said that quartz sand can wear a hole through corundum. This leads me to express my acknowledgments to General Tilghman, who is the inventor of the sand-blast. To his spontaneous kindness I am indebted for some beautiful illustrations of his process. In one thick plate of glass a figure has been worked out to a depth of three-eighths of an inch. A second plate seven-eighths of an inch thick is entirely perforated. Through a circular plate of marble, nearly half an inch thick, open work of the most intricate and elaborate description has been executed. It would probably take many days to perform this work by any ordinary process; with the sand-blast it was accomplished in an hour. So much for the strength of the blast; its delicacy is illustrated by a beautiful example of line engraving, etched on glass by means of the blast.f This power of erosion, so strikingly displayed when sand is urged by air,

renders us better able to conceive its ac

tion when urged by water. The erosive power of a river is vastly augmented by the solid matter carried along with it. Sand or pebbles caught in a river vortex can wear away the hardest rock; "potholes" and deep cylindrical shafts being thus produced. An extraordinary instance of this kind of erosion is to be seen in the Val Tournanche, above the village of this name. The gorge at Handeck has been thus cut out. Such waterfalls were once frequent in the valleys of Switzerland; for hardly any valley is without one or more transverse barriers of resisting material, over which the river flowing through the valley once fell as a cataract. Near Pontresina in the Engadin, there is such a case, the hard gneiss being now worn away to form a gorge through which the river from the Morteratsch glacier rushes. The barrier of the Kirchet above Mey

* The absorbent power, if I may use the phrase, exerted by the industrial arts in the United States, is forcibly illustrated by the rapid transfer of men like Mr. Tilghman from the life

of the soldier to that of the civilian. General McClellan, now a civil engineer, whom I had the honor of frequently meeting in New York, is a most eminent example of the same kind. At the end of the war, indeed, a million and a half of men were thus drawn, in an astonishingly short time, from military to civil life. It is obvious

that a nation with these tendencies can have no desire for war.

The sand-blast will be in operation this year at the Kensington International Exhibition. NEW SERIES.-VOL. XVIII., No. 1

ringen is also a case in point. Behind it was a lake, derived from the glacier of the Aar, and over the barrier the lake poured its excess of water. Here the rock being limestone was in great part dissolved, but added to this we had the action of the solid particles carried along by the water, each of which, as it struck the rock, chipped it away like the particles of the sandblast. Thus by solution and mechanical erosion the great chasm of the Fensteraarschlucht was formed. It is demonstrable that the water which flows at the bottoms of such deep fissures once flowed at the level of what is now their edges, and tumbled down the lower faces of the bar

riers.

Almost every valley in Switzerland furnishes examples of this kind; the untenable hypothesis of earthquakes, once so readily resorted to in accounting for these gorges, being now for the most part abandoned. To produce the Cañons of Western America no other cause is needed than the integration of effects individually infinitesimal.

And now we come to Niagara. Soon after Europeans had taken possession of the country, the conviction appears to have arisen that the deep channel of the river Niagara below the falls had been excavated by the cataract. In Mr. Bakewell's "Introduction to Geology," the prevalence of this belief has been referred to it is expressed thus by Professor Joseph Henry in the Transactions of the Albany Institute: "In viewing the position of the falls and the features of the country round, it is impossible not to be impressed with the idea that this great natural raceway has been formed by the continued action of the irresistible Niagara, and that the falls, beginning at Lewistown, have, in the course of ages, worn back the rocky strata to their present site." The same view is advocated by Sir Charles Lyell, by Mr. Hall, by M. Agassiz, by Professor Ramsay, indeed by almost all of those who have inspected the place.

A connected image of the origin and progress of the cataract is easily obtained. Walking northward from the village of Niagara Falls by the side of the river, we have to our left the deep and comparatively narrow gorge through which the Niagara flows. The bounding cliffs of

3

* Quoted by Bakewell. '

this gorge are from 300 to 350 feet high. We reach the whirlpool, trend to the northeast, and after a little time gradually resume our northward course. Finally, at about seven miles from the present Falls, we come to the edge of a declivity which informs us that we have been hitherto walking on table-land. Some hundreds of feet below us is a comparatively level plain, which stretches to Lake Ontario. The declivity marks the end of the precipitous gorge of the Niagara. Here the river escapes from its steep mural boundaries, and in a widened bed pursues its way to the lake which finally receives its

waters.

