Chapter VI: Part 6

Arrayed against Chalmers and Macgregor were conservatism and suspicion founded in ancient precedent, and a commercial avarice that saw in native exploitation the readiest means to convert New Guinea into a "white man's country." Aversion there was also in high places to embarking upon a possibly fruitless experiment, involving generations of labor and expense for a remote and uncertain harvest. Chalmers and Macgregor, however, through the force of their high convictions and the wisdom of their wide experience, won the great fight for fairness; for civilization's cardinal victories are those, not of the soldier, but of the civil servant who dares risk his reputation and his all for those things he deems just and generous; and when Papua comes to erect statues to her great leaders, those of these two patriots must surely occupy the highest places, as champions of the liberties of the weak. The noble policy of Macgregor is still, and let us hope it long may be, the keynote of the administration in Papua, which to-day is being ably carried forward under the great governor's disciple, the Honorable John H. P. Murray.

The proclamation given by Captain Erskine in 1884 declared that a British Protectorate had become essential for the safeguarding of the lives and property of the natives of New Guinea and for the purpose of preventing the occupation of the country by persons whose proceedings might lead to injustice, strife and bloodshed, or whose illegitimate trade might endanger the liberties and alienate the lands of the natives.

It is, however, one thing for a government to declare its altruistic intentions, but often quite another to carry them into effect.

In Papua, every effort has been made to prevent robbery of the natives by unscrupulous whites. The natives are firmly secured in the possession of their lands, which they can neither sell, lease nor dispose of, except to the government itself. Thus the natives and the government are the only two landlords in the country. To acquire land in Papua, the European settler must rent it from the government, for he is not permitted to acquire fee simple rights. The whites are thus tenants of the government, and are subject to such rules and regulations as their landlord may decree. The tenant is, however, recognized as the creator and owner of any improvements he may erect upon the land, and, at the expiration of his lease, the government undertakes to pay him a fair compensation for such improvements, provided he has lived up to the letter of regulations respecting his tenure.

For agricultural land a merely nominal rental is demanded, ranging from nothing for the first ten years to a final maximum of six pence per acre; yet this system has had the effect of retarding European settlement, for, although its area is twice that of Cuba, Papua had but 1,064 whites in 1912, and only one one hundred and seventy-fourth of the territory is held under lease.

Men of the type who can conquer the primeval forests and create industries prefer to own their land outright, and are apt to resent the restrictions of complex government regulations, however wisely administered. Socialism, while it may in some measure be desirable in old and settled communities, serves but to dull that sense of personal freedom which above all spurs the pioneer onward to success in a wild and dangerous region.

Possibly in the end, the government may find it advantageous to permit certain lands to be acquired by Europeans, in fee simple; for until this is done the settlement of the country must proceed with extreme slowness. Moreover, mere tenants owning nothing but their improvements, and even these being subject to government appraisement, may be unduly tempted to drain, rather than to develop, the resources of the land they occupy.

But the chief aim of the Papuan government is to introduce civilization among the natives, and a slow increase in the European population is of primary necessity to the accomplishment of this result.

At present the natives are not taxed, the chief sources of revenue being derived from the customs duties upon imports, the bulk of which are consumed by the Europeans, and this source of income is supplemented by an annual grant of about 25,000 pounds from the Australian Commonwealth, but, due to the duties upon food and necessities, the cost of living is higher than it should be in a new country.

Judging, however, from the experience of the English in Fiji and of the Dutch in Java, the natives would be benefited rather than oppressed by a moderate poll tax to be paid in produce, thus developing habits of industry, and in some measure offsetting the evil effects of that insidious apathy which follows upon the sudden abolition of native warfare.

Every effort should also he made to encourage and educate the Papuans in the production and sale of manufactured articles. One must regret the loss of many arts and crafts among the primitive peoples of the Pacific, which, if properly fostered under European protection to insure a market and an adequate payment for their wares, would have been a source of revenue and a factor of immeasurable import in developing that self respect and confidence in themselves which the too sudden modification of their social and religious Systems is certain to destroy. The ordinary mission schools are deficient in this respect, devoting their major energies to the "three R's" and to religious instruction, and, while it is pleasing to observe a boy whose father was a cannibal extracting cube roots, one can not but conclude that the acquisition of some money-making trade would be more conducive to his happiness in after life.

It is not too much to say that the chief problem in dealing with an erstwhile savage race is to overcome the universal loss of interest and decline in energy which inevitably follows upon the development of that semblance of civilization which is enforced with the advent of the white man. The establishment of manual training schools wherein arts and crafts which may be profitably practiced by the natives as life-professions, is a first essential to the salvation of the race. These schools should and would in no manner interfere with the religious teaching received from missionaries, but would indeed be a most potent factor in the spread of true Christianity among the natives. Whether Christianity be true or false does not affect the case, for the natives are destined to be dominated by Christian peoples, and it primarily essential that they should understand at least the rudiments of Christian ideals and behavior.

