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“SCIENCE” and “ “ progress” are both terms of the very widest significance. Three hundred years ago, Admirable Crichton, that famous Scotchman, knew practically all that was to be learned ; now it requires a life-time to master well the whole of a single, comparatively small section of one of the great divisions of science.

The great expansion of scientific knowledge has taken place during the present century, but especially during the last fifty years. It is my intention, first, to sketch a few of the grandest achievements in the field of physical science; and then I shall briefly consider the question suggested by my subject, that is, whether the civilized world moves forward abreast with science and upon parallel lines.

The term “science,” as has been remarked, has a very great wealth of meaning, and can be taken to cover almost all our acquired learning, though in the popular sense its meaning is much restricted. In many of the newspapers is to be found a column headed - Science and Progress,” which usually allures the eye of the curious. Very generally at the top is to be seen a large telescope pointed to the heavens, with a little cherub ciinging to the eyepiece and gazing through at the starry wonders, while over in the distance stands the prosperous city with its many towers and spires and factory chimneys.

Almost always the progress refers to the application of some branch of scientific inquiry to the many necessities of the human race. I might quote the subjects of some paragraphs picked out at random: “Waste in Handling Gold Coin ; " " How to Temper a Spring; " " Big Belts made of Paper;” “ Acid-resisting Lining for Boilers; " " Recovering Down from Beaver-skin Scraps;" "Cutting Coal by Machinery;" "The Laughing Plant," etc.

Almost every case, you will notice, is an instance of applied science.

But theoretical science is always far in advance. The crest of her sure-moving wave is “far away on its course over the illimi. table ocean of the unknown” before the flotsam and jetsam left behind is turned into the wages of workmen and the wealth of capitalists. Sometimes the natural philosopher works toward this mercenary goal, but more usually the applications which so jubilate the heart of the craftsman are only incidental advantages cropping out in the pursuit of truth.

Physical science is sometimes divided into three great parts physics, chemistry, and biology; though it must always be understood that the boundary lines between these three mighty provinces are by no means easily traced. This is particularly true of physics and chemistry, and upon the territory common to these two very much careful work has been expended. In each of the three divisions there has been a remarkable advancement


indeed, such grand generalizations have been made, that in the several cases an almost complete reorganization has been required. In physics we can point to that profound fundamental principle, the conservation of energy, which many men still living have assisted to elaborate; in chemistry, the atomic theory is of recent growth; while in biology, the rehabilitation of the doctrine of evolution has had the effect of unifying, revivifying and marvellously extending that branch of science.

Let us consider, first, the conservation of energy. Energy is the ability to do work, and the amount of resistance a body can overcome is a measure of the energy it possesses.

For our simplest illustrations, consider bodies in actual motion. We all know that a bullet, projected from a rifle, can penetrate an oaken plank, or (alas, that we should so often try it) can pierce the human body. In this case resistance is overcome, work is performed. The merry rivulet is it ripples onward down the hillside not only charms the eye, but often moves in channels of the greatest utility. It can make the mill-wheel quickly turn, and give us flour for our bread or lumber to build our houses. In these examples, the energy is that of a considerable mass of matter which the eye can perceive. The ultimate particles of matter, the molecules, are also supposed to be in a state of ceaseless activity and remain essentially unaffected, even though the mass which they make up may receive the most powerful blows. The energy of these units is thought to be immense, and the time of their oscillations is exceedingly small. Nikola Tesla, in his recent experimental investigations in electricity, succeeded in producing currents which alternated over a million times per second, and some wonderful phenomena appeared. suggested by some eminent men of science that the vibrations of the current corresponded to those of the molecule, and thus some of the latter's mighty energy was made use of. It is believed that these researches open the way for further investigations into the actions of those mysterious, minute bodies which comprise the life-blood of the universe.

These are instances of energy of motion; but there is another species, that of position. We are conscious that energy is expended in throwing upwards a stone; and, just when it reaches its highest point, let a person put out his hand and lodge it upon the top of a house. There it lies at rest, but the loss of energy is only apparent, for let the one that caught it drop it again; it reaches the earth with the velocity it had on leaving, and we all know well to keep out of the way lest the energy acquired be expended in felling us to the ground. Thus a stone upon the top of a house is a very different thing from one on the ground; it is said to possess potential energy, or energy of position.

This fact is sometimes painfully impressed upon the inhabitants of mountainous countries. The hamlet at the base sees a great difference between a field of innocent-looking snow lying beside them and the great mass far up the mountain side, which so frequently descends in a mighty avalanche, carrying everything

It was

before it. In the same way the pond of water at the high level is very different from one at low level. From the latter no work can be obtained.

In all these cases the force of gravity has been utilized, but in the case of a watch-spring wound up or a cross-bow ready to be released, we bend to our purpose the force of elasticity. This stored-up energy of position has been compared to money in a bank. By employing the workman, the rich man puts this

energy of position into energy of motion. The pendulum is a good illustration of the two kinds of energy; at its highest position the energy is entirely potential, or due to position; at the lowest point it is entirely kinetic, or due to the motion; and at intermediate points it is partly of one kind and partly of the other; and thus we see how easily one kind of energy changes to the other.

Let us again consider the stone thrown upward. As it rises its velocity continually diminishes, until at last it stops for an instant and then commences its downward course. It reaches the ground with the velocity of projection, and so also with the same energy. It strikes the earth and the energy at once disappears with the motion. What has become of it? The cases in which motion was destroyed by percussion or by friction, long were stumblingblocks in the pathway of advance of a comprehensive theory of energy, and only in recent years were these removed. The fact that by friction heat is produced had long been known, but philosophers were of the opinion that heat was due to the presence of a peculiar kind of matter called caloric, which made its appearance when called for in the right manner. Davy and Rumford, however, saw that this hypothesis was hardly tenable, and so the notion that heat is simply a mode of motion came to be discussed. It is to Joule that most credit is due for establishing a definite mathematical relation between heat and work.

