year, now show nothing but dry and stony channels, excepting when refilled for a time by occasional floods of rain.

in suspension, must have been scattered across the plains by the swollen waters; for it is the habit with large glacier rivers to be constantly changing their courses, and often disastrously to ravage the plains through which they flow. This is the reason why so much of the plains of Piedmont is covered by rounded stony debris, which to a great extent represents the water-worn débris of ancient moraines, the very relics of which still form important ranges of hills (comparable in the flatness of their tops to the Cotswolds seen from the valley of the Severn), rising above the plain of Piedmont to nearly half the height of Snowdon. The gravels of the great plain of the Rhine below Basle were probably formed in the same manner.

which, began thousands of years before history began, has largely altered the face of the country within historic times, and is powerfully in action at the present day.

The woods of the lowlands would therefore only tend to keep the Po unaffected by droughts, and always comparatively full; but what connection may the vast glaciers of the period have had on the average size and intermittent flooding of the river? It is difficult to answer this question with precision, but it seems certain that the outflow from the ends of the glaciers must have been smallest in winter and largest in summer. Such rains as there were in summer-time would chiefly fall on the plains and help to keep the river full as it slowly drained off the lowlying lands, and in the same season the summer heats, though far less intense than It will now be easily understood how now, would at intervals tend to melt the the vast plains that bound the Po and its surface of the glaciers beyond the usual tributaries were gradually formed by the average and swell the Po considerably constant annual increase of river gravels above its ordinary size, just as the glaciers and finer alluvia, and how these sediments of Spitzbergen and the southern half of rose in height by the overflow of the Greenland of the present day, in the sum-waters, and steadily encroached upon the mer, deliver an extra amount of water. sea by the growth of the delta; a process Everyone familiar with Alpine glaciers has seen in hot weather the wonderful daily rise and fall of the rivers that flow from their ends, dependent on the direct heat of the sun, and its withdrawal when sunset comes on; and the same effect on a larger scale accompanies the summer heat and the winter cold. Such must have been the case during the alternation of the seasons when the great old glaciers of the Alps filled to the brim the valleys of the | Rhone and the Rhine; and the same was the case in the valley of Aosta and many another valley both deep and long, whose tributary streams, some of them passing through lakes, still help to swell the Po. But even in winter, with the climate of the period, there could have been no great diminution of the average volume of water, for in thick glacier ice, a few feet beneath the surface, even with the temperature of the air far below zero (Fahr.), the whole of the under-ice is just about the meltingpoint; and in the very north of Greenland the sub-glacier rivers still never cease to pour forth perennial streams, often deep below the level of the sea, where glaciers sometimes protrude for miles beyond the

coast.

When we consider the vast size of the moraines shed from the ancient glaciers that fed the Po, it is evident that at all times, but especially during floods, vast havoc must often have occurred among the masses of loose débris. Stones, sand, and mud, rolled along the bottom and borne on

To persons accustomed to think of the world as having always been what we now see it, it is hard to realize such facts as these facts, too, that only relate to a very small portion of a late minor epoch in the geological history of the earth. And yet how greatly suggestive they are! Through all this time (and long before) the mountains have constantly been wasting away, and their crests getting lowered; the valleys, so many of which send tributary streams to the Po, have been widening on the upper slopes and deepening below, at one time by the power of ice, and now by the action of the petty glaciers which we are accustomed to esteem so large, combined with winds, frost, rain, and the torrents that tear along their bottoms. It has been estimated by Professor Geikie that the area drained by the Po is on an average being lowered foot in 729 years, and a corresponding amount of sediment carried away by the river.

one

To take an example-let us try rudely to estimate the quantity of matter still remaining in the moraine of the Dora Baltea, of which so much has already been carried away to form the alluvial plains of the Po and to help to enlarge its present delta. The circuit of the moraine is 'about sixty miles, its breadth in places

