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COSMOS . Cosmos : Sketch of a Physical Description of the Universe . By Alexander von Humboldt . Translated under the Superintendence of Major-General Sabine . Longmans , and John Murray . We have here the first part of the fourth and last volume of the Cosmos . In the previous volumes , as our readers will remember , Humboldt sketched , in the first instance , the general features of the universe , and then commenced a more detailed description of the various subdivisions of his work . The subject of the fixed stars and the solar system was discussed in the third volume ; and we have now to deal with the phenomena wh'ch more immediately concern our own planet . Here , again , we naturally have a twofold division , according as we consider tlie inorganic and the organic domains . The latter subject will appear in the second part of the present volume , and will conclude the work .
We have reason to congratulate ourselves that the veteran philosopher has been enabled to complete his task . In no other instance has an author enjoyed such vast opportunities combined with such eminent talent . Whilst the Prussian and Russian Governments have hastened to place their resources at his disposal , he has also enjoyed the intimacy of the most eminent philosophers in every branch of science . The result of his life-long labours has been the most comprehensive and perfect work which we possess on the phenomena of the universe at large . The three principal manifestations of the properties of matter are " attraction , light , and heat—exciting undulations , and the electro-magnetic processes . " Starting from this consideration , the first points to be examined in investigating the phenomena of the earth will be the magnitude , figure , and density of that planet , the internal distribution of heat , and terrestrial magnetism . The first of these points depends upon numerous delicate experiments and observations . The results which will be most readily understood those from
are arising measurements of the arc , and from pendulum experiments . The former process is of two kinds—either a measurement of degrees of latitude on an arc of the meridian , or a measurement of degrees of " longitude on different parallels . According to the determinations published by Bessel in 1841 , which are still our principal source of information , the semi-major axis of the spheroid , which represents the geometrical figure of the earth , is 3 , 272 , 077 . 14 toises ; the semi-minor axis , 3 , 261 , 179 . 8 ;* toises . The second process , that by" pendulum experiments , depends on the well-known fact that the force of gravity increases gradually between the equator and the poles . Our knowledge derived from this source is less certain than that derived from mensurements of arcs . The strata of the earth , by their difference , constitution , and position , occasion considerable variations in the apparent force of gravity . On the whole , however , when the results , obtained from different sources , are allowed to check each other , we find that the axis of the earth is about twenty-three miles less than an equatorial diameter .
Tie mean density of the earth has been determined by three methods : by the attraction exercised on a pendulum by the proximity of mountains , by the difference in the length of a seconds pendulum on the sea-shore at 600 O feet above tha sea , and by Mitchell ' s torsion balance . From these experiments it is found that the mean density of the earth is 5 . 62 ; that the density of the crust of the earth is barely 1 . 5 , that of the centre being 10 . 047 . As to the internal heat of the earth , we are as yet in possession of very slight information . If we depend on the results obtained from springs and mines , we are continually led astray by the infiltrations of other waters , and by the conducting power of neighbouring rocks . As far , however , as can be ascertained , the increase in temperature is 1 ° Fahrenheit for about 56 feet . In considering terrestrial magnetism , we may as well give , in Humboldt ' s own language , the principal points to be noticed : —
In the geographical distribution of ( he phenomena these present themselves more particularly to our attention : — 1 . Tvro magnetic poles , one in each hemisphere , at unequal distances from the earth ' s poles of rotation : these are points on the earth ' s surface at which the magnetic inclination is 90 ° , and at winch , therefore , the horizontal force vanishes . 2 . The magnetic equator : that ia , the curve or line encompassing the earth , on which the inclination of the needle is 0 ° . 8 . Lines of equal declination , and on which the declination of the needle is 0 ° . ( Iaogonic lines , and lines of no declination . ) 4 . Lines of equal inclination , or isoclinal lines . -5 . Four points of greatest intensity of the earth ' s magnetic force : two , of tinequal strength , in each hemisphere . 6 . Lines of equal terrestrial magnetic force , or isodynamic lines . 7 . The undulating line > vhich connects those points at which the . force ia weakest im ^ Sl ^ w * ' 1 wl " \ ; ° n tiiat account , been termed a dynamic equator , or equator offeree . It does not coincide either with the geographical or the magnetic
8 . The boundaries of the zone m which the diurnal variations of the needle at certain houra of the day conform , during one part of tha year to the diurnal variation of tb » phenomena in the northern , and during the other part of the year to So " S ^» W ^ " *" tflki " ** ' ' - ' <™ . * the varia ! It ia clear that these phenomena are due to the three principal manifestations of magnetic W-the inclination of the needle , tlie dec inat ion of the needle , and the intensity of the force The position of the magncUc poles has been determ . ned by S . r James Koss . He found that tho north magnetic pole is five degrees of latitude more distant from the pole of the enrtb than the south polo . The former is situated ontho island of Boothia Felix towards its western shore ; the latter has not been actually reached ^ bS * t probably lies in tho Antarctic land , culled South Victoria , ' west of ! Mount