He demonstrated experimentally, that to every amount of heat produced, corresponds an exact amount of mechanical work—that to raise the temperature of one pound of water one degree Fahr., requires the expenditure of 772 foot-pounds of work. The mechanical theory has been further elaborated by modern men of science, particularly by Mayer and Clausius in Germany, and Maxwell and Thomson in England, and is now universally accepted. The development of this theory of heat closed the gap in the doctrine of energy.

For many years the possibility of transforming one kind of energy into another without loss had been recognized, and when it was demonstrated that, when the motion of a body as a whole is suddenly stopped, this motion is taken up by the molecules which are violently agitated and produce heat, all was plain sailing.

In recent years the various species of energy have been thoroughly investigated and their mutual transformations examined with great care. Besides the energy due to visible motion, and that due to advantageous position, there is the energy of absorbed heat, the backward and forward motion of the molecules; the energy of molecular separation by virtue of the force of cohesion; that of atomic separation due to chemical affinity; that of electrical separation, which is another form of energy of position; that of electricity in motion, the electric current; and lastly, radiant energy. It is believed that there is very little matter between the sun and the earth, and yet we have a kind of energy which traverses this great distance at an enormous velocity. This is thought to consist of vibrations of the space-filling ether, and hence its energy is similar to that of the pendulum.

Now for the law of conservation. Let us conceive the universe as a whole, complete in itself, giving no energy away nor receiving any from without; then the algebraic sum of the various energies considered is a constant quantity; the different terms of the equation constantly vary amongst themselves, but the sum remains everlastingly the same.

The ocean, at the bidding of the sun, may Aling upwards to the heavens the clouds which are carried far over the earth; these may condense and bring forth her verdant mantle of vegetation, or trickle down in pearly spring, nourishing life, or mighty river, forming the country's arterial system, and bearing forward the nation's commerce as it rushes on to mingle again with the parent ocean. Or, again, we may use the potential energy of the atoms of coal and oxygen to give us heat; this heat will rend apart the molecules of water and furnish us with steam ; using its enormous mechanical power in the steam-engine, we give a tremendous speed of rotation to the dynamo, which, in its turn, sends forth the electric energy to light our streets, propel our railways, or do ten thousand kindly favours to man. In every case there is marvellous transformation and correlation, but the sum total never varies and can never change through all the ages that our earth shall last.

In the department of Chemistry, the great work has been the erection and continual improvement of that mighty edifice, the atomic theory. Indeed, much of the débris left by former workmen had to be cleared away before the work of construction could begin. This theory teaches that matter is not a continuous whole, but is made up of infinitely small ultimate particles called molecules and atoms.

From the earliest times philosophers had theories of the constitation of matter. Aristotle, who lived more than three hundred years before our era, wrote ten books on physical science. He believed that different combinations of the four qualities, heat and cold, and dry and wet, produced the four elements, air, fire, earth and water; and even in the eighteenth century, chemists believed that the principle which provided for combustion was the presence of a substance called phlogiston. If there was much phlogiston in a body it was very combustible. It was also believed that the essence of matter was always the same, but that by some mysterious transformation it changed its dress and so appeared quite different to us. Hence many years were spent in the vain attempt to transmute the baser metals into gold. Yet all this work of the old alchemists was not fruitless; it did much to foster a spirit of investigation, and in some cases it led to really useful results. A similar remark might be made concerning astrology, the cultivation of which certainly was of great assistance to the rising child, astronomy.

Thus philosophers had reasoned for over two thousand years upon the real manner in which substances were built up, but it was left for Dalton to found our present accepted system on a basis that can hardly be controverted. He was born in 1766 and died in 1844. Chemical investigation has been carried on by Boyle, Becher, Stahl, Cavendishi, Lavoisier and many others, and somewhat refined methods of experimentation had been introduced, especially by Lavoisier, but it was left for Dalton to found the new chemistry. In 1808 he published his “ New System of Chemical Philosophy," in which he speaks of the great advantage in discovering :

“The relative weights of the ultimate particles both of simple and compound bodies, the number of simple elementary particles which constitute one compound particle, and the number of less compound particles which enter into the formation of one more compound particle."

Dalton was not an expert mathematician, but he had a passion for experimental work. It is related of him, that on one occasion he was greatly troubled with catarrh, and a dose of James' powder was given him. The next day he was much improved and his medical attendant remarked the efficacy of the powder. "I do not well see,” replied Dalton,“ how that can be, as I kept the powder until I could have an opportunity of analyzing it.” On his laboratory researches his theory was built, and when in 1811 Avogadro enunciated the law that equal volumes of gases under the same pressure and temperature contain the same number of molecules, the way was cleared for working out the immense amount of detail which faithful labourers in the chemical field have given to the world.

The manufacture of optical instruments is improving all the time, but it is to be regretted that they will never be made powerful enough to detect the diminutive molecule.

And even though microscopes could be made to reveal to us an object whose diameter is not more than the one-three-hundred-millionth of an inch, it is believed that the little bodies are in such rapid motion back and forth or in straight lines, that they would escape our notice. But physicists the world over are sure that the molecule exists as truly as does the extended mass. By the microscope of faith, he sees the molecule of oxygen in his native war-paint as a vicious savage, dangerous to meet. But let a lady atom of hydrogen grasp each hand of the gentleman atom of oxygen, and at once he becomes a polished gentleman, the handsome water molecule.

Strong as is the atomic theory, and useful as it has been in colligating facts and predicting results, I think it is only in the constructive stage, and must be considered a working hypothesis

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