The Senses and the Mind

Anonymous

The Senses and the Mind

EAN 8596547223269

DigiCat, 2022

Contact: [email protected]

Table of Contents

CHAPTER I. ON THE GENERAL RELATIONSHIP OF MAN TO THE WORLD AROUND HIM, AND HIS ADAPTATION TO THE PLANET HE TENANTS.

CHAPTER II. MAN'S KNOWLEDGE OF THE QUALITIES OF MATTER OBTAINED THROUGH THE MEDIUM OF THE SENSES.

CHAPTER III. THE SENSES, AS THE INLETS TO KNOWLEDGE—SIGHT AND HEARING.

CHAPTER IV. OBSERVATIONS ON THE AGENCY OF THE SENSES, RELATIVE TO THE UNION BETWEEN MIND AND MATTER; AND ON THE OCCASIONAL IMPERFECTION OF THE BODILY ORGANS OF THE SENSES, WITH THE RESULTS DEPENDING THEREUPON.

CHAPTER I.

ON THE GENERAL RELATIONSHIP OF MAN TO THE WORLD AROUND HIM, AND HIS ADAPTATION TO THE PLANET HE TENANTS.

Table of Contents

There are few, at least among the reflecting portion of society, who have not either mentally or verbally asked the question: Is the sun—is the moon—are the planets, with their satellites—are the stars, those suns of other systems, tenanted, as is our planet, the earth, by living beings, which declare the omnipotence of God? This is one of many questions which cannot be answered. The probability, to judge from analogy, is, that some, if not all, are inhabited; that some are in a course of preparation for beings which God will, in his own time, call into existence; and that in all, changes have taken place more or less similar to those which have occurred on the globe we tenant, and which have been connected with the extinction of races, and the creation of others adapted and organized for an altered condition of the earth's surface, and of the circumambient atmosphere. But, granting these suppositions, it must be evident, that the living beings in the sun, the planets, and the asteroids, must not only be differently constructed from those which inhabit our planet, the earth; but, also, that in different worlds, the living inhabitants must be very diversely constituted, not only as regards their senses, but also their organization and their powers of locomotion.

We cannot conceive of beings unlike ourselves, and the animals, terrestrial and aquatic, which, called into existence by Almighty Power, people the surface of our earth; that, however, is no reason why such beings should not exist, for what is impossible with God? Nay, as it is, the senses, the operations, the powers, and economy of insects confound us, and lead us to suspect that they possess a sense, or senses, which, because denied to us, we cannot appreciate. In our world, atmospheric air, in which oxygen prevails, or water, also oxygenated, is essential to the maintenance of animal life. But cannot the Almighty construct organic beings, independent of our air or our water—vitalized, in fact, on principles of which we can form no idea? Undoubtedly. If, for example, no aquatic water-breathing animals, as fishes, crustacea, etc., existed on our earth, could we conceive of the possibility of their being? or, were our race, and all other animals furnished with gills instead of lungs, and ordained to a sub-aquatic life, making the wide ocean our home, could we form any idea of what creatures could be constituted for living in the thin atmosphere, and actively enjoying life under its pressure? Again, let the attractive force of this earth be altered, the organization of every living thing must (granting its existence to be guaranteed) be altered accordingly. We take the following from Miss Somerville's Connexion of the Physical Sciences, p. 73:—The densities of bodies are proportional to their masses, divided by their volumes. Hence, if the sun and planets be assumed to be spheres, their volumes will be as the cubes of their diameters. Now, the apparent diameters of the sun and earth, at their mean distance, are 1922″, 8, and 17″, 1552, and the mass of the earth is the 354,936th part of that of the sun, taken as the unit. It follows, therefore, that the earth is nearly four times as dense as the sun; but the sun is so large that his attractive force would cause bodies to fall through about 335 feet in 1″; consequently, if inhabited by human beings, they would be unable to move, since their weight would be thirty times as great as it is here. A man of moderate size would weigh about two tons at the surface of the sun; whereas, at the surface of the asteroids, (the clusters between Mars and Jupiter,) he would be so light that he could not stand steadily, since he would only weigh a few pounds.

