Quack

“ I consider the continual appearance of new quacks on the horizon a sure proof of the low state of our medical knowledge. The more so as these quacks, although they kill, do effect very remarkable cures. ”

“ Those who uphold the hypothesis of a fluid interior think the undulatory motion experienced at the surface is caused by movements in the underlying molten mass—an earthquake being thus 'the reaction of the liquid nucleus against the outer crust.' By others, again, earthquakes are supposed to be caused by the fall of large rock-masses from the roofs of subterranean cavities, or by any sudden impulse or blow, such as might be produced by the cracking of rocks in a state of tension, by a sudden volcanic outburst, or sudden generation or condensation of steam. ”

“ The close connection between the phenomena of volcanoes and earthquakes cannot be doubted. It is true that some of those vibrations or tremors of the earth's crust, to which we apply the name of earthquakes, occur in areas which are not now the seat of volcanic action; and it is equally true that the stratified rock-masses of our globe, far away from any volcanic centres, exhibit proofs of violent movement and fracture, in the production of which, concussions giving rise to earthquake vibrations, could scarcely fail to have occurred. ”

“ An earthquake is the vibration, sometimes violent, of the Earth’s surface that follows a release of energy in the Earth’s crust. This energy can be generated by a sudden dislocation of segments of the crust, by a volcanic eruption, or even by manmade explosions. Most destructive quakes, however, are caused by dislocations of the crust. ”

“ There are cases in which nature does try to thrust one rock under another. But to do that she requires a force so enormous, compared with what is employed in laying one rock on another, that (so to speak) she continually fails; and instead of producing a volcanic eruption, produces only an earthquake. Of that I may speak hereafter, and may tell you, in good time, how to distinguish rocks which have been thrust in from beneath, from rocks which have been laid down from above, as every rock between London and Birmingham or Exeter has been laid down. ”

“ An earthquake is transmitted from the focus through the elastic rocks of the crust, as a wave, or series of waves, of compression and rarefaction, much as a sound wave is transmitted through the elastic medium of the air. Each earth particle vibrates with exceeding swiftness, but over a very short path. The swing of a particle in firm rock seldom exceeds one tenth of an inch in ordinary earthquakes, and when it reaches one half an inch and an inch, the movement becomes dangerous and destructive. ”

“ We had laid down by our fire, and about ten o clock there came a most terrible earthquake, which shook the earth so that we rocked about like we had been in a cradle. We were very much alarmed; for though we were accustomed to feel earthquakes, we were now right in the region which had been torn to pieces by them in 1812, and we thought it might take a notion and swallow us up, like the big fish did Jonah. ”

“ Studies during the last fifty years have made it certain that the main cause of earthquakes is the sudden slipping of earth blocks past each other along fault fractures, the sudden slipping furnishing the impulse which sends out the vibrations into the surrounding more or less elastic crust of the earth. The low rumbling to roaring sound, which sometimes immediately precedes an earthquake, is probably due to the grinding of the rocks together below the surface. ”

“ The heavier particles, however, soon begin to fall, and before long the earth's surface both around the volcano, and often at considerable distances from it, is covered with a thick layer of ashes.
The sounds accompanying a volcanic eruption are often terrifying. Amid shakings and tremblings of the earth's crust, known as earthquakes, there are occasionally heard noises like the explosion of huge guns. ”

“ If the earth be now generally hot within, it must formerly have been hotter; in the process of cooling, the exterior solidified part and the interior fluid parts contract unequally, a general pressure and tension result, and the crust breaks locally to restore the equilibrium. Hence earthquakes, and fissures, on some of which volcanic vents are established, which serve more or less to relieve the subterranean pressure, as earthquakes also do. ”

“ It was hard to tell which frightened one the most, the terrible rain-storms or the awful earthquakes. In the house there was a magnificent glass chandelier. The first time we had a severe earthquake that chandelier swayed back and forth in such a wild way that it seemed as if it must fall and crush every prism, tiny light, and bell. I felt sure whenever a quake began that I should not live through it. ”