The realization of the importance of training them to the pursuit of useful arts and trades, which would enable the natives to become self-supporting in the European sense, has been perceived by certain thinkers among the missionaries themselves, and in certain regions efforts are being made the success of which should revolutionize our whole method of dealing with the problem of introducing civilization among a primitive people.

Keep their minds active and their hands employed in self-supporting work and their morals and religion will safely fall into accord with Christian standards.

Up to the present native education has been left to the devoted efforts of the missionaries, who have more than 10,000 pupils under their charge, but the time is coming when the government should cooperate in establishing trade schools wherein crafts, providing life-vocations to the natives, may be taught.

There may be more than 275,000 natives in Papua, but, due to lack of knowledge of the country, the actual number is unknown.

Among the mountain fastnesses, defending themselves in tree-houses, one finds a frizzly-headed black negrito-like race hardly more than five feet in height. These are probably remnants of the "pigmy" pre-Dravidian or Negrito-Papuan element, which constituted the most ancient inhabitants of the island and who long ago were driven inland from the coveted coast.

The burly negroid Papuans of the Great River deltas of western Papua differ widely from the lithe, active, brown-skinned, mop-headed natives of the eastern half of the southern coast; and Professors Haddon and Seligmann have decided that in eastern New Guinea many Proto-Polynesian, Melanesian and Malayan immigrants have mingled their blood with that of the more primitive Papuans. Thus there are many complexly associated ethnic elements in New Guinea, and often people living less than a hundred miles apart can not understand one another; in fact, each village has its peculiar dialect. Social customs and cultural standards in art and manufacture vary greatly from the same cause, and each tribe has some remarkable individual characteristics. In the Fly-River region, the village consists of a few huge houses with mere stalls for the families, which crowd for defence under the shelter of a single roof. Along the southern side of the eastern end of the island, however, each family has its own little thatched hut, and these are often built for defense upon piling over the sea, reminding one of the manner of life of the prehistoric Swiss-lake dwellers.

Nearly 12,000 natives are at present employed by the whites as indentured laborers in Papua, their terms of service ranging from three years, upon agricultural work, to not more than eighteen months in mining. Their wages range from about $1.50 to $5.00 per month, and all payments must be made in the presence of a magistrate and in coin or approved bank notes.

At every turn both employer and employed are wisely safeguarded; the native suffering imprisonment for desertion, and the employer being prohibited from getting the blacks into debt, or from treating them harshly or unjustly. Their enlistment must be voluntary and executed in the presence of a magistrate, and, after their term of service, the employer is obliged to return them to their homes.

One is impressed with the many manifestations of a fair degree of efficiency on the part of the native laborers, who are really good plantation hands and resourceful sailors. In fact, trade has always been practiced to a considerable extent by the shore tribes, the pottery of the eastern end of the coast being annually exchanged for the sago produced by the natives of the Fly River Delta. It is a picturesque sight to see the large lakatois, or trading canoes, creeping along in the shadow of the palm-fringed shores under the great wall of the mountains, the lakatoi consisting of a raft composed of six or more canoes lashed together side by side, and covered by a platform which bears a thatched hut serving to house the sailors and their wares. The craft is propelled by graceful crescent-shaped lateen sails of pandanus matting and steered by sweeps from the stern. Trading voyages of hundreds of miles are often undertaken, the lakatois starting from the east at the waning of the southeast trade wind in early November and returning a month or two later in the season of the northwest monsoon.

The Papuan is both ingenious and industrious when working in his own interest, and with tactful management he becomes a faithful and fairly efficient laborer. Perhaps the most serious defect in the present system of employment in Papua is the usually long interval between payments. The natives are not paid at intervals of less than one month and, often, not until the expiration of their three-year term of service. With almost no knowledge of arithmetic and possessed of a fund which seems large beyond the dreams of avarice, he is practically certain to be cheated by the dishonest tradesmen who flock vulture-like to centers of commercial activity. This evil might be in large measure prevented were the natives to be paid at monthly intervals, for they would then gradually become accustomed to the handling of money and would gain an appreciation of its actual value.

Generations must elapse before more than a moderate degree of civilization is developed in Papua, but the foundations are being surely and conservatively laid, and already in the civilized centers natives respect and loyally serve their British friends and masters.

In common with many another British colony, the safeguard of Papua lies not in the rifles of the whites, but in the loyal hearts of the natives themselves, and in Papua, as in Fiji, the native constabulary under the leadership of a mere handful of Europeans may be trusted to maintain order in any emergency. As Governor Murray truly states in his interesting book "Papua, or British New Guinea," the most valuable asset the colony possesses is not its all but unexplored mineral wealth or the potential value of its splendid forests and rich soil, but it is the Papuans themselves, and let us add that under the leadership of the high-minded, self-sacrificing and well-trained civil servants of Great Britain the dawn of Papuan civilization is fast breaking into the sunlight of a happiness such as has come to but few of the erstwhile savage races of the earth.