The densities, that of water being 1, as far as can be satisfactorily explained, are as follow:—Sun, 1²⁄15; Mercury, 9¹⁄6; Venus, 5¹¹⁄15; Moon, 4½; Mars, 3²⁄7; Ceres, 2; Pallas, 2; Jupiter, 1¹⁄24; Saturn, ¹³⁄32; Herschel, ⁹⁹⁄100.

Similar observations apply to the influence of the atmosphere, in whatever point of view we consider it, that is, whether we regard its weight, its electrical condition, its illumination, its temperature, its dryness, or humidity.

1. Its Weight.—The weight of the atmosphere (an elastic, compressible, and expansible fluid,) is calculated to be from fourteen to fifteen pounds avoirdupois on every square inch, (pure water, taking bulk for bulk, being about 828 times as heavy.) Now, reckoning the surface of a middle-sized man to be fourteen feet, he sustains the pressure of eleven tons. Many of our readers have seen the philosophical experiment of placing two hollow metallic hemispheres rim to rim, the rims being nicely adjusted and smeared with lard; this being done, the air, by means of a stop-cock on the lower hemisphere, screwed into a powerful air-pump apparatus, is drawn out or exhausted—the stop-cock is turned—the globe is unscrewed from the air-pump, and placed in the hands of those who may consent to try their strength in pulling the two hemispheres asunder. Enormous is the force required; if the diameter of the circle be fourteen inches, the least force that will separate them will be equivalent to half a ton.

Such, then, being the pressure of the atmosphere, as is clearly proved by simple experiments, it may at first create some surprise that the human body is capable of sustaining it without being crushed; that the tiny insect, with its delicate wings—and in some these amount to several square inches of surface—is not reduced to atoms. But the wonder will cease, when we reflect that this pressure, or a pressure little short of it, is essential to the existence, not of man only, but of all terrestrial organic beings.

Dr. Robinson justly observes, that the human body (he might have said every organic body) is a bundle of solids mixed with fluids, and there are few or no parts of it which are empty. All communicate either by vessels or by pores, and the entire surface is a sieve, through which the insensible perspiration is performed. The whole extended surface of the lungs is open to the pressure of the atmosphere; everything, therefore, is in equilibrio; and if free or speedy access be given to every part, the body will not be damaged by the pressure, however great, any more than a wet sponge would be deranged by pressing it to any depth in the water.[1]

[1] Mechanical Philosophy, vol. iii. p. 54.

On this we would remark, that the human body, and that of terrestrial animals in general, is not adapted for the pressure of water at great depths; even could man by any contrivance breathe, such a pressure would destroy life; and, indeed, few aquatic animals are constituted for oceanic existence in the depths of the sea. While the surface is alive with its myriads, the depths are still and untenanted; while bays, shores, reefs, and sandbanks, covered by many fathoms of water, are teeming with shelled mollusks, fishes, and thousands of wondrous creeping things, the profundity of ocean is a comparative desert; whatever lives there must be so constituted as to sustain a tremendous amount of aqueous pressure. Indeed, whales, which often plunge to a considerable depth, and remain submerged for twenty minutes, during which time respiration is suspended, are provided by their coating of blubber, and by the peculiar arrangement of their arterial and venous systems, for the pressure they then undergo; but this pressure often repeated, as it is when the animal is wounded and hard driven, soon produces great exhaustion. Captain Scoresby, for example, harpooned a whale, which, on receiving the weapon, descended four hundred fathoms, at the rate of eight miles an hour; but these animals, when suffering from the torture of the harpoon, often descend to a much greater depth, and sometimes strike so violently against a hard bed of the ocean as to fracture their jaws. At the depth of eight hundred fathoms, captain Scoresby calculates the pressure at 211,200 tons. On the other hand, the organization of man (and other animals) is as ill calculated for a much lighter pressure than that of our atmosphere at sea-level, as it is for great pressure in the depths of ocean.

