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Leader (1850-1860), 17th July 1858, Edition 2 of 2, Page 18

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      690 __ ' T H E X E A D E 11. __ [^ T O L...

      690 __ ' T H E X E A D E 11 . __ [^ o , July 17 , isc 8

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      Critics Are Nottiielegislators. Btit The...

      Critics are nottiielegislators . btit the judges and police ofliterature . They do not xnakelawa—they interpretand try to enforce them . —Edinburgh Review . — . —«— :

      Cosmos. Cosmos: Sketch Of A Physical Des...

      COSMOS . Cosmos : Sketch of a Physical Description of the Universe . By Alexander von Hum .-boldt . Translated under the Superintendence of Major-General Snbine . 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 an < l the solar system was discussed in th « third volume ; and we have now to deal with the phenomena which more immediately concern our own planet . Here , again , we naturally have a twofold division , according as we consider the 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 bis 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 electromagnetic 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 are those arising from 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 . 3 a toises . The second process , that by pendulum experiments , depends on the well-known fact that the force of gravity inex'eases gradually between the equator and the poles . Our knowledge derived from ' this source is less certain than that derived from measurements of arcs . The strata of the earth , by their difference , constjtut ion , 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 oheck each other , we find that the axis of the earth is about twenty-three miles less than an equatorial diameter .

      The 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 6000 feet above the 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 beinc 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 50 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 the phenomena these present themselves more particularly to our attention : —• ¦ . 1 . Two magnetic poles , one in each hemisphere , at unequal distances from the earth ' s poles of rotation : these are points on the earth ' s snrfuco at which the magnetic inclination is 90 ° , and at which , therefore , the horizontal force vanishes . 2 . The magnetic equator : that is , the curve or lino encompassing the earth , on which the inclination of the needle is 0 ° . 3 . Lines of equal declination , and on which the declination of the needlo is 0 ° . ( Isogouic 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 unenual strength , in each hemisphere . 6 . Lines of equal terrestrial magnetic force , or isodynamic lines .

      7 . The undulating line winch connects those points at which the force is weakest in eacn median , and which has , on that account , been termed a dynamic equator , or ^ uator C' d ° eS UOt coincido ^ ithor wlth the geographical or the magnetic 8 . Tho boundaries of tb « zone in which the dluraal variations of the needlo at certain hours of the day conform , during one part of the year to the diurnal variation of tho ^ eqoroena in the northern , and during the other part of tho year to SSo of ^ T ^ tS ^ ST ***"'* takinS pWt ' lherflfore ' ™ * * ^ v .

      ria-It is clear that these phenomena are due to the three principal manifestations of magnetic force—the inclination of tho needle , tl ! e declination of the aeedle , and the intensity of the force . The potion of the magnetic poles has been determined by Sir James Ross . He found that tho north ina « - n « tic pole is five degrees of latitude more diatont . from the pole of tho enrth , tlmn the south pole , lhe for . nor is situated on the ialand of Boothia * elix towards Us western shore ; the latter has not been actually reached , but it probably lies in tho Antarctic land , culled South Victoria , west of Mount

      Erebus . As the declination , of the needle is of . most essential serviced t ~ mariner , it is that with which we are most familiar , and which we in i therefore , stop to consider . In reference to the intensity of the f ^'• ^ should he . remarked that the four points of ' maximum intensity are of " ^ ' ' * unequal strength . -Taking the intensity of the loree at the magnetic om ? T as unity , it is found that the forces at the foci of the-southern immY i will be represented by 2 . 06 and 1 . 90 . These are stronger tlrn " liTf northern hemisphere , where the forces are estimated respectively bv 1 as and 1 . 76 . We have no space to discuss the periodical variations wl f result from various causes . We can only allude to the important law r e - covered by General Sabine , the editor of this volume , in accordance '•» fl " which the . terrestrial . ' variations are connected with the variations in Vl frequency and amount of the solar spots , that is of the ' fissure ' s-in the h nous envelope of the sun .

