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diff --git a/39566-8.txt b/39566-8.txt new file mode 100644 index 0000000..1312c05 --- /dev/null +++ b/39566-8.txt @@ -0,0 +1,6777 @@ +The Project Gutenberg eBook, Curiosities of Heat, by Lyman B. Tefft + + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + + + + +Title: Curiosities of Heat + + +Author: Lyman B. Tefft + + + +Release Date: April 29, 2012 [eBook #39566] + +Language: English + +Character set encoding: ISO-8859-1 + + +***START OF THE PROJECT GUTENBERG EBOOK CURIOSITIES OF HEAT*** + + +E-text prepared by the Online Distributed Proofreading Team +(http://www.pgdp.net) from page images generously made available by +Internet Archive (http://archive.org/) + + + +Note: Project Gutenberg also has an HTML version of this + file which includes the original illustrations. + See 39566-h.htm or 39566-h.zip: + (http://www.gutenberg.org/files/39566/39566-h/39566-h.htm) + or + (http://www.gutenberg.org/files/39566/39566-h.zip) + + + Images of the original pages are available through + Internet Archive. See + http://archive.org/details/curiositiesofhea00teff + + + + + +[Illustration: EFFECT of HEAT. + +Frontispiece.] + + +CURIOSITIES OF HEAT. + +by + +REV. LYMAN B. TEFFT. + + + + + + + +Philadelphia: +The Bible and Publication Society, +530 Arch Street. + +Entered according to Act of Congress, in the year 1871, by +The Bible and Publication Society, +In the office of the Librarian of Congress, at Washington. + +Westcott & Thomson, +Stereotypers, Philada. + + + + +CONTENTS. + + + PAGE + + CHAPTER I. + + MR. WILTON'S BIBLE CLASS 7 + + CHAPTER II. + + NEW THOUGHTS FOR THE SCHOLARS 26 + + CHAPTER III. + + A DIFFICULT QUESTION 58 + + CHAPTER IV. + + HEAT A GIFT OF GOD 83 + + CHAPTER V. + + CONVEYANCE AND VARIETIES OF HEAT 100 + + CHAPTER VI. + + MANAGEMENT AND SOURCES OF HEAT 120 + + CHAPTER VII. + + PRESERVATION AND DISTRIBUTION OF HEAT 152 + + CHAPTER VIII. + + MODIFICATION OF TEMPERATURE 176 + + CHAPTER IX. + + THE MINISTRY OF SUFFERING 190 + + CHAPTER X. + + TRANSPORTATION OF HEAT 213 + + CHAPTER XI. + + AN EFFECTIVE SERMON 233 + + CHAPTER XII. + + TRANSFER OF HEAT IN SPACE 254 + + CHAPTER XIII. + + OCEAN CURRENTS AND ICEBERGS 272 + + CHAPTER XIV. + + COMBUSTION.--COAL-BEDS 292 + + CHAPTER XV. + + ECONOMY OF HEAT 305 + + CHAPTER XVI. + + A DAY OF JOY AND GLADNESS 320 + + + + +CURIOSITIES OF HEAT. + + + + +CHAPTER I. + +MR. WILTON'S BIBLE CLASS. + + +"The book of Nature is my Bible. I agree with old Cicero: I count Nature +the best guide, and follow her as if she were a god, and wish for no +other." + +These were the words of Mr. Hume, an infidel, spoken in the village store. +It was Monday evening. By some strange freak, or led by a divine impulse, +he had determined, the previous Sunday afternoon, to go to church and hear +what the minister had to say. So the Christian people were all surprised +to see Mr. Hume walk into their assembly--a thing which had not been seen +before in a twelvemonth. Mr. Hume did not shun the church from a dislike +of the minister. He believed Mr. Wilton to be a good man, and he knew him +to be kind and earnest, well instructed in every kind of knowledge and +mighty in the Scriptures. He kept aloof because he hated the Bible. He had +been instructed in the Scriptures when a boy, and many Bible truths still +clung to his memory which he would have been glad to banish. He could not +forget those stirring words which have come down to us from the Lord +Jesus, and from prophets and apostles, and they sorely troubled his +conscience. He counted the Bible an enemy, and determined that he would +not believe it. + +At that time there was an increasing religious interest in the church. Mr. +Wilton had seen many an eye grow tearful as he unfolded the love of Christ +and urged upon his hearers the claims of the exalted Redeemer. He found an +increasing readiness to listen when he talked with the young people of his +congregation. The prayer-meetings were filling up, and becoming more +interesting and solemn. The impenitent dropped in to these meetings more +frequently than was their wont. Mr. Wilton himself felt the power of +Christ coming upon him and girding him as if for some great spiritual +conflict. His heart was filled with an unspeakable yearning to see +sinners converted and Christ glorified. He seemed to himself to work +without fatigue. His sermons came to him as if by inspiration of the Holy +Spirit. He felt a new sense of his call from God to preach the gospel to +men, and spoke as an ambassador of Christ, praying men tenderly, +persuadingly, to be reconciled to God, yet as one that has a right to +speak, and the authority to announce to man the conditions of salvation. + +A few of the spiritual-minded saw this little cloud rising, but the people +in general knew nothing of it. Least of all did Mr. Hume suspect such an +undercurrent of religious interest; yet for some reason, he hardly knew +what, he felt inclined to go to church. + +That afternoon the preacher spoke as if his soul were awed, yet lifted to +heavenly heights, by the presence of God and Christ. Reading as his text +the words, "Thou thoughtest that I was altogether such an one as thyself" +(Ps. l. 21), he showed, first, the false notions which men form of God, +and then unfolded, with great power and pungency, the Scripture revelation +of the one infinite, personal, living, holy, just, and gracious Jehovah. +This was the very theme which Mr. Hume wished most of all not to hear. +That very name, Jehovah, of all the names applied to God, was most +disagreeable; it suggested the idea of the living God who manifested +himself in olden time and wrought wonders before the eyes of men. But the +infidel, with his active mind, could not help listening, nor could he +loosen his conscience from the grasp of the truth. Yet he could fight +against it, and this he did, determined that he would not believe in such +a God--a God who held him accountable, and would bring him into judgment +in the last great day. In this state of mind he dropped into Deacon +Gregory's store. + +Deacon Gregory was accustomed to obey Paul's injunction to Timothy: "Be +instant in season, out of season; reprove, rebuke, exhort with all long +suffering and doctrine." Having taken Mr. Hume's orders for groceries, he +said, "I was glad to see you at church yesterday, Mr. Hume. How were you +interested in the sermon?" + +"I like Mr. Wilton," answered Mr. Hume; "I think him a very earnest and +good man." + +"But were you not interested and pleased with the discourse? It seems to +me that I shall never lose the impression of God's existence and +character which that discourse made upon me. I almost felt that Mr. Wilton +spoke from inspiration." + +"I suppose he was inspired just as much as the writers of that book which +men call 'the Bible.'" + +"But can you wholly get rid of the conviction that the Bible is the word +of God, written by holy men inspired by the Holy Spirit?" + +"You know, Deacon Gregory, that I do not believe what you profess to +believe. The book of Nature is my Bible. I agree with old Cicero: I count +Nature the best guide, and follow her as if she were a god, and wish no +other." + +Deacon Gregory had never read Cicero, and of course did not attempt to +show, as he might otherwise have done, that Cicero did not mean to deny +the existence of a living, personal God, who governs the world. + +"But," said he, "does not the book of Nature--your Bible, as you call +it--have something to say of God? Does it not speak of an infinitely wise +and good Creator and Governor? Do not the works of Nature tell of the same +God whose being and character were preached to us yesterday from the Holy +Scriptures?" + +"Nature has never spoken to me of any God except herself. What need is +there of a creator? Who can prove that the universe did not exist from +eternity? Nature has her laws of development, and under those laws all the +operations of nature go on. You had better read Darwin. If one must find +the character of God in nature, he may as well picture an evil creator and +governor as one that is good and righteous. Does Nature punish those whom +you call the wicked? Does Nature reward the righteous? Do not the laws of +Nature bring suffering to the good and the bad alike, and happiness also +to all classes of men? Would you, if you had power, create a world like +this--a world in which danger, pain, and death, in every shape, lie in +ambush against its inhabitants every hour of their poor existence? But I +must go." Pausing a moment, however, as if reluctant to go, with a voice +sad and almost tremulous, which revealed a great deal more of his heart +than he designed to express, he added: "God knows, deacon, if there be a +God, how I wish I knew the truth about these matters. The world and myself +are to me great and dreadful mysteries." + +"'He that will do his will shall know of the doctrine,'" answered Deacon +Gregory; and inviting him to come to church again, they separated. + +This conversation with the pious deacon, though he had himself done most +of the talking and had his say almost unopposed, did not tend at all to +bring rest to Mr. Hume's conscience. He saw that the deacon's faith in God +did for him more than belief in Nature and worship at the altar of Science +could do for unbelievers. He felt also that he had spoken a little too +freely, especially in revealing, at the last, his unrest of spirit from +the want of fixed convictions in regard to religious truth. Deacon +Gregory, by the sincerity and manliness of his address, was accustomed to +draw out the hearts of men so that they expressed them more freely than +they designed. + +Upon a bench in a shaded corner of the store sat a lad of sixteen or +seventeen years, unnoticed for the time being by either Mr. Hume or Deacon +Gregory. His name was Ansel, and he was the son of the senior deacon of +the church. He was in the village academy, and had there been nearly +fitted for college. He stood at the head of his class, and, with his sharp +intelligence, his impetuous energy, and high ambition, every one was +predicting for him a distinguished life. He had grown up thus far in the +bosom of a family where piety was no pretence. Earnest prayer had gone up +for him by day and by night. He had been well trained in the +Sunday-school, and for a year had been a member of the small class of +young men taught by Mr. Wilton. He had always shown a ready interest in +all Bible studies and a quick understanding of Scripture doctrine, so that +some thought him not far from the kingdom of God. But Deacon Arnold little +thought what was in the heart of his son. He might have known, for to +read his son's heart he had only to recall his own early manhood. For +years he had hung trembling upon the brink of ruin, swept, at times, +by his self-will and turbulent youthful passions, to the very verge +of the precipice, and had been preserved only by singular grace +from falling over. Now Ansel was following in his father's early +footsteps--self-willed, and stubborn against the Spirit of God, and, at +times, almost persuaded to cast off all religious restraint, that he might +carve out his worldly fortunes untrammeled by religious or conscientious +scruples. He had rarely heard infidel sentiments expressed, but the little +that he had heard had attracted him, and had encouraged him to give loose +reins to his own unbelieving disposition. It had not escaped his notice +that the two or three men whom he had heard spoken of as infidels were +among the most respectable and shrewdest business-men in the village. The +idea, moreover, of rejecting all authoritative doctrine, and believing +whatever should please him, carried with it so free and independent an +air, and harmonized so well with his natural disposition, that he easily +drifted in the direction of unbelief. + +Sitting this evening unobserved, he drank in every word which Mr. Hume +uttered. Some of the notions thrown out were quite new to him. "The book +of Nature my Bible"--"Nature reveals no God but her own laws"--"No proof +that the matter of the universe has not existed from eternity +uncreated"--"Nature has her laws of development"--"No need of a God to +govern the world,"--these were seed-thoughts in Ansel's mind. He had +before thought of the only alternative to be set over against belief in +the sacred Scriptures as simply unbelief--bare, blank denial of their +truth. He had not dreamed of building up a set of proud, rationalistic +notions, and denying the truths of religion in the character of a young +philosopher. He kept his thoughts to himself, and turned them over and +over in his mind during the week, and when again he met his pastor in the +Bible class his head was full of his new notions. The lesson went on, +however, and closed as usual. It so happened that this was the last in a +series of lessons upon the Gospel of John. It was necessary, therefore, +that another course of lessons should be decided upon. + +Mr. Wilton proposed the question to the class: "What shall be our next +course of lessons? Would you like to study one of the Epistles--the +Epistle to the Romans or that to the Hebrews?" And he briefly stated the +subject discussed in these Epistles of Paul. "Perhaps," he continued, "you +would prefer to study one of the historic books of the Old Testament?" The +class had no opinion. They wavered between an Epistle and a historic book +and topical lessons which should confine them to no one book of the Bible. +Then Ansel spoke up: + +"Mr. Wilton, why can we not study something which we know to be true?" + +Ansel meant to be very cautious as well as very respectful, and did not +design to commit himself by suggesting his own thoughts. He was +respectful, but in the confusion of the moment he had brought out the very +thoughts which he meant to conceal. + +Mr. Wilton was startled, though he did not fully understand the drift of +Ansel's question. + +"What do you mean, Ansel?" he asked; "do you think Genesis less +trustworthy than the Epistle of Paul?" + +Ansel saw that he had committed himself and must now make the best of his +situation. He therefore answered cautiously: + +"Some persons, I have heard said, do not believe the Bible to be inspired, +and they say that we have no evidence that it is true." + +"What have you been reading, Ansel, that has put such thoughts into your +mind?" + +"I have never read a book that said anything against the Bible." + +"But what did you mean? Do you wish to study the evidences of the truth +and inspiration of the Holy Scriptures?" + +"I should indeed like a course of lessons upon that subject, but that was +not quite what I was thinking of." + +"What book can you find which is true if the Bible is not true?" + +"I do not know, sir, but I heard Mr. Hume say that the book of Nature is +his Bible, and that we do not need any other, and that, whether the Bible +be true or not, we know that the teachings of Nature must be true." + +"But we should find," said Mr. Wilton, "that the teachings of Nature and +the Bible would perfectly agree. Did Mr. Hume say that what he calls 'The +book of Nature' contradicts the sacred Scriptures?" + +Now that Ansel could give the thoughts which filled his mind, not as his +own, but as Mr. Hume's, he showed no farther hesitation in speaking. + +"Yes, sir," he answered; "he said that Nature teaches us that there is no +God, because there is no need of any. He said that we cannot prove that +God created the universe, but that matter has existed from eternity +uncreated, and that all the changes in nature go on by certain laws of +development, and that a certain Mr. Darwin had written a book and proved +this." + +The reader will notice that in the report of Mr. Hume's language the +scholar went somewhat farther than his master had done. Mr. Wilton was +well acquainted with the present shape of scientific infidelity, and saw +that Ansel's statements were somewhat exaggerated, but he understood in a +moment the drift of Ansel's thoughts, though he could not tell as yet how +deep and fixed an impression had been made upon his mind. But he did not +care to probe Ansel's conscience just then and there, in order to learn +the exact state of the case. + +"If I understand you, then," he said, "you would like a course of lessons +in the teachings of Nature?" + +"Of course, I did not suppose that you would allow us to have a course of +lessons in the works of Nature instead of the Bible." + +"But if I were willing to give you a course of lessons showing the +footprints of the Creator, so to speak, in the physical world, how would +it please you?" + +"I should like it very much." + +"How would such a plan please the other members of the class?" + +The idea was entirely new; no one of them had ever dreamed of studying in +a Bible class anything except the Bible; but young people are not averse +to novelties, and they readily gave their assent. Yet I should do the +class injustice by leaving the impression that they were influenced simply +by the love of something new. They were of just that age when one hardly +knows whether to call them lads or young men; they had been well +instructed, and were just beginning to think independently. They were +rapidly becoming conscious of their own mental power, and were eager to +try their strength upon every line of thought. Their own weakness they had +hardly begun to learn. Perhaps they were all the more ready to undertake +such a course of study because they knew nothing of the difficulties +attending it. + +The tinkling of the superintendent's bell warned them to close their +conversation. + +"We have not time to-day," said Mr. Wilton, "to fix on the particular line +of study which we shall follow. Of course we cannot examine all the works +of Nature, and study every science, and trace the footprints of the +Creator in every place where he has walked; we must fix on some small part +of the works of God, and direct our attention closely to that. We shall +find this course more profitable than roaming carelessly over a much +larger space. Our next