. As essential service t tT > mariner , it is that with which we are most familiar , and which we nee 1 ° therefore , stop to consider In reference to the intensity of the f < r " ^ should be remarked that the four points of maximum intensity are of ' ^ unequal strength . Talcing the intensity of the force at the magnetic on triT ^ as unity , it is found that the forces at tho foci of the southern ln » mi i will be represented by 2 . 06 and 1 . 90 . These are stronger than m tl ^ northern hemisphere , where the forces are estimated respectively b 1 sr and 1 . 76 . We have no space to discuss the periodical variations vl' > l result from various causes . We can only allude to the important law d " * covered by General Sabine , the editor of this volume , in accordance ' with which tlie terrestrial variations are connected witli the variations in tl frequency and amount of the solar spots , that is of the fissures in the lui ^ nous envelope of the sun . u " _
We pass on to consider the second section of the book , which deals witl the reaction of the interior of the earth upon its exterior . Here ' we are chiefly indebted for oxn * latest results to the labours of Mallet and Hopkins The problems to be solved are of extreme difficulty , and depend upon a combined knowledge of geology and the higher analysis , which the latter " of thes « gentlemen was . amongst the first to possess . But we may hone before long to obtain some insight into the laws which regulate the circumstances of this reaction . We must be content , in this place , to describe the various classes into which the phenomena may be divided . In the first instance , then , the reaction of the interior of the earth manifests itself in the form of earthquakes . Here the action is purely dynamical , bein " characterized by change of place , agitation , uplifting , and the production of fissures . Various views have been entertained as to the origin of earthquakes- According to ono view , tlie interior of the earth islii a state of
igneous fluidity . Between the solid crust and the fluid nucleus elastic vapours are supposed to exist , which having great heat and tension give tlie first , impulse to the earthquake undulations . According to another view , which lias been abandoned , the interior of the earth consists of unoxidized masses of the metallic bases ; and these , when brought into contact with water or air , communicate the first impulse . A third view is that held by Boussingault , who supposes the . cause of earthquakes to be in the want of continuity of trachyte and dblerite . The Cordilleras of the Andes , for example , may be regarded as enormous rugged fragments , which have not been expelled from the interior of the earth in a state of fluidity , but have been heaped up upon one another iii a solid form . Between these fragments great spaces would exist , and when a subsidence took place the natural result would be an earthquake .
Next in order should be placed " that vast and tranquil system of springs , wells , and fountains , by which organic life is beneficially nourished and refreshed , and by means of which , for thousands of years , the moisture withdrawn from the atmosphere by the fall of rsiin is restored to the service of the organic creation . " Springs of-vapour , and gas salses , and so forth , will then firm a natural link in passing to volcanoes proper . Here the action is no longer purely dynamical , as in earthquakes , but is also chemical ,- anil the earths , which are molten at great depths , when expelled in the shape of scoria ; , are submitted to processes by which new substances sire formed . We have no space , however , to pursue the subject further . The great work of Humboldt must be consulted itself , by all who wish to attain to any adequate acquaintance with the phenomena of the Universe .
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THE PYRENEES . Voyage mix Pyrenees . Par II . Taine . Deuxieme Edition . 1858 . Paris : Hachctfe ct C' " . Thb present generation of literary men in Trance liave become a travelling generation within certain limits ; and , obeying their natural instincts , have almost all put on paper the record of their impressions . M . Thiers , we believe , was the first to set the example . His little volume of experiences in the south of France under the Restoration is valuable in many respects , but in none more than for the sketches it contains of the relations between the g-overnment and its subjects , travelling and otherwise . It should be referred to frequently as an historical document marking the progress of society in France , for , despite present appearances , progress there has been . Certain conquests of opinion can never be recalled .
Since that period , as we have observed , almost every writer who lias attained celebrity in any way has thought it necessary to communicate to tho world any experiences he may have gained in his search afti'r . lic .-tlth or pleasure during the slack literary season in Paris . This is the origin ol many very dull lucubrations—as also of tiiis volume , which we would not describe by such a name , but which , nevertheless , is not worthy of the reputation of its author . Mr . Henri Taine , nlthough still young in years , is one of the most celebrated of French critics . His recent articles on Halz / ic , in the Journaldes De / mtsy attracted the attention of the whole literary world . Many thought them exaggerated , wirc-dnnvn , uncritical j but all read them . The other volumes and essays which M . Taino has published have been perhaps still move successful among thoughtful minds , They have ono defect , however , which pervades them from beginning to end—tho absence
of elevation . They are keen , clear , witty , full of knowledge nml observation ; but tho writer never suggests that his thoughts have travelled beyond the horizon . Hia mind is essentially material , lie is a philosopher of th be pre-eminently coloured anil impassioned . A perfect innstcr of language , he sometimes produces do scriutiona thnt alruoet remind one of tho author of tho Petite 7 'W ^ V , but
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w Critics are not the legislators , but the judges and -police of literature . They do not makelaws—they interpret and try to enforce them . —Edinburgh Review .
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Erebus the declination of the needle is of most Y I 690 THE / LJ ^ JDjS jU ; _^^_^^ i ^ j ^ . 17 , 1858 . T 3 1 A _ , V . _ T _ 1 ? , * _ jC * j-1 - 11- i * . . _ ^^^^ " ^¦ ^¦ ^^ : iilz
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Leader (1850-1860), July 17, 1858, page 690, in the Nineteenth-Century Serials Edition (2008; 2018) ncse.ac.uk/periodicals/l/issues/vm2-ncseproduct2251/page/18/
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