The fact that in historic times, even within the memory of man, the fall has sensibly receded, prompts the question, how far has this recession gone? At what point did the ledge which thus continually creeps backwards begin its retrograde course? To minds disciplined in such researches the answer has been and will be, at the precipitous declivity which crossed the Niagara from Lewiston on the American to Queenston on the Canadian side. Over this transverse barrier the united affluents of all the upper lakes once poured their waters, and here the work of erosion began. The dam, moreover, was demonstrably of sufficient height to cause the river above it to submerge Goat Island; and this would perfectly account for the finding by Mr. Hall, Sir Charles Lyell, and others, in the sand and gravel of the island, the same fluviatile shells as are now found in the Niagara river higher up. It would also account for those deposits along the sides of the river, the discovery of which enabled Lyell, Hall, and Ramsay to reduce to demonstration the popular belief that the Niagara once flowed through a shallow valley.

The physics of the problem of excavation, which I made clear to my mind before quitting Niagara, are revealed by a close inspection of the present Horseshoe Fall. Here we see evidently that the greatest weight of water bends over the very apex of the Horseshoe. In a passage in his excellent chapter on Niagara Falls, Mr. Hall alludes to this fact. Here we have the most copious and the most violent whirling of the shattered liquid; here the most powerful eddies recoil against the shale. From this portion

of the fall, indeed, the spray sometimes rises without solution of continuity to the region of clouds, becoming gradually more attenuated, and passing finally through the condition of true cloud into invisible vapor, which is sometimes reprecipitated higher up. All the phenomena point distinctly to the centre of the river as the place of greatest mechanical energy, and from the centre the vigor of the Fall gradually dies away towards the sides. The horseshoe form, with the concavity facing downwards, is an obvious and necessary consequence of this action. Right along the middle of the river the apex of the curve pushes its way backwards, cutting along the centre a deep and comparatively narrow groove, and draining the sides as it passes them.* Hence the remarkable discrepancy between the widths of the Niagara above and below the Horseshoe. All along its course, from Lewiston Heights to its present position, the form of the Fall was probably that of a horseshoe; for this is merely the expression of the greater depth, and consequently greater excavating power, of the centre of the river. The gorge, moreover, varies in width as the depth of the centre of the ancient river varied, being narrowest where that depth was greatest.

The vast comparative erosive energy of the Horseshoe Fall comes strikingly into view when it and the American Fall are compared together. The American branch of the upper river is cut at a right angle by the gorge of the Niagara. Here the Horseshoe Fall was the real excavator. It cut the rock and formed the precipice over which the American Fall tumbles. But since its formation, the erosive action of the American Fall has been almost ́nil, while the Horseshoe has cut its way for 500 yards across the end of Goat Island, and is now doubling back to excavate a channel parallel to the length of the island. This point, I have just learned, has not escaped the acute observation of Professor Ramsay. The river bends; the Horse

*In the discourse of which this paper is a re port, the excavation of the centre and drainage of the sides was illustrated by a model devised by my assistant, Mr. John Cottrell.

His words are:-"Where the body of water is small in the American Fall, the edge has only receded a few yards (where most eroded) during the time that the Canadian Fall has receded from the north corner of Goat Island to the innermost

shoe immediately accommodates itself to the bending, and will follow implicitly the direction of the deepest water in the upper stream. The flexibility of the gorge, if I may use the term, is determined by the flexibility of the river channel above it. Were the Niagara above the Fall sinuous, the gorge would obediently follow its sinuosities. Once suggested, no doubt geographers will be able to point out many examples of this action. The Zambesi is thought to present a great difficulty to the erosion theory, because of the sinuosity of the chasm below the Victoria Falls. But assuming the basalt to be of tolerably uniform texture, had the river been examined before the formation of this sinuous channel, the present zigzag course of the gorge below the Fall could, I am persuaded, have been predicted, while the sounding of the present river would enable us to predict the course to be pursued by the erosion in the future.

But not only has the Niagara river cut the gorge; it has carried away the chips of its own workshop. The shale being probably crumbled is easily carried away. But at the base of the fall we find the huge boulders already described, and by some means or other these are removed down the river. The ice which fills the gorge in winter, and which grapples with the boulders, has been regarded as the transporting agent. Probably it is so to some extent. But erosion acts without ceasing on the abutting points of the boulders, thus withdrawing their support and urg

ing them gradually down the river. Solution also does its portion of the work. That solid matter is carried down is proved by the difference of depth between the Niagara river and Lake Ontario, where the river enters it. The depth falls from seventy-two feet to twenty feet, in consequence of the deposition of solid matter caused by the diminished motion of the river.*

In conclusion, we may say a word regarding the proximate future of Niagara. At the rate of excavation assigned to it by Sir Charles Lyell, namely, a foot a year, five thousand years or so will carry the Horseshoe Fall far higher than Goat Island. As the gorge recedes it will drain, as it has hitherto done, the banks right and left of it, thus leaving a nearly level terrace between Goat Island and the edge of the gorge. Higher up it will totally drain the American branch of the river; the channel of which in due time will become cultivable land. The American Fall will then be transformed into a dry precipice, forming a simple continuation of the cliffy boundary of the Niagara. At the place occupied by the fall at this moment we shall have the gorge enclosing a right angle, a second whirlpool being the consequence of this. To those who visit Niagara a few millenniums hence I leave the verification of this prediction. All that can be said is, that if the causes now in action continue to act, it will prove itself literally true,-Macmillan's Magazine.