about seven, and its height above 1,600 for a length of about 200 miles from feet. Let us attempt au average, and call Piacenza to its mouth, and throughout its height only 500 feet, and its breadth this course its breadth varies, from 400 to three miles; then the total amount of 600 yards. Through all its many winddébris in the moraine is 225,781,000,000 ing, from Chivasso downward, alluvial cubic yards of material, or, in printed islands diversify its course, and deserted words, two hundred and twenty-five thou- channels here and there mark the anc ́ent sand seven hundred and eighty-four mil- aberrations of the river. To guard against lions of cubic yards of debris. And this is the devastating effects of floods and to only a relic of what was originally worn check such aberrations, the dikes were away from the old Alps; for when the raised; and in this contest of man with rubbish was being deposited, the chief Nature, the result has been that the allubusiness of the streams that flowed from vial flats on either side of the river outthe end of the glacier was constantly to side the dikes have for long received but dispose of the moraine material and to little addition of surface sediment, and bear away it to lower levels. What may their level is nearly stationary. It thus be said of the Dora Baltea may be said of happens that most of the sediment that in many another Alpine river and moraine, old times must have been spread by overon scales almost or perhaps equally great. flows across the land, is now hurried along Furthermore, as already said, one chief towards the Adriatic, there, with the help occupation of the great old glaciers in the of the Adige, steadily to advance the far larger valleys was to scoop out the rock-spreading alluvial flats that form the delta basins, large and small, in which almost of the two rivers. As the embanking of all the lakes on both sides of the Alps now the river went on from age to age, so just lie, and many another lake besides, now in proportion has the annual amount of filled with alluvium and forming broad the formation of the delta been accelerated. meadows. In the Val d'Aosta the flat on The town of Adria, a sea-port of the Adriwhich the town of Aosta stands is a case atic in the reign of Augustus, is now fourin point; and in many another valley in teen miles from the shore, and the ancient the Alps, and in Cumberland and the lagoon of Ravenna has long since been Yorkshire dales, on a smaller scale, the filled up, chiefly by the mud brought down same is apparent. The time indeed must by an ancient arm of the Po. But the come when the lakes of Maggiore, Como, confined river, unable by annual floods to and Lugano, and many another Alpine dispose of part of its sediment, just as the lake besides, shall be filled with alluvium, dikes were increased in height, gradually and become green meadows, unless re- raised its bottom by the deposition there newed upheavals of the Alps should take of a portion of the transported material, place, of a kind slow to the eye yet com- so that to prevent its overflow it is said paratively quick, though by no means sud- that the embankments have been raised den, in the sense in which man under-so high that at Ravenna the full-flooded stands the word.

When the day arrives in which the great Italian lakes shall be filled with alluviu a, a new modification of the history of the Po may commence, and its delta and the filling up of the Adriatic will advance more rapidly than before.

All these considerations help to show, though only in part, how complicated is the history of any great river; but before closing this sketch something may be said about the later history of the Po.

It is hard to get at the historical records of the river more than two thousand years ago, though we may form a good guess as to its earlier geological history. Within the historical period extensive lakes and marshes (some of them probably old sea lagoon) lay within its plains, since gradually filled with sediment by periodical floods. Great lines of dikes, partly of unknown antiquity, border the winding river

river often runs higher than the tops of the houses, and the safety of the neighbouring country is a constant source of anxiety to the inhabitants. All these dangers have been much increased by the wanton destruction of the forest of the Alps and Apennines, for when the shelter of the wood is gone, the heavy rains of summer easily wash the soil from the slopes down into the rivers, and many an upland pasture has by this process been turned into bare rock. In this way it happens that during the historical period the quantity of detritus borne onward by the Po has much increased, the level of its bottom is therefore more rapidly raised, and whereas be tween the years 1200 and 1699 the delta advanced on an average only about twentyfive yards a year, from 1600 to the year 1800 the increase has been more than seventy yards.

At last a season comes like the present,

.

when long-continued rain fails alike on mountains and plains, and the floods, swelled by the rapidly thawing glaciers, steadily increase the volume of the rivers, till at length they rise to the very brims of their embankments; and in spite of the loug-continued precautions of man, the rivers, and most of all the Po, have broken across their prescribed bounds and whelmed in sheets of water hundreds of square miles of the fertile plains of Lombardy. When these vast lakes subside, or are absorbed by the air and the soil, who can estimate the havoc and destruction produced by the whelming waters out of which the tree-tops and roofs of buildings are now standing? Houses and even churches have been swept away, sand and gravel bury the meadows, and many a year must pass before the 20,000 families now houseless shall, by unremittent la- the MS. was submitted, as it was written bour, restore the ravaged fields to their old fertility.

Her first important contribution to science was made in 1826, when she presented to the Royal Society a paper on the magnetizing powers of the more refrangible solar rays, the object of which was to prove that these rays of the solar spectrum have a strong magnetic influence. This paper led to much discussion, which was not set at rest till the researches of Riess and Moser showed that the action upon the magnetic needle was not caused by the violet rays.

Mrs. Somerville's first work of any extent was her "Mechanism of the Heavens" (1831), written at first at the request of Lord Brougham, as one of the series of publications by the Society for the Diffusion of Useful Knowledge. As, however, the work was on too large a scale, and, according to Sir John Herschel, to whom

for posterity, and not for the class whom society designed to instruct, it was pubIt is a hard thing to say, but such is one lished as an independent work, eliciting of the almost inevitable results of man's from all quarters the highest encomiums, struggle with great rivers, when for ages especially as being the work of a woman. he has striven to confine them. But by It was founded to some extent on La foresight and skill much may be done; Place's treatise, though the authoress exand if the great old forests of the moun-ercised her own judgment in the accepttains were allowed to reassert themselves, ance or rejection of his theories. the recurring danger would in time become less than now. But to be even nearly safe, dredging must, if possible, be added to embanking, so as to keep the long incline of the river bottom at an average level, otherwise the time in the far future must come when Nature will of necessity overcome even the best directed efforts of

mau.

born on

From Nature.

