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Leader (1850-1860), 13th December 1856, Edition 1 of 2, Page 1193, Untitled Article

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      ction , andu little aided fy conjecture , hoicecer plausible and possible . " i forgotten that deduction itself is but conjecture , until it is verified ; otten that all the greatest discoveries in science are made on the of conjecture ; it is forgotten that Kepler framed seventeen guesses don . framed several successive conjectures , before the one dishe true path , of the planets , and the other the true composition of ige ' s plan is first to lay down the principles and more conspicuous essary for the understanding of each section of the subject , and lose the section with an explanatory and recapitulatory survey . He aerous woodcuts , and an extensive glossary . Solicitous of being instructive to the young geologist , he Las indicated many details ler -writers pass over as trivial , but ior which the student will be But the work is really of interest to others besides mere students , i best acquainted with geology will be its warmest admirers . 11 extract a passage or two which can be read without reference to iXt : ¦ . ¦ ¦ ¦ ¦ ¦ ¦ ' ¦ . . ¦

      inciea that now operate on and modify the surface of the Globe—that scoop a and wear down hills ; that fill up lakes and estuaries and seas ; that subdry land and elevate the sea-bottom into new islands ; that rend the rocky throw up new inountain-clniins '; and that influence the character and dis-Df plants and animals , are tbe same in kind , though , differing it may "be in those that have operated in all time past . The layers of mud and sand si now deposited in our lakes and estuaries and along the sea-bottom , and solidifying Snto stone before our eyes , are the same in kind with the shales tones and conglomerates that compose the rocky strata of the globe : the > ur lakes , the shell-beds of our estuaries , and the coral-reefs of existing seas , year increasing and hardening , belong to the same series of materials , and of time will be undistinguishable from the chalks and limestones and

      maruarr 3 ' : the peat-niosse .

      ollowing passage , on the operation of Rivers , is a good specimen of pact , clear style in which the work is-written : — is and rivers—in fact all winter currents—act chiefly in a mechanical way , influence depends partl y on the nature of the rocks over which they run , the of their flow , and the size or volume of ' water . If the rocks over which they of a soft ot friable nature , they soon cut out channelsj and transport the aterial in the state of mud , sand , and gravel to the lower level of some lake , jstuaries , or "to the bed of the ocean . Their cutting as well as transporting greatly aided by the rapidity of their currents ; hence the power of mountain : ompared with the quiet and sluggish flow of the lowland river . It has been d , for example , that a velocity of 3 inches per second will tear up fine clay , dies will lift fine sand , 8 inches sand as coarse as linseed , and 12 inches fine while it requires a velocity of 24 inches per second to roll along rounded

      m inch in diameter , and 36 inches per second to sweep angular stones of the hell ' s egg . During periodical rains and land-floods the currents of rivers often ixceed this velocity ; hence the tearing up of old deposits of gravel , the ; away of bridges , and the transport of blocks many tons in weight- —an i greatly facilitated by the fact that stones of ordinary specific gravity ( from B ) lose more than a third of their weight by being immersed in water- Nor mere velocity of rivers which produces their eroding or cu-tting power , but int and nature of the debris carried down by their torrents—every pebble and shingle rubbing and striking and grinding still deeper and deeper the chani wliich they are borne . The geological effects of livers on tho crust is thus fold nature—viz ., to waste and wear down the higher lands , and then to bear J waste material and deposit it in valleys , ia lakes , or in the ocean , in the nud , clay , sand , or gravel . By such deposits lakes are silted or filled up , and Uuvial valleys ; estuaries converted into level plains ; and even large tracts 1 from the sea . . . . Every person must have observed the rivers in his

      met , how they become muddy and turbid during floods of rain , and how their : urrents eat away tho banks , deepen the channels , and sweep away the sand el down to some lower level . And if , during this turbid state , he will have sity to lift a gallon « f the water , and allow it to settle , he will be astonished nount of sediment or solid matter that falls to tlio bottom . Now , let him this gallon by tho number of gallons daily carried down by the river , and by years and centuries , and he will arrive at some faint idea of the quantity f worn from the land bj r rivers , and deposited by them in the ocean . In the y as one river grinds and cuts for itself a channel , so does every stream and jurrent of water . The rain as it fulls washes away what the winds and frosts 3 ened ; the rill takes it up , and , mingling it with its own burden , gives it to m ; the stream takes it up and carries it to the river ; and tho river bears it to i . Thus tlie whole surface of the globe is worn and grooved and channeled gher places- being continually worn down , and the wasted material carried to level .