lesson will have to be a general one--a kind of +preface to what shall come after. In the mean while, you can be collecting +your thoughts upon the subject, and calling to mind anything that you have +read bearing upon the handiwork of God manifest in Nature." + +The school closed, and as the scholars pass out let me introduce to you +the members of the pastor's class. This class was small for several +reasons. The church to which Mr. Wilton preached was not the popular +church. The fashionable people and all who loved popularity and drifted +with the tide went to another church. Careless, thoughtless young people +naturally went with the crowd, and of those who attended his church some +did not care to join his class. He was too much in earnest to please them. +He made religion a reality, and his instruction compelled them to think, +and of course those who did not like to think were not well pleased with +him. But there were a few of the young men who were greatly interested in +his instructions. They were earnest readers of instructive books; they +liked conversation which called out thought; they were most of all +pleased with questions and themes which gave them new ideas. Indeed, in +the community, there were two classes of persons who held Mr. Wilton in +the highest esteem and regard: one of these was composed of men and women +of earnest, intelligent piety, experienced Christians; the other, of those +who were not Christians, but who respected sincerity and disinterested +godliness, and liked sermons filled with meat and marrow. + +Thus, at the present time, we find his class composed of but three young +men. With Ansel you are already acquainted. The second is Peter Thornton, +the son of a master-carpenter. He was frank, outspoken, quick in the +acquisition of almost every kind of knowledge, but very little given to +silent reflection. He listened to his pastor's instruction as he would go +to a well-filled library, to draw out its stores of information. Morals +and moralizing he did not like. He was not pious, and gave no indication +of serious impressions. The third was Samuel Ledyard, the son of a poor +widow. By painful industry and economy his pious mother was giving him the +best advantages for education which the village afforded, praying the +Lord to give him a part in the blessed work of preaching the gospel and +winning sinners to Christ and salvation. When but twelve years of age he +gave himself to Christ, and had been trying faithfully to follow his Lord. +The long winter evenings were spent in reading books of history and +science--books fitted to furnish and strengthen his mind--and long ere the +light dimmed the morning star he was poring over his Bible, alternately +reading the word and praying that his mind might be opened to understand +the truth in its beauty and greatness, and that the truth might be wrought +in him by vital experiences. + +With such habits it was no wonder that he grew in grace--it was no wonder +that he grew in all manly qualities. He was silent, meditative, and +retiring, as gentle in his ways as a quiet girl, yet all who knew him +recognized in him a singular weight and worth of character. Those to whom +the Lord revealed his secrets began to say that Samuel was appointed of +God to preach the gospel, and his mother felt the assurance growing strong +in her heart that her prayer was granted, and that the Lord was preparing +her only son and only child for a place in the gospel ministry. If only +she might train up a son to such a work, and when she should go to her +rest leave in her place a man working for Christ in his harvest-field, +gathering sheaves unto everlasting life, she felt that her cup would be +full. She was ready to say with Simeon: "Now lettest thou thy servant +depart in peace, for mine eyes have seen thy salvation." How unlike she +was to those mothers who lay all hindrances in the way of their sons +entering the work of the Christian ministry, willing that they should do +anything but this! and how different from those who declare that their +daughters shall never wed ministers of the gospel, teaching them to +despise the service of a pastor's wife! How often God gives over such sons +and daughters--children consecrated from their birth to worldliness--to be +entangled and lost in worldly snares! As such mothers sow, thus also do +they reap. + +These were the three lads, just growing into young manhood, at this time +under the instruction of Mr. Wilton. He was not ashamed of his class, +though it was small. As he saw them expanding in thought and taking shape +under his hand, he felt that in them he was perpetuating his influence in +coming generations. He believed that in one or more of them he should +preach the gospel after his body was sleeping in the earth awaiting the +resurrection. + +I trust the kind reader will be interested in following the course of +study through which their pastor shall lead them. + + + + +CHAPTER II. + +NEW THOUGHTS FOR THE SCHOLARS. + + +The little class which has been introduced to the reader came together the +next Lord's Day interested and expectant, yet not knowing what to expect. +They had chosen a course of study, yet they could not tell what that +course was to be. They had tried to think of something definite about it, +but could fix their minds upon nothing. In fact, the whole subject was +new, and they could not decide where or how to take hold of it. They came +together, therefore, with no more knowledge of the subject than when they +separated. + +Mr. Wilton himself came before his class in a state of doubt. He had given +the subject many hours of thought, and had carried it to his closet and +besought the guidance of the Holy Spirit, for he believed the divine +Spirit to be the best guide in understanding the works as well as the +word of God. He felt that his prayer had been heard and answered. He was +prepared, therefore, to speak with the force of clear understanding and +positive convictions. But the precise line of study he had left to be +determined by circumstances, perhaps by the previous studies of his class +in their academic course. This was to be decided by further consultation. + +"Since no lesson was assigned upon which you could prepare yourselves," +Mr. Wilton said, after the opening exercises of the school were finished, +"I shall spend the half hour to-day in a kind of conversational lecture. +You may call this the preface or introduction to the lessons which will +follow. I shall try to make plain some general principles which we must +keep in mind, whatever department of God's works we shall attempt to +examine. I wish you to feel entirely free to interrupt me at any time, and +ask any question or present any objection which may strike your minds. We +must, if possible, have no prowling bands of enemies in the rear. I wish +to make everything as plain as the case will admit. + +"One thing let me remind you of in the beginning: I shall not try to prove +to you that there is a God. I shall not try to prove that the world had a +creator. There are some things which men do not believe merely on account +of good evidence, nor disbelieve for want of proof. Men believe in their +own existence, but not from a course of argument. Most men believe in the +real existence of the outward world--the earth, the hills, the rivers, the +trees, everything which we see and hear and feel--but not on account of +proof. Here and there a strange man is found who professes to disbelieve +the real existence of all material things, but he disbelieves not for want +of proof. Men believe that their sight and hearing and touch do not +deceive them, but their confidence in them is not the result of a course +of reasoning. To believe in our own existence, and in the existence of the +world outside of us, and in the truthfulness of our senses, is natural; to +disbelieve these things is unnatural: it shows a state of disordered +mental action. When such disbelief is not practically corrected by a man's +understanding he is counted insane, and is treated accordingly. + +"Belief in the existence of God is also a natural belief. A denial of +God's existence shows, not disordered mental action, but a disordered +moral and spiritual state. It shows the absence of that spiritual faculty +by which we receive spiritual impressions, and are brought into contact +with the spiritual world, and hold intercourse with God and Christ and the +Holy Spirit. Men must be convinced of the existence of God through their +conscience, their moral and spiritual nature. Do not misunderstand me. I +do not say that good evidence cannot be brought to prove to one's reason +the existence of God, but God has not left his existence to be _proved_: +he has _revealed_ himself to men's consciences and to their faith; and +those in whom conscience and faith are well developed, sound, and right do +not need an elaborate argument to prove the divine existence. I shall +simply try to show that the works of creation exhibit the wisdom and +goodness of God. If any man, looking at such indications of wisdom and +kindness, can believe that it all comes by chance or is the work of some +evil agency, and that no Being of boundless intelligence, wisdom, power, +and goodness has anything to do with the making and governing the world, +he certainly shows great prejudice: he does not want to recognize God's +existence. He must be one of those spoken of by the Psalmist who say, 'no +God.' + +"During my recent visit to Greenville I visited a mill, the largest of its +kind in the country. In one room was a machine, something like a huge +straw-cutter, working with great power. In another room was a large steam +boiler hung upon a shaft and made slowly to revolve while filled with +steam. In a third room were large oval tanks, or cisterns, which might be +filled with water. Across each tank was a heavy shaft carrying a drum set +with steel blades, and as the drum revolved these blades passed other +blades in the bottom of the tank, cutting whatever came between like +scissors. In a fourth room were certain long and complicated machines. +Each machine was composed mostly of rollers. There were large rollers and +small rollers, solid rollers of enormous weight, and hollow rollers to be +heated by steam within. Over and around a portion of these rollers passed +a broad wirecloth belt. Over others passed a like belt of felted cloth. +With these machines before you, could you tell me whether the inventor +were a wise and skillful machinist?" + +"How could we tell," asked Peter, "without knowing what kind of work the +machine was designed to do?" + +"You could not tell," answered Mr. Wilton; "you would need to know both +what the machine was designed to do and all the processes by which the +work was to be carried on. This brings out the first point which I wish +you to fix in mind. It is this: To judge of the wisdom of any contrivance, +we must understand the purpose, or object, which the inventor had in view; +we must understand the work to be accomplished, and also the difficulties +to be overcome. An ordinary locomotive steam-engine is admirably fitted to +run on iron rails, but he would be a foolish man who should purchase such +an engine to draw a train of loaded wagons over a common road of earth. On +such a road it could not even move itself. It is good for that for which +it was made, and for nothing else. How would you apply this principle to +the subject we are now considering? You may answer, Samuel." + +"I think you mean," said Samuel, "that, in order to judge of the wisdom +and goodness of God in creating and governing this world, we must know +the object he had in view in making such a world." + +"That is my meaning, and I am glad that you understand me so perfectly. If +this world were created with no other object than to be the grazing-field +for herds of cattle, which see no difference between the beauty of the +violet and the dull shapelessness of the cold earth upon which it grows, +and never lift their eyes above the horizon, then all the beauty of earth +and sky would be useless; there would be no wisdom or goodness in the +creation of this beauty. There would be no wisdom or goodness in laying up +in store beds of coal, buried deep beneath the surface of the earth, if +God designed the world to be inhabited only by savages too rude and +ignorant ever to mine it, and turn it to some practical use. + +"But let me give you another illustration, which can better be applied to +the condition of things in this world. Just in the outskirts of one of our +inland cities I once saw a large and elegant building, whether a private +dwelling or a public institution I could not at first tell. It stood high +and airy, commanding the most pleasing prospect that all the region +presented. We will follow a visitor as he goes to examine that noble +establishment. + +"As he comes nearer, he sees that the edifice is simple and classic in its +style and chaste in its architectural adornment. It is a pleasure for the +eye to rest upon its graceful symmetry. But in place of the light and +graceful fence which he expects to find enclosing its grounds, he sees a +stockade strong and high. The janitor turns the heavy key, the rusty bolt +flies back, and the visitor enters the enclosure. Within the stockade he +finds a portion of the ground laid out with taste and cultivated with +choice and beautiful flowers; another part is devoted to the culture of +garden vegetables. He finds workshops also for the manufacture of pails +and tubs, brooms and mattresses. The visitor is ushered into the mansion +itself. He finds everything more than comfortable; the rooms are heated +from furnaces below; every part is perfectly ventilated; the windows +command a view of the country around which must please the most cultivated +eye; a school-room is provided with all needed apparatus for the most +thorough instruction. 'Surely,' says the visitor, 'the founder of this +institution must have been both wise and good. He must have loved the +young in order to study and supply all their needs so completely.' But +some things strike the visitor painfully. The windows are grated with +iron, and some of the rooms are almost like prison cells. 'Can it be +possible,' he thinks within himself, 'that the young need to be confined +by a stockade in so pleasant a place and shut in by grates of iron for the +enjoyment of such advantages?' The master as he teaches his pupils seems +as kind and gentle as a mother, yet there is a firmness and authority in +his tones and a rigidity in his training, as if his government were kept +braced against a mutinous spirit. The means of punishment also are +provided, and, when occasion requires, stern chastisement is employed. All +this seems to the visitor like an enigma. The institution appears to him +like a bundle of contradictions. A father could not have provided a +pleasanter home or larger advantages for his children, but fathers do not +commonly surround their homes with stockades, and cover their windows with +bars of iron, and train their obedient children with a hand of such firm, +unyielding force. 'Pray, sir,' he says to the master, 'what is this +strange contradictory institution?' 'It is the State Reform School,' the +master answers. 'And who are these lads and young men for whom all this +work and wisdom is expended?' 'They are those who have taken the first +steps in crime, but have not as yet become hardened and fixed in +wickedness, and are sent here with the hope of overcoming their vicious +propensities and training them to virtue and an honorable manhood.' + +"Everything is now made plain. The need of the stockade, and the grated +windows, and the rigid government, as well as of the pure air, the +garniture of beauty, and the kind loving care, is manifest. It is a place +unsuited to a family of obedient children, and equally unsuitable as a +place of confinement for confirmed criminals, shut up, not for reform, but +for punishment. It is wisely adapted to the work designed to be +accomplished, and to no other. + +"In like manner, if we would judge of the wisdom and goodness of God in +the creation and government of this world, we must understand the use for +which the world was designed. Is this plain to you, Ansel, and does it +seem reasonable?" + +"Yes, sir; I think I understand it, and I can see no objection to the +principle. I think even Mr. Hume could find no fault with that. But how +shall we know the object for which God made and governs the world?" + +"That is the next point to be considered. Perhaps you will tell us what +seems to you to be that object? Young people sometimes have thoughts and +opinions upon the greatest questions." + +"I have never formed an opinion of my own," Ansel replied, "but I have +always heard it said that God designed to show how perfect and good and +beautiful a world he could make. But many things in the world seem to me +neither perfect, nor good, nor beautiful." + +"Why, Ansel!" exclaimed Samuel; "the Bible says that 'God saw everything +that he had made, and behold it was very good.'" + +"And, Mr. Wilton," asked Peter, "does not the Bible say that 'God created +all things for his own glory'?" + +"Before answering any of these questions, let me ask Samuel a question. +What do you understand to be the meaning of the words you quoted from the +last verse of the first chapter of Genesis?