“ Hopkins has shown that the earthquake-wave, when it passes through rocks differing in density and elasticity, changes in some degree not only its velocity, but its direction; being both refracted and reflected in a manner analogous to that of light when it passes from one medium to another of different density. [3] When a shock traverses the crust through a thickness of several miles it will meet with various kinds of rock as well as with fissures and plications of the strata, owing to which its course will be more or less modified. ”

“ Since any concussion within the crust sets up an earth jar, there are several minor causes of earthquakes, such as volcanic explosions and even the collapse of the roofs of caves. The earthquakes which attend the eruption of volcanoes are local, even in the case of the most violent volcanic paroxysms known. When the top of a volcano has been blown to fragments, the accompanying earth shock has sometimes not been felt more than twenty-five miles away. ”

“ It is not easy to divert the Quaker from his course; we swung to the right, but the wing of the car, on my side, struck the man full in the chest. He fell as instantly and solidly as if he were a stone pillar, and, like a stone, he lay in the mud. ”

“ The entire interior is filled with rock hot enough to melt at the level of the sea, but under too great pressure to melt. If this be granted, as it is by perhaps the greatest number of men who are competent to judge, the phenomena of earthquakes can be readily explained, as can, indeed, the phenomena of those great movements whereby great changes of level take place in different parts of the earth. ”

“ The same great quaking likewise arises from this cause, when on a sudden the wind and some enormous force of air gathering either from without or within the earth have flung themselves into the hollow of the earth and there chafe at first with much uproar among the great caverns and are carried on with a whirling motion, and when their force, afterwards stirred and lashed into fury, bursts abroad and at the same moment cleaves the deep earth and opens up a great yawning chasm. ”

“ Inasmuch as compression would crush the rocks constituting the earth’s crust, we must conclude with Captain Dutton that these cracks are formed by tension. By elevation, the upper rigid crust of the earth is stretched, and fissures are produced. The sudden formation of these fissures or faults gives rise to earthquakes, and perhaps also to volcanic vents. That earthquake and volcanic regions are situated on areas where there is evidence of rapid elevation is strikingly illustrated round the shores of the Pacific. ”

“ The soil of the Piana was granite at the base of the Apennines, but in the plain the debris of every sort of earth, brought down from the mountains by the rains, constituted a mass of unequal solidity, resistance, weight, and form. On this account, whatever might have been the cause of the earthquake, whether volcanic or electrical, the movement assumed every possible direction--vertical, horizontal, oscillatory, vorticose, and pulsatory; producing every variety of destruction. ”

“ How do deep earthquakes stem from friction 300 miles down under the Cordillera and the west Pacific? Do earth and moon spheres as rounded tetrahedra crack similarly? Because of rotation are north-south cracks dominant? Are the core fluids changing volcanism through the ages?
The twenty-eight percent of earth surface which lies above the sea in continents is made up of siliceous sediments of shallow water basins, with quartz as the dominant mineral, their strata wrinkled, and eroded into mountain ranges. Desert and lake or river bottoms make up most of the remainder. ”

“ The artificial earthquake, or volcano of Lemery, is formed by mixing into a paste with water, about equal parts of sulphur and steel or iron filings, and burying the mixture in the earth. The composition in a short time, will grow hot, and burst out; the earth will break, and open in several places. ”

“ For hundreds of millions of years, the forces of plate tectonics have shaped the Earth as the huge plates that form the Earth’s surface slowly move over, under, and past each other. Sometimes the movement is gradual. At other times, the plates are locked together, unable to release the accumulating energy. When the accumulated energy grows strong enough, the plates break free. If the earthquake occurs in a populated area, it may cause many deaths and injuries and extensive property damage. ”