      tins explanation of the process of petrifaction will be rend with ( , ¦ rocoss of petrifaction , generally speaking , consists in the infiltration of stony into tho pores of vegetable or animal substances . In some instances tho body has almost entirely disnppenrcd , and the stony matter has been so y substituted , particle for particle , that the petrifaction presents a perfect reco in its minutest parts to the original structure . Petrifaction has been ly imitated by burying bones in mud " , ¦¦ cl ay , and lime , aud it has been found > r a time tlio bones become black , liiudor , and heavier ; and had the process itinucd , they would have eventually been undistiiiguishablo from true fossils , holding lime or flint in solution arc familiar examples of petrifying agents Ley convert pieces of moss , straw , twigs , and branches , into calcareous and matter . I-imo and flint arc perhaps the most abundant petrifying substances e ; but many fossil bonea and sliella are converted into metallic crystals , a remains into bituminous masses like coal , and not unfrenucntly trunks of vc thoir forma perfectly prcecrved in strata of fine-grained sandstone . "WitU-

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      MISCELLANIES LIGHT AND LEARNED . Precedence to beauty—we have Sir ' Walter Scott ' s Lord of the Isles ( Edinburgh : A . and 0 . Black ) , in a rich binding of red , bhueYand gold , exquisitely printed on tinted paper v and illustrated by seventy-two illustrations , from drawings by John Gilbert and Birket Foster . The introductions by Scott are all reproduced , together with a variety of notes . The volume is superb ; its external appearance will entice : many an eye in search of a seasonable gift-book . Some of the illustrations are of the highest merit , and wonderfully in keeping with the character of the poem . These bright editions almost atone at Christmas for the absence of ftowers . But we are

      dealing , at present , with works of all classes wliich do not admit of more ample treatment . Let us note , then , that Miss Meteyard , the Silverpen of former days , presents , as ' tier . Christmas offering , liliarfs Golden Hours ( Routledge . )—It is an elegant tale for the young , elegantly illustrated by Absolon . We must forgive Miss Meteyaxd her didactisnos and her moralities , as well as the simple egotisms of her preface , on account of the genial , generous sentiments with which her writings are imbued . Mrs . Hubback , too , must be mentioned with praise , as the author of Agnes Milboume ; or , Foy' pour Devoir ( Skeet ) . — -The praise , however , applies to the form , rather than to the matter of her story , which is a variation from . the three-volume conventionality . Tlie volumes , besides being only two in number , are small in size . As for the novel , those who remember " Tie Wife ' Sister" and " The Old Vicarage , ' - will know what amusement and what edification to anticipate from the history of Agnes Milbourne . We are really at a loss how to apply the teachings conveyed in Mrs . Hubback's Qesta .

      Help in Time of Need- ; or , the Lord Careth for his Own ( Edinburgh : Kennedy ) , is a tale founded on the persecution of the Huguenots , by Miss Catherine D . Bell , who reminds her friends and the public that she has produced eleven similar volumes , the names of which are set forth , with conscious pride , upon her title-page . The story is carefully executed , and exhibits a good deal of liberal and healthy feeling . It may be recommended to young readers . Another sort of narrative comes to us from America . It is anonymous , but purports to be The Autobiography of a Female Slave ( Triibner ) . — -We have no doubt that it is a mere fiction , the scenes being of a grossly exaggerated description , the characters theatrical , the style that of a Lascar pamphlet . One remark has been suggested to us by this epic of stripping , whipping , and melodramatic atrocity . The * friends of the black have a singular abhorrence of the true Nigritian stain . They almost invariably make their heroines white or nearly so ;• accordingly , the female

