I. Without prejudging the future, we have been obliged to acknowledge that the problem of the specific origin of man cannot be solved, or even attempted, with the scientific data which we at present possess. This is not quite so much the case with certain questions which are naturally suggested to the mind by the preceding.
We know that our globe has passed through several geological and palæontological epochs; that living beings have not appeared simultaneously, and that the present fauna and flora have been preceded by very different ones. It is natural to ask the question, when man began to inhabit the earth, and to endeavour to determine the moment of the appearance of this being, so similar to other beings in many respects, so exceptional in his most noble faculties, and superior to everything around him.
This question of time should be stated precisely; we must understand the sense which may be attributed to it.
Let us observe, in the first place, that here we can have no dates properly so called. They only exist in history. Now primitive mankind can have no history in the scientific sense of the word. Most great religions have endeavoured to fill up this gap. But my readers are already aware that Ihave refused all considerations drawn from such a source, and that I intend to bring forward here none but the results of experiment and observation. I shall then try how far back we can go with the aid of these guides alone, quoting in the first place a few historic dates as terms of comparison.
II. The Greeks and Romans, with whom classical education too often terminates, do not take us very far. The former had much more ancient records than the latter, and yet the era of the Olympiads only brings us to the year 776 before our era; according to Hecateus of Miletus, it was in the ninth or tenth century before our era that the gods ceased to intermarry with mortals, and the Trojan war is regarded approximately as having taken place in the eleventh or twelfth century. Beyond this period, it is evident that we are led by Greece into mere mythology, or rather into those legendary times where truth and fable are confounded.
The Aryan traditions go further. M. Vivien de Saint Martin, summing up the works of which he is so good a judge, refers the arrival of the Hindoos on the river of Cabul to about the sixteenth or eighteenth century before our era. These tribes were only an offshoot of the great emigration which the Zend-Avesta takes back almost as far as the Bolor. We can, therefore, refer the latter to the twentieth or twenty-eighth century before our era.
Jewish history, starting with Abraham, goes back almost to the same period (2296 years); the deluge of Noah, according to the estimation generally received, to the year 3308. Say about thirty centuries.
In China, the Chou-King places the reign of Hoang-ti in the year 2698, and that of Jao in the year 2357 before our era. This would correspond almost to a century, with the date of the migration of Abraham.
Egypt had no Chou-King, but her monuments are the most magnificent of books. Champollion has taught us how to read them, and we can decipher them page by page. Now Lepsius and Bunsen place the fifth dynasty about the fortieth century, and according to Mariette Bey, the lists ofManetho, upon the subject of which the eminent Egyptologist makes formal reserves, go back to the year 5004 before our era. We should, then, be separated from the earliest historical times of Egypt by an interval of about seventy centuries. If, instead of counting by years, we count by the human life, which we will estimate at about twenty-five years, we find that we are only separated from these times, which constitute the extreme limit of past history, by 280 generations.
These numbers are undoubtedly interesting. They tend to modify some of the impressions which we have received in our childhood; but they tell us nothing of the antiquity of the human race. At most, in showing us that at this period there existed people in the valley of the Nile sufficiently civilised to possess the art of writing, and to raise monuments worthy of our admiration, they refer the first appearance of man far beyond the limits which they reach themselves.
III. The Egyptians themselves have, then, a past anterior to all history. With much greater reason is this the case with the Chinese, Hindoos, Greeks, and still more so with nations less well endowed, or accidentally retarded in their evolution. To plunge into this obscurity with the hope of finding in it any certain land-marks, and to discover facts of which even legends say nothing, would thirty years ago have appeared a senseless enterprise. It is, nevertheless, the work accomplished by one of the most recent of sciences,Prehistoric Archæology. We should therefore regard the year 1847 as a memorable date, when three Danish savants, a geologist, a zoologist, and an archæologist, were charged by the Society of Northern Antiquaries to carry out the studies which have served as its foundation. By a study of the Kitchenmiddens and peat-mosses of their country, Forchammer, Steenstrup and Worsaar have done for the history of man what De Buch, Elie de Beaumont, and Cuvier have done for the history of the globe.