In proportion as we ascend the alpine elevations of our globe, or mount upwards in a balloon, we find the air more and more rarefied. These elevations are, however, but trifling; nevertheless, trifling as they are, what an effect the decrease of pressure produces on the human frame! The heart beats with violence, the lungs gasp for more air, they have not pressure enough; the blood begins to ooze out of the minute vessels ramifying through the tissue of their delicate cells; blood issues from the nose, the eyes, the ears; the slightest exertion becomes oppressive—a mile or two higher, and death is inevitable. The difficulties attendant upon the ascent of Mont Blanc, the vast Himalaya chain, and the heights of the Cordilleras, are quite as much connected with the state of the air as with the terrible ravines and precipices which obstruct the way. Indeed, as is well known, on the elevated plateaus of South America or Thibet, men and animals accustomed to low plains, or even to gently undulating grounds, are for a long time distressed for breath, and incapable of bodily exertion. Time alone habituates them to the rarer and lighter atmosphere. But what is an elevation of 13,000 or 14,000 feet, nay of 15,668 feet, (Mont Blanc,) of 25,747 feet, or 28,077 feet, (Jewahir and Dhawalagiri, peaks of the Himalaya,) to that of twenty or thirty miles? At an elevation of twenty miles, the heart of a human being would burst, his lungs become gorged with blood, from every pore of his body a sanguine stream would gush forth—he would immediately die. Is not, then, the pressure of the atmosphere necessary for the existence of man, constituted as he is for the planet which he inhabits? But the atmosphere, with regard to its relationship to the solid globe it environs, demands a few words.

This elastic fluid must be considered as a body of air revolving with the earth, whence it must be evident that the velocity of the strata of air, if we may use the word, increases as we recede from the earth's axis; for example, at the equator, that stratum of air, (if such there be,) which is twice as distant from the centre of the earth as the surface is, must revolve with twice the actual velocity of the air at the surface. Taking this fact into consideration, it results that, however attenuated, however rarefied, the atmosphere cannot extend beyond 20,000 miles from the surface of the earth; far above that elevation the centrifugal force would counteract the centripetal, or, in other words, the tendency of the particles to the earth would cease, and, consequently, unless air pervaded the universe, which is not the case, 20,000 miles are within the utmost range of possibility. The fact, however, appears to be demonstrated, that the limits of our atmosphere do not exceed an elevation of above forty-five or fifty miles, and that beyond this there is no refraction or reflection of the solar rays—that, in fact, air ceases. The finite extent of the atmosphere has been ably discussed by Dr. Wollaston,[2] his arguments being based upon the Atomic Theory of matter. We may thus condense his train of reasoning, as far as it bears more immediately upon the present subject.—If air extend throughout the universe, we shall be obliged to admit that every planet must collect an atmosphere around itself proportionate to its attractive power. In this case, as he argues, Jupiter, at whose surface the force of gravity must be much greater than that of our earth, would certainly collect a large and dense atmosphere around him. The effect of the refraction of light through this atmosphere would become visible on the approach of the satellites to the planet, when they disappear behind his disc, and would cause a sensible retardation in their rate of approach. Now, it is allowed that no such retardation, even in the minutest sensible degree, can be observed, and hence it follows that Jupiter has no such atmosphere as that of our earth, nor the means of collecting it; consequently, air, such as that composing our atmosphere, is not diffused in any degree of rarefaction through the solar system. This finite character of our atmosphere is, as Dr. Wollaston contends, more conformable to the atomic theory than to that of the infinite divisibility of matter; since, in the first case, a boundary is possible, and will exist at the point where the weight of a single atom is as great as the repulsive force of the medium; while, in the latter case, it is difficult to see the possibility of any boundary.

[2] Phil. Trans., 1822.

By way of note we would here add, that the theory of the infinite divisibility of matter, which all the laws of chemistry seem to deny, has no good grounds for our acceptance. God made matter, and, as we may humbly conceive, in the form of ultimate atoms, which, however inconceivably minute, must be definite—otherwise what is meant