitable pilot came on board, and he guided us in behind the Mole, which had suffered much damage last year from an unexplained outburst of waves from the Mediterranean. Both port and bow anchors were cast into deep water. With three huge hawsers the ship's stern was made fast to three gun-pillars fixed in the Mole ; and here for a time the ' Urgent' rested from her labours.
M. Janssen, who had rendered his name celebrated by his observations of the eclipse in India in 1868, when he showed the solar flames to be eruptions of incandescent hydrogen, was already encamped in the open country about eight miles from Oran. On the 2nd of December he had quitted Paris in a balloon, with a strong young sailor as his assistant, had descended near the mouth of the Loire, seen M. Gambetta, and received from him encouragement and aid. On the day of our arrival his encampment was visited by Mr. Huggins, and the kind and courteous Engineer of the Port drove me subsequently in his own phaeton to the place. It bore the best repute as regards freedom from haze and fog, and commanded an open outlook, but it was inconvenient for us on account of its distance from the ship. The place next in repute was the railway station, between two and three miles distant from the Mole. It was inspected, but, being enclosed, was abandoned for an eminence in an adjacent garden, the property of Mr. Hinshelwood,a Scotchmanwho had settled some years previously as an esparto merchant in Oran,' and who in the most liberal manner placed his ground at the disposition of the party. Here the tents were pitched on the Saturday by Captain Salmond and his intelligent corps of sappers, the instruments being erected on the Monday under cover of the tents.
Close to the railway station runs a new loopholed wall of defence, through which the highway passes into the open country. Standing on the highway, and looking southwards, about twenty yards to the right is a small bastionet, intended to carry a gun or two. Its roof I thought would form an admirable basis for my telescope, while the view of the sur-. rounding country was unimpeded in all directions. The authorities kindly allowed me the use of this bastionet. Two men, one a blue jacket named Elliot, and the other a marine named Hill, were placed at my disposal by Lieutenant Walton ; and thus aided, on Monday morning I mounted my telescope. The instrument was new to me, and I wished to master all the details of its manipulation.
After some hours of discipline, and as the day was sobering towards twilight, the telescope was dismounted and put under cover. Mr. Huggins joined me, and we visited together the Arab quarter of Oran. The flat-roofed houses appeared very clean and white. The street was filled with loiterers, and the thresholds were occupied by picturesque groups. Some of the men are very fine ; we saw many straight, manly fellows who must have been six foot four in height. They passed us with perfect indifference, evincing no anger, suspicion, or curiosity, hardly caring in fact to glance at us as we passed. In one instance only during my stay at Oran was I spoken to by an Arab. He was a tall, good-humoured fellow, who came smiling up to me, and muttered something about ' les Anglais.' The mixed population of Oran is picturesque in the highest degree : the Jews, rich and poor, varying in their costumes as their wealth varies—the Arabs more picturesque still, and of all shades of complexion—the negroes, the Spaniards, the French, all grouped together, and each preserving their own individuality, formed a picture intensely interesting me.
On Tuesday, the 20th, I was early at the bastionet, with the view of schooling both myself and my men. The night had been very squally. The sergeant of the sappers took charge of our key, and on Tuesday morning Elliot went for it. He brought back the intelligence that the tents had been blown down, and the instruments overturned. Among these was a large and valuable equatorial from the Royal Observatory, Greenwich. It seemed hardly possible that this instrument, with its wheels and verniers and delicate adjustments, could have escaped uninjured from such a fall. This, however, was the case ; and during the day all the overturned instruments were restored to their places, and found to be in practical working order. This and the following day were devoted to incessant schooling. I had come out as a general star-gazer, and not with the intention of devoting myself to the observation of any particular phenomenon. I wished to see the whole—the first contact, the advance of the moon, and the successive swallowing up of the solar spots, the breaking of the last line of crescent by the lunar mountains into Bailey's beads, the advance of the shadow through the air, the appearance of the corona and prominences at the moment of totality, the radiant streamers of the corona, the internal structure of the flames, a glance through a polariscope, a sweep round the Iandscape with the naked eye, the reappearance of the solar limb through Bailey's beads, and, finally, the retreat of the lunar shadow through the air.