--'God saw everything that he +had made, and behold it was very good.'" + +"I suppose it means," answered Samuel, "that God made everything just as +good and beautiful as it can be, so that any change must be a change for +the worse. The lecturer last winter said that if men could entirely +destroy any one of the most troublesome species of insects, their +destruction would be a great loss to the world, and that if a single atom +of matter belonging to the earth were annihilated, it might throw the +solar system out of balance, so that it would finally be destroyed." + +"I remember," said Mr. Wilton, "that some lecturer last winter made +statements of that kind, and I have heard other people declare that the +least possible change in the world would be injurious, if not destructive, +to the interests of man, and that the most troublesome beasts and insects +and the most loathsome reptiles are necessary to human happiness. Does +that seem to you to be true, Samuel?" + +"I have always tried to believe it, because I thought I ought to believe +it. It has seemed to me to be dishonoring God to believe that he did not +make the best possible world." + +"You are right in trying to believe what seems to be right and true, even +though difficulties do lie in the way. Difficulties do not by any means +show that an opinion is false. We must certainly believe that God made +this world perfect for the object which he had in view in making it. But +not a few skeptics deny the existence of a good, wise, righteous Creator +and Governor, because they have a wrong idea of the end for which the +world was created, and, consequently, a wrong idea of that in which its +perfection must consist. Let me ask you a few questions which will lead +your minds in the right direction. Do not men produce by cultivation +better fruits and vegetables than Nature ever grows when left to herself?" + +"Yes, sir," said Ansel; "the peach and apple and potato have been brought +up to their present state of excellence by great care and exertion. +Originally, they were almost worthless." + +"And not only that," said Mr. Wilton, "but when once that careful culture +is relaxed they begin to return to their former badness. Again, do we not +improve upon Nature by drainage and improve upon the climate by +irrigation?--in fact, do not men by drainage and irrigation and all +manner of culture greatly improve the natural climate of a country?" + +"I think that is true," said Ansel. + +"I never thought of that before," said Peter. + +"Moreover, do you not suppose that heaven will be more beautiful than the +earth, and that a thousand troublesome things besides sin--loathsome +sights, discordant and jarring noises, disgusting and nauseous odors--will +be absent from that 'better land'?" + +"And _I_ never thought of that before," said Samuel. "I am sure that many +unpleasant things besides those which sin has brought into the world will +not be found in heaven. I see that this world might be changed and not be +made worse for holy beings to live in." + +"The world is very good," said Mr. Wilton, "for the purpose for which it +was created, but we need not look upon it as designed for a specimen of +the most beautiful, pleasant, and desirable world which the Creator could +produce." + +"But you have not told us," said Peter, "what the Bible means when it says +that God created all things for his own glory. Does it not mean that he +made the world so good and perfect that all creatures ought to praise him +on account of it?" + +"We ought," said Mr. Wilton, "to praise God for the wisdom and goodness +displayed in the works of creation. That is the teaching of the Bible in +many places; it is also the sentiment of the Bible that God created the +world and carries on all things for his own glory, but it nowhere uses the +exact language which you have employed. In Isa. xliii. 7, speaking of +'every one that is called by my name,' the Lord says, 'I have created him +for my glory.' In Prov. xvi. 4 it is written, 'The Lord hath made all +things for himself; yea, even the wicked for the day of evil;' and the +four and twenty elders fell before the throne of God saying: 'Thou art +worthy, O Lord, to receive glory and honor and power; for thou hast +created all things, and for thy pleasure they are'--that is, exist--'and +were created.' I might quote other texts of similar meaning. We are taught +also that our first and supreme aim in all our conduct should be the glory +of God. 'Whatever ye do, do it all to the glory of God.' But here two +questions arise: What is the glory of God? and, What is it for God to +glorify himself by his works of creation and government? Who will tell +us?" + +All were silent, and Mr. Wilton went on speaking: "The word glory means, +first and literally, a halo of light. The glory of God is the radiance, or +halo, so to speak, of his infinite attributes and holy character. God +glorifies himself when he reveals himself, and makes known his character, +and causes the uncreated splendor of his attributes to break forth, so +that his creatures recognize them and adore him. This, you see, is very +different from the idea of glory among ambitious men. God glorified +himself in the creation of the physical world, because from that creation +his wisdom, power, and goodness are manifest. He glorified himself in the +creation of angels and men, because they were created in the image of God +and are finite pictures, so to speak, of the infinite Creator--a +revelation of his spiritual being and personality. He glorifies himself in +his government of the world, because his administration of affairs +exhibits his justice, mercy, and holiness. This is what we mean by the +glory of God and his working all things for his own glory. This is +somewhat difficult for persons of your age, so we will leave it and +return to the exact subject of discussion. Admitting that God created the +world and governs it for his own glory--that is, to reveal himself--for +what specific purpose did he design this earth?" + +"I don't know," said Peter, "that we understand what you mean by 'specific +purpose.'" + +"Very well, then," said Mr. Wilton; "I will suggest the answer. Does the +world seem as if fitted up to be the dwelling-place of holy beings?" + +"I have never thought of the question before," said Ansel; "but it seems +to me that many things in this world would give pain even to angels if +they lived here with bodies like ours." + +"I agree with you, Ansel. If men were sinless and holy as the angels of +heaven, many things in this world would bring them distress. But does it +seem reasonable that the world was designed merely as a place of +punishment for men by reason of their wickedness?" + +"Some men are not wicked," replied Samuel. "There have always been men +willing to die rather than disobey God. Surely, God does not punish such +men. And many beautiful and pleasant things are found in the +world--arrangements plainly designed for the welfare and happiness of +men." + +"I think you are right, Samuel. But, without asking further questions, I +will give you the conclusions to which my study upon this subject has +brought me, and some of the reasons for those conclusions. + +"This world was made chiefly as the dwelling-place of man. The world was +not planned merely as the abode of brute animals. Men are nobler than the +brutes. Men have permanent interests and advantages. Aside from the glory +of God, men are an end unto themselves. To become and be _men_ is the +noblest object of human life, but the animal tribes exist for the use and +benefit of others. To be an end to itself, a creature must be immortal; +but the brutes exist for the use and advantage of man, live out their +transient life, and exist no more. This is the view presented in the +sacred Scriptures. God gave to man lordship over the earth--not only over +the soil to subdue it, and over the great forces of Nature to bring them +into subjection for human advantage, but also over the brute creation, +'over the fish of the sea, the fowls of the air, and every living thing +that moveth upon the earth.' I conclude also that God did not prepare this +world as a prison-house and place of punishment for rebels against his +government. Too many pleasant things abound for me to believe that. The +pleasant breezy air, the glorious sunlight, the refreshing showers, the +treasures of mineral wealth stored up in the earth, the fertile land and +golden wheat, the beauty spread over all nature, the sweet consciousness +of existence, so that just to live and act is joy, and the comfort and +hope of immortal pleasure enjoyed by truly Christian men,--all these +things, and many more, assure me that not the subtle shrewdness of a +tormentor nor the unmingled justice of an inexorable judge, but the heart +of a kind and loving Father, planned our earthly dwelling-place. You said, +Samuel, with truth, that there are many pious men in the world who are +dear to God, and Paul says, 'We know that all things work together for +good to them that love God.' For those dear ones Christ has such love that +he counts everything--whether good or bad--that is done to them as if done +to himself. 'Inasmuch,' he says, 'as ye have done it unto one of the least +of these my brethren, ye have done it unto me.' Moreover, Jesus said: +'For God so loved the world, that he sent his only begotten Son, that +whosoever believeth in him should not perish, but have everlasting life.' +From these words of Jesus we see that there is love manifested in the +dealings of God with the inhabitants of our world. Were it not so, there +would nothing remain but a 'fearful looking-for of judgment and fiery +indignation, which shall devour the adversaries.' + +"On the other hand, I conclude that God made the world as the +dwelling-place, not of obedient, holy children, but of those who are +disobedient, fallen, and alienated. These disobedient and alienated ones +he holds under discipline and chastisement, in order to keep their +wickedness in check, to recover them from their sins, and train them up in +virtue and holiness, or to remove from the obstinate and incorrigible all +excuse for their sins and all plea against their final condemnation. In +doing this he glorifies himself by manifesting his wisdom, goodness, +mercy, and holiness. + +"This opinion seems probable from the fact that this is the purpose for +which God has actually used and is now using the world. Here he keeps and +governs the human race. This race is made up neither of holy beings nor of +hopeless reprobates. They are the creatures of God; fallen indeed, yet +loved; sinful, but objects of divine compassion; deserving of righteous +wrath, but the recipients of the offers of salvation through Christ. Even +penitent believers in Christ and devoted servants of God are not free from +evil propensities, but need to be kept under constant training and +discipline. This is the use to which the Creator has actually put the +world. Is it not reasonable to believe that he designed it for their use? +Ought we to believe that God planned the world for an object for which it +never has been and never will be employed? + +"If sin were removed from the world, the chief part of human suffering +would be removed. This no man can deny. Wars would cease; the want, +disease, and woe resulting from selfishness, idleness, and vice would +disappear, and nothing would stand between man and his Maker. What new +life and joy would fill the world if free communication were restored +between man and God, and the divine smile were again to enlighten the +world! It would seem that heaven had enlarged her borders to embrace this +earthly ball. But the fact would still remain that this physical world is +unfitted to be the dwelling-place of sinless beings. The constitution of +the world would bring upon them pains and evils which would seem a most +unworthy heritage for loving and obedient children of our heavenly Father. +Let sin be taken away, and wearisome toil in subduing the earth would +remain. The soil of the earth is hard and clogged with stones, and clammy +with stagnant waters, and sown well with the seeds of noxious weeds, and +overgrown with thorns and thistles. Endless watchfulness and toil is the +price of a livelihood. With the sweat of his face man must eat his bread. +An army of enemies have pre-empted the soil which man must till. This +state of things the word of God refers to sin: 'Cursed is the ground for +thy sake; in sorrow shalt thou eat of it all the days of thy life. Thorns +also and thistles shall it bring forth to thee.' The necessity of toiling +as we do now for our daily bread, God denounced upon man as a curse on +account of sin. We cannot, therefore, regard this as a suitable condition +for sinless beings. + +"This burden of toil is lightened by the progress of modern sciences and +inventions much less than some men think. Every step of progress has been +made by the sacrifice of hecatombs of human lives. From our laboratories +and workshops products of human skill, rich and rare, are sent forth; but +what are they but smelted and hammered and graven and woven human bones +and sinews, the health and life of men? No means have been discovered by +which the most necessary processes of the arts can be made otherwise than +dangerous to health. Only when thousands of miserable workmen had perished +was Sir Humphrey Davy's safety-lamp invented; and now the danger, to say +nothing of the hard toil, of the collier's life is only lessened, but not +removed. Still, our furnaces roar and the whole tide of civilization goes +on by the health-destroying servitude of men, buried alive as it were in +the dark bosom of the earth. Would that seem to be a fitting employment +for the sinless children of the all-loving Father? Employés in many kinds +of manufacture slowly sink under the accumulated evils of daily toil, and +no means of making their employments healthful have been discovered. The +friction-match, which has become so nearly a necessity, is made by a +process so destructive to health that only a certain class of laborers can +be prevailed upon to do the work. I might go on to speak of other painful +circumstances in which men find themselves by the almost antagonistic +attitude of Nature. But if we reject these dangerous processes of +manufacture and art, we go back at once to the wooden plough, the distaff +and tinder-box of primitive times, and also to primitive poverty and +primitive toil, and, I may also add, to primitive exposure to the hostile +and pitiless forces and inclemencies of Nature. Purge the earth of sin, +and wearisome toil would still remain. Nature must be nursed and +cultivated or she yields no bread. Her hostile attitude must be overcome; +the thorns and thistles must be rooted out; and every step of progress, +won by suffering, must be held by painful work and watchfulness; otherwise +Nature returns to the wild and savage state. Relax the culture of the +choicest fruit, and it begins to deteriorate; leave the best-blooded breed +of cattle to itself, and it returns again to the level of native, +uncultured stock. + +"The inhabitants of this world are also liable at all times to diseases +and destructive accidents. This condition of things could not be changed +without changing the entire structure and plan of the world. Is that a fit +dwelling-place for a sinless being where chilling winds one day shrivel +his skin and fill his bones with rheumatic pains, and the next, sweltering +heats pervade all his system with languid lassitude--where miasma lies in +wait unseen to poison his blood, kindle the malignant fever, and bring him +to the shades of death, and every form of accident crouches in ambush, +ready to spring upon his victim unawares and tear him limb from limb? We +cannot see that the absence of sin would dissipate this liability to +disease and the danger of accidents. Nay, this liability and danger are +written upon the very constitution of the human body. The finger of God +has engraved it upon every muscle and bone and life-cell. The Creator gave +the body that wonderful power called the _vis medicatrix_--the power of +recovering from injuries and repairing damage done to itself. Pull a leg +from a grasshopper and another grows in its place. By this we know that +the Creator understood the liability of this little insect to lose a limb, +and prepared him for it. In like manner the power in man's body to heal a +wound or join a broken bone gives us to understand that the Creator +expected man to live in the midst of danger. The precaution proves the +risk. + +"These accidents are such as no possible carefulness could guard against. +To say nothing of the fact that all our knowledge of these perils comes +from a painful experience of danger and death, what care, even after ages +of sad experience, could ward off the thunderbolt? What carefulness could +guard against the tornado on the land, or the hurricane and the cyclone +upon the sea? Who should stand sentinel against the unseen poison borne +upon the wings of the wind? What power should save him from the bursting +of the volcano and the jaws of the earthquake? What care could give him +knowledge of the qualities of all natural substances, that he might avoid +their dangerous properties? We can suppose a divine care over man that +should do all this and save men from harm, but it would be a providence +superseding all human knowledge and exertion--it must be a providence to +which the human race is now a stranger; miracles would then be the rule, +and the undisturbed course of Nature the exception. + +"If, however, we suppose that God designed the world as a training-school, +so to speak, of fallen beings, such as the word of God declares the human +race to be, all is plain, everything is suitable and harmonious. We can +see the fitness of at least the chief outlines of man's earthly condition, +and can perceive God's wisdom and goodness in the constitution of the +world. + +"The pain and woe-producing agencies of Nature are seen to be not at all +contradictory to goodness, but on the other hand eminently wise and +righteous. The whole sum of human misery expresses God's displeasure at +sin. By their sufferings men learn how abhorrent is sin in God's sight. By +the consequences of evil-doing they learn not to transgress. As none are +free from the taint of depravity, none are free from pains. The necessity +of labor--one of the elements of the primal curse--is a check to sin on +the part of the vicious, and a discipline and trial to virtue on the part +of the penitent. The multiform trials of life--which can indeed be borne +well only by the grace of God--while they teach the evil of sin and keep +the heart chastened and subdued, nourish heroic and dauntless virtue in +the faithful. 