Without belittling the nobility of purpose or disregarding the self-sacrificing devotion of the missionary for his task, let us also grant to the civil servant his due share of praise. His duty he also performs in the dangerous wilds of the earth; beset with insidious disease, stifling in unending heat, exiled from home and friends, with suspicious savages around him, he labors with waning strength in that struggle against climate wherein the ultimate ruin of his body is assured. Yet in his heart there lives, growing as years elapse, the English gentleman's ideal of service, and for him it is sufficient that, though he is to be invalided and forgotten even before he dies, yet his will have been one of those rare spirits who have extended to the outer world his mother country's ideal of justice and fair play.

CONTACT ELECTRIFICATION AND THE ELECTRIC CURRENT

BY PROFESSOR FERNANDO SANFORD

STANFORD UNIVERSITY

IN a previous paper in this journal, entitled "The Discovery of Contact Electrification" (November, 1913), it was shown that the production of electric charges by the mere contact of two dissimilar metals was first discovered by Rev. Abraham Bennett, in 1789, and that it was verified by a different method by Tiberius Cavallo, in 1795. Meantime, in 1791, Dr. Galvani discovered the twitching of a frog's muscle, due to electrical stimulus. Galvani's discovery was described by himself as follows:[1]

[1] Translation from "Makers of Electricity," p 143.

'I had dissected a frog and had prepared it, as in Figure 2 of the fifth plate, and had placed it upon a table on which there was an electric machine, while I set about doing certain other things. The frog was entirely separated from the conductor of the machine, and indeed was at no small distance away from it. While one of those who were assisting me touched lightly and by chance the point of his scalpel to the internal crural nerves of the frog, suddenly all the muscles of its limbs were seen to be so contracted that they seemed to have fallen into tonic convulsions. Another of my assistants, who was making ready to take up certain experiments in electricity with me, seemed to notice that this happened only at the moment when a spark came from the conductor of the machine. He was struck by the novelty of the phenomenon, and immediately spoke to me about it, for I was at the moment occupied with other things and mentally preoccupied. I was at once tempted to repeat the experiment, so as to make clear whatever might be obscure in it. For this purpose I took up the scalpel and moved its point close to one or the other of the crural nerves of the frog, while at the same time one of my assistants elicited sparks from the electric machine. The phenomenon happened exactly as before. Strong contractions took place in every muscle of the limb, and at the very moment when the sparks appeared, the animal was seized as it were with tetanus.'

Following this original observation, Galvani made a great many experiments on the effect of electric stimulus upon the nerves of frogs and other animals. He found that the twitching of the frog's muscles could be produced by atmospheric electricity, both at the time of lightning and at other times when no lightning was visible. During these investigations he observed that when the legs of the frog were suspended from an iron railing by a hook through the spinal cord, and when this hook was of some other metal than iron, the muscles would twitch whenever the feet touched the iron railing. He tried out a number of pairs of metals, and found that when the nerve was touched by one metal and the muscle or another point on the nerve was touched by another metal and the two metals were then brought into contact or were connected through another metal or through the human body, the muscles would contract as they would when stimulated by electricity.

Galvani concluded that the contraction in this case, as in the earlier experiments, was produced by an electric stimulation, and since the metals seemed to him to serve merely as the conductors of the electric discharge, he concluded that the source of the electricity must be in the tissues of the animal body. This seemed all the more probable since it was known that certain fishes and an electric eel were capable of giving violent electric shocks. This electricity of the eels and fishes had been named animal electricity, and Galvani concluded that all animals were capable of producing this electricity in the tissues of their bodies.

He believed this electricity was to be found in various parts of the body, but that it was especially collected in the nerves and muscles. The especial property of this animal electricity seemed to be that it discharged from the nerves into the muscles, or in the contrary direction, and that to effect this discharge it would take the path of least resistance through the metal conductor or through the human body. Since during this discharge the muscle was caused to contract, Galvani concluded that the purpose of this animal electricity was to produce muscular contractions.

Galvani seems to have concerned himself principally with the physiological processes which he believed gave rise to the electric charges, but physicists began immediately to seek for other sources of the electricity. The one observation which seemed to offer a definite suggestion as to the possible source of the electrical charge was the fact that, in general two different metals must be used to connect the muscle and nerve before a discharge would take place from the one to the other. This made Galvani's theory that the metals served merely as conductors seem improbable. On the other hand, it was sometimes possible to get the muscular contractions by using a single bent wire or rod to connect the nerve and muscle, especially if the two ends were of different degrees of polish, or if one end was warmer than the other.

