Scientific Side-Lights

It may well be doubted whether the annual average of destruction to life and property caused by all kinds of subterranean action exceeds that produced either by floods or by hurricanes. Yet we know that the circulation of water and air over our globe are beneficial and necessary operations, and that the mischief occasionally wrought by the moving bodies of water and air is quite insignificant compared with the good which they effect. In the same way, we shall be able to show that the subterranean energies are necessary to the continued existence of our globe as a place fitted for the habitation of living beings, and that the mischievous and destructive effects of these energies bear but a small and insignificant proportion to the beneficial results with which they must be credited.

The projecting apparatus is next removed and replaced by the polarizing eyepiece. Sir William Herschel used to avoid the blinding effects of the concentrated solar light by passing the rays through ink and water, but the phenomena of "polarization" have been used to better advantage in modern apparatus. [In this instrument] the light is polarized with three successive reflections through three tubes. By its aid the eye can be safely placed where the concentrated heat would otherwise melt iron. In practise I have often gazed through it at the sun's face without intermission from four to five hours, with no more fatigue or harm to the eye than in reading a book. By its aid the observer fills in the outline already projected on the paper. 

But when the lava contains no ready-formed crystals, but consists entirely of a glassy substance in a more or less perfect state of fusion, the liberation of steam gives rise to the formation of the beautiful material known as "pumice." Pumice consists of a mass of minute glass bubbles; these bubbles have not usually, however, retained their globular form, but have been elongated in one direction through the movement of the mass while it was still in a plastic state.

Certainly, no one familiar with the facts could suppose that floating ice or icebergs had abraded, polished, and furrowed the bottom of narrow valleys as we find them worn, polished, and grooved by glaciers. And it must be remembered that this is a theory founded not upon hypothesis, but upon the closest comparison. I have not become acquainted with these marks in regions where glaciers no longer exist, and made a theory to explain their presence. I have, on the contrary, studied them where they are in process of formation. I have seen the glacier engrave its lines, plow its grooves and furrows in the solid rock, and polish the surfaces over which it moved, and was familiar with all this when I found afterwards appearances corresponding exactly to those which I had investigated in the home of the present glaciers. I could therefore say, and I think with some reason, that "this also is the work of the glacier acting in ancient times as it now acts in Switzerland."

AGASSIZ Geological Sketches, ser. ii, p. 39. (H. M. & Co., 1896.)

The vast ice-sheet covering nearly all of Greenland is of the continental type, and, as is well known, is the largest existing ice-body in the northern hemisphere. Its extension northward has not been fully determined, but as nearly as can be judged it terminates in about latitude 82°. Its area is in the neighborhood of 600,000 square miles. If transferred bodily to the eastern portion of the United States, it would extend from northern Maine to Georgia, and cover a belt of country 500 miles broad. Vast as this ice-sheet is known to be, it takes what may be said to be second or third rank when contrasted with the continental glaciers that occupied Canada and a large portion of the United States in Pleistocene times. The exploration of existing glaciers derives one of its principal attractions from the fact that such studies assist in interpreting the records left by ancient glaciers in various parts of the world. This in turn brings one to the consideration of the still broader problems of the cause of climatic changes which favored the growth of vast Pleistocene glaciers in regions now enjoying a temperate climate, and inhabited by the most civilized people of the earth.

All the phenomena of motion, on which the idea of viscosity [a view still held by eminent observers, as at least a partial explanation of glacial phenomena see Russell, " Glaciers of North America "] has been based, are brought by such experiments as the above [of breaking and freezing together the fragments of ice] into harmony with the demonstrable properties of ice. In virtue of this property, the glacier accommodates itself to its bed while preserving its general continuity, crevasses are closed up, and the broken ice of a cascade, such as that of the Taléfere or the Rhone, is recompacted to a solid continuous mass.

We have seen, however, that Alpha Centauri gives out about three times as much light as our sun. It follows that Sirius shines in reality three hundred times more brightly than the sun. Now, this implies that if the surface of Sirius is of the same intrinsic brightness as the sun’s—that is, if on the average each square mile of the surface of Sirius gives out the same quantity of light as each square mile of the sun's surface—then the surface of Sirius must be 300 times as large as the sun's. It would follow that the diameter of Sirius is between 17 and 18 times as large as the sun's. (For 17 times 17 are less than 300, and 18 times 18 are greater than 300.) Hence the volume of Sirius would be about 2,200 times as great as the sun's (this number 2,200 being obtained by multiplying 300 by 17 1/3, which is nearly equivalent to multiplying 17 1/3, twice into itself). This is on the supposition of equal surface luster; and it cannot be regarded as certain that Sirius is not considerably brighter than our sun as respects his actual surface. Of course if this is the case we cannot assume that Sirius is larger in so great a proportion as when we suppose his intrinsic luster the same as the sun's.