For these observations I was provided with a telescope of admirable definition, mounted, adjusted, packed, and most liberally placed at my disposal by Mr. Warren De la Rue. The telescope grasped the whole of the sun, and a considerable portion of the space surrounding it. But it would not take in the probable extreme limits of the corona. For this the ' finder' was suitable ; but, instead of it, I had lashed ou to the large telescope a light but powerful instrument, constructed by Ross, and lent to me by Mr. Huggins. I was also furnished with an excellent binocular by Mr. Dallmeyer. In fact, no man could have been more efficiently supported than I was. It required a strict parcelling out of the two minutes and some seconds of totality to embrace in them the entire series of observations. These, while the sun remained visible, were to be made with an unsilvered diagonal eyepiece, which reflected but a small fraction of the sun's light, this fraction being still further toned down by a dark glass. At the moment of totality the dark glass was to be removed, and a silver reflector pushed in, so as to get the maximum of light from the corona and prominences. The time of totality was distributed as follows :
1. Observe approach of shadow through the air: totality.
2. Telescope 30 seconds.
It was proposed to begin and end with the telescope, so that any change in the field of view occurring during the totality might be noticed, Elliot stood beside me, watch in hand, and furnished with a lantern. He called out at the end of each interval, and I moved from telescope to finder, from finder to polariscope, from polariscope to naked eye, from naked eye back to finder, from finder to telescope, abandoning the instrument finally to observe the retreating shadow. All this we went over twenty times, while looking at the actual sun, and keeping him in the middle of the field. It was my object to render the repetition of the lesson so mechanical as to leave no room for flurry, forgetfulness, or excitement. Volition was not to be called upon, nor judgment exercised, but a well-beaten path of routine was to be followed. Had the opportunity occurred, I think the' programme would have been strictly carried out.
But the opportunity did not occur. For several days the weather had been ill-natured. We had wind so strong as to render the hawsers at the stern of the ' Urgent' as rigid as iron, and, therefore, to destroy the navigating lieutenant's sleep. We had clouds, a thunder-storm, and some rain. Still the hope was held out that the atmosphere would cleanse itself, and if it did we were promised an air of extraordinary limpidity. Early on the 22nd we were all at our posts. Spaces of blue in the early morning gave us some encouragement, but all depended on the relation of these spaces to the surrounding clouds. Which of them were to grow as the day advanced ? The wind was high, and to secure the steadiness of my instrument I was forced to retreat behind a projection of the bastionet, place stones upon its stand, and, further, to avail myself of the shelter of a sail. My practised men fastened the sail at the top, and loaded it with boulders at the bottom. It was tried severely, but it stood firm.
The clouds and blue spaces fought for a time with varying success. The sun was hidden and revealed at intervals, hope oscillating in synchronism with the changes of the sky. At the moment of first contact a dense cloud intervened, but a minute or two afterwards the cloud had passed, and the enchroachment of the black body of the moon was evident upon the solar disc. The moon marched onward, and I saw it at frequent intervals; a large group of spots were approached and swallowed up. Subsequently I caught sight of the lunar limb as it cut through the middle of a large spot. The spot was not to be distinguished from the moon, but rose like a mountain above it. The clouds, when thin, could be seen as grey scud drifting across the black surface of the moon ; but they thickened more and more, and made the intervals of clearness scantier. During these moments I watched with an interest bordering upon fascination the march of the silver sickle of the sun across the field of the telescope. It was so sharp and so beautiful. No trace of the lunar limb could be observed beyond the sun's boundary. Here, indeed, it could only be relieved by the corona, which was utterly cut off by the dark glass. The blackness of the moon beyond the sun was, in fact, confounded with the blackness of space.
Beside me was Elliot with the watch and lantern, while Lieutenant Archer, of the Royal Engineers, had the kindness to take charge of my note-book. I mentioned, and he wrote rapidly down, such things as seemed worthy of remembrance. Thus my hands and mind were entirely free ; but it was all to no purpose. A patch of sunlight fell and rested upon the landscape some miles away. It was the only illuminated spot within view. But to the north-west there was still a space of blue which might reach us in time. Within seven minutes of totality another small space towards the zenith became very dark. The atmosphere was, as it were, on the brink of a precipice ; it was charged with humidity, which required but a slight chill to bring it down in clouds. This was furnished by the withdrawal of the solar beams ; the clouds did come down, covering up the space of blue on which our hopes had so long rested. I abandoned the telescope and walked to and fro, like a leopard in its cage. As the moment of totality approached, the descent towards darkness was as obvious as a falling stone. I looked towards a distant ridge, where I knew the darkness would first appear. At the moment a fan of beams, issuing from the hidden sun, was spread out over the southern heavens. These beams are bars of alternate light and shade, produced in illuminated haze by the shadows of floating cloudlets of varying density. The beams are really parallel, but by an effect of perspective they appear divergent, like a fan, having the sun, in fact, for their point of intersection. The darkness took possession of the ridge to which I have referred, lowered upon M. Janssen's observatory, passed over the southern heavens, blotting out the beams as if a sponge had been drawn across them. It then took successive possession of three spaces of blue sky in the south-eastern atmosphere. I again looked towards the ridge. A glimmer as of day-dawn was behind it, and immediately afterwards the fan of beams which had been for more than two minutes absent revived. The eclipse of 1870 had ended, and, as far as the corona was concerned, we had been defeated.