TheKitchenmiddensare essentially formed by the accumulation of shells strewn on the sea-shore, which sometimesattain considerable proportions. With the shells are found the remains of fish, and bones of birds and mammalia. Man alone could have formed this accumulation, and his presence, moreover, is revealed by the implements, tools, and weapons, which he once mislaid, and which are now found among the remains of his meals. They consist of stone, almost always rudely shaped. In some of these artificial hills, among the traces of a very rudimentary industry, we meet with other stone objects which betray workmanship of the most remarkable perfection.
The Kitchenmiddens, then, reveal the existence of a population now forgotten, which at first lived in an entirely savage state, but afterwards acquired a certain amount of civilisation. From a chronological point of view, however, this information is still very imperfect. The mixture of implements, sometimes almost without form, and sometimes again showing wonderful workmanship, permits of various interpretations, which have in fact been given.
It is different with the objects found in the peat-mosses, and especially in those which the Danes callskovmoses, that is,forest mosses. These formations are found in hollows of irregular form which have been excavated in Quaternary clays, reaching at times a depth of thirty feet or more. The detailed study which Steenstrup especially has made of them led him to distinguish among them thecentral regionorpeat-moss, and theexterior regionorforest region.
The first is formed by the cavity itself. It is the peat-moss properly so called, formed by the layers of peat which fill the cavity, and have been deposited subsequently to its formation. A meagre vegetation grew upon the surface, which divides this mass of vegetabledébrisinto distinct zones. They are, proceeding downwards:—1st, certain trees, such as the birch, alder, and hazel, etc., mixed with heaths; 2nd, small stunted, but sturdy pines (Pinus sylvestris), which had grown upon peat in which mosses of a high organisation, such as the hypnum, were found; 3rd, compact, amorphous peat, the elements of which for a long time it was consideredimpossible to discover, but in which MM. Steenstrup and Nathorst discovered in 1872 undoubted remains of five species of plants now confined to the Arctic circle, such as,Salix herbacea,S. polaris,S. reticulata,Betula nana,Dryas octopetala; 4th, a bed of clay evidently resulting from material washed down by rain from the sides of the hollow, when the latter were still bare.
The forest region occupies the sides themselves. The trees were there protected from the wind, and extending their roots into a fertile clay they attained a magnificent development. Now we at once meet with a very remarkable fact, the beech tree is not foundin the skovmoses. At the present day it is the essential constituent of the Danish forests; it is the national tree, and the most ancient traditions give no suspicion that it has ever been wanting in Denmark. In its place the peat-mosses contain at first nothing but oaks (Quercus robur sessilifolia) which disappeared from the country in prehistoric times, and is only found in a few places in Jutland. Then, as we descend deeper into the peat, the oaks give way to pines. In their turn the latter gain the ascendant, and occupy the lowest parts of the peat exclusively.
Oaks and pines, when they fell from old age, accident, or human agency, generally fell towards the interior of the bog. Their interlaced branches supported and consolidated the peat, which was then in the best condition for preserving, as they fell, any solid substances which may have been dropped or thrown into the bog.
Man used to frequent the skovmoses, and it is well known that he cannot live in any place without losing a number of objects, even those upon which he sets most value. He lost in the bogs weapons, tools, and instruments of all kinds, and they all remain where they fell. The skovmoses have thus become a kind of chronologically stratified museum, where each generation has left its trace in the contemporaneous peat. We have only to explore it layer by layer to obtain many definite ideas about the predecessors of the presentDanes, and to find in this prehistoric pastrelative datesorepochs. In this manner the Scandinavian savants have arrived at the idea of theAges of Iron,Bronze, andStone, which are now universally adopted. I shall not here follow the development which these fundamental ideas have received, nor the manner in which they have been applied to theLake dwellingsof Switzerland and elsewhere. I shall not insist further upon the different degrees of civilization betrayed by the use of two metals and of polished or ground stone. I shall confine myself to the remark that in Denmark the Iron age entirely corresponds with that of the beech tree, while the Bronze age corresponds with the entire period of the oak, and the close of that to the pine. Lastly, the pine is the tree of the Stone age.