'Daily cares' become 'a heavenly discipline.' Dangers and +calamities startle the stupid conscience, and keep alive the sense of +responsibility to God on the part of the wicked; they quicken the sense of +weakness and dependence in the believing and educate their faith in God. +The more sudden and overwhelming these evils, and the more these dangers +are placed beyond the possibility of being warded off by human care, the +more do they awaken in men a sense of the divine presence and of +responsibility to God. + +"But would not all these natural agencies subserve essentially the same +ends in the discipline of unfallen and sinless beings? By no means. If +sufferings came upon a sinless being, he could not feel that they came as +chastisements; he could not feel them to be deserved. They would be to him +a 'curse causeless,' and hence would bring no advantage. He could only cry +out in astonishment, 'Father, why am I, thine obedient son, thus smitten?' +Calamity falling upon the innocent would be an anomaly in the universe. +But now the sufferer, pierced through and through with a sense of ill +desert, meekly bows his head, murmuring, 'Father, all thy judgments are +just and right.' + +"One very important feature of the world we live in is its moral +symbolism. The world is full of most suggestive symbols and emblems of +moral good and evil. There are all beautiful and glorious things, to stand +as types of goodness, truth, and righteousness; there are all loathsome, +malignant, and hideous things, to serve as the types of folly and +wickedness. Was it merely an accident that the dove was fitted to become +the emblem of purity and of the Holy Spirit? the lamb, to be the emblem of +gentleness, of Christ the gentle Sufferer, and of his suffering people? +the ant, to be the type of prudent industry? the horse, of spirit and +daring? and the lion, of strength and regal state? Was it only an accident +that prepared cruel beasts and disgusting, poisonous reptiles as the types +of evil passions and sins--that made the venom of the viper, the cunning +of the fox, the blood-thirstiness of the wolf, the folly of the ape, and +the filth of the swine, symbols of foul, subtle, malignant sin and folly? +Nature is full of these emblems. The palm tree with its crown of glory, +the cedar of Lebanon, the fading flower and withering grass, the early dew +and the morning mist, the thorn hidden among the leaves of the fragrant +rose, poisons sweet to the taste, and medicines bitter as gall,--how all +these natural things preach to men sermons concerning spiritual verities! +There is no virtue or grace which is not commended to man by its image of +beauty in the animal tribes; there is no vice against which men are not +warned by its loathsome, disgusting form shadowed out in the instinctive +baseness of irresponsible brutes. + +"Thus we find earth, air, and sky to be full of silent voices proclaiming +in the ears of man that which he most of all needs to remember. These +types and symbols of virtue and vice are specially needed by fallen +beings. They seem fitted for beings whose spiritual eyes are blinded and +all their spiritual senses blunted--beings with whom there is no longer +'open vision' of spiritual realities. These pictures of evil are most +impressive to men who see in them the reflection of their own base +passions. How the fetid goat and the swine wallowing in the mire speak to +the lecherous man and the drunkard! In a world of sinless beings these +mimic vices would seem rather to mar God's handiwork. + +"Set the human race, fallen as it is, in a world where the patience of +daily industrious toil would not be needed, and the race would rot with +putrid, festering vice. Remove all danger, and men would forget and deny +that the Creator holds them responsible. Let no evil consequences follow +evil-doing, and men would cease to make a distinction between right and +wrong. Take away death, and they would deny the existence of a spiritual +world. But in this world God has hedged men around with checks and +penalties and painful discipline, such as are of use only in dealing with +sinners. + +"I conclude, therefore, that God prepared this world as it now is as a +place of discipline for a fallen race. This is the use to which he has +devoted it in the past; and when there is no longer need of such a world +for the discipline of men, we learn from the word of God that a 'new +heaven and a new earth' shall be provided. This world is thus declared to +be an unfit abode for the glorified saints. To judge, then, of the wisdom +and goodness of God in the works of nature, we must keep in mind the +object for which the Creator prepared the world. Ansel, tell us how this +strikes you." + +"I never thought of it in this way before," he answered; "indeed I have +thought very little of this subject, but--" Tinkle, tinkle went the bell +upon the superintendent's desk. This was the second time the +superintendent had struck his bell, but Mr. Wilton had been so intent upon +his subject that he did not hear the first ringing. + +The school was dismissed, but Mr. Wilton remained with his class to fix +upon the particular department of nature which they would study. He found +that all were studying natural philosophy, and had recently gone over the +subject of heat. At his recommendation, therefore, they agreed to examine, +as a specimen of God's works, his management of heat in the world. Mr. +Wilton requested them to review the subject during the week, and be +prepared to state and apply the general principles touching the nature, +phenomena, and laws of heat which they had already learned. This work they +will enter upon next Lord's Day. + + + + +CHAPTER III. + +A DIFFICULT QUESTION. + + +During the week, Ansel, Peter, and Samuel were busy reviewing and fixing +in memory what they had already learned of the nature and laws of heat. +They were not only interested in the new line of study, and desirous of +pleasing Mr. Wilton, but they also felt that their scholarship was to be +tested, and each one was ambitious of standing equal to the best. + +Ansel, of course, was busy and ambitious. The lesson was coming somewhat +upon his own ground, and he felt in no wise unwilling to show how well he +had mastered the subject. He entered upon it with feelings a little +different, however, from his anticipations. The explanation which Mr. +Wilton had given of the purpose of the Creator in making such a world +seemed to him very reasonable. He could make no objection to it. But that +explanation had taken away at one sweep a whole store of objections to +God's goodness which he was waiting to bring out as soon as a good +opportunity was presented. A world designed for the dwelling-place of +sinners--sinners not already given over and doomed to final wrath, but to +be recovered from sin and trained in virtue and holiness, or, if +incorrigible, to be held in check and used as helps in the discipline of +the righteous--he plainly saw must be as unlike a world fitted up for holy +beings as a reform school is different from a home for kind and obedient +children. Those arrangements which he had thought the most painful and +objectionable might, after all, be the wisest and best. He did not see +where to put in a reasonable objection to Mr. Wilton's unexpected +argument, yet he did not feel quite satisfied to confess to himself that +he was so soon and so easily defeated. + +In this state of mind, on Saturday morning he met Mr. Hume upon the +street. + +"Good-morning, Ansel," said Mr. Hume. + +"Good-morning," returned Ansel. + +"I hear," said Mr. Hume, "that you have given up studying the Bible in +your Bible class, and have begun the study of natural philosophy. Is that +so?" + +"Not quite true, Mr. Hume. We are to examine some department of the works +of Nature, and see what indications appear of the Creator's wisdom and +goodness." + +"That is a little different from the report which came to me. But what did +you learn last Sunday?" + +"Mr. Wilton told us that in order to judge of the wisdom and goodness of +God in any of the affairs of this world we must consider the object for +which that arrangement was designed. He said that if a man examine a +cotton-gin, supposing it to be a threshing-machine, he would be likely to +pronounce it a foolish and worthless contrivance; and that the fine edge +of a razor would be worse than useless upon the cutter of a breaking-up +plough. He told us that the earth was not prepared as the dwelling-place +of sinless beings, but as a place of discipline for the fallen human race, +and that we ought not to look upon it as the choicest specimen of +workmanship which the Creator could construct." + +"I have heard that Mr. Wilton believes something of that kind. Ansel, +have you studied geology?" + +"I have read a little upon that subject and have heard some lectures." + +"Can you tell me, then, whether or not the natural laws which prevailed on +the earth ages and ages ago, before the earth was fit for men to live upon +it, are the same as those which have been in operation in these later +ages, since men have inhabited it?" + +"I suppose that the same laws have prevailed from the beginning of the +geologic periods. I think that geology makes that very evident." + +"If that were not so," said Mr. Hume, "the past history of the globe would +be a riddle to us; it would be confusion worse confounded. In regard to +those early ages we could not reason from cause to effect, for we should +know nothing of the forces and principles then in existence. In geologic +studies we judge the past from the present, and if that be not a +trustworthy method of reasoning, all the conclusions of geologists are as +worthless as dreams. Have you any reason to suppose, from what you have +read on this subject, that a curse changed the character of the earth as a +dwelling-place for man some six thousand years ago? Is it true, as Milton +says, that then + + 'The sun + Had _first_ his precept so to move, so shine, + As might affect the earth with cold and heat + Scarce tolerable, and from the north call + Decrepit winter--from the south to bring + Solstitial summer's heat'? + +Did the Creator then + + 'Bid his angels turn askance + The poles of earth twice ten degrees and more + From the sun's axle'? + +Or was death then first introduced among the brute creation, as Milton +fancies?-- + + 'But Discord first, + Daughter of sin, among the irrational + Death introduced through fierce antipathy; + Beast now with beast 'gan war, and fowl with fowl, + And fish with fish; to graze the herb all leaving, + Devoured each other.'" + +"Animals must have died," said Ansel, "for their remains lie imbedded in +rock which certainly existed before man lived on the earth." + +"I wish you would ask Mr. Wilton one question for me." + +"I am willing to ask him any proper question, and I suppose you would not +wish me to ask any other." + +"I certainly would not. Will you ask him how it was possible for man not +to sin and fall if God created the world for a sinful race myriads of ages +before man was brought into existence? It would seem that if man had +remained obedient he could not have lived pleasantly in a world prepared +for sinners, and at the same time, by man's obedience, all the Creator's +plans touching this world would have been dislocated and disappointed." + +"I will ask him, sir," said Ansel, "at the first good opportunity." + +This good opportunity occurred sooner than Ansel expected, for, before +entering upon the proposed lesson the next Lord's Day, Mr. Wilton said to +the class: + +"I wish in these lessons to advance carefully and safely, and, as far as +possible, have everything well understood. For that reason I invite you to +speak freely of any difficulties or objections which may suggest +themselves to your own minds or which you may hear presented by others. At +the close of the last lesson the views which I had presented to you seemed +very reasonable, but it is possible that, as you have thought upon the +subject during the week, objections may have arisen in your minds. If so, +I should be glad to hear them now." + +"There are many things," said Peter, "of which I cannot see the use, even +if we suppose that the earth was designed as the dwelling-place of +sinners." + +"It would be very surprising indeed if you could unravel all the mysteries +of creation in a week's time. Wiser men than any of us have spent a +lifetime in searching out the meaning of God's works, and died still in +the dark upon many points. We need not expect to unravel and understand +all the deep, complex, and delicately-interwoven contrivances in a world +so vast and curious as this. The world is a great mystery--mysterious as a +whole, and mysterious in all its parts--upon any supposition. But the +explanation which I gave of its design furnishes a sufficient reason for +the great outline of creation. This gives a reason for the pains and +miseries which dog man at every step. This gives a reason for the earth's +being left rugged and sluggish, bringing forth thorns and thistles, and +requiring to be subdued by patient industry. It shows a ground for the +necessity of exhausting toil under a frowning sky and mid miasmatic +airs--for the liability to diseases and accidents, and the hard necessity +of death. These great elements of divine providence are not stripped of +their halo of mystery, but with this explanation they are seen to form a +harmonious whole for the accomplishment of a great and glorious purpose." + +Mr. Wilton paused. Then Ansel said, "Mr. Hume wished me to ask you a +question." + +"Very well, I should be glad to hear it. I hope, indeed, that he sends his +question from interest in the subject, and not with the design of +perplexing us. I wish also that he were here to ask the question and hear +the answer for himself. But what is the question?" + +"He wished me to ask how it was possible for man not to sin and fall if +God placed him in a world prepared for a race of sinners and unfitted for +a sinless race. He said that in such a case, if man had remained obedient, +the plans of God would have been disarranged." + +"What answer did you try to give him, Ansel?" + +"I did not try to make any explanation. It seemed to me a very great +objection. I did not see how such a course was consistent with God's +righteousness." + +"And you are not the first person who has objected to this as a great +inconsistency. I am afraid the discussion will take more time than we +ought to spare, but now that the question has been asked and the objection +presented, I must take time to answer it, even if it consume the whole +half hour. + +"In considering this subject, as well as many others, we need to remember +that the existence of difficulties is no objection to a principle or a +fact. Difficulties wholly inexplicable by man attend facts and principles +which must be true. A fact may be incomprehensible, though undeniable. The +great Doctor Johnson said, 'There are insuperable objections against a +plenum, and insuperable objections against a vacuum, yet one of these must +be true.' What did he mean by that, Samuel?" + +"He meant, I suppose, that we could not explain the possibility that any +space should be wholly empty of matter, and could no more explain the +possibility that any space should be filled with matter, but that all +space must be filled, or else there must be empty space. Whether we can +explain the possibility or not, one of them must be true." + +"That is right. The same is true of many other facts besides a plenum and +a vacuum. We cannot conceive of infinite space; we cannot conceive that +space should not be infinite, but bounded. We cannot conceive of the +creation of the world from nothing, and no more can we conceive of its +eternal existence. The truth is that the mind of man cannot grasp such +subjects so as to reason upon them correctly. No sooner do we attempt to +reason about the infinite things of God than we run into absurdities and +reach the most contradictory conclusions. And in this respect it makes no +difference with what principle or proposition we start if it only contain +some infinite element. Let me give you a simple illustration from +geometry--an illustration which, very likely, is familiar to you: the +larger a circle, the less is the curvature of the line which bounds it; +that is, the more nearly does that line approach a straight line. An +infinite circle must be bounded by a straight line, because with any +degree of curvature the circle would be less than infinite. But a +straight line cannot bound a circle. The attempt to reason about an +infinite circle brings us at once to the most palpable absurdities and +contradictions. Or take this illustration: the whole of a thing is greater +than any of its parts. But divide a line of infinite length in the middle, +and each part is infinite. We reach the conclusion either that the half is +equal to the whole or that other wholly incomprehensible proposition, that +one infinity is twice as great as another infinity. I have made these +statements to show you that the existence of difficulties does not +indicate, much less prove, that a fact is not real and true. + +"Mr. Hume thinks the fact that the earth existed in its present condition +before men sinned an insuperable objection to the view that this world was +prepared as a place for the discipline of a fallen race. But let us look +at the other side, and see if equal objections do not exist. The Creator +foresaw the fall of man; is there no objection to the supposition that, +knowing that man would sin, God made no provision for it? On the one +supposition he foresees the evil and makes no provision; on the other, he +foresees it and provides for the catastrophe. The former supposition +certainly involves the greater difficulties. + +"The objector may reply that the plan of God, by embracing the fall of man +and including it as one of its essential elements, made that fall +necessary. But why should not God embrace in his plan that great