were in existence, and nothing to prevent, so far as time was concerned, their being united together all over the world into similar structural combinations. And, in truth, as the botany of the Coal period proves, there was a far more extensive sameness than we see at present, simply because the distribution of heat was more uniform and climates were less marked. But from this point the diversity of form in climate distribution becomes more and more conspicuous, though we must descend, perhaps as late as the Wealden, before we discover any flowering plants, except Gymnosperms, as Conifers and Cycads. All this is what might be expected on the doctrine of external influence, but not on the doctrine of an innate and interior developemental force.

If, at this stage, attention is once again turned to the animal kingdom, we find our opinion confirmed. The diminution of carbonic acid in the atmosphere, the deposit of coal in the earth, the precipitation of carbonate of lime in the sea, the disengagement of an increased quantity of oxygen in the air, and the reduction of atmospheric pressure,-different effects contemporaneously occurring, -were soon followed by the consequence which they made possible, the appearance of hotblooded mammals. Perhaps those first arising might, like our Cold and hibernates, lead a sluggish existence, with imperfect respira- mammals. tion; but as the media improved and the temperature declined, more vigorous forms of life emerged, though we have probably to descend to the Tertiary epoch before we meet with birds, which of all animals have the most energetic respiration, and possess the highest heat.

Variations in its
contains. With

Before the sun

hot blooded

The orga

As with the atmosphere, so with the sea. composition must control the organisms it its saline constituents its life must change. light had removed from the atmosphere so much of its carbonic acid, decomposing it through the agency of plants, the nisms of weight of carbonate of lime held in solution by the highlycarbonated water was far greater than was subsequently possible, and the occurrence of limestone became a necessary event. With such a disturbance in the composition of the sea-water, its inhabiting organisms were necessarily disturbed.

VOL. II.

Y

the sea.

Nature of

sion.

And so again, subsequently, when the solar heat began to preponderate on the surface over the subsiding interior heat, the constitution of the sea-water, as respects its salinity, was altered through difference of evaporation in different latitudesan effect inevitably making a profound impression on marine animal life.

Supported by the facts that have been mentioned respecttransmising the later fossils of Australia and Brazil, and their analogy to forms now existing in those countries, much stress was laid on the hereditary transmission of structure, and hence the inference was drawn that such examples are of a mixed nature, depending in part on external agency, in part on an interior developemental force. From marsupial animals, marsupials will issue; from placental ones, those that are placental. But here, perhaps, an illustration drawn from the inorganic kingdom may not be without interest and use. Two pieces of carbonate of lime may be rolling among the pebbles at the bottom of a brook, one perpetually splitting into rhomboids, the other into arragonitic prisms. The fragments differ from one another not only thus in their crystalline form, but in their physical qualities, as density and hardness, and in their optical qualities also. We might say that the calc-spar crystals gave birth to calc-spar crystals, and the arragonitic to arragonite; we might admit that there is an interior propensity, an intrinsic tendency to produce that result, just as we say that there is a tendency in the marsupial to engender a marsupial; but, if, in our illustration, we look for the cause of that cause, we find it in a physical impression long antecedently made, that the carbonate of lime, crystallizing at 212° Fahr., produces arragonite, and, at a lower temperature, calcspar; and that the physical impression thus accomplished, though it may have been thousands of years ago, was never cast off, but perpetually manifested itself in all the future history of the two samples. That which we sometimes speak of as hereditary transmission, and refer to an interior property, peculiarity, or force, may be nothing more than the manifestation of a physical impression long antecedently made.

In the last place, the idea of an intrinsic force of developement

organic

is in connection with time and a progression, and only comes The broken into prominence when we examine a limited portion or num- chain. ber of the things under consideration. The earth, though very beautiful, is very far from being perfect. The plants and animals we see are only the wrecks of a broken series, an incomplete and therefore unworthy testimonial of the Almighty power. We should judge very inadequately of some great author if only here and there a fragmentary paragraph of his work remained; and so, in the book of organization, we must combine what is left with what we can recover from past ages and buried strata before we can rise to a comprehension of the grand argument, and intelligibly grasp the whole work.