MRS. SOMERVILLE.

Her next work "On the Connection of the Physical Sciences," was published in 1831, and was referred to by Humboldt as "the generally so exact and admirable treatise."

In 1818 appeared the work by which, perhaps, she is most generally known, her ·Physical Geography," which, along with some of her other works, has passed through many editions, been reprinted frequently in America, and translated into several foreign languages. Notwithstanding the numerous works on the same subject that have since appeared, Mrs. Sɔmerville's book still holds place as a first authority, even with the initiated.

In 1830 appeared her last work, "On Molecular and Microscopic Science," which, to quote a writer in the Edinburgh Review,

MARY SOMERVILLE (born Fairfax), long ago known for her scientific researches and long well known for her popular and educational scientific works, died in the neighbourhood of Naples, where she has contains a complete conspectus of some lived for some years, on Friday, Novem- of the most recent and most abstruse reber 23, aged nearly 92 years, having been searches of modern science, and describes December 23, 1780. She be-admirably not only the discoveries of our longed to a good Scotch family, her father day in the field of physics and chemistry, having been the late Vice-Admiral Sir but more especially the revelations of the William George Fairfax, was a great microscope in the vegetable and animal reader, learned Euclid surreptitiously while quite a girl, and at the same period got up a knowledge of Latin in order to be able to read Newton's Principia, and was educated at a school in Musselburgh, near Edinburgh.

worlds." The fact that Mrs. Somerville was close on her 90th year when she published this work, in which is contained a résumé of the most interesting results of recent scientific investigations, may give one some idea of the undying vigour and

clearness of her mind, as well as of her intense love of science.

lip, and a host of other women dear to modern publishers, he might have remarked So long ago as 1835 Government recog- that all our ladies write now, which is annized Mrs. Somerville's great merits, by other great extension. He might also bestowing upon her a literary pension of have observed how in these days the bur300; and in the same year she was made den of reading "what the world reads at an honorary member of the Royal Astro- the moment" has become almost greater nomical Society, the only other lady on than we can bear. Under the pressure whom this honour was conferred having of sensational novels and special cerrebeen Miss Caroline Herschel. The Geo- spondence, he might perhaps have become graphical Society awarded Mrs. Somer-less willing to acknowledge the necessity ville the Patron or Victoria Medal in of conforming to the world in this matter. 1869, and about thirty years earlier the Fellows of the Royal Society subscribed for her bust, which was executed by Chantrey, and now adorns the Society's library. She certainly deserved all the honours she obtained, for during her long life she has done very much to raise the standard of scientific text-books, and to spread among general readers the accurate results of scientific research.

Dr. William Somerville was his wife's second husband, her first husband having been Captain Greig, a naval officer, fond of mathematics, and who took pleasure in giving his wife instruction in his favourite subject, thus probably giving her mind a bent towards science which has led to important results.

From The Saturday Review.
READING TRASH.

And if the incautious Boswell were now to confess that, much as he desired to read something solid, he found that the quantity of current literature had grown so enormous that he had no time to spare for anything else, we can well imagine the severity with which he would be rebuked by his venerable friend.

Some men are apt to fancy that reading trash is peculiarly a woman's weakness. "It is perfectly true," they say, "that many of us read little enough of any kind; but what we do read is not suca abominable stuff as what our wives and sisters read." And this hypothesis seems to have lately received some support from the writings and speeches of divers strongminded ladies, who, in pursuit of a more or less worthy object, have paraded before the public the hollowness and frivolity of Englishwomen's lives. But the hypothesis is not altogether defensible. It is true perhaps that women read more of the trash of fiction than men do. But it does not at "WE must read,” said Dr. Johnson, in all follow that, because a man does not read one of his contentious conversations with trashy novels, therefore what he does read Sir Joshua and others, "what the world is worth reading. On the contrary, there reads at the moment." And he added, is probably quite as much unworthy readafter some other remarks, "It must be con- ing among men who read at all as among sidered that we have now more knowledge women. The trash upon which men waste generally diffused. All our ladies read their time is not so much the trash of novnow, which is a great extension." He did els as the trash of newspapers. It is true not stop to criticize the worth of what all perhaps that an excessive devotion to the ladies were reading. He took for newspapers does not produce such palpagranted that the step from reading noth-bly evil effects as are produced by an uning to reading something was a great in- due devotion to novels. But the evil done tellectual advance. And he was quite is nevertheless real and considerable. Exright. We, however, live under somewhat cessive newspaper reading may not stimudifferent literary couditions from those late a morbid self-consciousness, or fill the which prevailed in Dr. Johnson's day. mind with all sorts of absurd fancies about There is a much greater amount of trash friends and enemies, about the tyranny of written now than was written then, and society, the rights and wrongs of lovers, consequently there is a much greater num- | and the poetry of an unreasonable or unber of readers of trash, not only among lawful attachment; but it is nevertheless a women, but among men also, than there sure destroyer of mental health. Its efwas then. The ladies have made a great fect is to corrupt the judgment, to weaken advance since the day when Dr. Johnson the sense of mental discrimination, to dissaid that they all read. Had the learned courage intellectual initiative, and generDoctor been a contemporary of Mrs. Henry ally to deaden the mental powers by subWood, Miss Broughton, Mrs. Pender Cud-stituting a habit of mechanical for a habit