Volta was apparently the first to suggest that the electricity which seemed to be generated in Galvani's experiments might have its source in the contact of the two metals. Several writers called attention to an apparent relation between Galvani's experiments and a phenomenon announced by J. G. Sulzer, in 1760. Sulzer found that if pieces of lead and silver were placed upon the tongue separately no marked taste was produced by either, but that if while both were on the tongue the metals were brought into contact a strong taste was produced which he compared to the taste of iron vitriol. Here was a case of undoubted stimulation of the nerves of taste by the contact of two metals, and it seemed not improbable that other nerves might be stimulated in the same manner. In the meantime Mr. John Robison had increased the Sulzer effect greatly by building up a pile of pieces of zinc with silver shillings and placing these in contact with the tongue and the cheek.

It was the question as to the possibility of producing the electric charge by mere metallic contact which led Cavallo to make his experiments upon contact electrification. Thus Cavallo says in Volume III. of "A Complete Treatise on Electricity," published in 1795:

'The above mentioned singular properties, together with some other facts, which will be mentioned in the sequel induced Mr. Volta, to suspect that possibly in many cases the motions are occasioned by a small quantity of electricity produced by the mere contact of two different metals; though he acknowledges that he by no means comprehends in what manner this can happen. This suspicion being entertained by so eminent a philosopher as Mr. Volta, induced Dr. Lind and myself to attempt some experiment which might verify it; and with this in view we connected together a variety of metallic substances in diverse quantities, and that by means of insulated or not insulated communications; we used Mr Volta's condenser, and likewise a condenser of a new sort; the electrometer employed was of the most sensible sort; and various other contrivances were used, which it will be needless to describe in this place; but we could never obtain the smallest appearance of electricity from those metallic combinations. Yet we can infer to no other conclusion, but that if the mere combination, or contact, of the two metals produces any electricity, the quantity of it in our experiments was too small to he manifested by our instruments.'

Later, on page 111 of the same volume, he says:

'After many fruitless attempts, and after having sent to the press the preceding part of this volume, I at last hit upon a method of producing electricity by the action of metallic substances upon one another, and apparently without the interference of electric bodies. I say apparently so, because the air seems to be in a great measure concerned in those experiments, and perhaps the whole effect may be produced by that surrounding medium. But, though the irregular, contradictory, and unaccountable effects observed in these experiments do not as yet furnish any satisfactory theory, and though much is to be attributed to the circumambient air, yet the metallic substances themselves seem to be endowed with properties peculiar to each of them, and it is principally in consequence of those properties that the produced electricity is sometimes positive, at other times negative, and various in its intensity.'

Cavallo then proceeds to describe the experiments on contact electrification which were described in the previous paper referred to at the beginning of the article.

Cavallo's experiments were evidently made in 1795. In the following year Volta announced the discovery of the electrical current. In a letter written to Gren's Neues Journal der Physik, August, 1796, Volta says:

'The contact of different conductors, particularly the metallic, including pyrites and other minerals as well as charcoal, which I call dry conductors, or of the first class with moist conductors, or conductors of the second class, agitates or disturbs the electric fluid, or gives it a certain impulse. Do not ask in what manner: it is enough that it is a principle and a great principle.'

It will be seen that at this stage of his discovery Volta was inclined to attribute tho origin of the current to the contact between the metals and his moist "conductors of the second class," though later in the same article he says it is impossible to tell whether the impulse which sets the current in motion is to be attributed to the contact between the metals themselves or between the two metals and the moist conductor, since either supposition would lead to the same results.

Later, as was shown in the previous paper by the present writer Volta came to regard the metallic contact as the cause of the electromotive force. In a letter written to Gren in 1797 and published as a postscript to his letter of August, 1796, Volta says:

'Some new facts, lately discovered, seem to show that the immediate cause which excites the electric fluid, and puts it in motion, whether it be an attraction or a repulsive power, is to be ascribed much rather to the mutual contact of two different metals, than to their contact with moist conductors.'

The new facts, "lately discovered," to which Volta attributes his change of view were his repetitions of Bennett's experiments of 1789.

Volta apparently thought that the current was not only set up by the contact of the two metals of a pair, but that it was kept up by the mutual action of the metals on each other. He accordingly made no attempt to discover whether any changes took place in his circuit while the current was being generated. The chemical action on his metals and the dissociation in his electrolyte seem to have entirely escaped his attention. At least, he did not attach enough importance to them to mention them anywhere in his description of his apparatus.

In the meantime a chemical explanation of the phenomena observed by Galvani had been proposed in 1792 by Fabroni, a physicist of Florence. After discussing the Sulzer phenomenon already mentioned in this paper, Fabroni argues that the peculiar taste caused by bringing the two metals into contact while on the tongue is due to a chemical, rather than to an electrical, action. He then discusses the different chemical behavior of metals when taken singly and when placed in contact with other metals. He says:[2]

[2] The following quotations from Fabroni have been translated by the present writer from the German of Ostwald's "Elektrochemie," pp. 103, ff.

I have already frequently observed that fluid mercury retains its beautiful metallic luster for a long time when by itself; but as soon as it is amalgamated with any other metal it becomes rapidly dim or oxidized, and in consequence of its continuous oxidation increases in weight.