Even in the heart of the eclipse the darkness was by no means perfect. Small print could be read. In fact, the clouds which rendered the day a dark one, by scattering light into the shadow, rendered it less intense than it would have been had' the atmosphere been without cloud. In the more open spaces I sought for stars, but could find none. There was a lull in the wind before and after totality, but during the totality the wind was strong. I waited for some time on the bastionet, hoping to get a glimpse of the moon on the opposite border of the sun, but in vain. The clouds continued, and some rain fell. The day brightened somewhat afterwards, and, having packed all up, in the sober twilight Mr. Crookes and myself climbed the heights above the fort of Vera Cruz. From this eminence we had a very noble view over the Mediterranean and the flanking African hills. The sunset was remarkable, and the whole outlook exceedingly fine.
The able and well-instructed medical officer of the ' Urgent,' Mr. Goodman, observed the following temperatures during the progress of the eclipse :
Hour Deg. Hour Deg.
11.45 . . 56 12.43 51
The minimum temperature occurred some minutes after totality, when a slight rain fell.
The wind was so strong on the 23rd that Captain Henderson would not venture out. Guided by Mr. Goodman, I visited a cave scooped into a remarkable' stratum of shell-breccia, and, thanks to my guide, secured specimens. Mr. Busk informs me that a precisely similar breccia is found at Gibraltar at approximately the same level. During the after-noon Admiral Ommaney and myself drove to the fort of Marsa el Kibir. The fortification is of ancient origin, the Moorish arches being still there in decay, but the fort is now very strong. About four or five hundred dragoons, fine-looking men, were looking after their horses, waiting for a lull to enable them to embark for France. One of their officers was wandering in a very solitary fashion over the fort. We had some conversation with him. He had been at Sedan, had been taken prisoner, but had effected his escape. He shook his head when we spoke of the termination of the war, and predicted its long continuance. There was bitterness in his tone as he spoke of the charges of treason which had been so lightly levelled against French commanders. The green waves raved round the promontory on which the fort stands, smiting the rocks, breaking into snow, and jumping, after impact, to a height of a hundred feet and more into the air. On our return our vehicle broke down through the loss of a wheel. The Admiral went on board, while I hung long over the agitated sea. The little horses of Oran well merit a passing ward. Their speed and endurance, which are both heavily drawn upon by their drivers, are extra-ordinary.
The wind sinking, we lifted anchor on the 24th. For some hours we went pleasantly along ; but during the afternoon the storm revived, and it blew heavily against us all the night. When we came opposite the Bay of Almeria, on the 25th, the captain turned the ship, and steered into the bay, where, under the shadow of the Sierra Nevada, we passed Christmas night in peace. Next morning ' a rose of dawn' rested on the snows of the adjacent mountains, while a purple haze was spread over the lower hills. I had no notion that Spain possessed so fine a range of mountains as the Sierra Nevada. The height is considerable, but the form also is such as to get the maximum of grandeur out of the height. We got away at eight A.M., passing for a time through shoal water, the bottom of which had been evidently stirred up. The adjacent land seemed eroded in a remarkable manner. Doubtless it has its times of flood, which excavate these valleys and ravines, and leave those singular ridges behind. Towards evening I climbed the mainmast, and, standing on the crosstrees, saw the sun set amid a blaze of fiery clouds. The wind was strong and bitterly cold, and I was glad to return to the deck along a rope which stretched from the mast-head to the ship's side. That night we cast anchor beside the Mole of Gibraltar.
