18 



LIMITATION AND TREATMENT 



ingly concede the old title, Physical History 

 of the Globe, treats, among other matters, of 

 the distribution of magnetism over our planet, 

 with reference to intensity and direction ; not 

 of the laws of magnetical attraction and repul- 

 sion, nor of the means of exciting electro-mag- 

 netical effects, now of a more passing, now of 

 a more permanent character. Physical cos- 

 mography displays, in bold outlines, the parti- 

 tionings of continents and the distribution of 

 their masses in either hemisphere — points that 

 influence climate and the more important me- 

 teorological processes in the most remarkable 

 manner ; it goes farther — it indicates the pre- 

 vailing characters of the several great mount- 

 ain ranges, their extension in more continuous 

 and even chains, or their connections in the 

 manner of a grating, and their association with 

 the several epochs and systems of formation ; 

 it determines the mean height of continents 

 above the present level of the sea ; the points 

 of the centres of gravity of their volumes ; the 

 relations of the higher peaks of extensive chains 

 to their acclivities, to neighbouring seas, and 

 to the mineral nature of their constituent rocks ; 

 it informs us how these mountain masses, now 

 active and moving, breaking through a super- 

 imposed crust, now passive and moved, pre- 

 sent their strata under every variety of inclina- 

 tion — level, sloping, perpendicular ; it consid- 

 ers the succession or isolation of volcanoes ; 

 the indications of their manifestations of activ- 

 ity, the extent of the circles they severally 

 shake, and which in the course of centuries 

 enlarge or contract. It farther informs us, to 

 select a few examples from the conflict of the 

 fluid with the solid, of the points of resemblance 

 between all mighty streams in one part or an- 

 other of their course : how they are liable to 

 bifurcate, either in their superior or inferior 

 channels ; how at one time they cut across 

 colossal mountain chains at right angles, at an- 

 other, run in lines parallel to them, whether 

 this be near the declension of the chain, or at 

 some considerable distance from it, as a con-" 

 sequence of the influence which an elevated 

 mountain system has exerted upon the surface 

 of entire districts of country, and on the saline 

 bottoms of neighbouring plains. Only the chief 

 results of comparative orography and hydrog- 

 raphy belong to the science which I here cir- 

 cumscribe, not minute descriptions of mount- 

 ain masses ; of volcanoes that are now active ; 

 of the volume of waters of particular rivers, 

 &c. : all this, according to my views, belongs 

 to special or descriptive geography, and will be 

 comprised in the notes which illustrate my 

 work. The enumeration of similar, or closely- 

 allied, natural relations, the general survey of 

 terrestrial phenomena with reference to their 

 distribution in space, or their relations to par- 

 ticular zones of the Earth, is not to be con- 

 founded with the consideration of the individu- 

 al things of Nature, to wit, terrestrial substan- 

 ces, animated organisms, physical phenomena ; 

 a consideration which would only lead to a 

 systematic arrangement of objects, according 

 to their intimate analogies. 



Special geographical descriptions are, it is 

 true, the most available material for a general 

 physical geography ; but the most painstaking 

 accumulation of such descriptions would as lit- 



tle convey to the mind the characteristic idea 

 of terrestrial nature at large, as the mere co- 

 ordination of all the individual floras of the 

 earth would give a notion of the geography of 

 plants. It is the business of the combining in- 

 tellect, out of the individualities of organic 

 forms (morphology, the doctrine of the exter- 

 nal forms of plants and animals), to extract 

 the common in climatic distribution ; to fix the 

 numerical laws — the proportions in the num- 

 ber of certain forms of natural families, to the 

 entire number of plants or animals of the more 

 perfect types ; to determine in what zone each 

 of the principal forms attains its maximum in 

 point of numbers of kinds and organic develop- 

 ment, and even to show how the impression 

 made upon the mind by a landscape at different 

 distances from the equator, in so far as this ia 

 connected with the vegetable growths that 

 cover the surface of our planet, is mainly de- 

 pendent on the laws of vegetable geography. 



Those systematically arranged catalogues of 

 organic forms, which in former times were 

 designated by the somewhat ostentatious titles 

 of Systems of Nature, present a wonderful 

 enchainment in reference to similarity of form 

 (structure), to the conception of a gradual un- 

 folding or evolution of leaf and calyx into col- 

 oured blossom and fruit, but not any concate- 

 nation with reference to distribution in space, 

 that is to say, to climate, elevation above the 

 level of the sea, and to temperature, to which 

 the whole surface of the globe is exposed. The 

 highest aim of physical geography, however, as 

 already observed, is the recognition of unity in 

 multiplicity, the investigation of the Common 

 and Intimately-connected in all terrestrial phe- 

 nomena. Where individualities are indicated, 

 no more is done than may help to bring the 

 laws of organic arrangement into unison with 

 those of geographical distribution. The mass 

 of living forms, in this point of view, appears 

 to be arranged rather according to the zones 

 of the earth, or to the course of isothermal 

 lines, than in conformity with internal rela- 

 tionship, or the principle of gradation and indi- 

 vidualizing development of organs inherent in 

 the whole of nature. The natural sequence of 

 vegetable and animal forms will therefore be 

 here assumed from our ordinary descriptive 

 botany and zoology. It is the province of phys- 

 ical geography to investigate the mysterious 

 generical relations in which, with an apparent 

 dispersion of families and species over the sur- 

 face of the earth, the most dissimilar forms 

 still stand to one another ; to show how the 

 various organisms constitute a natural whole ; 

 how they modify the atmosphere by the slow 

 processes of combustion and assimilation that 

 go on in their interior ; and how, influenced 

 by promethean light in their evolution, in their 

 very being, despite their inconsiderable mass, 

 they act upon the whole life of the globe. 



The mode of presenting the subject which I 

 here propose as alone appropriate to physioal 

 cosmography, gains in simplicity when we ap- 

 ply it to the uranological portion of the Cos- 

 mos, to the physical history of heavenly space, 

 and of the heavenly bodies. If we distinguish 

 physics, or natural philosophy, as used former- 

 ly to be done, but as deeper and clearer views 

 of nature allow us no longer to do — physics, 