      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 iv chiefly indebted for our latest results to the labours of Mallet and Hopkins The problems to be solved are of extreme difficulty , and depend upon -i combined knowledge of geology and tho higher analysis , which the latter of these gentlemen was amongst the first to possess . But we may hope before long to obtain some insight into the laws which regulate the eircum . stances of this reaction . We must be content , in this place , to describe the various classes into which the phenomena maybe divided . In the first instance , then , the reaction of the interior of the earth manifests itsdf . in . the form , of earthquakes . Here the action is purely dynamical , beunr characterized by change of place , agitation , uplifting , and the production of fissures . Various views have been entertained ¦ as to the oriyin of earthquakes . According , to one view , the interior of the earth is * in 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 givetlie first impulse to the earthquake undulations . According to another view which has been abandoned , the interior of the earth consists of tinoxidized 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 tlie want of continuity of trachyte and dolerite . The Cordilleras of the Andes , for example , may be regarded as enormous rugged fragments , which have not been expelled from the interior of tlie earth in a state of fluidity , but have been heaped up upon one another in a solid form . Between . . thes-c 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 rain is restored to tlie service of the organic creation . " Springs of vapour , and gas SalseSj and so forth , will then form a natural link in passing to volcanoes proper . Here the action is no longer purely dynamical , as in earthquakes , but is also chemical ; ami the earths , which are molten at great depths , when expelled in the shape of scoriae , are submitted to processes by which new substances are formed . We have no space , however , to pursue the subject further . The great work of Humboldt must be consulted itself , by all whowish to attain to any adequate acquaintance with the phenomena of the Universe .

      The Pyrenees. Voyage Aiix Pyrenees. Par ...

      THE PYRENEES . Voyage aiix Pyrenees . Par H . Taiue . Deuxieme Edition . 1858 . ' Paris : Hacliettc et O ' . The present generation of literary men in Trance have become a travelling generation within certuin limits ; and , obeying tlieir natural instincts , Lave almost all put on paper the record of their impressions . M . Thieis , -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 buttveon the government 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 bus attained celebrity in any way has thought it necessary to communicate to the world any experiences he may have gained in his search after health or pleasure during tho slack literary season in . Paris . This is tho origin of many very dull lucubrations—as also of this 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 , although still youn « in years , is one of the most celebrated of French critics . His recent articles on liulznc , in the Journal des Debuts , attracted the attention of the whole literary world . Many thought them exaggerated , wire-drawn , uncritical ; but all read them . The other volumes and essays which M . Taine has published have been perhaps still more successful among thoughtful minds . They havo one defect , however , which pervades them from beginning to end—the absence observa

      of elevation . They arc keen , clear , witty , full of knowledge and - tion ; but the writer never suggests that his thoughts have travelled beyond the horizon . His mind is essentially material . He ia a philosopher of the Boulevard , who believes in nothing save Voltaire and tho best lestuur .-mt . In taking up a volume of travels by such -a writer we naturally expect , therefore , to bo amused and instructed—fur these youthful cynics often see things in a very unexpected way—but wo do not anticipate anything like poetry or enthusiasm for tho beauties of nature . M . Tuinu socnw to havo been aware of this , and to have resolved at onco to disappoint , and j liuzlo his readers . He has succeeded in the first of hia objects , but not in the second . Whilst sneering at George tiand and nil other coloured and impassioned writers , ho endeavours himself to be pre-eminently coloured and impassioned . A perfect master of languugo , ho sometimes produces do scriptioua tliat , al # u > 8 |; remind one of tho author of tho Polite I'Wclfc ,

  • Citation
    • Leader (1850-1860), July 17, 1858, page 18, in the Nineteenth-Century Serials Edition (2008; 2018) ncse-os.kdl.kcl.ac.uk/periodicals/l/issues/cld_17071858/page/18/