The presence of objects formed by human industry proves the presence of man. Thanks to their irrefutable testimony, there is no difficulty in tracing him through the zones of the oak and the pine. The immense number of objects, which have been left by him in the peat period, points to the existence of a somewhat dense population. These objects, on the contrary, become very rare, and at the same time ruder, in the layer of amorphous peat. They were, for some time, even thought to be wanting altogether, till they were finally discovered by Steenstrup associated with the remains of the reindeer.
Man, then, was living in Denmark when Arctic plants, such asBetula nanaandSalise polarisgrew at the bottom of the skovmoses; he was accompanied by the reindeer, which completes the resemblance between the past state of that country and the present state of Lapland. Now we know that such a state of things could only have existed in Denmark in the latter part of the Quaternary epoch, when the ice, retreating from the south northwards, would still be far removed from its present limits. We can then affirm that man existed and lived in Europe at the very dawn of the present geological epoch.
This fact is again proved by the discovery of a human station, made by M. Fraas, at Schussenried in Wurtemberg.Here man, whose presence is attested by worked flints of various forms, by weapons and instruments of bone, by phalanges of reindeer made into whistles, lived with the reindeer, the glutton, and the polar fox, and gathered mosses which are now confined to Northern Europe, such asHypnum sarmentosum,fluitans, andaduncum. As in Denmark, he seems to have followed the glaciers step by step, as the melting of the latter opened out new lands to his activity.
IV. Without claiming such accuracy for the historic dates, or even such an approximation as that derived from the Aryan traditions on the most ancient monuments of Egypt, is it possible to estimate the number of years which have elapsed since the times we have just been discussing?
This question has often attracted the attention of geologists and anthropologists, and several attempts have been made to solve it. But the results are still far from being satisfactory. They are none the less interesting, and calculated, to a certain extent, to encourage fresh research. The method is good; it has only been hitherto wanting in sufficiently precise dates, and we may hope that they will be sooner or later forthcoming.
This method is easily comprehended. For example, let us admit that the peat has a regular growth in the skovmoses, and suppose, in addition, that a coin, recognised as belonging to the twelfth century, has been found at a depth of 1·50 metres (4·9 feet); we shall conclude that the layer of peat has only required about 600 years for its formation. The age of a bronze hatchet found at greater depth, 8 metres (26·24 feet), will be given by the proportion lm·50 : 6 :: 8m: x. The hatchet would then be 3,200 years old, and would date from the fourteenth century before our era.
Many natural phenomena are available for calculations of this kind. Such are the alluvium of a river, the silting up of a lake, the erosion of a hill or plateau, etc. Put in order that the results of these calculations may have a real value, the phenomenon which serves as the basis, and the calculationsresulting from the data must satisfy three conditions which have been very clearly stated by M. Forel.
1. The phenomenon should be perfectly constant and regular, which is never the case. At least, it ought to be possible to regard its action as giving an annual mean or constant centennial result, by means of compensations which are produced naturally.
2. When super-imposed strata are used as a means of estimation, the age of the strata serving as a term of comparison, ought to be rigorously determined; the nature of the objects compared should leave no doubt.
3. We ought to be certain that the objects found in any stratum really belong to it, that they have not been displaced by any reformation or by their mere weight. (Peat.)
Should even one only of these conditions be unfulfilled, the calculation is necessarily erroneous. Now, hitherto, we cannot be absolutely certain that the conditions laid down by M. Forel are satisfied. Nevertheless, I repeat, it is interesting to know what results have been obtained by these attempts at prehistoric chronology.
It would seem, at first sight, that the skovmoses must be useful for researches of this kind. It is not so. Steenstrup, an excellent judge of these matters, after having estimated at forty centuries the time necessary for the formation of the peat accumulated in these bogs, declares that it might be twice, or even four times as much.