event, +the fall of man, which he foresaw in the future? Would it have been wiser +and better to leave out of account that most stupendous fact in the +history of the human race? This same objection, which Mr. Hume and many +others have brought forward, lies with equal force against the great +central fact of the gospel, the death of Christ. God's plan touching this +world included the incarnation and death of his Son. Jesus, the 'Lamb of +God,' is spoken of as 'slain from the foundation of the world.' Rev. xiii. +8. But the incarnation and death of Christ presuppose the apostasy of the +human race. Did this plan touching Christ make the apostasy of man a +necessity? If preparing a world--fallen, so to speak, beforehand--for a +race which God foresaw would fall, be inconsistent with his righteousness, +it must be equally inconsistent to prepare a Saviour beforehand for that +same race. + +"Again, the divine plan touching the death of his Son included his +betrayal by Judas and his crucifixion by the Jews. If Judas had known that +God had poised the salvation of man upon the pivot of his treachery, he +would doubtless have argued as Mr. Hume and others are accustomed to do. +But did God's plan excuse his treason against his Lord? His own +conscience, piercing and rending his soul with remorse, drove him to +self-destruction, and Christ confirmed the sentence of his conscience and +called him the 'son of perdition.' The fact that God weaves the foreseen +crimes of men into his plans is no palliation of their guilt. + +"Would it be wise and well to take no account of foreseen events? Jesus +has gone to prepare mansions for those who will, as he foresees, believe +in him: why not make provision for foreseen evils also? Our civil +government, knowing the liability to crime among men--a liability which +the experience of man has shown to be a practical certainty--makes +provision for those crimes by maintaining a police, reform schools, +prisons, and armies. The Governor of the universe, knowing the liability +of man to sin and fall--a liability which by his foreknowledge was to him +a certainty--made provision for that foreseen apostasy. He made provision, +both by the creation of a world suited to a sinful race kept under a +probation of mercy, and by appointing a Redeemer, the 'Lamb of God,' +slain, in the eternal purpose, before the foundation of the world. If Mr. +Hume's objection has force at all, it has force against every wise +provision of God to meet the consequences of man's foreseen wickedness. It +is wise, forsooth, on man's part, to foresee coming evil and prepare for +it; but if God do this, men count it worse than folly: they declare it to +be an endorsement of the evil! So foolishly do men reason about the high +things of God! My answer to Mr. Hume, then, has four parts: + +"1. The existence of unexplainable difficulties does not disprove the +truth and reality of any fact or principle. + +"2. The supposition that God made provision for the present apostasy of +the human race is burdened with fewer and smaller difficulties than its +denial. + +"3. The word of God declares that he did make provision for the fall of +man by the pre-appointment of a Redeemer. + +"4. That style of reasoning which seeks to justify or palliate man's first +sin because God prepared this world for a fallen race would palliate and +justify all wickedness, because the sins of men are woven into every +figure of the web of divine providence. Not the treason of Judas alone, +but the whole sum of man's evil-doing, is embraced in the far-reaching +plan of God. How this magnifies the wisdom of God! He binds together in +one bundle his own righteousness and the sins of men, in a most intricate +interlacing, yet without blending the two and without staining the glory +of his holiness. + +"I hope I have made this plain. Do you think, Ansel, that you can repeat +the substance of this answer to Mr. Hume?" + +"I will try, sir, if he asks." + +"You will all notice," added Mr. Wilton, "that I have not denied that +there is a deep mystery in this preparation for the sins of men not yet +created, and that I have not attempted to explain this mystery. I have +only tried to show that the admission of the view I have given you is more +satisfactory to reason than its denial, and that the mysteries of this +view are not unreasonable and self-contradictory, for the greatest +mysteries are often the most reasonable things in the world. + +"My introduction has become much longer than I designed, but now let us +turn our attention to the subject of the lesson. + +"To aid us in understanding God's wise arrangements in the management of +heat, we need, first, to consider what heat is and to review the laws of +its action. Without this, we could look on and wonder at God's working in +nature, but could not explain that which we saw. + +"Ansel, will you state the theories which have been held touching the +nature of heat?" + +"I will do it as well as I can. The ancient philosophers supposed fire to +be one of the four elements of which all bodies were composed. The three +other elements were earth, air, and water. These four elements were +mingled in various proportions. Of these, fire was esteemed the purest and +most ethereal; this constantly tended upward to the empyrean, the highest +heaven, where the element of fire and light was supposed to exist +unmingled and pure. In the seventeenth century, Beccher and Stahl, two +German chemists, brought forward what is known as the _phlogistic +hypothesis_. They supposed that every combustible body held in +composition a pure, ethereal substance which they called _phlogiston_, a +Greek word which signifies _burned_, and that in combustion this +phlogiston escaped. Flame was supposed to be this escaping phlogiston. +These were the notions held about fire and combustion, but they are hardly +worthy to be called theories of heat. The discovery of oxygen by Dr. +Priestley of England, in 1774, and the introduction of the balance by +Lavoisier of France, joined with the ever-enlarging circle of facts to be +explained, rendered the phlogistic hypothesis untenable, and it was thrown +aside. + +"Until a few years since the _caloric_ theory was generally received. +According to this theory, heat is a _substance_, a subtle ether, diffused +through all bodies and surrounding their atoms. This ether has been +supposed to have a strong attraction for the atoms of every other +substance, while between its own atoms a strong repulsion exists. In solid +bodies each atom of matter, or in compound bodies each cluster of atoms, +has been supposed to be surrounded by a little atmosphere, so to speak, of +caloric, which prevented the atoms from coming into absolute contact. +According to this theory, heat expands bodies by increasing and deepening +these minute atmospheres, thus pressing the atoms farther from each +other." + +"You need not explain this theory farther," said Mr. Wilton; "we have +hardly time to go into the history of theories. Tell us the latest +received theory." + +"The theory now commonly believed is called the _mechanical_ or _dynamic_ +theory. According to this theory, the essence of heat is _motion_. A hot +body is one whose atoms are in a state of rapid and intense motion or +vibration; and the sensation of heat on touching a hot body arises from +the impact, or rapid blows, of the agitated atoms, communicating the same +atomic vibration to the flesh and nerves of the hand." + +"Very well stated, Ansel. This is the theory now more commonly received. +The caloric theory, like the crude notions of the old Greek philosophers +about fire, and like the phlogistic hypothesis, has been rejected because +it failed to explain the phenomena of heat. Whether the dynamic theory is +destined to share the same fate remains to be seen. It seems, however, to +have a better foundation than its predecessors. The dynamic theory, +though recently made popular, is by no means a recent conception. It was +advocated by such men as Bacon, Newton, Rumford, Davy, Locke, and others. +Locke, the distinguished intellectual philosopher who lived in the latter +half of the seventeenth century (born 1632, died 1704), said, 'Heat is a +very brisk agitation of the insensible parts of an object, which produces +in us that sensation from which we denominate the object hot, so that what +in our sensations is heat in the object is nothing but motion.' Benjamin +Thompson, an American gentleman who went to Europe in the time of our +revolution, and for his scientific fame was made Count Rumford, and became +the founder of the Royal Institution of England, declared that he could +form no conception of the nature of heat generated by friction unless it +were motion. + +"A beautiful generalization has been made to show how well this idea of +heat harmonizes with the entire plan of the universe. In the whole +boundless universe each system of worlds, like our solar system, may be +regarded as a molecule, or complex atom. These cosmical molecules, or +complex atoms of the universe, are in motion through unmeasured space. In +these systems of worlds the planets, with their satellites, are the +molecules, and they are in motion--indeed, they commonly have several +motions. Our earth, for example, rotates upon its axis once each day; it +revolves in its orbit around the sun once each year, and the axis of the +earth has a slow wabbling motion which produces the precession of the +equinoxes, requiring 25,868 years for a complete revolution. The earth +also is made up of parts, and all these are in ceaseless motion. As said +the old Greek philosopher, 'All things flow'--that is, everything is in a +state of change. Solomon has well described this perpetual movement and +change: 'One generation passeth away, and another generation cometh. The +sun also ariseth, and the sun goeth down, and hasteth to his place whence +he arose. The wind goeth toward the south, and turneth about unto the +north. It whirleth about continually, and the wind returneth according to +his circuits. All the rivers run into the sea; yet the sea is not full; +unto the place from whence the rivers come, thither do they return again. +All things are full of labor; man cannot utter it. The eye is not +satisfied with seeing, nor the ear filled with hearing. The thing that +hath been, it is that which shall be; and that which is done is that which +shall be done, and there is no new thing under the sun.' Eccles. i. 4-9. +It is certainly in harmony with this universal movement that the atoms of +matter, though they seem so closely packed, should in their inconceivable +smallness through inconceivably minute spaces vibrate, or rotate, or +revolve through an orbit, never at rest. Intensity of heat we may think of +as intensity of this atomic motion--a wider swing, so to speak, in their +vibration or revolution. This, of course, requires a wider separation of +the atoms and a consequent expansion of bodies. A feebler atomic motion +permits the atoms to approach each other. In this manner we explain the +enlargement of bodies by heat and their contraction by decrease of +temperature. 'The ideas of the best-informed philosophers are as yet +uncertain regarding the exact nature of the motion of heat, but the great +point at present is to regard it as a motion of some kind, leaving its +more precise character to be dealt with in future investigation.' This is +the most we can do at present." + +"What is the evidence," asked Samuel, "that the dynamic theory of heat is +true?" + +"The evidence that any theory is true is its ability to explain the facts +or phenomena with which it has to do. If it explains all the facts and +contradicts no known principles, it is regarded as true, or at least no +objection can be made to it. Let me illustrate. Astronomers had long +inquired what force or law controlled the movements of the heavenly +bodies. At length Newton answered, A force of attraction between bodies +which decreases in proportion as the square of the distance between them +increases. This explanation has been found sufficient to explain all the +known facts in the working of the heavenly bodies. Upon the basis of this +theory astronomers calculate the positions of planets and comets for years +and centuries to come. + +"This theory led to the discovery of the planet Neptune, the last +discovered of the primary planets. For thirty years irregularities in the +motion of Uranus had been noticed. These variations were so slight that if +another planet had revolved in the proper orbit of Uranus they would have +seemed to the naked eye, throughout their course, one and the same star. +This slight irregularity of motion was so nicely measured that the place +of the unseen planet which caused it was almost exactly calculated from +the estimated force and direction of its attraction. This theory of a +universal attraction of gravitation so well explains all the facts in the +case, and has become so universally received, that we are liable to forget +that, after all, it is nothing but a theory. + +"Our idea of the structure of the solar system was at first only a theory. +The astronomer does not see the planets revolving in regular circles +through the heavens and moving around the sun. He only sees the shining +points moving back and forth upon the concave vault, doubling and crossing +their tracks apparently in the greatest disorder. How shall their motions +be explained? Astronomers have found that the motions of planets revolving +around a central sun, when seen from one of the planets, must present just +these apparent irregularities. This explanation is so full and complete +that it is now counted not a theory, but an established fact. The same may +be said of the shape of the earth. + +"The dynamic theory of heat explains the phenomena of heat better than +any other explanation that has been proposed. It explains the radiation of +heat from the sun or from any other hot body: vibrations or impulses are +propagated through that ether which is supposed to fill all space. It +explains the conduction of heat through solid bodies in the same manner. +It explains the expansion of bodies: the atomic motion forces the atoms of +bodies farther apart. It explains the production of heat by friction or +collision, which no other theory is able to do: the shock of the collision +generates this atomic vibration. It explains the production of heat by +combustion: the atoms of oxygen and carbon or hydrogen dash against each +other and generate heat by the collision. This theory explains the +transmutation of motion, or living force, and electricity, into heat, and +the transmutation of heat into electric or mechanical force. These points +will come up again, and I now only refer to them in answering Samuel's +question. The dynamic theory explains the phenomena of heat and its +relations to force, light, and electricity exceedingly well, and for this +reason men look upon it with favor and count it as probably true. If in +the progress of scientific investigation it shall be found to explain all +the new facts discovered and meet well all the demands made upon it, it +will at length be received as an admitted principle in physical science. +The _wave_ theory of light and the _vibratory_ theory of sound may be +looked upon as thus established. + +"At our next lesson we shall take a rapid review of the effects and laws +of heat." + + + + +CHAPTER IV. + +HEAT A GIFT OF GOD. + + +The class is again promptly in place and ready for work. + +"As I announced a week ago," said Mr. Wilton, "we will to-day take a rapid +review of the effects and laws of heat. Will you tell us, Peter, the first +and chief of these effects?" + +"Yes, sir: combustion." + +"What is combustion?" + +"Commonly the rapid union of oxygen with some combustible substance, +attended with the evolution of heat." + +"Was your answer correct, then?" + +"No, sir," said Peter, blushing; "I spoke before I thought." + +"Will you correct your answer?" + +"The first and chief effect of heat is expansion." + +"That is right. Our sensation of heat is of course only a +_sensation_--merely the _feeling_ which results from the effects of heat +upon our nerves--but the chief physical effect of heat is the expansion of +bodies. The chemical qualities of bodies are not changed: they are not +made either heavier or lighter. A sufficiently high temperature renders +bodies luminous, and then we call them red hot or white hot. Solid bodies +begin to be luminous at a temperature of about one thousand degrees. But +the one invariable effect of heat, with two or three apparent exceptions, +is expansion. You may mention, Samuel, some familiar illustrations of the +effect of heat in expanding bodies." + +"The blacksmith heats the wagon-tire in order that it may easily slip over +the wheel. If a kettle be filled with cold water, by heating it the water +is expanded and runs over. I have noticed that the spaces between the ends +of the successive iron rails upon the railroad are larger in winter than +in summer, showing that the rails are shorter in winter than in summer. +While skating during the cold winter evenings upon the mill-pond, I have +seen cracks in the thick ice start and run across the mill-pond with a +roar almost like thunder. The ice was contracted by the cold till it +could no longer fill the whole space between the banks, and being frozen +fast to the banks, it was torn asunder. The mercury in the tube of a +thermometer is constantly expanding or contracting by every change of +temperature." + +"Yes, those are all good illustrations, and we might go on to mention +others equally good by the score. In cold countries, during the intense +cold of winter, the surface of the earth cracks by shrinkage, just as you +have seen the ice upon the mill-pond torn in two. The Britannia iron +tubular bridge over the St. Lawrence at Montreal rises and falls two and +one-half inches on account of greater expansion of the upper surface when +exposed to the heat of the sun, while a loaded freight train causes a +depression of but one-fourth of