But it is worthy of notice that the eminent French physicist Ste.-Clair-Deville considers it impossible that under any circumstances a surface can be much hotter or more luminous than the solar surface. We shall probably be within the limits of fact if we regard the surface of Sirius as not more than twice as bright as the sun's. This would leave his surface 150 times larger than the sun's, or, for convenience of reckoning, say 144 times; his diameter would thus be twelve times the sun's, and his volume 1,728 times the sun's.

Have I not rightly called Sirius a "king of suns"? From that glorious orb, nearly 2,000 such orbs as the sun, that great and mighty globe, instinct with fire and life, might be formed, each fit to be the center of a scheme of circling worlds as important as that over which our sun bears sway!

Questions of size are always difficult to settle or determine from a popular point of view, and, when we seek to gain some adequate idea of the dimensions of germs, we are met with the difficulty of translating into terms of common life those of the infinitely little. If we speak of a germ which in length is the one-ten-thousandth part of an inch that is, equals one part of an inch which has been divided, as to its length, into ten thousand parts we utterly fail to grasp any notion of the size indicated. An appeal to figurative description, while more graphic in character perchance, yet leaves us with the dimmest conceptions of the dimensions of germs. One writer tells us that on the area of a single square inch we could place, in a single layer, a population of common germs or bacteria one hundred times as great as the population of London. Graphic as is this estimate, the idea of the actual size of the individual germs remains simply unattainable. It is this diminutive size compared with the great results in the way of disease certain of these germs may and do produce, which is more than sufficient to appal us.

WILSON Glimpses of Nature, ch. 26, p. 84. (Hum., 1892.)

It has been a common objection of abiogenists that, if the doctrine of biogeny is true, the air must be thick with germs; and they regard this as the height of absurdity. But Nature occasionally is exceedingly unreasonable, and Professor Tyndall has proved that this particular absurdity may nevertheless be a reality. He has demonstrated that ordinary air is no better than a sort of stirabout of excessively minute solid particles; that these particles are almost wholly destructible by heat, and that they are strained off, and the air rendered optically pure, by being passed through cottonwool. 

HUXLEY Lay Sermons, serm. 15, p. 360. (A., 1895.)

If a botanist be asked the difference between an oak, a palmtree, and a lichen, he will declare that they are separated from one another by the broadest line known to classification. 'Without taking into account the outward differences of size and form, the variety of flower and fruit, the peculiarities of leaf and branch, he sees even in their general architecture types of structure as distinct as Norman, Gothic, and Egyptian. But if the first young germs of these three plants are placed before him. and he is called upon to define the difference, he finds it impossible. He cannot even say which is which. Examined under the highest powers of the microscope, they yield no clue. Analyzed by the chemist with all the appliances of his laboratory, they keep their secret.

DRUMMOND Natural Law in the Spiritual World, essay 8, p. 257. (H. Al.)

It must be clearly understood that elementary geometry was not actually invented by means of definitions, axioms, and demonstrations like Euclid's. Its beginnings really arose out of the daily practical work of land-measurers, masons, carpenters, tailors. This may be seen in the geometrical rules of the altar-builders of ancient India, which do not tell the bricklayer to draw a plan of such and such lines, but to set up poles at certain distances, and stretch cords between them. It is instructive to see that our term straight line still shows traces of such an early practical meaning; line is linen thread, and straight is the participle of the old verb to stretch. If we stretch a thread tight between two pegs, we see that the stretched thread must be the shortest possible; which suggests how the straight line came to be defined as the shortest distance between two points. Also, every carpenter knows the nature of a right angle, and he is accustomed to parallel lines, or such as keep the same distance from one another. 

The chain of life in geological time presents a wonderful testimony to the reality of a beginning. Just as we know that any individual animal must have had its birth, its infancy, its maturity, and will reach an end of life, so we trace species and groups of species to their beginning, watch their culmination, and perhaps follow them to their extinction. ... But its revelation of the fact that nearly all the animals and plants of the present day had a very recent beginning in geological time, and its disclosure of the disappearance of one form of life after another as we go back in time, till we reach the comparatively few forms of life of the Lower Cambrian, and finally have to rest over the solitary grandeur of Eozoon, oblige it to say that nothing known to it is self-existent and eternal.