I have preserved pure tin for many years without its changing its silvery luster, while different alloys of this metal which I have prepared for technical purposes have behaved quite otherwise.

I have seen in the museum at Cortonne Etrusean inscriptions upon plates of pure lead which are perfectly preserved to this day' although they date from very ancient times; on the other hand, I have found with astonishment in the gallery of Florence that the so-called "piombi" or leaden medallions of different popes, in which tin and possibly some arsenic have been mixed to make them harder and more beautiful, have fallen completely to white powder, or have changed to their oxides, though they were wrapped in paper and preserved in drawers.

In the same way I have observed that the alloy which was used for soldering the copper plates upon the movable roof of the observatory at Florence has changed rapidly and in places of contact with the copper plates has gone over into a white oxide.

I have heard also in England that the iron nails which were formerly used for fastening the copper plates of the sheathing of ships were attacked on account of contact, and that the holes became enlarged until they would slip over the heads of the nails which held them in position.

It seems to me that this is sufficient to show that the metals in these cases exert a mutual influence upon each other, and that to this must be ascribed the cause of the phenomena which they show by their combination or contact.

After discussing some of the experiments on nerve stimulation which had been made by Galvani and others, Fabroni argues that these are principally, if not wholly, due to chemical action, and that the undoubted electrical phenomena which sometimes accompany them are not the cause of the muscular contractions.

In discussing the nature of the chemical changes produced in two metals by their mutual contact, Fabroni says:

'Since the metals have relationships with each other, the molecules must mutually attract each other as soon as they come into contact. One can not determine the force of this attraction, but I believe it is sufficient to weaken their cohesion so that they become inclined to go into new combinations and to more easily yield to the influence of the weakest solvents.'

In order to further show the weakening of cohesion by the contact of two metals, Fabroni describes the results of some experiments which he has made. He says:

'In order to assure myself of the truth of my assumptions, I put into different vessels filled with water:

(1) Separate pieces, for example, of gold in one, silver in another, copper in the third, likewise tin, lead, etc.

(2) In other similar vessels I put pieces of the same metals in pairs, a more oxidizable and a less oxidizable metal in each pair' but separated from each other by strips of glass

(3) Finally, I put in other vessels pairs of different metals which were placed in immediate contact with each other.

The first two series suffered no marked change, while in the latter series the more oxidizable metal became visibly covered with oxide in a few instants after the contact was made.'

Fabroni found that under the above circumstances his oxidizable metals dissolved in the water, and in some cases salts were formed which crystallized out. He then compares the metals in contact with each other in water with the metals on the tongue when brought into contact, as in Sulzer's experiment, and the two metals touching each other by which different points on a nerve were touched to produce the muscular twitchings in Galvani's experiments, and concludes that the chemical action upon the metals was the same in each case, and that the other phenomena observed must have resulted from this chemical action. It is not strange that when Volta showed later that an electric current passed between the metals in all of tho above cases Fabroni should regard the chemical action which he had previously observed as the cause of this current.

Ten years after the publication of Fabroni's original paper, Volta wrote a letter to J. C. Delamethrie which was published in Vol. I of Nicholson's Journal. This letter was written after the chemical changes in the voltaic cell had received a great deal of attention by many experimenters, the most prominent of whom was Davy. To show that Volta's theory as to the source of the current was not affected by these investigations, a quotation from this letter is given below.

'You have requested me to give you an account of the experiments by which I demonstrate, in a convincing manner, what I have always maintained, namely, that the pretended agent, or GALVANIC FLUID, is nothing but common electrical FLUID, and that this fluid is incited and moved by the simple MUTUAL CONTACT OF DIFFERENT CONDUCTORS, particularly the metallic; strewing that two metals of different kinds, connected together, produce already a small quantity of true electricity, the force and kind of which I have determined; that the effects of my new apparatus (which might be termed electromotors), whether consisting of a pile, or in a row of glasses, which have so much excited the attention of philosophers, chemists, and physicians; that these so powerful and marvelous effects are absolutely no more than the sum total of the effects of a series of several similar metallic couples or pairs; and that the chemical phenomena themselves, which are obtained by them, of the decomposition of water and other liquids, the oxidation of metals, &c., are secondary effects; effects, I mean, of this electricity, of this continual current of electrical fluid, which by the above mentioned action of the connected metals, establishes itself as soon as we form a communication between the two extremities of the apparatus, by means of a conducting bow; and when once established, maintains itself, and continues as long as the circuit remains interrupted.'[3]

[3] This seems to be a misprint for uninterrupted.

