Popular Science Monthly/Volume 39/May 1891/Editor's Table
THE YOUNGEST OF THE SCIENCES.
TO know is to be able, to ken is to can: philology proclaims it, and experience confirms it. Centuries ago the commoner phenomena of electricity and magnetism had attracted attention, but no one suspected that they meant anything in particular, or that they afforded indications of a power everywhere present, and only waiting a summons to enter into the service of man. Yet, let us not too severely blame our ancestors for lack of attention or intelligence. The doors of knowledge have had to be opened one by one, and in early times, when so many doors still remained closed, and others were at best but slightly ajar, it is not to be wondered at that the somewhat recondite and elusive laws of electricity should have remained unexplored. Even in our own century, what a long gap there was between the first production of the electric light and its application to practical purposes! It all seems very plain now, but two generations had to elapse before the electric light, as produced by Sir Humphry Davy in 1808, became available for general use. But if the progress made by electrical science was slow in its earlier stages, amends are truly being made now in the rapidity with which new views and new applications of electricity are crowding upon the world. The alleged miracles of olden time seem poor and commonplace in comparison with the miracles wrought by a little accurate knowledge. Here we have a power that has been in the world from the beginning, but from which, down to the present century, not one single valuable result was drawn, for the simple reason that we, or our predecessors, did not know how to use it, did not even know enough to recognize it in some of its manifestations. To-day, mankind has no more obedient, or, it may be added, capable servant. The early students of electricity had a task that closely resembled putting together a complicated puzzle of which there was no plan; but, as piece was joined to piece, the plan began to reveal itself, and subsequent progress was rapid. To-day, if the puzzle is not complete, at least we have, as far as it goes, a very symmetrical and intelligible pattern before our eyes.
It would be vain to attempt, within the limits of a brief article like the present, to give even a catalogue of the various applications of electricity now in daily use. Like chemistry, electricity has undergone a process of subdivision, and no one man can pretend to keep abreast of the latest developments in all its branches. The year 1837 saw the first telegraph for practical business purposes, and from that time to this there has been a constant stream of improvements in the methods and appliances of the telegraphic art. The whole world is girdled round and round with lines quivering with the impulses that translate the thoughts of men. Enormous as has been the extension of telegraph lines, well-nigh a million miles being now in use in this country alone, they would be utterly inadequate to the needs of the community but for the improvements that have been made in the way of duplex and multiplex telegraphy. The whole business of the world has adapted itself to the changed conditions which the telegraph has introduced. Without the telegraph the railway would be shorn of far more than half its efficiency, and the press of even metropolitan cities would shrink to provincial dimensions. It is becoming difficult to conceive what the state of business would be without even the telephone, which, in every large city, does the work of a whole army of messenger boys. How little we think of electricity when we press the button that closes an electric circuit and rings a bell 1 Yet the electric bell is certainly one of the most convenient of so-called modern improvements. Without it our great hotels, our public offices, our monster steamships would be much more difficult of management. Our signal service depends upon electricity to outrun the swiftest blasts of storm and herald their approach. The observations of the astronomer would lose much in precision were it not for the simple yet admirable instrument known as the chronograph. For all purposes of instantaneous registration, there is nothing equal to the action of electricity, the velocity of which is equivalent to that of light itself, and its applications for this purpose must go on increasing in number from year to year. Even as it is they are legion.
The electric light would seem to have furnished the world with the final and definitive source of illumination. It is not twenty years since even so good an authority as Prof. Tyndall spoke doubtfully of the possibility of distributing the electric light from house to house; but to-day the problem does not present any greater practical difficulty than the distribution of water or gas. When Sir Humphry Davy first made an exhibition of the arc light he used for the purpose a battery of two thousand voltaic cells. Light so produced could never have come into general use on account of the excessive cost. Faraday had to formulate the laws of induction, and the dynamo had to be developed, before Davy's discovery could be turned to practical account, and even then a vast amount of ingenuity had to be expended in the arrangement of details. The incandescent light was a later development. An incandescent lamp is a simple thing to look at, but only those who have studied the subject know how much of laborious experiment and research it took to bring it to its present condition of perfection. The dynamo which, practically speaking, gives us the electric light, gives us also electric traction and electric power generally. We are only beginning to realize the advantages which our newfound force may have in store for us in this direction. Every month the electric street car is more and more displacing the horse car, with added comfort to passengers and diminished wear of our thoroughfares. Power is conveyed silently over wires from central stations and distributed wherever it may be required for manufacturing purposes, saving a vast outlay in separate boilers and engines, and greatly economizing space. In great telegraph centers the dynamo is displacing cell batteries for the production of current. It is also used for electrolytic operations on a large scale. Nothing, perhaps, is more impressive than to witness the operation at the same moment and on the same spot of three distinct forms of force, mechanical or physical, electrical and chemical, one merging into the other. The waterwheel or the steam-engine furnishes mechanical power; the dynamo, taking up that power, converts it into electrical energy, which again, conducted to an electrolytic cell, is further changed into chemical action. Nothing could more powerfully bring home the lesson that, in the last analysis, all energy is one. Vast industries would disappear from the earth if the various applications of electrolysis could by any means be lost—electro-plating, electrotyping, electrometallurgy, and a hundred other special applications of electro-chemistry. It takes a considerable effort of thought and memory to realize the extent to the every-day operations of the modern world are dependent upon a power which but a few generations ago was a matter of more or less crude speculation and idle wonder. In electro-welding we have a process, strictly speaking, analogous to the production of the electric light; the energy of electricity is converted into heat at a given point with the most marvelous results. The new science is stretching forth its hands in every direction, and its achievements to-day are but an earnest of what it is destined to accomplish in the near future.