IN the year 1863, shortly after the last visit paid by Mr. Senior to Paris, he selected from his journals the conversations which threw most light upon the character of Louis Napoleon.

Many of them were with statesmen who are still playing a distinguished part in public life, and could not therefore be published with the names of the speakers. Thus their chief value would be lost. But the same objection does not apply to the most interesting portion of the book: the conversations with Madame R., a lady who was brought up as a sister with the Em

curve of the Horseshoe Fall."-Quarterly Fournal of Geological Society, May 1859.

peror, and who continued her intimacy with him till the Coup d'état, which she, as a woman of integrity, and a staunch Republican, could not forgive.

Mr. Senior made her acquaintance in 1854, shortly before the Crimean War.

February 17, 1854.-I went in the evening to Mdme. Mohl's and found there Madame R. We began, of course, with the letter of Louis Napoleon to the Czar :

"It was Louis Philippe," said Madame R.," that made Louis Napoleon un homme

* Near the mouth of the gorge at Queenston, the depth, according to the Admiralty Chart, is 180 feet; well within the gorge it is 132 feet.

de lettres. It was at Ham that he acquired the habit of solitary study and meditation. The lesson was a useful one, but it lasted too long. For five years his health and mental activity were unimpaired, but in the sixth he began to droop. He would have become stupid, perhaps mad, if it had continued."

"I have always suspected," I said, "that the French Government connived at his escape."

66

"Your suspicion," she said, was perfectly unfounded. The French Government took every precaution in its power to prevent it. If you like I will tell you the whole story.

"His apartment was at the bottom of a court; on each side of the door was a bench on which sat a gendarme. The sentinels at the gate of the fortress allowed no one to pass without calling for the concierge to examine him. The gendarmes and the concierge were well acquainted with his features. When he had formed his plans, he did all the damage he could to his rooms, and then complained of their dilapidated state. Some workmen were sent in to repair them. His servant was allowed to go to a neighboring town, about a couple of miles off, to buy books and execute commissions, and for that purpose to hire a one horse carriage, which he drove himself. Through him Louis Napoleon obtained a workman's dress,* and could have a carriage to meet him. The workmen were to be twenty-four days at work. He waited till the twenty-third to accustom, as he says, the guards to see the workmen coming and going, but also, I think, from his habit of procrastination. At length, about a quarter to seven in the morning, at the time when he supposed the two gendarmes would be at breakfast, sitting with their sides to the door, he went out with a plank on his shoulder. But he was five minutes too late. They had finished, and thier faces were towards him. He thought himself lost, and intentionally let the plank strike the head of the man on his right. This succeeded; the man who was struck thought only of his head-the other ran to assist him, and while they were abusing him for his awkwardness he walked on, knowing that they would

* This workman's name was Badinguay, hence one of the nicknames of Louis Napoleon.-M. C.

M. S.

not quit their posts to follow and recognise him. The soldier at the gate knew him, smiled, and, without calling the concierge, said, 'Passez.' A hundred yards from the gate his servant met him with the carriage. and his dog. The dog, not being in the secret, leapt on him with great demonstrations of joy. This was seen by a sentinel on the rampart, who knew the dog, but he was as discreet as the man at the gate had been. They drove straight towards the Belgian frontier, and reached it in about five hours.

"In the meantime the Commandant, whose duty it was to see Louis Napoleon three times a day, came to pay his first visit at seven o'clock. Louis Napoleon had been complaining of illness for some days, and his physician, who was in the plot, stopped the Commandant in the antechamber, and begged him to go no further, as his patient, after a very bad night, was sleeping. The Commandant acquiesced, and returned at two for his second visit. The same answer was given: Louis Napoleon was still sleeping. This is very serious,' said the Commandant. 'Do you apprehend danger?' 'I do,' said the physician, 'I do not think that he is quite safe.' 'Then,' said the Commandant, I must send a telegraphic message to Paris; what would become of us if he were to die in our hands? And for that purpose I must actually see him.' 'You can see him, of course,' said the physician, but, whatever the danger may be, and I have not much fear, it will be increased if you wake him.' Then,' said the Commandant, ‘I will sit by his bedside till he awakes naturally, that no time may be lost in sending to Paris.' They went into the room and sat at the side and the foot of the bed, in which lay a figure wrapped in bed-clothes and a nightcap, with its face to the wall. After a quarter of an hour, the Commandant exclaimed, 'I do not see him breathe, he must be dead.' The physician was silent, the Commandant turned down the clothes, and found a stuffed figure.