Further along in the same letter Volta reiterates his conviction that the contact of the two metals furnishes the true motive power of the current. Thus he says (p. 138):

'As to the rest, the action which excites and gives motion to the electric fluid does not exert itself, as has been erroneously thought, at the contact of the wet substance with the metal, where it exerts so very small an action, that it may be disregarded in comparison with that which takes place, as all my experiments prove, at the place of contact of different metals with each other. Consequently the true element of my electromotive apparatus, of the pile, of cups, and others that may be constructed according to the same principles, is the simple metallic couple, or pair, composed of two different metals, and not a moist substance applied to a metallic one, or inclosed between two different metals, as most philosophers have pretended. The humid strata employed in these complicated apparatus are applied therefore for no other purpose than to effect a mutual communication between all the metallic pairs, each to each, ranged in such a manner as to impel the electric fluid in one direction, or in order to make them communicate, so that there may be no action in a direction contrary to the others.'

At the end of the above letter as published in Nicholson's Journal, the editor, William Nicholson, comments at length on Volta's theory of the source of current in the cell and calls attention to the fact that Davy had already made cells by the use of a single metal and two different liquids. At the conclusion of his comments he calls attention to the fact that Bennett and Cavallo had performed experiments with contact electrification prior to Volta's experiments, and says in conclusion, after referring to Bennett,

'This last philosopher, as well as Cavallo, appears to think that different bodies have different attractions or capacities for electricity; but the singular hypothesis of electromotion, or a perpetual current of electricity being produced, by the contact of two metals is, I apprehend, peculiar to Volta.'

This peculiar theory of Volta's probably never gained many adherents and was necessarily abandoned as soon as the energy relations of the current were considered, but the controversy as to whether the electrical current or the accompanying chemical changes was the primary phenomenon soon became transferred to a quite different field, viz., to the origin of the electrical charges which Bennett had shown resulted from the contact of different metals. Bennett attempted to account for the phenomena which he had observed on the hypothesis that different substances "have a greater or less affinity with the electric fluid," and Cavallo says:

'I am inclined to suspect that different bodies have different capacities for holding the electric fluid.'

Volta reaches a similar conclusion after repeating some of Bennett's experiments. In referring to this decision of Volta as to the origin of the electric charge in contact electrification, Ostwald says:

'We stand here at a point where the most prolific error of Electrochemistry begins, the combating of which has from that time on occupied almost the greater part of the scientific work in this field.'

The error, from Ostwald's point of view, lies in the assumption that the transference of electricity from the one metal to the other is a primary phenomenon of metallic contact. He, with many others, including some of the most distinguished physicists and chemists of the past century, regard the electrical transference as a secondary phenomenon resulting from the previous oxidation of one of the metals. Thus Lodge, in discussing the opposite electrification of plates of zinc and copper when brought into contact says:

'The effective cause of the whole phenomenon in either case is the greater affinity of oxygen for zinc rather than copper.'

The apparent conflict of opinion between those who hold that the different affinities of the metals for oxygen is the cause of the rearrangement of their electrical charges when brought into contact and those who hold with Bennett and Cavallo that the metals in their natural state have different affinities for the electrical fluid must disappear when we recognize that all affinity, and consequently the affinity for oxygen, must be an electrical attraction. If zinc has an affinity for oxygen, it must be because the zinc is either electropositive or electronegative to oxygen. If it has a greater affinity for oxygen than copper has, then the zinc must be either electropositive or electronegative to copper. This being the case, and both being conductors, it is not surprising that some electricity will flow from one to the other when the two metals are brought into contact.

Those writers who attribute the oxidation theory of contact electrification to Fabroni apparently overlook the fact that not oxidation, but the weakening of the cohesion of at least one of the metals due to their contact, was the primary phenomenon in Fabroni's theory. When this is remembered, it is seen that the observations of Bennett and Fabroni, instead of furnishing arguments for two conflicting theories, actually serve, as all true scientific observations must, to supplement each other.

Thus we now know that cohesion or affinity is an electrical attraction between the atoms or molecules of a body. The only known methods of changing the electrical attraction between two bodies whose distances and directions from other bodies remain constant is by varying the magnitude of their charges or by changing the specific inductive capacity of the medium between them. Bennett observed that when two pieces of different metal in their normal electrical condition are placed in contact, there is a redistribution of the charges of their surface atoms. Fabroni observed under the same conditions a change in the surface cohesion of the two metals.

To the present writer this seems the actual sequence of phenomena, viz., a redistribution of the charges of the surface atoms of the metals, a consequent change in surface cohesion and a resultant oxidation of one of the metals.

ON CERTAIN RESEMBLANCES BETWEEN THE EARTH AND A BUTTERNUT

BY PROFESSOR A, C. LANE

TUFTS COLLEGE

THE drama of the earth's history consists in the struggle between the forces of uplift and the forces of degradation. The forces of uplift are mainly the outward expression of the inner energy and heat of the earth, whether they be the volcano belching its ashes thousands of meters into the air, or the earthquake, with the attendant crack or fault in the earth's crust, leading to a sudden displacement, and sending, far and wide, a death-dealing shock, or those mountain-building actions, which, though they may be as gentle and gradual as might be produced by the breathing of mother earth and the uplifting of her bosom thereby, nevertheless, end in the huge folds of our mountain ranges.