On the morning of the 27th, in company with two friends, I drove to the Spanish lines, with the view of seeing the rock from that side. It is an exceedingly noble mass. The Peninsular and Oriental mail-boat had been signalled and had come. Heavy duties called me homeward, and by transferring myself from the ' Urgent' to the mail-steamer I should gain three days. I hired a boat, rowed to the steamer, learned that she was to start at one, and returned with all speed to the ' Urgent' Making known to Captain Henderson my wish to get away, he expressed doubts as to the possibility of reaching the mail-steamer in time. With his accustomed kindness, he, however, placed a boat at my disposal. Four hardy fellows and one of the ship's officers jumped into it; my luggage, hastily thrown together, was tumbled in afterwards, and we were immediately on our way. We had nearly four miles to row in about twenty minutes ; but we hoped the mail-boat might not be punctual. For a time we watched her anxiously ; there was no motion ; we came nearer, but the flags were not yet hauled in. The men put forth all their strength, animated by the exhortations of the officer at the helm. The roughness of the sea rendered their efforts to some extent nugatory : still we were rapidly approaching the steamer. At length she moved, punctually almost to the minute, at first slowly, but soon with quickened pace. We turned to the left, so as to cut across her bows. Five minutes' pull would have brought us up to her. The officer waved his cap and I my hat. 'If they could only see us, they might back to us in a moment.' But they did not see us, or if they did, they paid no attention to us. I returned to the ' Urgent,' discomfited, but grateful to the fine fellows who had wrought so hard to carry out my wishes.
Glad of the quiet, in the sober afternoon I took a walk towards Europa Point. The sky darkened, and heavy squalls passed at intervals. Rain began to fall, and I returned home. Private theatricals were at the Convent, and the kind and courteous Governor had sent cards to the eclipse party. I failed in my duty in not going. I had heard of St. Michael's Cave as rivalling, if not outrivalling, the Mammoth Cave of Kentucky. On the 28th Messrs. Crookes, Carpenter, and myself, guided by a military policeman who understood his work, explored the cavern. The mouth is about 1,100 feet above the sea. We zigzagged up to it, and first were led into an aperture in the rock some height above the true entrance of the cave. In this upper cavern we saw some tall and beautiful stalactite pillars.
The water drips from the roof charged with bicarbonate of lime. Exposed to the air, the carbonic acid partially escapes, and the simple carbonate of lime, which is hardly at all soluble in water, deposits itself as a solid, forming stalactites and stalagmites. Even the exposure of chalk or lime-stone water to the open air partially softens it. A specimen of the Redbourne water exposed by Messrs. Graham, Miller, and Hofmann in a shallow basin, fell from eighteen degrees to nine degrees of hardness. The softening process of Clark is virtually a hastening of the natural process. Here, however, instead of being permitted to evaporate, half the carbonic acid is appropriated by lime, the half thus taken up, as well as the remaining half, being precipitated. The solid precipitate is permitted to sink, and the clear supernatant liquid is limpid soft water.
We returned to the real mouth of St. Michael's Cave, which is entered by a wicket. The floor was somewhat muddy, and the roof and walls were wet. Our guide took off his coat, but we did not follow his example. We were soon in the midst of a natural temple, where tall columns sprang complete from floor to roof, while incipient columns were growing to meet each other, upwards and downwards. The water which trickles from the stalactite, after having in part yielded up its carbonate of lime, falls upon the , floor vertically underneath, and there builds the stalagmite. Consequently, the pillars grow from above and below simultaneously along the same vertical. It is easy to distinguish the stalagmitic from the stalactitic portion of the pillars. The former is always divided into short segments by protuberant rings, as if deposited periodically, while the latter presents a uniform surface. In some cases the points of inverted cones of stalactite rested on the centres of pillars of stalagmite. The process of solidification and the architecture were alike beautiful.
