--- title: Improvement Era description: Monthly periodical of the Mormon church, 1897 onward. This library holds the issues of November 1897 to December 1930. authors: - John A. Widtsoe collections: - periodicals tags: - magazine - improvement-era periodical: Improvement Era volume: 4 number: 2 published: 1900-12 publisher: Young Men’s Mutual Improvement Associations publisher_place: Salt Lake City language: en type: magazine reference: 'John A. Widtsoe, "One of Aristotle’s Elements," *Improvement Era* 4, no. 2 (December 1900): 131–137.' source: url: https://archive.org/details/improvementera0402unse transcription: Transcribed from the Internet Archive scan of each issue (the item for each issue is named in the issue's own source); unnumbered advertising leaves are omitted, printed page numbers are kept as page markers. identifier: improvementera0402unse start_page: 131 end_page: 137 rights: status: public-domain basis: US publication 1930 or earlier (published 1900-12) source: https://archive.org/details/improvementera0402unse publication_year: 1900 note: The Internet Archive item metadata carries a blanket "© Copyright by Intellectual Reserve, Inc." notice. The library owner judged it inapplicable because this issue was published in 1900, before 1931; a scan-level notice does not restore copyright. --- # One of Aristotle’s Elements ONE OF ARISTOTLE'S ELEMENTS. BY DR. JOHN A. WIDTSOE. Aristotle, the greatest of Greek natural philosophers, originated a theory of the composition of the Earth, which held an almost perfect sway for many centuries. All things, he said, are composed of four elements in varying proportions. They are earth air, water and fire. Earth is cold and dry; air is warm and moist; water is moist and cold, and fire is dry and warm. Warm things contain much air and fire, cold things much earth and water, dry things much fire and earth, and wet [things much water and air. Even today, when this view of Aristotle has lain in ruins for two centuries or more, we pay our homage to the great Greek in speaking of the -fury of the elements when the disturbed air raises gigantic waves on the ocean, or when a mighty city is devastated by fire. However, whatever our daily speech may be, we know that the theory of Aristotle is erroneous; that not four, but seventyfour elements or more go to make up our wonderful world, and that earth, air and water are themselves composed of other elements. The overthrow of established theories, however false they may be, is a difficult process, and the development of new and better ones is slow. It Vvas not until the 18th century that actual proof was given that air, which had always been looked upon as a simple or elementary substance, was really a mixture of several substances. Dr. Joseph Priestley, a poor dissenting clergyman, who is now considered one of the great philosophers of his day, isolated from ordinary atmospheric air a gas which we know at the present day as oxygen. The other chief constituent of air he ]32 IMPROVEMENT ERA. found to be another gas, known as nitrogen. At the same time (about 1774) there lived in London an old, bashful and extremely rich bachelor, the Honorable Henry Cavendish, who was described by one of his contemporaries as the richest of learned men, and the most learned of the rich. His wonderful mind and great wealth he devoted to the study of nature. He took up the results of Dr. Priestley, and proved beyond a doubt that the atmosphere is in fact a mixture of two gases, oxygen and nitrogen. In addition, he showed that the composition of air, at any place on the earth's surface, and in any weather, is practically constant. Approximately, air consists of one part of oxygen to four parts of nitrogen. This result, of course, overthrew completely the Aristotelian conception of the elementary nature of air, and marked a great advance in the knowledge of mankind. Questions were now propounded concerning the nature of oxygen and nitrogen, and their value to man. It was shown, and it has since been confirmed by thousands of experimenters, that in their properties, these two gases are almost exactly opposite to each other. Oxygen is the substance which makes ordinary burning possible. When wood burns, it unites with oxygen to form another gas which passes out of the chimney. When iron rusts, it unites with the oxygen of the air; and, in fact, rust is only iron united with some oxygen and a little water. When we take air into our lungs, the oxygen it contains unites with the impure blood found there, burns it, and thus purifies it. In the cases of the rusting of iron and the purification of blood, the burning is very slow and gentle, but it is nevertheless burning, just as truly as when the coal glows in our stoves. Without the oxygen in the air, all animals would die, for the heaping up of impure blood within the system would in a short time lead to the end of existence. The discovery of oxygen in the air gave us therefore a deep knowledge of the nature of life and of animal physiology. Nitrogen was found to be an inert substance, which unites with other bodies with great difficulty. Its main purpose in the air seems to be to dilute the oxygen. In pure oxygen, all things burn with increased vigor. A candle which will burn in air for an hour will exhaust itself in oxygen in a few minutes. Red hot iron, thrust into a jar of pure oxygen, bursts into a bright ONE OF ARISTOTLE'S ELEMENTS. 