an inch. A few years since, in order to +make some philosophical experiments connected with the rotation of the +earth upon its axis, a ball was suspended by a wire in the interior of +Bunker Hill monument. By this means it was accidentally discovered that +the heat of the sun, expanding the sides of the monument exposed to its +rays, caused the whole monument to sway back and forth daily." + +Here Ansel raised his hand. + +"What is it, Ansel?" + +"I was going to mention the belief of geologists that the mountain ranges +were thrown up by the contracting of the earth's crust on account of +cooling." + +"That is an illustration of contraction by loss of heat on an enormous +scale. The materials which form our globe may have existed in the +beginning in a nebulous or gaseous state. There is certainly very good +reason for believing that the earth was once in a fluid state, the whole +of its substance molten by intense heat. It is certain that the interior +is now hot, and portions of it molten. It is by very many believed that +the whole interior is molten. The crust of the earth may have been formed +by cooling. If after an outer crust had been formed, and its temperature +had fallen so low as to become nearly stationary, the interior mass +continued to cool, the molten mass would tend to sink away from the crust +and the crust would sink in upon it by wrinkling. Thus mountains may have +been formed. Along the line of fracture the easiest vents would be formed +for volcanoes. But this carries us somewhat aside from our subject, and +as the expansion of bodies by heat has been sufficiently illustrated, we +will leave it. Will some one now state the manner in which the dynamic +theory of heat explains this expansion?" + +Samuel answered: "I think you have already given us the explanation." + +"I have briefly referred to it, but you may give it again." + +"The atomic motion which is supposed to constitute what we call heat, +whatever that motion be, whether a vibration or rotation or revolution, +requires that the atoms of bodies shall not be packed in absolute contact, +and the more intense the agitation or the wider the swing of the vibration +or revolution, the greater must be their separation. Hence heat expands +bodies by thrusting their atoms farther apart." + +"That will do," said Mr. Wilton. "Let us look now at some of the secondary +effects of heat. You may mention some of them, Ansel." + +"Heat relaxes or overpowers the cohesive attraction of bodies." + +"What is cohesive attraction?" + +"It is that force which binds together the atoms of matter in simple +substances, that is, bodies like iron or copper or silver, composed of but +one kind of substance, or in compound bodies it is the force which unites +the compound molecules of matter." + +"Give us now some illustrations of the effect of heat in overcoming +cohesive attraction." + +"The blacksmith heats his iron in order to overcome its cohesive +attraction and render it soft, that he may easily hammer it. The founder +heats his metal till its cohesion is so far destroyed that it becomes +fluid and can be poured into the mould. Heat relaxes the cohesive force of +ice and changes it to water, and by farther heating its cohesion is +entirely overcome and the water is changed to a gas." + +"We use heat also in cooking our food," spoke up Peter: "is it not because +heat destroys the cohesive attraction, and thus softens it?" + +"If that were the only effect of heat upon food," said Mr. Wilton, "we +should be obliged to eat our food hot, for as soon as it cooled the +cohesion would return and the food would be raw again. The operation of +heat in cooking is various, and part of the effect is commonly to be +ascribed to the water in which the food is cooked or to that which is +contained in it. By the combined agency of heat and water starch swells to +twenty or thirty times its original bulk and the minute starch grains +burst open. In cooking potatoes the starch of the potato absorbs a portion +of the water that is in it, and thus renders it dry and mealy. The action +of heat and water upon rice, wheat, and other grains is similar to their +operation upon starch. In the baking of bread the starch is converted into +gum. In boiling flesh the effect is partly due to the solvent powers of +water: the juices of the flesh are extracted, the gelatin is dissolved, +the fat is liquefied, and the cells in which the fatty matter is held more +or less burst, the albumen is solidified, and by long boiling the texture +and fibre of the flesh are destroyed. The albumen of an egg, that is, the +white, coagulates by heat. But in most of these processes the action of +heat cannot be separated from that of water. + +"But there is another effect of heat very important both in nature and in +the arts. What is that?" + +"The quickening of chemical affinity," answered Samuel. + +"That is right: heat is necessary for the operation of chemical affinity. +Perhaps this is only a weakening of the cohesive force, thus allowing the +chemical attractions to assert their strength. But the fact is that, while +in many cases the chemical affinities act with great energy at ordinary +temperatures, in other cases they slumber, however closely the substances +are brought into contact, till their temperature is raised. Samuel, you +may mention some illustrations of this principle." + +"A few months ago I visited Hazard's powder mills, in Enfield, +Connecticut, and there learned how gunpowder is made. The charcoal, the +sulphur, and the nitre are first finely pulverized, then ground together +for hours till thoroughly mixed, and afterward pressed together. This mass +is then broken into grains and the grains polished. But though these +elements are brought into so close contact, yet they do not combine and +explode till heat is applied. The same is true of the combustion of wood +and coal. The carbon and the hydrogen of the fuel are constantly +surrounded with the oxygen of the air, but they do not take fire and burn, +that is, they do not combine with the oxygen, till they are raised to a +red heat, or perhaps even to a higher temperature. If a stove filled with +burning coal be cooled down to a low temperature by applying ice, the +combustion will cease, the fire will go out. Our teacher at the academy on +one occasion heated a steel watch-spring red hot and plunged it into a jar +of oxygen, and the steel spring began quickly to burn with great fury." + +"You have given us good illustrations, Samuel, and that which is true of +carbon and hydrogen and oxygen is true of substances in general. The +effect of heat in producing chemical changes is very important everywhere. +It is seen not only in the chemist's laboratory and in the artisan's shop, +but also in the laboratory of Nature. Plant a grain of corn in midwinter: +why does it not germinate and grow? Nothing is needed but the requisite +heat to quicken the chemical affinities into action. Earth and air furnish +the needed material for the growth of forest trees in winter as well as in +summer, but the cold holds in check the chemical forces and prevents the +requisite chemical combinations. No sooner does the sun quicken that +atomic vibration or revolution which we call heat than vegetable growth +begins. Heat is necessary for those chemical changes by which food is +digested in the stomach and the processes of nutrition carried on in every +part of the body. If a man finish his dinner with ice cream or ice water, +the process of digestion is delayed till the contents of the stomach +recover their proper temperature. This is one chief reason why warm, +comfortable clothing is so very important, especially for children. All +the vital processes are chemical processes: they are carried on through +chemical affinities. Unless the body be kept at a suitable temperature, +these processes are feeble and imperfect, nutrition and vital combustion +are hindered, and diseases are engendered. + +"These, then, are the chief effects of heat. It expands bodies, weakens +cohesive attraction, and quickens the chemical affinities into activity." + +Ansel again raised his hand. + +"What do you wish?" + +"Will you please tell us, Mr. Wilton, how this weakening of cohesive +attraction is explained upon the dynamic theory of heat?" + +"I will do so with pleasure. The increased atomic motion in the heated +body throws the atoms farther apart, as we have already learned, and by +this increase of distance their attraction is diminished. If the earth +were twice its present distance from the sun, their attraction for each +other would be four times less than it now is; if its distance were three +times as great, their attraction for each other would be nine times less. +The attraction of gravitation diminishes in proportion as the square of +the distance through which it must act increases. Perhaps cohesive +attraction diminishes according to the same law, though the spaces are so +small that this cannot be demonstrated, but it is certainly weakened by +the expansion of bodies through the agency of heat." + +Here Peter raised his hand. + +"What will you say, Peter?" + +"Do not men heat and burn bricks, not to soften them, but to harden them?" + +"That is true," said Mr. Wilton; "but in this there is a process of drying +as well as of heating, and the hardening is due chiefly to the complete +drying by the intense heat. Too great heat will melt bricks while in the +process of burning. I once heard a brick-burner say that he could melt the +brick around the arches in his kiln in half an hour, if he pleased to put +in fuel and let the fire burn. Indeed, almost every known solid substance +has been fused by heat. Whether carbon has ever been melted is an +unsettled question." + +"I would like to inquire," said Samuel, "why water will not burn. Is it +because it evaporates before it reaches a sufficiently high temperature?" + +"This is a little aside from our subject, but the incombustibility of +water is a provision of the Creator so very important that we will stop to +notice it. I think, however, that by a little thought you yourself can +answer the question. Tell me again what combustion is." + +"Combustion is commonly the combining of oxygen with some other substance +called a combustible. The rusting of iron and the decay of organic bodies +are forms of slow combustion." + +"Now tell us the composition of water." + +"Water is composed of oxygen and hydrogen--eight parts of oxygen to one of +hydrogen, by weight, or two parts of hydrogen to one of oxygen, by +measure." + +"How is water formed from these two gases? Are they mixed together as +oxygen and nitrogen are mingled in the air, or are they chemically +united?" + +"They are chemically united: they are burned together. When hydrogen +burns, the product is water." + +"Water is then a _product_ of _combustion_. Can you not now tell why water +is incombustible?" + +"I think I now see the reason. The oxygen, being itself the supporter of +combustion, will not burn, and the hydrogen has been already once burned +in the formation of water." + +"And that which is true of water is true, in a greater or less degree, of +other products of combustion. The burning of charcoal produces carbonic +acid, and carbonic acid will not burn because it is the production of +combustion. A candle is extinguished by it as quickly as by water. By a +recent invention carbonic acid is used to extinguish conflagrations. The +carbon has once united with oxygen, and a second combination with an +additional amount, or, as a chemist would say, with another equivalent, of +oxygen is much more difficult." + +"I think," said Samuel, "I now understand why water will not burn, but +will you please also to tell us why water puts out fire better than +almost anything else?" + +"In order to extinguish fire one of two things must be done: either the +supply of oxygen must be cut off or the combustible must be cooled down to +a temperature below the burning point, when the combustion will cease of +itself. When we shut the draught of an air-tight stove, we check the +combustion by shutting off the full supply of oxygen. If we could wholly +prevent the access of oxygen to the fuel, the fire would at once be +extinguished. If oxygen should then be admitted again before the fuel had +cooled down below the burning point, combustion would at once begin again. +A blazing brand is extinguished by being thrust into ashes, because it is +shut away from oxygen. In the same way we extinguish the flame of a candle +with a tin extinguisher. On the other hand, fires often go out because the +necessary temperature is not maintained. Water puts out fire in both these +ways, but especially by the second. Water poured in torrents from a fire +engine upon a fire forms a film of water, and the burning material shuts +out the oxygen. But the water acts chiefly by lowering the temperature. +No other known substance except hydrogen gas requires so much heat to +raise it through a given number of degrees of temperature as water. As +much heat is required to heat one pound of water as thirty pounds of +mercury. Hence, water poured upon burning timber cools it to so low a +temperature that it ceases to burn. + +"In addition to this, we may notice that wood saturated with water cannot +be heated above the boiling point of water till the water is evaporated. +As fast as the wood and the water rise or tend to rise above two hundred +and twelve degrees, the water changes into steam and carries away the +additional heat. The consumption of heat in the formation of vapor we must +look at more carefully in a future lesson. We will suppose that a house is +in flames. A fire engine throws a stream of cold water into the midst of +the conflagration. The cold water, dashing against the burning wood, cools +the heated surface; it is absorbed into the pores of the wood and hinders +its rapid heating; a portion of the water, being changed into steam, +carries off the heat; the steam, mingling with the flame, lowers the +temperature of the burning gas, and in proportion as steam fills the +surrounding space oxygen is driven away. A burning coal mine in England +was once extinguished by forcing steam into it, thus driving out the air +which supported the combustion and cooling down the burning coal. + +"The advantages which men receive from these agencies of heat are so +manifest that we cannot help noticing them. I do not refer to the comfort +of a pleasant temperature, nor the impossibility of living in a +temperature extremely low, but to all those processes by which man subdues +nature, provides for himself food, clothing, and dwelling-places, and +builds up civilization. Heat is that force which enables man to accomplish +his ends. Heat brings the iron from the native ore, and heat renders it +malleable and plastic to be shaped for man's uses. Heat quickens the +chemical affinities and renders the arts of civilized life a possibility. +Heat brings together oxygen and carbon in ten thousand furnaces, and the +heat engendered by the combustion, changed to force, drives the ponderous +or nimble machinery which carries on the work of the world. Heat quickens +the chemical affinities and causes the wheat to grow; heat prepares the +wheat for man's food; and by the aid of heat that food is changed in +man's body, nutrition goes on, the body is built up, waste matter is +removed, and all the vital processes are supported. Without these agencies +of heat--softening and subduing stubborn matter on the one side, and +quickening its forces on the other--man could not exist. + +"Let me remind you that these agencies of heat are of God's devising. If +the operations of heat are beneficent to man, it is because God wished to +bless his creatures. I am not much given to moralizing, but when I see how +completely these simple effects of heat meet man's wants, I cannot help +remembering and admiring the wisdom of the great Designer. It is _God_ and +not blind, unconscious Nature that is working." + +"This reminds me," said Samuel, "of the tradition in Greek mythology that +Prometheus stole fire from Jupiter and brought it down to man in a reed as +a precious treasure. It seems to me like a gift from heaven." + +"This mythological tradition has, however, one falsehood: there was no +need that men should steal fire from the gods; God freely gave it. Heat is +indeed a gift from heaven." + + + + +CHAPTER V. + +CONVEYANCE AND VARIETIES OF HEAT. + + +"To-day we review the modes in which heat passes or is conveyed from place +to place. It is evident that if heat were confined to the very place or +point where it is generated, it could subserve none of those uses to which +it is now applied in the economy of Nature or in the works and arts of +man. But heat passes from place to place with great facility, and by one +method, with the speed of light, it tends to diffuse itself evenly through +all; it seeks an equilibrium. The modes of its diffusion, or conveyance, +are three in number. Ansel may name them." + +"Heat passes from place to place and from body to body by 'conduction,' by +'radiation,' and by 'convection.'" + +"What is meant, Ansel, by the 'conduction' of heat?" + +"The passing of heat from atom to atom and from particle to particle +through a body is called conduction." + +"That is right. I will call upon Peter to give some illustrations of the +conduction of heat." + +"The examples are so many," Peter answered, "that I hardly know what to +mention first. If I hold a pin in the flame of a lamp, the part of the pin +that touches the flame is first heated, but soon the heat runs along the +whole length of the pin and burns my fingers. The parts of a stove which +touch the fire are first heated, and from them the heat spreads through +the whole stove. A pine-wood shaving, kindled at one end, is heated by +conduction, but the heat passes through it very little faster than the +flame follows. Heat escapes from our bodies by being slowly conducted +through our clothing. There is no end to the examples of conduction which +one might give." + +"We must not think