In reality, the uncertainty as to the results obtained from the growth of peat, is very much greater than the Danish savant admits. In adding to the data collected by Brandt, those kindly presented to me by my colleague, M. Bésal, I find that for a period of 443 years the mean annual growth of peat is 0·032 metre (1·26 inch). But this mean is the result of numbers whose extremes are 0·065 metre (2·56 inch) and 0·0065 metre (0·26 inch). That is to say, that the means found by different observers for the annual growth of peat, vary from one to ten.
The calculations of MM. Gillieron and Troyon, resting uponthe deposition of silt, which has caused the retreat of the Lakes of Bienne and Neuchâtel, have but little connection with the present subject. Both have sought to determine the age of the Lake dwellings, which belong, probably, to a much later period than the one which we are now endeavouring to determine. We may, however, notice the numbers, 6,000 years and 3,300 years, found by these observers.
The chronological results derived from the littoral accumulation of silt, of which I have just spoken, exhibit chances for error which Vogt has rightly pointed out. For some time the results have been thought more worthy of confidence which were based upon the researches made by M. Morlot upon the conical accumulation of silt deposited by the Tinière. This cone, which was cut through by the railway for a distance of 133m(436 feet), and to a depth of 7·7m(25 feet), exhibited in the midst of the mass of gravel three undisturbed soils, the highest of which contained Roman instruments and coins; the second, pottery of the Bronze age; and the third, split bones, charcoal, and different objects referable to the close of the Stone age. Fixing the commencement of the Roman period in Switzerland at the first century of our era, and the end of it at the year 563, and making some corrections which cannot be detailed here, M. Morlot has considered himself able to propose the following numbers as approximatedates:—
These numbers are not high. The number given by M. Morlot as the age of the Stone period in Switzerland, leads us back to an antiquity which does not exceed that given by the Egyptian monuments; and it is impossible to avoid being struck with the differences of civilization exhibited by the two countries. Nevertheless, this fact cannot constitute a reason for doubting the results of the Swiss savant. It is well known that man during the same time has not everywhereequally advanced in civilization, and thatthe Esquimaux arestill in the Neolithic period.
But other criticisms have been brought forward against M. Morlot, the result of which is that the numbers furnished by the cone of the Tinière cannot be accepted as giving a real approximation to the date which we are seeking for.
V. M. Forel, who has taken an active part in this discussion, has tried to solve the problem in an indirect way. Instead of seeking directly for the age of a prehistoric fact, he has proposed to have recourse to the rule of false position, which allows the determination either of a maximum which the numbers cannot possibly exceed, or a minimum below which they cannot fall. He has applied this plan, which is as correct as it is ingenious, to the Lake of Geneva.
It is well known that the waters of the Rhone, especially during the floods caused by the melting of the snow, enter the lake in a very turbid condition, and flow on remarkably clear. The mud thus deposited evidently tends to fill up the lake, and has already silted up a part of the great depression which was filled by the ice of the Quaternary epoch. M. Forel has first determined the annual volume of the deposit. He has then calculated the volume of the present lake, basing his calculations on the soundings made by La Bèche. He has thus been enabled to calculate the time necessary for the sediment of the Rhone to fill up the entire lake. Then, admitting that the part of the original lake already filled up had a mean depth equal to that of the present lake, he has compared the surface of the alluvial deposits already formed with the surface of the lake itself. The proportion is almost one to three. These deposits have then been formed in a third of the time necessary to fill up the present lake. Now their formation commenced immediately after the retreat of the glaciers. The date thus obtained is, then, that of the modern geological epoch.
Such is the method by which M. Forel arrives at the number of 100,000 years. This is a maximum which is probably much exaggerated. M. Forel shows this himselfvery clearly. He has always taken the lowest numbers for the estimation of the increase of alluvium; he has considered on the whole year ninety days only as contributing to this increase; he has only included the Rhone in this estimation, and taken no account of other rivers, streams, etc.; he has not taken into consideration inundations, extraordinary falls of rain, landslips, etc.; he has assumed the floods of the Rhone have always resembled the present floods, while they must originally have been much more considerable, and have carried away much more material from mountain slopes but recently relieved from their covering of ice; he has said nothing of the gravel and sand which must necessarily be carried along the bed of a rapid stream like the Rhone, etc.