There is, however, another aspect of the matter which is deserving of attention. From having been, up to a short time ago, a subject concerning which the most vague and confused ideas were generally entertained, electricity is now furnishing matter for the formation of one of the most exact sciences. It is true there is a vast amount of popular ignorance respecting it still; one might not, perhaps, have far to go to find "educated" people who imagine that Edison and electricity are almost convertible terms, or at least that electricity was fished bodily out of the depths of the unknown by Edison; nevertheless, the light is spreading, and the very operations which the applications of electricity involve are furnishing a valuable education to a large section of the community. Electricity is above all things measurable, and measurable in a great variety of ways; and the measurement of electricity implies the investigation from a new standpoint of the various substances used as its conductors. The study of this particular agency, therefore, involves the study of a great number of related things, and thus directly tends to an enlargement of mental grasp. It has, if we mistake not, another most interesting side. All natural sciences, by the analogies they supply, throw more or less light upon the operations of mind and the movements of social forces. Electricity, we believe, will furnish the most instructive ones of all, but we can not to-day more than throw out the hint. Physical science, let us say in conclusion, is bringing noble gifts to the feet of mankind; it is for mankind to see that they use these nobly and wisely.
THE DOCTRINE OF NATURAL SELECTION.
There has been a very industrious outcry in certain quarters lately, to the effect that the doctrine of Natural Selection was losing ground; and certain reactionaries have been allowing themselves to entertain great hopes that all might yet be well with their antiquated ideas. As a very apt and powerful answer to this contention came Mr. Wallace's book on Darwinism, in which, in the line of animal creation, he claimed more for the action of natural selection than even Darwin had done. Following close on it came the interesting treatise of Mr. E. B. Poulton, F. R. S., on the Colors of Animals. The last paragraph of Mr. Poulton's preface is worth quoting entire:
"Above all, I should wish to acknowledge, although I can never fully express the depth of my indebtedness to the principles which first made Biology a science, the principles enunciated by Charles Darwin. It is common enough nowadays to hear of new hypotheses, which are believed by their inventors to explain the fact of evolution. These hypotheses are as destructive of one another as they are supposed to be of natural selection, which remains as the one solid foundation on which evolution rests. I have wished to express this conviction, because my name has been used as part of the support for an opposite opinion, by an anonymous writer in the Edinburgh Review. In an article in which unfairness is as conspicuous as the prejudice to which it is due, I am classed as one of those 'industrious young observers' who 'are accumulating facts telling with more or less force against pure Darwinism.' On the strength of this and other almost equally strange evidence, the reviewer triumphantly exclaims, 'Darwin, the thanes fly from thee!' In view of this public mention of my name, I may, perhaps, be excused for making the personal statement that any scientific work which I have had the opportunity of doing has been inspired by one firm purpose—the desire to support, in however small a degree, and to illustrate by new examples, those great principles which we owe to the life and writings of Charles Darwin, and especially the pre-eminent principle of natural selection."
Mr. Poulton may express himself, perhaps, a little over-enthusiastically; but surely there is much significance in the protest which he raises against being quoted on the anti-Darwinian side. One substantial piece of manufactured evidence not only vanishes entirely, but has its place taken by an energetic assertion of the contrary position. Evidences, indeed, that the doctrine of evolution has become almost a fixed principle with scientific workers are to be found on every hand. When men of any scientific eminence whatever, like the late Prof. Sedgwick, in England, or Sir William Dawson, of Canada, refuse it their adhesion, their position becomes one of such singularity as powerfully to prove the rule as to the direction the scientific world at large has taken. One of the most conservative publications of the day in England is the Quarterly Review, and this is what we find in the very last number of that periodical on the subject of Sedgwick's non-acceptance of the modern standpoint in geology: "In coordinating the vast array of (geological) facts so as to form out of them a basis for the great cosmical theories which are the inheritance of his successors, he lagged behind his more philosophical contemporaries. He never broke loose from the entanglement of attempted reconciliations with the biblical cosmogony, never ceased to invoke 'successive creations of the organic kingdoms' to account for the order of life revealed in the rocks and clays. Lyell's great generalization of uniformity was always a stumbling-block to him, and evolution in every shape was to the end hated by him with a perfect hatred. It was years before he could discard the puerile idea that the 'vast masses of diluvial gravel scattered almost over the surface of the earth' were all due to the single catastrophe of the Noachian Deluge; and not till after half a century of geological study could he bring himself to ascribe any validity to the evidences for the vast antiquity of the human race, as contrasted with the historical period." The Quarterly Review, in spite of its general conservatism, is evidently in line with modern thought on these subjects. All the more amazing is it that some men should be found to talk as if the old conceptions were still valid, and the work of the evolutionist school had been in vain.