“ Every half hour some considerable area of the earth’s surface is sensibly shaken by an earthquake, but earthquakes are by no means uniformly distributed over the globe. As we might infer from what we know as to their causes, earthquakes are most frequent in regions now undergoing deformation. Such are young rising mountain ranges, fault lines where readjustments recur from time to time, and the slopes of suboceanic depressions whose steepness suggests that subsidence may there be in progress. ”

“ If the earth crust broke up and the blocks variously sank in the core matter, leaving continents as a complex of high blocks, then the blocks are deep and are still moving. The movements are in years, year-thousands and year-millions. Volcanism up the cracks releases core energy. So does much of fault movement, namely earthquakes. ”

“ Secondly, almost all volcanic eruptions are preceded by Earthquakes; and the Earthquakes generally cease, or, at least become less violent, when the subterranean fire breaks out in the form of a Volcano. And, Thirdly, it is plain that the condensed steam which is generated by internal heat, and the expansive power of the heat itself, must, of necessity, when pent up in the caverns of the Earth, tend to produce those very phenomena by which Earthquakes are distinguished. ”

“ Coming, as shocks often will, from a region of volcanoes, the study of these disturbances may enable us to understand something about the nature and working of a volcano. As an earthquake wave travels along from strata to strata, if we study its reflections and changing velocity in transit, we may often be led to the discovery of certain rocky structures buried deep beneath our view, about which, without the help of such waves, it would be hopeless ever to attain any knowledge. ”

“ Now, when the earthquake waves moving horizontally over the surface produce movements that squeeze these fissures together, the water in the fissures is spurted out in high jets, and carries with it the finely divided rock or sand formed by the rubbing together of the rock surfaces. In the case of the reservoirs consisting of beds of sand or gravel, lying between impervious layers, if, during an earthquake motion, the land areas are suddenly lowered, the water rushing into the cavity thus left will afterwards be shot out with considerable force, when the land is suddenly raised again. ”

“ But we also know by the study of regions liable to earthquakes, that there are causes at work in the interior of the earth capable of producing a sinking in of the ground, sometimes very local, but sometimes extending over a wide area. The frequent repetition, or continuance throughout long periods, of such downward movements seems to imply the formation and renewal of cavities at a certain depth below the surface, whether by the removal of matter by volcanos and hot springs, or by the contraction of argillaceous rocks by heat and pressure, or any other combination of circumstances. ”

“ Something is always snapping or giving way in its interior, and producing trembling fits that sometimes can be felt hundreds of miles away, and sometimes can be felt all over the earth. There are on the average at least twenty earthquakes a year which make the whole of this round globe tremble.
It would seem, therefore, that either these shocks or -24- breakages in the earth's crust, or the earth's interior, must be very great indeed, or else that the earth must be composed of rather shaky materials. ”

“ Long after this notion was discarded, and a more scientific appreciation of volcanic action was reached, it was still thought that earthquakes should be regarded as manifestations of the same source of energy as that which displays itself in volcanic eruptions. It is true that earthquakes are frequent in districts of active volcanoes, and they may undoubtedly be often due there to the explosions of the magma, or to the rupture of rocks caused by its ascent towards the surface. ”

“ The still more modern theory is that the surface of the earth is only a thin crust over a mass of melted matter; that we live on the outside of a ball of liquid fire, which is liable to explode at any time, and put an end to us and all around. It is argued that the volcanoes now in activity are the outlets for this internal fire, and the [Pg 115] occasional eruptions and earthquakes are the result of the fire seeking vent, in consequence of the clogging of the subterranean passages. ”

“ When we have examined into the origin of these impulses, and the way in which they are transmitted through the rocks, we obtain a basis for understanding earthquake shocks. The commonest cause of the jarrings in the earth is found in the formation of fractures, known as faults. If the reader has ever been upon a frozen lake at a time when the weather was growing colder, and the ice, therefore, was shrinking, he may have noted the rending sound and the slight vibration which comes with the formation of a crack traversing the sheet of ice. ”