133 flame and burns as a piece of wood. A man who should be compelled to breathe pure oxygen, would live too rapidly. He would perhaps show great brilliancy for a short time, but the effort would doubtless shorten his life by many years. The truth seekers, however, were not satisfied with this knowledge. They persisted in seeking for new facts concerning the composition and nature of air, and succeeded in discovering that, besides oxygen and nitrogen, the atmosphere contains, invariably, very small quantities of watery vapor, and of a gas called carbon dioxide, or carbonic acid gas. The presence of water vapor was to be expected, as the sun's heat acting on the oceans, lakes and streams would naturally evaporate water into the air. The quantity is small, and quite variable. Near the oceans and in low-lying districts, the proportion of water in the air is much higher than in districts of high altitudes, and far removed from large bodies of water. The presence of carbon dioxide was just as expected, for this is the gas which is formed when wood or coal burns, when organic matter decays, or when animals breathe. Carbon dioxide is a compound body consisting of carbon, one well known variety of which is charcoal, and of the gas oxygen, which we have just found to constitute about one fifth of the atmosphere. As burning, decay and breathing are constantly going on at the earth's surface, there must be of necessity, a small, though appreciable quantity, of carbon dioxide in the air. I say small, but only in a relative sense, for there is more carbon in the form of the gas carbon dioxide in the atmosphere than is contained in all the coal mines and all the forests in the world. So much accomplished, scientists next asked what benefit the presence of water vapor and carbon dioxide in the atmosphere conferred upon mankind. It was soon discovered that the presence of carbon dioxide is absolutely necessary for the existence of life upon the earth. Plants, as we know, acquire the food on which they live in a manner wholly different from animals. From the soil, by means of roots, several mineral substances are taken up, which are necessary for the well being of the plant, but which, in quantity, are rather unimportant. Water forms a large portion of growing plants; it is also taken from the soil. The bulk of the 134 IMPROVEMENT ERA. dry matter of plants, however, is composed of the element carbon; and this is obtained from the carbon dioxide in the atmosphere. The under sides of the leaves of most higher plants are covered with microscopic pores that lead into the leaf. As the leaves move back and forth, the air is caused to enter these pores, and to be distributed within the leaves. A green substance, called chlorophyll, that is found in the leaves of all higher plants, seizes upon the carbon dioxide thus brought into the leaf, and breaks it up into carbon and oxygen. The oxygen is allowed to escape into the air again, but the carbon is kept within the leaf, and from it are made sugar, starch, fat, and many of the other important constituents of plants. In this manner it is seen that plants eat the gas carbon dioxide found in the air, and, since animals cannot live unless there are plants to serve as their food, it is also seen that human life depends on the presence of a very small quantity of carbon dioxide in the atmosphere. This discovery threw more light upon the nutrition of plants and of animals, than any discovery previously made. But atmospheric carbon dioxide and water vapor, have other offices to perform of prime importance to mankind. Among them is the power of keeping all animals and plants warm. The warmth of the earth is due to the rays of light which the sun sends out at all times. Light, as we know it, cannot warm us as we need to be warmed; it must first be changed into a form of light which is dark, or invisible to our eyes, — this we call heat. Light and heat are only two different manifestations of the same form of energy, and may easily be changed from the one to the other. Light, for instance, striking upon soil, or the parts of plants, is converted into heat. Though light and heat are so nearly related, they still differ in many of their properties. Light will pass through glass easily, so that glass is no protection against the energy of the sun. A glass shield before a heated stove, however, will prevent effectually the direct transmission of the dark light or heat proceeding from the stove. This accounts for the action of hothouses. The light from the sun passes easily through the panes of glass, but when it strikes the ground and the plants, it is changed into heat and it cannot get out again. A hothouse, therefore, is simply a light trap. Not only glass, but other bodies possess similar prop- ONE OF ARISTOTLE'S ELEMENTS. 135 erties. Carbon dioxide and water vapor will allow light to pass through them freely, but refuse to allow the passage of heat. Oxygen and nitrogen, on the other hand, will let both light and heat pass through them without difficulty. If, now, the atmosphere were composed of oxygen and nitrogen only, the light from the sun would pass through it; would strike the earth, and be changed into heat, which would, with the same readiness, pass out into space and be lost to us. As a result, the earth would be intensely cold, and everything upon it would suffer and perhaps die. The presence of small quantities of water vapor and carbon dioxide change all this. The sun's light passes through the atmosphere as it is, with little hindrance. As soon, however, as it strikes the soil and is changed into heat, it can not pass out again, for the presence of the water vapor and the carbon dioxide in the air forbids it. Thus the heat is kept near us; the soil is kept warm, and all plants and animals are kept at