of the conduction of heat," said Mr. Wilton, "as if it +were a fluid slowly absorbed by a porous body, as water poured upon the +ground soaks into it, or as water percolates through a lump of sugar and +moistens the whole of it. We must remember that the transfer of heat is +not a transfer of any substance, but a transfer of motion. One atom is set +in motion, and strikes against another atom and sets that in motion, and +thus motion is communicated from atom to atom and from molecule to +molecule through the whole mass of matter till every atom is agitated with +the heat vibrations. Do all bodies conduct heat with equal rapidity?" + +"No, sir," replied Ansel; "there is the greatest possible difference. Some +substances are called good conductors, because heat permeates them so +readily and rapidly; others conduct heat very slowly, and are called poor +conductors or bad conductors." + +"That is right. Every child soon learns by experience to make a practical +distinction of this kind. He very soon understands that he can hold a +stick of wood without burning his hand, even though it be blazing at the +other end, but that when a piece of iron is red hot at one end he must not +take hold of it at the other. The child very soon learns to know the +different feeling of a cotton night-gown from one of flannel, and the +difference in apparent warmth between a linen pillow-case and a woolen +blanket. After a room has been heated for a considerable time the various +objects in it all become of the same temperature, and the same is true in +a cold room; but how great the difference in the sensations produced by +touching the oil-cloth and a woolen carpet in a cold room! Good conductors +of heat, if hot, feel very hot; or if cold, feel very cold; while poor +conductors make a much less decided impression. Why is this, Samuel?" + +"The good conductors receive heat or part with it very readily. If the +good conductor be hotter than our bodies, it imparts its heat rapidly to +our hand, and because we receive heat rapidly from it, it feels to us very +hot. Or if it be colder than our bodies, it takes heat from our hands very +rapidly, and gives the impression of being very cold. Poor conductors +impart heat to the skin or take it away more slowly, and hence feel as if +their temperature were more nearly like that of the body." + +"The conducting qualities of bodies," said Mr. Wilton, "seem to depend +chiefly upon their structure or the arrangement of their atoms. Bodies +which are compact and solid in their structure convey heat more rapidly +than those which are loose and porous. Hence solids are better conductors +than fluids, and fluids are better conductors than gases, and among solids +the metals are better conductors than organized bodies, like wood or +flesh, and better than the loose and porous minerals. In bodies of loose, +porous, or fibrous texture, the continuity of the conductory substance is +constantly broken. The particles in a mass of sawdust touch only at a few +points, leaving frequent spaces. In woolen and cotton fabrics the points +of junction of the fibres are very few, comparatively. For this reason the +motion is not readily communicated from atom to atom. + +"The crystalline arrangement of atoms has an influence upon conduction of +heat. Heat is conducted more rapidly in a direction parallel with the axis +of crystallization than across that axis. Wood conducts heat more rapidly +in the direction of the grain. This arrangement seems to be well adapted +for keeping trees warm in winter. Their roots reach down into the earth, +which remains warm in the coldest weather. This heat of the earth travels +along the fibres up through the tree, while the heat conducted across the +fibres escapes much more slowly into the open air. The bark also, being a +very bad conductor, hinders the escape of heat. Of metals, silver is the +best conductor. I will give you a brief table which will show the great +difference in the conducting qualities of some of the metals. Counting the +conducting qualities of silver as 100, the table is: 'Silver, 100; Gold, +53; Copper, 74; Iron, 12; Platinum, 8; German Silver, 6; Bismuth, +2.'--_Youmans._ + +"What is the second method by which heat passes from place to place?" + +"It is radiated," replied Ansel. + +"And what is radiation?" + +"It is motion in straight lines or rays diverging from a centre. From a +hot body heat is passing off in straight lines in every direction. As a +lamp radiates light, so does a hot body radiate heat." + +"Radiant heat," said Mr. Wilton, "moves with the same velocity as light, +that is, one hundred and ninety-two thousand miles per second. It also +follows the same general principles as light in all its motions. It is +absorbed, reflected, or transmitted in the same manner as light. And this +is true of either luminous heat--that is, heat radiated from a body which +is red hot--or obscure, or dark heat. + +"As there are good and poor conductors, so there are good and bad +radiators of heat. The radiation of heat depends upon three conditions: + +"1. Upon the temperature of the body. The higher the temperature, the more +rapid and energetic is its radiation. + +"2. Upon the surface of the radiating body. A dull, rough surface radiates +heat more rapidly than a surface bright and polished. + +"3. Upon the substance of the radiating surface. With surfaces equally +smooth and bright, some substances radiate heat much better than others. A +surface of varnish radiates heat much more powerfully than a surface of +gold or silver. + +"Ansel, you may, if you can, explain the radiation of heat." + +"I can give no other explanation than that radiation is conduction through +that subtle ether which is supposed to pervade all space." + +"Very well; perhaps that is as good an explanation as can be given. But it +seems rather like the propagation of an impulse than the spreading of +atomic vibrations in every direction. The motion is propagated in +straight lines. If it be conduction, it must be carried on by different +vibrations from those of ponderable substances. Heat, light, and +electricity are supposed to be all propagated through the same theoretical +ether. Sir Isaac Newton estimated the density of the ether as seventy +thousand times less than the density of our atmosphere, and its elasticity +in proportion to its density as four hundred and ninety millions times +greater. But the very existence of this universally-diffused ether is a +supposition made to account for the phenomena of light, heat, and +electricity; and, of course, all its qualities must be theoretical also. +Radiation is believed to be the propagation of a motion or impulse through +an inconceivably rare and elastic ether. + +"Peter, what is the third method by which heat passes from place to +place?" + +"Convection," was his reply. + +"What is meant by convection of heat?" + +"The conveyance of heat by carrying a heated body. If I remove a hot iron +or a kettle of hot water, I must of course carry the heat which it +contains." + +"A very good illustration of the convection of heat," said Mr. Wilton, +"is seen in the common method of heating water. The heat is applied at the +bottom of the vessel containing the water; as fast as the water at the +bottom next the fire is heated, it rises and carries the heat to the top; +cold water comes to take its place, and this in turn is heated and rises +and carries heat to the top. This process is carried on till all the water +comes to the same temperature. Thus water is heated by convection of heat. + +"A grander illustration is seen in winds and ocean currents. Warm winds +carry heat enough to warm a continent, and the mighty ocean currents are +still more efficient in transferring heat from one part of the earth to +another. + +"Another point we need to understand. When radiant heat falls upon a body, +what becomes of it?" + +"It is disposed of," answered Samuel, "in one of three ways: it may be +reflected according to the same principles by which light is reflected; or +it may be transmitted, that is, pass through the body; or it may be +absorbed, that is, stop in it." + +"Very well stated, Samuel. In regard to reflection I need to say very +little. You know how light is reflected from a polished surface, such as +a lamp reflector: heat is reflected in the same manner. One fact you must +bear in mind touching reflected heat: it does not heat the reflecting +body. + +"There is no need of telling you that light passes through certain +substances. It passes through gases and through some liquids and some +solids. The best of glass, though it is so solid, interposes very little +hindrance to the passage of light. Heat in like manner radiates through +certain solids. Luminous heat is radiated through glass. Rock-salt +transmits dark heat also. A plate of alum permits light to pass, but stops +both luminous heat and dark heat. Remember that transmitted heat, as was +said of reflected heat, does not heat the body through which it passes. I +have seen boys make burning-glasses of ice. The heat passes through them +and burns that upon which it is concentrated, while the ice itself through +which the heat passes is not melted. + +"If a body have a good radiating surface, that is, if its surface be dull +and rough, the heat which falls upon it will be mostly absorbed. The +reflecting and absorbing qualities hold an inverse ratio to each other; +the better the reflecting qualities, the worse the absorbing, and the +worse the reflecting, the better the absorbing. Heat which is absorbed by +a body commonly raises its temperature, and remains in the body till it is +slowly radiated or is conducted away by the air or other bodies which come +in contact with it. + +"What is that heat called, Ansel, which is absorbed by a body with no rise +of temperature?" + +"It is called _latent_ heat." + +"That is the old and common expression, but what is meant by latent heat?" + +"The word _latent_ signifies _lying hidden_ or _concealed_. Latent heat, +as you suggested in your first question, is that heat which a body +receives without showing it by a change of temperature." + +"That name 'latent heat,'" said Mr. Wilton, "expresses the opinion of +those who invented it; they supposed that heat was in some manner hidden +in certain bodies. We must not suppose, however, that this latent heat +continues to exist in bodies as heat; latent heat is that heat which is +converted into force or some other motion than the atomic heat vibrations, +and is employed otherwise than in raising the temperature. You will +understand this best by an illustration. + +"Take one hundred pounds of ice at the temperature of thirty-two degrees, +that is, as warm as is possible without melting. That one hundred pounds +of ice will absorb heat which would raise one hundred pounds of ice water +through one hundred and forty degrees, and by receiving that heat it is +melted, but the water produced has the temperature of thirty-two degrees. +It has received one hundred and forty degrees of heat, but its temperature +is not raised a single degree. This one hundred and forty degrees of heat +has been transmuted into force and employed in overcoming the crystalline +attraction of the atoms of water. + +"Let that ice water at thirty-two degrees of temperature receive one +hundred and eighty degrees of heat, and the water rises to two hundred and +twelve degrees, the temperature of boiling. But whatever additional heat +is absorbed brings no increase of temperature, but transforms the water +into steam. It is employed in overcoming the cohesive attraction of the +molecules of water and changing the liquid to a gas. About one thousand +degrees of heat is thus expended, but the steam which is produced has +only the temperature of two hundred and twelve degrees. If the process be +reversed, the steam gives up, as it is said, the one thousand degrees of +heat in returning to the condition of water and the one hundred and forty +degrees in resuming the crystalline structure of ice. The heat which was +employed as force in overcoming the atomic and molecular attractions is +transmuted again to heat, and shows itself in raising the temperature. And +that which is true of water is true of any other substance in changing its +form from a solid to a liquid or from a liquid to a gas, or the opposite. +In an amount different for each kind of matter, in all these changes of +condition, heat is transmuted to force or force to heat. + +"These transmutations are going on ceaselessly in the operations of +Nature, and without understanding them we cannot appreciate the wonderful +operations of heat in the world. The heat of the sun beams upon the ocean; +the greater part of that heat is expended as force in overcoming the +molecular attraction of water, thus converting it to vapor, and in raising +that vapor to the higher regions of the atmosphere. This heat-force, or, +as we might call it, 'sunpower,' expended upon the earth, amounts to +thousands of millions of horse-power daily. + + +[Illustration: TRANSMUTATION of HEAT. + +Page 113.] + + +"Examples of the transmutation of force into heat abound everywhere. A boy +strikes his heel upon the stone pavement; from the point of contact +between the stone and the steel points in his boot heel sparks of fire fly +out. Force is changed to heat so intense that particles of steel are set +on fire. Savages who have no better methods of kindling fire rub dry wood +together till the sticks ignite. The force expended in overcoming the +friction is changed to heat. In the combustion of coal beneath the steam +boiler we see both processes going on. The atoms of carbon dash against +the atoms of oxygen, and the force of the collision generates the heat of +the combustion. This heat, born thus of force, is again transmuted to +force, and drives the engine and the machinery attached. In our study of +God's management of heat we shall constantly meet with these changes. You +will need, therefore, to study carefully this subject of latent heat. + +"Dr. Joule, of Manchester, England, has discovered the ratio between heat +and force, that is, the amount of force which by transmutation produces +any given amount of heat. The force of a one-pound weight which has fallen +one foot is taken as the unit of force, and the amount of heat which is +required to raise one pound of water one degree is taken as the unit of +heat. By many and various careful experiments, Dr. Joule demonstrated that +772 units of force are the equivalent of one unit of heat. A pound weight +falling 772 feet, or 772 pounds falling one foot, and then arrested, +produces heat sufficient to raise one pound of water one degree. The +result is the same whatever the method by which the force is expended. If +water be agitated or shaken, if sticks of wood or iron plates be rubbed +together, if an anvil be struck with a hammer, or if a bar of iron or +copper be moved back and forth between the poles of an electromagnet, the +force expended is changed to heat. You must remember, however, that force +becomes heat only so far as the force is actually expended, or used up so +that it no longer exists as force. + +"These conclusions are supported by other beautiful experiments. 'An +electric current which, by resistance in passing through an imperfect +conductor, produces heat sufficient to raise one pound of water one +degree, sets free an amount of hydrogen which, when burned, raises exactly +one pound of water one degree. Again, the same amount of electricity will +produce an attractive magnetic force by which a weight of 772 pounds may +be raised one foot high.'