We followed our guide through various branches and arms of the cave, climbed and descended steps, halted at the edges of dark shafts and apertures, squeezed ourselves through narrow passages, where the sober grey of my coat suffered less than the black of my companions'. From time to time we halted, while Mr. Crookes illuminated with ignited magnesium wire the roof, columns, dependent spears, and graceful drapery of the stalactite. Once, coming to a magnificent cluster of icicle-like spears, we helped ourselves to specimens. There was some difficulty in detaching the more delicate ones, their fragility was so great. A consciousness of vandalism which smote me at the time haunts me still ; for, though our requisitions were moderate, this beauty ought not to be at all invaded. Pendent from the roof in their natural habitat, nothing can exceed their delicate beauty; they live, as it were, surrounded by organic connections. In London they are curious, but not beautiful. Of gathered shells Emerson writes :
I wiped away the weeds and foam,
The promontory of Gibraltar is so burrowed with caverns that it has been called the Hill of Caves. They are apparently related to the geologic disturbances which the rock has undergone. The earliest of these is the tilting of the once horizontal strata. Suppose a force acting upon the promontory at its southern extremity, near Europa Point, tending to twist the strata in a direction opposed to that of the hands of a watch, and suppose the rock to be of a partially yielding character, such a force would turn the strata into screw-surfaces, the greatest amount of twisting being endured near the point of application of the force. Such a twisting the rock appears to • have suffered ; but instead of the twist fading gradually and uniformly off in passing from south to north, the want of uniformity in the material has produced lines of dislocation where there are abrupt changes in the amount of twist. Thus, at the northern end of the rock the dip to the west is nineteen degrees ; in the middle hill it is thirty-eight degrees ; in the centre of the south hill, or Sugar Loaf, it is fifty-seven degrees. At the southern extremity of the Sugar Loaf the strata are vertical, while further to the south they actually turn over and dip to the east.
The rock is thus divided into three sections, separated from each other by surfaces of dislocation, where the rock is much wrenched and broken. These places of dislocation are called the Northern and Southern Quebrada, from the Spanish ' Tierra Quebrada,' or broken ground ; and it is at these places that the inland caves of Gibraltar are almost exclusively found. Based on the observations of Dr. Falconer and himself, an excellent and most interesting account of these caves, and of the human remains and works of art which they contain, was given by Mr. Busk at the meeting of the Congress of Prehistoric Archaeology at Norwich, and after-wards printed in the ' Transactions' of the Congress.' Long subsequently to the operation of the twisting force just referred to, the promontory underwent various changes of level. There are sea-terraces and layers of shell-breccia along its flanks, and numerous caves which, unlike the inland one, are the product of marine erosion. The Apes' Hill, on the African side of the strait, Mr. Busk informs me has undergone similar disturbances.'
In the harbour of Gibraltar, on the morning of our departure, I resumed a series of observations on the colour of the sea. On my way out I had collected a number of specimens, with a view to subsequent examination. But the bottles were claret bottles, and I could by no means feel sure of their purity. At Gibraltar, therefore, I purchased fifteen white glass bottles, with ground glass stoppers, and at Cadiz, thanks to the friendly guidance of Mr.. Cameron, I secured a dozen more. These seven-and-twenty bottles were filled with water, taken at different places between Oran and Spithead.
And here let me express my warmest acknowledgments to Captain Henderson, the commander of H.M.S. ' Urgent,' who aided me in my observations in every possible way. Indeed, my best thanks are due to all the officers for their unfailing courtesy and help. The captain placed at my disposal his own coxswain, an intelligent fellow named Thorogood, who skilfully attached a cord to each bottle, weighted it with lead, cast it into the sea, and, after three successive rinsings, filled it under my own eyes. The contact of jugs, buckets, or other vessels was thus avoided, and even the necessity of pouring the water out afterwards through the dirty London air.
The mode of examination applied to these bottles after my return to London is in some sense complementary to that of the microscope, and may I think materially aid enquiries conducted with that instrument. In microscopic examination attention is directed to a small portion of the liquid, the aim being to detect the individual suspended particles. In my case, a large portion of the liquid is illuminated by a powerfully condensed beam, its general condition being revealed through the light scattered by suspended particles. Care is taken to defend the eye from the access of all other light, and, thus defended, it becomes an organ of inconceivable delicacy. Were water of uniform density perfectly free from suspended matter, it would, in my opinion, scatter no light at all. The track of a luminous beam could not, I think, be seen in such water. But an amount of impurity so infinitesimal as to be scarcely expressible in numbers, and the individual particles of which are so small as wholly to elude the microscope, may, when examined by the method alluded to, produce not only sensible, but striking, effects upon the eye.
Here, in the first instance, we have three specimens of water, described as green, a clearer green, and bright green, taken in Gibraltar Harbour, at a point two miles 'from the harbour, and off Cabreta Point. The home examination showed that the first was thick with suspended matter, the second less thick, and the third still less thick. Thus the green brightened as the suspended matter be-came less.