a comfortable temperature. As Professor LeConte puts it, "The blanket put about the earth to keep it warm is woven of carbon dioxide and water vapor." Leaving, now, the numerous other relations which the atmosphere bears to human welfare, let us pass on to the most recent discoveries concerning air. Some years ago a wealthy individual left a large bequest to the Smithsonian Institution, the income of which should be used for advancing our knowledge of air. A prize of $10,000 was offered for the most important discovery that could be made in the domain of the atmosphere. Many scientists shrugged their shoulders at this, and said, "There is very little about the atmosphere which is not known; and, as for its composition, we know with certainty all of its constituents." About this time two scientists were working in London on the subject of air, and they had several times observed certain irregularities that led them to suspect that all about air was not known so well as it might be. Several years were spent by these men in the endeavor to explain the variations from the expected. At last, a few years ago, their labors were rewarded with a glorious success. It was found that besides oxygen, nitrogen, carbon dioxide and water vapor, atmosphere always contains about one per cent of another gas, which, up to the time of 136 IMPROVEMENT ERA. this discovery, was unknown. This gas, on being further studied was shown to be an element, and was named Argon. It is an inert, inactive substance, much resembling nitrogen. Thus, not only was our knowledge of the air extended, but a new element was added to the already long list of elements. The Smithsonian prize of $10,000 was unhesitatingly awarded to Lord Rayleigh and Professor Ramsay, for this capital discovery. It is not so difficult a thing to make discoveries in untrodden fields, but it requires genius, industry, skill and patience of the highest order, to hunt out on a well worn road important facts, that generations of searchers have overlooked. The scientific world shouted for joy when argon was discovered in the atmosphere. It is a glorious thing to learn a new truth. But science was not satisfied. If one new substance had been discovered, might it not be that another existed, undiscovered, in the air? So the workers began new investigations, and during the past three or four years, four or five new elements have been found in the atmosphere. True, they occur in very small quantities, and they have not yet been studied in greatest detail. Still there are no good reasons for doubting that they exist. The study of air is still going on, and no man can say that the last discovery has been made. There is no doubt that new truths will be recognized in the future, and our knowledge of the "air we breathe" extended. Aside from the discovery of new elements, the most interesting new fact concerning the atmosphere is that it may now, by subjecting it to great cold and pressure, be liquefied. For many years oxygen and nitrogen were called permanent gases, i. e., gases which could not be liquefied and solidified. The fact that they have now been obtained in the liquid state marks a great advance in our knowledge of the physics of gases. Liquid air promises to become a valuable adjunct to the progress of the world, as it is already a commercial article. For a discussion of liquid air, reference may be made to an article on this subject, by Dr. J. E. Talmage, that appeared in the Era about a year ago.* The countless other and more complex facts regarding the atmosphere can not be mentioned in this sketch. It must be suf- Page 53, Vol.3. ONE OF ARISTOTLE'S ELEMENTS. 137 ficient to present a table of the composition of air, according to modern knowledge. One thousand parts of air contain approximately: Nitrogen 781 parts Oxygen 209 Carbon dioxide 05 " Water vapor (about) .05 " Argon 10 " Small quantities of other elements that resemble argon. We may gain from the story of air many suggestions that should be applied in our daily lives. The growth of science is slow and gradual; all truth is obtained in the same manner. It is seldom that a finished truth bursts forth upon mankind without warning. Thus patience is taught us. The beliefs of mankind concerning the most common things are often erroneous, and must be modified, as shown in the Aristotelian theory of the elements. We must hold all our beliefs in readiness to be changed when greater light comes. Even when we possess truth, we must not carelessly claim the whole truth. The discovery of argon in the air shows how unsafe it is to say, "We know all, there is no more." The unknown in nature is greater than the known. Faith should not be pinned absolutely to any man-made theory, for we know not at what moment a new observation will change, extend or enlarge it. But, the greatest lesson which the atmosphere teaches seems to me to be the perfect mutual dependence of every part of nature on every other part. Everything found in the air is of vital importance to the living things of the earth. Without oxygen in the air, animals could not breathe; without carbon dioxide in the air, plants could not grow; without aqueous vapor in the air, we should be chilled to death, and so on. The whole number of this magazine might be filled in showing how necessary all the constituents of the air are to human welfare. Nothing is useless; if it so appears, then science is at fault, and has something to learn. Such a wonderful structure as this our earth, where everything has its place and purpose, betokens a mighty mind and a beneficent power in him who made it, who is our God.