M. Forel’s result must therefore undergo serious reduction before it approximates to the truth. Without attempting a precise statement, we can (at least) admit with almost absolute certainty that the present geological epoch commenced less than 100,000 years ago.
On the other hand, M. Arcelin has sought for a solution of the same problem in the deposits of the Saône. The present river flows in a channel hollowed out in the alluvium of the Saône of Quaternary times, the banks of which have been raised by the sediment deposited during floods. The two deposits are very easily distinguished. The homogeneity of the modern alluvium indicates, moreover, a remarkably regular phenomenon. The banks of the Saône at different points form more or less abrupt hills which constitute so many natural geological sections. The erosions of the river have laid bare objects easily recognised as belonging to the Roman period, the Bronze age, and the Neolithic age. These objects are found at a constant height, showing that they are in situ. The hills of the Saône, then, constitute one of those means of estimating prehistoric chronology, which are so valuable to us. MM. Arcelin and De Ferry have attempted first to determine the age of the different layers. The numbers so obtained show a certain amount of discordance, undoubtedly due to the fact that M. deFerry has based his calculations upon a single section, while those of M. Arcelin represent the mean taken from 33 points. The latter has, however, afterwards had recourse to the method of M. Forel, and to the rule of false position. But instead of seeking a maximum, he has endeavoured to determine a minimum. This calculation gives the following results:—
This represents a very moderate antiquity, and corresponds almost entirely with the dates of Manetho. But the minimum of M. Arcelin appears to me to be too low, and the error greater than in the case of the maximum of M. Forel. I shall only point out the most important of the causes which have led to this result. The calculations of the author are based upon the hypothesis of the equality of the floods, and of the alluvial deposit in the period between the present and the Roman period, and in times previous to that. He thus confounds the epochs when the basin of the Saône was left to Nature alone, with other epochs when the same basin was stripped of its forests, cleared and cultivated as it is at present. Now everyone knows how much more powerful the action of atmospheric agents, of rain in particular, are upon cultivated land than upon uncultivated. The upper layers, which served as the basis for the calculations of M. Arcelin, have necessarily diminished to a considerable extent the final result, since they must have been formed much more rapidly than a great part of the lower layers.
I shall say, then, of the minimum of M. Arcelin what I have said of the maximum of M. Forel. It leaves us the certainty that the present geological period goes back much further than 7-8000 years.
VI. What corrections ought the extreme numbers which I have just quoted to undergo in order to approximate to the truth? It is still impossible to say. But the path which should be followed in order to diminish the spacewhich separates them is henceforth clear. The alluvium of the Saône has always appeared to me to present conditions of uncertainty which it would be difficult to overcome, and the best means of determining the age of the present period by prehistoric chronology, appears to me to be the Lake of Geneva.
In order to correct the first results obtained by M. Forel, it would be necessary to take into account all the circumstances pointed out above, and several others also. It would be especially necessary, at different seasons of the year, in dry and wet weather, to gauge the smallest rivulets and ravines all round the lake, to measure the amount of mud their waters contain, and the amount of gravel and sand they carry down with it. This task is beyond the power of a single man; it would require the formation of anAssociationfor this end. The problem would be worth the trouble, and the Swiss savants, so justly proud of their beautiful lake, might easily make arrangements to obtain its solution.
Such as they are, the works of MM. Arcelin and Forel lead to some important conclusions. The total age of our globe, used till lately to be restricted to a little more than 6,000 years; the alluvial deposits of the Saône show that the present geological epoch alone surpasses this by several centuries. On the other hand, under the influence of Darwinian prejudices, men have begun to handle time with a strange laxity, and it has been affirmed that millions of years separate us from glacial times. The deposits of silt in the Lake of Geneva show that these times terminated less than 100,000 years ago. As M. Forel well says, “This does not yet constitute historic chronology; it is, nevertheless, a little more than simple geological chronology;” and we see once more experience and observation doing justice to theoretical conceptions.