Previous to the fourth observation our excellent navigating lieutenant, Mr. Brown, steered along the coast, thus avoiding the adverse current which sets in through the Strait of Gibraltar from the Atlantic to the Mediterranean. He was at length forced to cross the boundary of the Atlantic current, which was defined with extraordinary sharpness. On the one side of it the water was a vivid green, on the other a deep blue. Standing at the bow of the ship, a bottle could be filled with blue water, while at the same moment a bottle cast from the stern could be filled with bright green water. Two bottles were secured, one on each side of this remarkable boundary. In the distance the Atlantic had the hue called ultramarine ; but looked fairly down upon, it was of almost inky blackness—black qualified by a trace of indigo.
What change does the home examination here reveal? In passing to indigo, the water becomes suddenly augmented in purity, the suspended matter has become suddenly less. Off Tarifa, the deep indigo disappears, and the sea is undecided in colour. Accompanying this change, we have a rise in the quantity of suspended matter. Beyond Tarifa, we change to cobalt-blue, the suspended matter falling at the same time in quantity. This water is distinctly purer than the green. We approach Cadiz, and at twelve miles from the city get into yellow-green water ; this the London examination shows to be thick with suspended matter. The same is true of Cadiz Harbour, and also of a point fourteen miles from Cadiz in the homeward direction. Here there is a sudden change from yellow-green to a bright emerald-green, and accompanying the change a sudden fall in the quantity of suspended matter. Between Cape St. Mary and Cape St. Vincent the water changes to the deepest indigo. In point of purity, this indigo water is shown by the home examination to transcend the emerald-green water.
We now reach the remarkable group of rocks called the Burlings, and find the water between the shore and the rocks a strong green ; the home examination shows it to be thick with fine matter. Fifteen or twenty miles beyond the Burlings we come again into indigo water, from which the suspended matter has in great part disappeared. Off Cape Finisterre, about the place where the ' Captain ' went down, the water becomes green, and the home examination pronounces it to be thicker. Then we enter the Bay of Biscay, where the indigo resumes its power, and where the home examination shows the greatly augmented purity of the water. A second specimen of water taken from the Bay of Biscay held in suspension fine particles of a peculiar kind; the size of them was such as to render the water richly iridescent. It showed itself green, blue, or salmon colour, according to the direction of the line of vision. Finally, we come to our last two bottles, the one taken opposite St. Catherine's lighthouse, in the Isle of Wright, the other at Spithead. The sea at both these places was green, and both specimens, as might be expected, were pronounced by the home examination to be thick with suspended matter.
Two distinct series of observations are here referred to—the one consisting of direct observations of the colour of the sea, conducted during the voyage from Gibraltar to Portsmouth ; the other conducted in the laboratory of the Royal Institution. And here it is to be noted that in the home examination I never knew what water I had in my hands. The labels, which had written upon them the names of the localities, had been tied up, all information regarding the source of the water being thus precluded. The bottles were simply numbered, and not till all the waters had been examined were the labels opened, and the locality and sea-colour corresponding to the various specimens ascertained. I must, therefore, have been perfectly unbiassed in my home observations, and they, I think, clearly establish the association of the green colour of sea-water with fine suspended matter, and the association of the ultramarine colour, and more especially of the black-indigo hue of sea-water, with the comparative absence of such matter.
What, in the first place, is the cause of the dark hue of the deep ocean ?' A preliminary remark of two will clear our way towards an explanation. Colour resides in white light, appearing generally when any constituent of the white light is with-drawn. The hue of a purple liquid, for example, Is immediately accounted for by its action on a spectrum. It cuts out the yellow and green, and allows the red and blue to pass through. The blending of these two colours produces the purple. But while the liquid attacks with special energy the yellow and green colours, it enfeebles the whole spectrum ; and by increasing the thickness of the stratum we absorb the whole of the light. The colour of a blue liquid is similarly accounted for. It first extinguishes the red; then, as the thickness augments, it attacks the orange, yellow, and green in succession ; the blue alone finally remaining. But even it might be extinguished by a sufficient depth of liquid.