of intelligent reading. The confirmed vague and floating conceptions, and partly news reader the man who reads through, also because they wanted something to at least, the Times before going to business produce in conversation. But now the in the morning, who after business hours necessity for taking even so much mental gets through large portions of one or two trouble as this is removed. The short other morning papers, skims the Pall Mall paragraphs in the evening papers in which Gazette, and dips into the Echo and Globe, it is so neatly and clearly stated what only varying or amplifying his studies, ac- "The Times informs us," what "The Daily cording to the day of the week or the Telegraph believes," and what "The Standamount of his leisure time, by excursions ard laments," answer all the purpose, with into the prolific regions of the weekly, the a tenth of the trouble. They come out monthly, the comic, and the illustrated in plenty of time for dinner-table talk, periodicals, and who finds that all the time and, being done by professionals, are of he can spare for reading is fully occupied course absolutely trustworthy. Consein the pursuit of this fugitive literature- quently all that the inveterate news reader is destroying his brain power as surely as now does is languidly to run his eye over the man who smokes a short pipe at every the leading articles in the hope of encounspare hour is destroying his digestion. tering an anecdote, or a statistical paraAnd yet there are thousands of reason- graph, which shall put facts in a new or able and fairly well-educated men who are surprising form, so as to afford him a senmore or less slaves to such a slovenly sation. All the rest he leaves to the scishabit of reading. Their mode of opera- sors-man of the evening journal, who certion is as follows:- They take up a news-tainly extracts for him the essential thought paper, and turn first of all to the tele- of a leading article far more skilfully than grams. This they do, not because they are he could do it for himself. From the in the least degree anxious about the leading articles he passes on, with no sencourse of affairs, but because they have sible alteration in his frame of mind, to got into the habit of wanting to be fed the home and foreign correspondence. He with the latest intelligence." They de- skims the letter from Dublin in search of sire to know the news, not because of a Fenian outrage, and the letter from Paris its antecedents or its consequences, but in search of an intrigue or a duel. Letsimply because it is "the news," and be- ters on the Old Catholic movement and cause they have contracted a craving for on the Athanasian Creed jostle through it, as for snuff, or for sherry and bitters. his mind with letters. on Australian mutHaving read all the news, home and for- ton and railway unpunctuality. He dips eign, great and small, with an equal amount into the law and sporting intelligence to of interest and an equal lack of reflection, see whether there is any bit of fun about they pass on to the leading articles. Some Mr. Whalley and the Claimant," and few years ago, before the Pall Mall Ga- whether "the Leviathan" has been making zette and the Echo were started, they used a sensational score at Montreal. He beto read the leading articles of one or two stows a little extra care on the repor. from of the morning papers with a certain Lord Penzance's Court, and finally he amount of attention; seldom, indeed, with takes refuge in the crops, the weather, the a view of considering whether what was money-market, and the little odds and ends said in any column was true or exagger- of provincial news. Nine times out of ten ated, or altogether erroneous, or of com- he puts the paper down, after a long inparing their own previous notions on any vestigation, with the important conclusion subject with those of the writer, but with that there's nothing in it." But this does sufficient care at all events to enable them not deter him from taking up another, and to make out to their own satisfaction the going through it in much the same manner general drift of what was written. The and with much the same result. All this more intelligent among them would take time he is doing very little more than exsome trouble to ascertain, for instance, ercising a mechanical art of reading. What whether the Times did or did not consider he reads makes no sort of impression on such a piece of foreign news to be import- him; or, at best, affects him about as much ant, or what the Daily Telegraph thought as Aristotle says that the misfortunes of Mr. Gladstone would do in consequence of the living affect their dead relatives. It an adverse vote, or what the Standard passes through his mind like water through had to say in disparagement of any Lib- a sieve; or sounds to him as the voices of eral success; partly because they wanted the great and middle-sized bears did to to get hold of something simple and tan- Southey's little girl. gible on which to rest and collect their'

From the circumstances of their lives