"Of course the telegraph was set to work, and pursuit was made on every road but Louis Napoleon had been in Belgium an hour before he was missed."

Wednesday, April 19, 1854.-I called early this morning on Madame R. Her brother is the architect who superintends the works at the Elysée.

His story to her was, that at seven in the morning of Good Friday, the Emperor and the Empress met him at the Elysée, and she told him that she must give a ball on Monday to the Duke of Cambridge, that there was a difficulty in doing so at the Tuileries, and that he must get ready the Elysée for it.

"But," he said, "there are 3,000 cubic yards of stone in the court, there is no staircase, the walls are mere wet stone and mortar, nothing in fact is finished, except the roof; it is impossible;" and he looked. towards the Emperor for protection. "C'est un caprice de femme," said the Emperor. "I am sure," said the Empress, "that nothing is impossible to you." he promised it. The workmen who had gone home were sent for, and 400 of them were kept at work from that time until Monday evening, when the ball began. They were well fed, and a little brandy was added to their wine. When they left off they had been at work for nearly eightytwo consecutive hours: that is, from the morning of Good Friday until the evening of Easter Monday. In that time, besides fitting up the existing rooms, they had built three kitchens and a new ball-room in the garden, 90 feet by 35, and 30 feet high. All night they had 700 lamps, and thirty men carrying torches. One of their difficulties was the presence every day of the Empress, ordering, interfering, and not understanding technical objections. On Monday morning the Emperor came. looked with dismay at the court, still covered with the 3,000 square yards of stone, and at the gap where the staircase was to be. Lacroix then explained to him that he meant to employ these vast masses of stone in building up a vast straight outside staircase, from the court to the first floor, protected by a roof of glass. This was done by seven o'clock that evening, and while it was doing, 400 loads of rubbish were carted out. The poor architect was nearly killed by the incessant worry, want of sleep, and fatigue. "He seemed to me, yesterday," said Madame R., "to have grown ten years older in four days.

He

"It is remarkable," she continued, "that while this was going on in the house of the head of the State, the head of the Church was publishing from every pulpit in Paris, a protest against Sunday labor. The circular of the Archbishop of Paris on the Repos du dimanche,' which was read

throughout his diocese on Easter Sunday, denounces such labor as sacrilege and cruelty, as insolently disobedient to God, oppressive to the laboring classes, and degrading to the national character. The Archbishop must have felt secure in popular sympathy when he ventured to choose such a moment to rebuke his most Christian Majesty. The matter seems trifling, but its childish recklessness will do Celuici* great mischief; not the less because the ball was given to an English Prince.”

June 10, 1855.—I breakfasted with the Mohls, and met there Madame R. Joseph's letters were mentioned, and some one expressed surprise at Louis Napoleon's having allowed a work so injurious to the moral character of his uncle to appear.

"I doubt," said Madame R., "whether, supposing him to have moral sense sufficient to perceive the immorality of Napoleon's letters, he would have thought that an objection to their publication. He is beginning to be jealous of his uncle. He hopes to become his rival. At first he was satisfied to be Augustus-now he wishes to be also Cæsar.

"He has mistaken," she added, "his vocation. He aspires to be a statesman, perhaps to be a soldier—what nature intended him for was a poet. He has an inventive, original, and powerful imagination, which, under proper training, would have produced something great."

"Is his taste good ?" I asked. "He cannot tolerate French poetry," she answered. "He is insensible to Racine, but he delights in Shakespeare, Goethe, and Schiller. The great, the strange, and the tragic, suit his wild and somewhat vague habits of thought and his melancholy temperament. Of the fine arts the only one that interests him is architecture, probably from the vastness of its products. He hates music, and does not understand painting or sculpture.

"Among the mistakes," she added, "which the public makes with respect to that family, one of the greatest is the treating Jerome as an unimportant member of it. Jerome has as much courage and as much ambition as Louis Napoleon himself. His ambition, however, is less selfish, for it looks towards his heir. He idolises his son, and in the improbable event of his

* Louis Napoleon.-M. C. M. S.