      slave of this " Autobiography" is depicted as having a a very fair and beautiful complexion , " " no perceptible shade darker" than that of her free-born mistresses . She is , indeed , altogether lovely , and devotes many a page to revelations of shame and suffering connected with her own displays at tho whipping-post ; . We much question whether this sort of literature helps the . abolitionist cause , and sometimes arc disposed to doubt whether it is published with that object . Connected with the same subject is an interesting \ olume , Anthony JBtirns : a Ilhtory , by ( J . K . Stevens ( Triibner ) , being a minute narrative of an extradition case wliich occurred in Boston two years ago , under the Fugitive Slavo Act . In the course of his relation , Mr . Stevens sketches the portraits of two abolitionist orators , Wendell l'hillips and Theodore Parker . The contrast being thoroughly American in tone and spirit , wo will make room for it : —

      There wore two men in the Hall for whose words , more than for those of all others , the assembly impatiently wxitcd . These were Wendell Phillips and Theodore Parker . Kegavded by the public ns tho leaders of tlie present enterprize , closely associated in spirit and purpose , and . eminent , both , for tho power of speech , they yet differed from each other in many particulars . Mr . Phillips belonged to tho aristocracy , so far ns such a class may be supposed to exist in this country . Ho had an ancestry to boast of ; his fmnily name ivaa' interwoven with the history of the Commonwealth ; and some of those who had borne it had filled high offices in the government . Mr . Parker , on the other hand , ¦ vas of more plebeian origin ; he had been the architect of his own fortunes , and was by far the most distinguished person of his lineage . In

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      out entering upon the obscure , and as yet little studied , processes by which organic substances are preserved in the crust of the earth , we may notice a few of the more obvious , rather with a view to indicate the nature of the subject than attempt to teach its details . A shell , like the common cockle , may be burried in a mass of calcareous nmd , and when so enclosed it is of itself composed of carbonate of lime and a little animal matter . As it remains imbedded chemical changes take place—the animal matter decomposes and passes off in a gaseous state , and its place is supplied by an additional infiltration off lime from the mass . If iron in solution be present in the nmd , the sulphuretted hydrogen arising from the animal decomposition will unite with the iron , and the shell will become coated or incrusted with shining iron pyrites , or sulphuret of iron . As the calcareous mass becomes consolidated into limestonerock , the shell will also , become hard and stony , but still preserving its form to the minutest ridge aud corrugation of its exterior surface . By-and-by , carbonated waters may filtrate through the pores of the limestone ; the shell may he dissolved entirely .

      and leave only a hollow cast of its form . Another change may now take place : water holding siliceous matter may percolate through the reck , and tlie hollow shell-cast be filled entirely with flint . As with flint , so with crystallized carbonate of lime , with , iron pyrites , or even with a soft clayey deposit that yields to the scratch of the naiL All these are possible changes , and changes which every day present themselves to the palaeontologist ; and as with a sliell , so with a tooth , a fragment of bone , a fish scale , a mass of coral , the net-work of a leaf , or the woody fibre of a drifted pine-branch . The structure of the organism is always more or less preserved , and forms a basis for the lietrifying solution , which thoroughly pervades it without disturbing the arrangement of those -parts on which its characteristic form depends . It ia this form or external character which enables the paleontologist to compare and classify fossils with existing plants and animals ; and it is this internal arrangement of cell and fibre , as revealed to the microscope , that enables him to detect bone from shell , and the bone of a bird from tlxc bone of a mammal .

      These three passages sufficien tly indicate the quality of the book ; its merits as a text-book can only be estimated by the student himself . If it ' Joes not drive many a student , hammer in hand , into quarries and railway cuttings fox * immediate experience of geological phenomena , nothing will .

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      BMBEitl 3 1856 . ] _ __ ^^^ THJ LEADER , ll 93

  • Citation
    • Leader (1850-1860), Dec. 13, 1856, page 1193, in the Nineteenth-Century Serials Edition (2008; 2018) ncse-os.kdl.kcl.ac.uk/periodicals/l/issues/vm2-ncseproduct2171/page/17/