Against these, there are always working the forces of degradation--the slow rotting of weathering caused by the direct chemical action of the moist atmosphere or the alternation of hot and cold which crumbles rocks far above the line where rain never falls. Once the rock is rotten and decayed, it yields readily to the forces of degradation, which drag it down--the beating of the rain, the rush of the avalanche or of the landslide, the tumult of the torrent, the quieter action of the muddy river in its lower reaches or the mighty glacier which transfers fine and coarse material alike toward the sea.

These actions are always going on. Are they always equally balanced, or are there periods when the forces of elevation are more active, the forces of degradation not so powerful, as against other times in which the forces of degradation alone are at work? If there is inequality in the balance and struggle of these contending forces, the great periods or acts in the geologic drama might thus be marked off as Chamberlin suggests. Newbery, Schuchert and others have pointed out that there seem to have been great cycles of sedimentation which may be interpreted as due to the alternate success, first of the factors of elevation, then of those of degradation.

Suppose, for instance, that there has been an epoch of elevation, that mountain chains have been lifted far into the sky and volcanoes have sent their floods of lava forth, and fault-scarped cliffs run across the landscape and that then, for a while, the forces of elevation cease their work. Little by little, the mountains will be worn down to a surface of less and less relief, approaching a plain as a hyperbola approaches its asymptote--a surface which W. M. Davis has called peneplain.

But where will the material thus worn go? Into the sea. Going into the ocean it will raise the level of the sea slowly but surely. At present, for every four feet of elevation taken off the land, there will be something like one foot rise of the ocean level, and this rise may take only thirty thousand years--a long time in human history, but not so long in the history of the earth. All the time, then, that the forces of the atmosphere are wearing down the surface of the earth to the sea level the sea is rising and its waves are producing a plain of marine denudation which rises slowly to meet the peneplain which is produced by degradation. In the beginning of this cycle, where the forces of degradation have their own way, coarse material may be brought down by torrents from the mountains, and the glaciers, which find their breeding place in these high elevations, may drag down and deposit huge masses of boulder clay. But, little by little as the mountains are lowered, the sediments derived from them will become finer and finer and glaciers will find fewer and fewer sources.

Not only that, but the growth of seas extending over the continents will tend to change the climate, we shall have a moister, more insular climate, we shall have a greater surface of evaporation, and thus, on the whole, a more equable temperature throughout the world. We know that, at present, the extremes of cold and hot are found far within the interior of the continents. Continental climates are the climates of extremes, and on the whole extremes are hurtful to life. So then as the forces of degradation tend to lower the continents beneath the sea level glaciers and deserts and desert deposits alike must also disappear. Vegetation will clothe the earth, and marine life swarm in the shallow seas of the broadening continental shelf. Under the mantle of vegetation, mechanical erosion will be less, that is, the breaking up of rocks into small pieces without any very great change, but the rich soil will be charged with carbon dioxide, and chemical activity will still go on. Rivers will still contain carbonates, even though they carry very little mud, and in the oceans the corals and similar living forms will deposit the burden of lime brought into the sea by the rivers. Thus, if forces of degradation have their own way, in time there will be a gradual change in dominant character, from coarse sediments to fine, from rocks which are simply crumbled debris to rocks that are the product of chemical decay and sorting, so that we have the lime deposited as limestone in one place and the alumina and silica, in another. We shall have a change from local deposits, marine on the edges of large continents, or land deposits, very often coarse, with fossils few and far between, to rocks in which marine deposits will spread far over the present land in which will appear more traces of that life that crowded in the shallow warm seas which form on the flooded continents. We shall have a transition from deposits which may be largely formed on the surface of the continents. lakes, rivers, salt beds and gypsum beds, due to the drying up of such lakes and the wind-blown deposits of the steppes, to deposits which are almost wholly marine.

Now, I need not say (to those who are familiar with geology) that we have indications of just such alternations in times passed. There are limestones abounding in fossils, with a cosmopolitan life very wide spread to be recognized in every continent, such as used to be known as the Trenton limestone, the mountain limestone, the chalk. Perhaps every proper system and period should be marked by such a limestone in the middle. The time classed as late Permian and Triassic on the other hand was one of uplift, disturbance, volcanic action and extreme climates, which gave us the traps of Mt. Tom, the Palisades of the Hudson, the bold scenery of the Bay of Fundy and the gypsum and red beds which are generally supposed to be quite largely formed beneath the air and beds of tillite formed beneath glaciers. Then in the times succeeding, in many parts of the world, degrading forces were more effective than uplifting so that the mountains became lower, and the seas extended farther over the continents. Then the prevalence of lime sediments was so great that the "chalk" was thought to be characteristic everywhere. And about the time the "chalk" the land was reduced to a peneplain. A similar cycle may be traced from the Keweenawan rocks to the group of limestones so widespread over the North American continent and so full of fossils, which to older geologists and oil drillers have been known, in a broad way, as Trenton.