And now we are prepared for a brief, but tolerably complete, statement of the action of sea-water upon light, to which it owes its darkness. The spectrum embraces three classes of rays—the thermal, the visual, and the chemical. These divisions overlap each other ; the thermal rays are in part visual, the visual rays in part chemical, and vice versa. The vast body of thermal rays is beyond the red, being invisible. These rays are attacked with exceeding energy by water. They are absorbed close to the surface of the sea, and are the great agents in evaporation. At the same time the whole spectrum suffers enfeeblement ; water attacks all its rays, but with different degrees of energy. Of the visual rays, the red are attacked first, and first extinguished. While the red is disappearing the remaining colours are enfeebled. As the solar beam plunges deeper into the sea, orange follows red, yellow follows orange, green follows yellow, and the various shades of blue, where the water is deep enough, follow green Absolute extinction of the solar beam would be the consequence if the water were deep and uniform ; and if it contained no suspended matter, such water would be as black as ink. A reflected glimmer of ordinary light would reach us from its surface, as it would from the surface of actual ink ; but no light, hence no colour, would reach us from the body of the water.
In very clear and very deep sea-water this condition is approximately fulfilled, and hence the extraordinary darkness of such water. The indigo, to which I have already referred, is, I believe, to be ascribed in part to the suspended matter, which is never absent, even in the purest natural water, and in part to the slight reflection of the light from the limiting surfaces of strata of different densities. A modicum of light is thus thrown back to the eye before the depth necessary to absolute extinction has been attained. An effect precisely similar occurs under the moraines of the Swiss glaciers. The ice here is exceptionally compact, and, owing to the absence of the internal scattering common in bubbled ice, the light plunges into the mass, is extinguished, and the perfectly clear ice presents an appearance of pitchy blackness.
The green colour of the sea when it contains matter in a state of mechanical suspension has now to be accounted for, and here, again, let us fall back upon the sure basis of experiment. A strong white dinner-plate was surrounded securely by cord, and had a lead weight fastened to it. Fifty or sixty yards of strong hempen line were attached to the plate. With it in his hand, my assistant, Thorogood, occupied a boat fastened as usual to the davits of the ' Urgent,' while I occupied a second boat nearer to the stern of the ship. He cast the plate as a mariner heaves the lead, and by the time it had reached me it had sunk a considerable depth in the water: In all cases the hue of this plate was green even when the sea was of the darkest indigo, the green was vivid and pronounced. I could notice the gradual deepening of the colour as the plate sank, but at its greatest depth in indigo water the colour was still a blue-green.'
Other observations confirmed this one. The 'Urgent' is a screw steamer, and right over the blades of the screw was an orifice called the screw-well, through which one could look from the poop down upon the screw. The surface glimmer which so pesters the eye was here in a great measure removed. Midway down a plank crossed the screw-well from side to side, and on this I used to place myself to observe the action of the screw underneath. The eye was rendered sensitive by the moderation of the light, and, still further to remove all disturbing causes, Lieutenant Walton had a sail and tarpaulin thrown over the mouth of the well. Underneath this I perched myself and watched the screw. In an indigo sea the play of colour was indescribably beautiful, and the contrast between the water which had the screw-blades for a back-ground, and that which had the bottom of the ocean as a background, was extraordinary. The one was of the most brilliant green, the other of the deepest ultramarine. The surface of the water above the screw-blade was always ruffled. Liquid lenses were thus formed, by which the coloured light was withdrawn from some places and concentrated upon others, the colour being thus caused to flash with metallic lustre. The screw-blades in this case played the part of the plate in the former case, and there were other instances of a similar kind. The white bellies of the porpoises showed the green hue, varying in intensity as the creatures swung to and fro between the surface and the deeper water. Foam, at a certain depth below the surface, is also green. In a rough sea the light which has penetrated the summit of a wave sometimes reaches the eye, a beautiful green cap being thus placed upon the wave even in indigo water.
But how is this colour to be connected philosophically with the suspended particles ? Take the dinner-plate which showed so brilliant a green when thrown into indigo water. Suppose it to diminish in size until it reaches an almost microscopic magnitude. It would still behave substantially as the larger plate, sending to the eye its modicum of green light. If the plate, instead of being a large coherent mass, were ground to a powder sufficiently fine, and in this condition diffused through the clear sea-water, it would send green light to the eye. In fact, the suspended particles which the home examination reveals act in all essential particulars like the plate, or like the screw-blades, or like the foam, or like the bellies of the porpoises. Thus I think the greenness of the sea is physically connected with the matter which it holds in suspension.
We reached Portsmouth on the 5th of January 1871. There ended a voyage which, though its main object was not realised, has left behind it pleasant memories, both of the aspects of nature and the genial kindliness of men.