Enormous

age of the

Of that book it is immaterial to what page we turn. It tells us of effects of such magnitude as imply prodigiously long earth. periods of time for their accomplishment. Its moments look to us as if they were eternities. What shall we say when wè read in it that there are fossiliferous rocks which have been slowly raised ten thousand feet above the level of the sea so lately as since the commencement of the Tertiary times; that the Purbeck beds of the upper oolite are in themselves the memorials of an enormous lapse of time; that, since a forest in a thousand years can scarce produce more than two or three feet of vegetable soil, each dirt-bed is the work of hundreds of centuries? What shall we say when it tells us that the delta of the Mississippi could only be formed in many tens of thousands of years, and yet that is only as yesterday when compared with the date of the inland terraces; that the recession of the Falls of Niagara from Queenstown to the present site consumed thirty thousand years; that if the depression of the carboniferous strata of Nova Scotia took place at the rate of four feet in a century, there were demanded 375,000 years for its completion-such a movement in the upper direction would have raised Mont Blanc; that it would take as great a river as the Mississippi two millions of years to convey into the Gulf of Mexico as much sediment as is found in those strata? Such statements may appear to us, who with difficulty shake off the absurdities of the Patristic chronology, wild and impossible to be maintained, and yet they are the conclu

Summary as respects

the world

in time.

The life of the uni

verse.

Multiplicity of worlds im. plies suc

cession of worlds.

sions that the most learned and profound geologists draw from their reading of the book of Nature.

Thus, as respects the age of the earth and her relations in time, we approach the doctrine of the Orientals, who long ago ascertained that the scales of time and of space correspond to each other. More fortunate than we, they had but one point of resistance to encounter, but that resistance they met with dissimulation, and not in an open way. They attempted to conceal the tendency of their doctrine by allying or affiliating it with detected errors. According to their national superstition, the earth is supported on the back of an elephant, and this on a succession of animals, the last of which is a tortoise. It is not to be supposed that the Brahmans, who wrote commentaries on the Surya Siddhanta, should for a moment have accepted these preposterous delusions—that was impossible for such great geometers; yet led, perhaps, by a wish to do nothing that might disturb public feeling, they engaged in the hopeless task of showing that their profound philosophical discoveries were not inconsistent with the ancient traditions; that a globular and revolving earth might be sustained on a descending succession of supporting beasts. But they had the signal advantage over us, that those popular traditions conceded to them that limitless time for which we have had to struggle.

The progression of life on the surface of our planet is under the guidance of preordained and resistless law,—it is affiliated with material and correspondingly changing conditions. It suggests that the succession of organic forms which, in a due series, the earth's surface in the long lapse of time has presented, is the counterpart of a like progress which other planets in the solar system exhibit in myriads of years, and leads us to the conception of the rise, developement, and extinction of a multiplicity of such living forms in other systems,—a march of life through the universe, and its passing away.

Magnitudes and times therefore go parallel with one another. With the abandonment of the geocentric theory, and of the doctrine of the human destiny of the universe, have vanished the unworthy hypotheses of the recent date of creation and

the approaching end of all things. In their stead are substituted more noble ideas. The multiplicity of worlds in infinite space leads to the conception of a succession of worlds in infinite time. This existing universe, with all its splendours, had a beginning, and will have an end; it had its predecessors, and will have its successors; but its march through all its transformations is under the control of laws as unchangeable as destiny. As a cloud, which is composed of myriads of separate and isolated spherules of water, so minute as to be individually invisible, on a summer's afternoon changes its aspect and form, disappearing from the sky, and being replaced in succeeding hours by other clouds of a different aspect and shape, so the universe, which is a cloud of suns and worlds, changes in the immensity of time its form and fashion, and that which is contemporary with us is only an example of countless combinations of a like kind, which in ancient times have one after another vanished away. In periods yet to come the endless succession of metamorphoses will still go on, a series of universes to which there is no end.