A century ago there was none [geology]. Science went out to look for it, and brought back a geology which, if Nature were a harmony, had falsehood written almost on its face. It was the Geology of Catastrophism, a geology so out of line with Nature, as revealed by the other sciences, that on a priori grounds a thoughtful mind might have been justified in dismissing it as a final form of any science. And its fallacy was soon and thoroughly exposed. The advent of modified uniformitarian principles all but banished the word "catastrophe" from science, and marked the birth of geology as we know it now. Geology, that is to say, had fallen at last into the great scheme of law. Religious doctrines, many of them at least, have been up to this time all but as catastrophic as the old geology. They are not on the lines of Nature as we have learned to decipher her. If any one feels, as science complains that it feels, that the lie of things in the spiritual world as arranged by theology is not in harmony with the world around, is not, in short, scientific, he is entitled to raise the question whether this be really the final form of those departments of theology to which his complaint refers. He is justified, moreover, in demanding a new investigation with all modern methods and resources; and science is bound by its principles, not less than by the lessons of its own past, to suspend judgment till the last attempt is made.

By these researches into the state of the earth and its inhabitants at former periods, we acquire a more perfect knowledge of its present condition, and more comprehensive views concerning the laws now governing its animate and inanimate productions. When we study history, we obtain a more profound insight into human nature, by instituting a comparison between the present and former states of society. We trace the long series of events which have gradually led to the actual posture of affairs; and by connecting effects with their causes, we are enabled to classify and retain in the memory a multitude of complicated relations the various peculiarities of national character the different degrees of moral and intellectual refinement, and numerous other circumstances, which, without historical associations, would be uninteresting or imperfectly understood. As the present condition of nations is the result of many antecedent changes, some extremely remote and others recent, some gradual, others sudden and violent; so the state of the natural world is the result of a long succession of events; and if we would enlarge our experience of the present economy of Nature, we must investigate the effects of her operations in former epochs.

Scientific men began to believe that no form of life arose de novo (abiogenesis), but had its source in previous life (biogenesis). It remained to Pasteur and Tyndall to demonstrate this beyond dispute and put to rout the fresh arguments for spontaneous generation which Pouchet had advanced as late as 1859. Pasteur collected the floating dust of the air, and found by means of the microscope many organized particles, which he sowed on suitable infusions, and thus obtained rich crops of "animalculæ.” He also demonstrated that these organisms existed in different degrees in different atmospheres, few in the pure air of the Mer de Glace, more in the air of the plains, most in the air of towns. He further proved that it was not necessary to insist upon hermetic sealing or cotton filters to keep these living organisms in the air from gaining access to a flask of infusion. If the neck of the flask were drawn out into a long tube and turned downwards, and then a little upwards, even tho the end be left open, no contamination gained access. Hence, if the infusion were boiled, no putrefaction would occur. The organisms which fell into the open end of the tube were arrested in the condensation water in the angle of the tube; but even if that were not so, the force of gravity acting upon them prevented them from passing up the long arm of the tube into the neck of the flask. [See PASTEUR.]

NEWMAN Bacteria, ch. 1, p. 4. (G. P. P., 1899.)

Even in our own time we may hope to see some improvement; but the unselfish mind will find its highest gratification in the belief that, whatever may be the case with ourselves, our descendants will understand many things which are hidden from us now, will better appreciate the beautiful world in which we live, avoid much of that suffering to which we are subject, enjoy many blessings of which we are not yet worthy, and escape many of those temptations which we deplore, but cannot wholly resist.

It may indeed be said that we have as yet no data for estimating the relative volume of matter simultaneously in a state of fusion at two given periods, as if we were to compare the columnar basalt of Staffa and its environs with the lava poured out in Iceland in 1783; but for this very reason it would be rash and unphilosophical to assume an excess of ancient as contrasted with modern outpourings of melted matter at particular periods of time. It would be still more presumptuous to take for granted that the more deep-seated effects of subterranean heat surpassed at remote eras the corresponding effects of internal heat in our own times. Certain porphyries and granites, and all the rocks commonly called Plutonic, are now generally supposed to have resulted from the slow cooling of materials fused and solidified under great pressure; and we cannot doubt that beneath existing volcanoes there are large spaces filled with melted stone, which must for centuries remain in an incandescent state, and then cool and become hard and crystalline when the subterranean heat shall be exhausted. That lakes of lava are continuous for hundreds of miles beneath the Chilean Andes seems established by observations made in the year 1835.