All this introduces a question--to which I wish to suggest an answer--How is it that these cycles came to be? Were the outer rock crust of the earth perfectly smooth the oceans would cover it to the depths of thousands of feet and it is only by the wrinkling of such a crust that any part of it appears above the ocean. If the earth had a cool thin crust upon a hot fluid interior, and that thin crust were able to sustain itself during geologic ages so that the shrinkage should accumulate within, until finally collapse came, giving an era of uplift, it is obvious that we could account for such cycles. There is very clear evidence that the outermost layer of the earth's crust is but a thin shell like the outer shuck or exocarp of a butternut, so thin that it is not at all possible that it can sustain itself for more than a hundred miles or so, or for more than a very few years at the outside. Hayford's[1] investigations are the latest that show that the continents project because, on the whole, they are lighter, they float, that is, above the level of the oceans because there is a mass of lighter rock below, like an iceberg in the sea. Here the likeness between nut and earth fails and it would be more like the earth if the outer shuck were thicker in certain large areas. If this extra lightness or "isostatic compensation" is equally distributed, Hayford finds[2] that the most probable value of the limiting depth is 70 (113 km.) miles, and practically certain that it is somewhere between 50 (80 km.) and 100 (150 km.) miles; if, on the other hand, this compensation is uniformly distributed through a stratum 10 (16 km.) miles thick at the bottom of the crust so that there is a bulging of the crust down into a heavier layer below to balance the projection of the mountains above, as I think much more likely, then the most probable depth for the bottom of the outer layer is 37 (60 km.) miles. This layer is much thinner than the outer layer of the figure and is supposed to yield to weight placed as, though more slowly than, new thin ice bends beneath the skater.

[1] The figure of the earth and isostasy from measurements in the U.S. Dept. of Commerce and Labor, 1909, p. 175.

[2] loc. cit., p. 175.

There are a number of facts which support this so-called theory of isostasy, according to which the crust of the earth is not capable of sustaining any very great weight, though it may be at the outside rigid, but is itself essentially like a flexible membrane resting on a layer of viscous fluid. However viscous this fluid may be and rigid to transitory quickly shifting strains like those produced by the earth's rotation, it does NOT REMAIN AT REST in a state of strain (at any rate if this strain passes limits which are relatively quite low). Not only are, according to Hayford's observations, the inequalities of the North American continent compensated for by lighter material below, so that the plumb- bob deflections are only one twentieth what they would be if they rested upon a rigid substratum of uniform density, but other facts that lead to the same conclusion are the apparent tendency of areas of sedimentation to slowly settle under their load, the apparent settling of the Great Lake region under a load of ice and springing up again since the removal of the ice. But if the theory of isostasy is true, one would at first say that there could be no great accumulation through a geologic period of stresses which would finally yield in the shape of folded mountain ranges. It has, in fact, been suggested that mountain ranges have been slowly folded and lifted as the stress which produced them accumulated and this would seem to be true if one considers only the outer crust, but on the other hand, as we have pointed out, there are indications in the history of the earth of periods of relative quiescence followed by periods of relatively considerable disturbance.

How can these two theories be reconciled in accordance with what we know of the laws of physics and chemistry and those of the earth's interior? It seems to me they can by making suppositions which are perfectly natural regarding the state of the earth's interior.

We are at liberty to suppose if the facts point that way that there are the following layers in the earth's masses:--First, the external, rigid and brittle layer; second, a layer under such temperature and pressure that it is above its plastic yield point and may be considered as a viscous fluid. The pressure must continue to increase toward the center. We do not know what is the temperature, but it is perfectly possible that at a greater depth the earth may become rigid once more if the effect of pressure in promoting solidity and rigidity continues, as Bridgman tells me he thinks probable. We do not even have to assume a change in the chemical composition of the earth's substance, though it is perfectly allowable. This, then, will be a third layer, once more rigid, perhaps extending to the center and of very considerable thickness and capable of accumulating strain from long periods. Blanketed as it would be by thousands of meters of the first two layers, any change must be relatively slow.

Kelvin in his computation of the age of the earth from cooling assumed for the interior of the earth constant conditions. It is now generally accepted that this is not probable, and that whether it cooled from a gas or coagulated from planetesimals, it became solid first at the center which then would be hottest, and both Becker[3] and A. Holmes[4] assume an initial temperature gradient. If that gradient were greater than the gradient of steady flow the conditions of steady flow would be approached most rapidly at the exterior, the loss of heat and energy would be altogether from within and it is easy to arrange for conditions mathematically in which almost all the loss of energy would come from the very interior, near the center. What will be the effect? A paradoxical one, if the part outside the center is rigid enough to be self-sustaining. The central core will become a gas!

[3] Bull. Geol. Soc. Am., Vol. 26, 1915, p. 197, etc. [4] Geological Magazine, March and April, 1913.