--_Youmans._ We conclude from experiments like +these that heat, mechanical force, and electricity are interchangeable +forces; they may be transmuted the one into another. + +"By this principle of the transmutation of heat and mechanical force we +explain the production of heat by compression and the loss of heat by +expansion. Samuel, you may state the fact upon this point." + +"If any substance be suddenly compressed," answered Samuel, "heat appears; +if it be expanded, cold is produced. Since gases expand or yield to +pressure so readily, they furnish the best illustration of this +principle." + +"The suddenness of the compression or expansion," said Mr. Wilton, "is a +matter of no consequence. The effect is the same whether the operation be +sudden or slow, but if the compression or expansion be slow, the heat or +cold generated is less apparent; the heat is dissipated as fast as +produced and the colder gas is warmed by the vessel which contains it. +Ansel, how shall we explain this?" + +"I cannot explain it, sir." + +"The explanation is very simple," said Mr. Wilton. "Mechanical force is +employed in the compression of the gas; the force is expended and used up +upon the gas, and appears again in the form of atomic heat motion. In the +expansion of gases the operation is just the reverse; the atomic heat +motion is expended in producing expansion, and hence disappears as heat. +The general principle is that no force can be expended in two ways at the +same time. + +"One other point we must notice to-day, that is, _specific heat_. What is +understood, Ansel, by this term, specific heat?" + +"The relative amount of heat which different substances require to raise +their temperature through any given number of degrees." + +"That is right. I think that you all must have noticed that it requires +much more heat to raise the temperature of some bodies than others. What +an amount of heat is required to raise the temperature of water! That heat +which will raise one pound of water one degree will cause an equal +increase of temperature in five pounds of sulphur, or four pounds of air, +or nine pounds of iron, or eleven pounds of copper, or thirty pounds of +mercury, lead, or gold. This is what is meant by saying that one substance +has a greater capacity for heat than another. The specific heat of water +is greater than that of any other known substance except hydrogen gas. +This fact, taken in connection with its great specific latent heat and its +poor conducting qualities, renders it exceedingly important in regulating +climate and moderating extremes of temperature; of this you will be +reminded very often as our lessons go on. + +"No law or principle determining the specific heat of the various elements +and explaining the different capacities for heat has as yet been +discovered. It has been suggested that specific heat depends upon the +number of atoms, that it holds an inverse ratio to their combining +numbers, or, what is the same thing, a direct ratio to the number of +atoms. This would harmonize well with the dynamic theory of heat, but the +harmony between the specific heat of substances and the number of atoms is +not sufficiently uniform to establish this supposition. + +"This completes our review of first principles. I hope that this not very +entertaining review of your academic studies has not wearied you of the +very word _heat_ and worn out your interest in examining God's management +of heat before making a beginning." + +"I think," said Samuel, "that we are not in the habit of becoming +disgusted with our studies." + +"You may expect," continued Mr. Wilton, "if the past has been interesting +to you, that the lessons to come will prove more interesting still. Next +week we shall consider the abundant provision which the Creator has made +for warming the earth." + +And let me say to you, patient reader, that if I had known that you were +as familiar with the laws and principles of heat as Ansel, Peter, and +Samuel seem to have been, this and the preceeding chapter would not have +been written. However dull this review may have seemed to you, it was +needful, perhaps, for others, that they might understand the wonderful +works of God which we shall now proceed to examine. And, reader, do not +forget that heat itself, that subtle motion and mighty force, with all its +laws and principles, is one of God's works. Already have we been looking +at the Creator's handiwork. Already have we been trying to trace out the +thoughts of God as they are written in the "Bible of Nature." The thoughts +of God are great and wonderful. It has been useful and interesting to read +thus far in this book written with the finger of the Creator of worlds and +of man, even if we turn not another page. + + + + +CHAPTER VI. + +MANAGEMENT AND SOURCES OF HEAT. + + +While the lessons which have been reported were going on, the religious +interest in the church was deepening. Mr. Wilton did not cease to make his +sermons instructive, but, in addition to the instruction, he made them +more and more pungent and persuasive. He aimed to gather up the +impressions and convictions already wrought in the minds of his hearers +and combine them for united and immediate effect. He believed that this +was to be a reaping-time. + +Mr. Hume was becoming interested, not because he had been at church, for +he had not been there, but the Holy Spirit of God was working upon his +heart. He was becoming uneasy in his unbelief. For some reason, he knew +not why, his opinions were becoming more and more unsettled. He did not +like to go to the house of God; his self-will and pride of consistency +rebelled against the thought of hearing and believing the gospel; but he +was restless and discontented away from the place of worship. His +associations with his infidel comrades grew distasteful. His Sundays were +days of distress: with his attention relieved from business cares, +thoughts of God and eternity pressed upon him, and he could not escape +them. At length he determined to go and hear Mr. Wilton again: perhaps he +should hear something which he could so positively reject as to set his +mind at rest. He went, accordingly, the next Lord's Day, and heard a very +impressive sermon. + +The text for the forenoon was Ps. lxvi. 5: "Come and see the works of God: +he is terrible in his doing toward the children of men." The sermon gave +first a brief and rapid review of some striking displays of God's +displeasure at the sins of men: that ancient world of men whose "thoughts +were only evil continually" he overwhelmed with the flood; he burned with +fire from heaven Sodom and Gomorrah, Zeboim and Admah, those lascivious +and festering cities of the plain; he sent his torturing and consuming +plagues upon the Egyptians, and sunk the army of Pharoah like a stone in +the deep waters of the Red Sea: "they sank as lead in the mighty waters;" +he caused the earth to open and receive Korah and his adherents, and bade +his angel in "one night" to touch with death the thousands of +Sennacherib's army. This record of divine wrath against evil-doers has +startled the consciences of wicked men, and will continue to startle them +so long as the ungodly live upon the earth. It is easy for unbelievers to +call the word of God a record of fabulous wonders, but that record lives +and will live, and its words assert their divinity by touching and burning +the consciences of men as if they were tongues of fire. + +"But to the thoughtful man," said Mr. Wilton, "there is a manifestation of +God's displeasure at sin even more impressive than these miraculous +judgments. The Creator has built his wrath against sin into the very +fabric of the universe; he has written it upon the very atoms and elements +of matter and of mind, and graved it upon the 'nature of things.' The +forces of Nature are all instinct with holy wrath against ungodliness. +Evil doing works out evil consequences by the regular course of nature. +Babylon, Nineveh, and Tyre were great and prosperous, and as mighty in +wickedness as in commerce and war. In the height of their prosperity God +denounced upon them disaster and desolation, and by the natural processes +of evil their decay and destruction came upon them. No miracle broke the +harmony of their mighty march to decay and the silence of death. Great +nations have perished, but not till they became corrupt. Rome fell, but +luxury first gendered luxuriant vices, and vices enervated her hardihood +and undermined the defences of her courage. No righteous nation ever +perished. No nation ever fell into decay till ripe in sin and ready for +moral putrefaction. But against wicked and corrupt nations wars and +desolations are determined, and the end thereof is with a flood. The very +forces of Nature seem allied in firm compact with the laws of God, ready +with resistless hand to avenge their transgression and to visit evil upon +evil-doers. This steady march of all the forces of the world in bringing +decay and wretchedness upon sinners is more impressive than any single +desultory example of avenging wrath. + +"But perhaps an unbeliever replies, 'Not so; there is a natural law of +development, decay, and death, apart from sin. Trees grow up, become old, +and die. Men pass from childhood up to manhood, and from manhood down to +second childhood, and return to the dust whence they came. By a like +principle, nations pass through similar changes of development, decay, and +desolation. But in all this there is no manifestation of divine favor or +disfavor.' + +"This is narrow and false reasoning. If a single great city had become +corrupt while all the world beside remained righteous, and God had +denounced his displeasure upon it and had executed his wrath by sudden and +tremendous judgment, that one city standing out in single and solitary +ungodliness and desolation, who would deny, who could deny, that the fate +of that unhappy city was a manifestation of divine displeasure? If a +second example were made of a second ungodly city, would the expression of +divine wrath be weakened? Nay; every man would say that it is made +stronger. What if a third example be made of a third city? What if every +wicked city is made an example? What if God embody his displeasure at +evil-doing in the structure of the world, and give to the very atoms of +matter and the elements of mind such natures that by the working of their +own proper forces, without a miracle, they shall bring pain and evil, +decay and death, upon the ungodly? What is this but writing his wrath +against sin upon the earth and sky, upon matter and the consciences of +men, declaring by this that till the heavens and the earth and the spirits +of men be no more he will never withdraw his indignation? This is what God +has done. The wicked man sets in motion the machinery which works out his +own everlasting undoing. His own hand sows the seeds of death, and as +those seeds germinate they strike their roots into his corruptions and +draw their nourishment from his evil life. Thus do sinners go on +'treasuring up wrath against the day of wrath and revelation of the +righteous judgments of God.' + +"But remember that God has not left the world in these later ages without +the testimony of wrathful judgments which ought to startle and alarm the +consciences of the wicked like the fires of Sodom. Let me give you what I +suppose to be a true record of the fate which befell a band of bold +blasphemers. In that uprising of infidelity which took place near the +close of the last century there was formed at Newburg, N. Y., through the +influence of a man known as 'Blind Palmer,' an association of infidels +under the name of the Druidical Society. The object of the society was to +uproot and destroy revealed religion. In pursuit of this object they +descended to the most blasphemous mockery. At one of their meetings they +burned the Bible, baptized a cat, partook of the bread and wine as +appointed for the ordinance of the Lord's Supper, and gave the elements to +a dog. Then the wrath of God broke out upon them. 'On the evening of that +very day he who had administered the mock sacrament was attacked with a +violent inflammatory disease; his inflamed eyeballs were protruded from +their sockets; his tongue was swollen, and he died before morning in great +bodily and mental agony. Dr. H----, another of the same party, was found +dead in his bed the next morning. D---- D----, a printer who was present, +three days after fell in a fit, and died immediately. In a few days three +others were drowned. Within five years from the time the Druidical +Society was organized all the thirty-six original members--actors in the +blasphemous ceremonies spoken of--died in some strange or unnatural +manner. Two were starved to death, seven were drowned, eight were shot, +five committed suicide, seven died on the gallows, one was frozen to +death, and three died, the record says, _accidentally_.' Be sure of this: +God has not left the world nor forgotten his judgments against his +enemies, neither is he tied up and hampered by the laws of Nature. 'God is +angry with the wicked every day. If he turn not, he will whet his sword: +he hath bent his bow and made it ready. He hath also prepared for him the +instruments of death.' + +"But remember, also, that God does not limit his expression of wrath to +these natural agencies. The smile of God beams direct upon the soul as the +warm rays of the sun fall upon the cold earth, and the frown of God throws +a shadow which darkens the soul with the gloom of eternal death." + +This discourse stirred the mind of Mr. Hume in a wonderful manner. The +story of God's judgments upon wicked men and dissolute cities he had read +many a time in his boyhood, but the rapid review of them by Mr. Wilton +seemed to bring them up with a lifelike vividness. And that view of the +forces of Nature, as allied with the moral laws of God to work out wrath +upon evil-doers, was new to him, but his own mind quick as thought +suggested many more illustrations than Mr. Wilton had time to give. He +remembered that all manner of vices--drunkenness, lust, devotion to gay, +sensual pleasures--bring ruin to men. He had noticed that the saddest +faces are those of worn-out lovers of pleasure, and he knew that lovers of +pleasure are very quickly worn out--that five years of sensuality will +waste the powers of life more than fifty years of good work. He knew also +that infidels and blasphemers, whatever else they might be, were unhappy +men, and died joyless, foreboding deaths. He was not exactly angry, but +his heart rebelled against thus being held by the mighty power of God, +willing or unwilling, and against the thought that even Nature herself had +conspired against him. It seemed to him hard that he was born into such a +world, and that there was no escape from it. He did not consider at the +moment that God and his works were against him only because he was +against God, and that by submitting to God in loving obedience all the +forces of God's world and God's providential government would turn in his +favor--"that all things work together for good to them that love God." + +At length better thoughts came to him. "I must know," he said to himself, +"whether these things are so. I have never examined the subject to +discover the truth, but have tried to find reasons for disbelieving the +Bible and denying the gospel. I ought to look at the other side. If Nature +and Nature's God have blessings in store for the willing and the obedient, +why should not I know this and receive my share?" + +Under the impulse of thoughts like these he formed the sudden resolution +to join Mr. Wilton's Bible class--that is, if he would receive him +willingly, of which he had no small doubt. Coming directly forward at the +proper time, he said to Mr. Wilton: + +"I have learned what your class is studying, and should like, I hardly +know why, to join your class for a few Sundays, if you are entirely +willing." + +Mr. Wilton, of course, did not know the exact state of Mr. Hume's mind; +he did not know but that he came with a contentious spirit to bring up +objections and propose hard questions; but he felt certain that, whatever +his state of mind, the Spirit of God was bringing him to take this step. +He had prayed for him; in prayer his soul had travailed in pain for him; +and he felt that by way of the throne of grace he had obtained a hold upon +Mr. Hume--that the Holy Spirit had bound a cord between them which could +not be broken. He believed, therefore, that, whether he came penitent or +angry, good would result from his coming. He gave him, therefore, a hearty +welcome. + +"I am not only willing," he said, "but very glad, to have you come; and as +I know that you have kept yourself informed of the latest phases of modern +science, I hope we shall have your help in unfolding the subject which we +are engaged in studying. I think you will be able to do us good." + +"Your kind welcome ought certainly to incline me to do anything which I +can to help the interest of your study, but I only ask the privilege of +sitting with your class as a silent listener." + +The Sunday-school opened as usual, and the classes entered upon their +work. + +"You have come in, Mr. Hume, at just the proper point in the progress of +our lessons," said Mr. Wilton. "We have been preparing the way by a brief +review of the laws of heat. We have gone over the effects of heat; the +conduction, radiation, and convection of heat; thermal reflection, +absorption, and transmission; specific and latent heat. We have tried to +form a conception of the existence and operations of heat according to the +dynamic theory that heat is a mode of atomic motion. This review would +have had little interest to you. We are now prepared to look at the +goodness and wisdom of God in the management of heat. We are not trying to +prove the existence of a Creator and Governor--we are only looking at the +mighty and wise works of that God in whom we already believe. We shall +find the works of God planned and wrought out with wondrous skill, and +that wonderful skill is employed in the interest of goodness. God has +planned and wrought for the benefit of his creatures. His wisdom and +goodness are exhibited on the grandest scale and in gigantic proportions. +This is all that is needed practically to demonstrate the existence of +God. A good conscience does the rest. Being once assured that there is a +Creator, a good conscience leaps to the conclusion that we ought to obey +and serve him. Nay, the very work and existence of a conscience implies a +divine Lawgiver and Ruler. To a good conscience a God is a necessity. But +as we are not now attempting to show that there is a God, but to study his +works, we will pass this point. + +"With respect to the subject before us, let us first notice that heat is a +necessity to the world and to man, and that God has made ample provision +for that need. What the condition of the world would be without heat we +can only conjecture. In the polar regions a natural temperature of seventy +degrees below zero has been observed. At this temperature all the water +upon the globe would turn to ice hard as adamant; all vegetation would +cease, and with the disappearance of vegetable life all animal life must +perish. The whole earth would be a frozen, lifeless, silent waste in the +midst of silent space. Some lines in Byron's picture of universal darkness +would fitly describe the state of the world: + + 'The waves are dead, the tides are in their grave, + The winds are withered in the stagnant air, + And the clouds are perished.' + +This description would be no figure, for motion as well as life depends +upon heat. Yet seventy degrees below zero is but the beginning of cold. +'By mixing liquid protoxide of nitrogen with bisulphate of carbon in a +vacuum, M. Natterer produced a temperature of two hundred and twenty +degrees below zero.' At this temperature some of the so-called permanent +gases--as carbonic acid, chlorine, and ammonia--can be compressed into +liquids, and it is believed that in the complete absence of all heat all +the gases would become solids. But by the agency of heat the world teems +with active life. Vegetation clothes the earth with a garment of beauty; +and earth, air, and sea swarm with living creatures full of enjoyment. +This great need of the world is bountifully supplied. The power and wisdom +of God are employed in producing happiness. + +"This, however, is but a part of the benefit which heat confers upon the +world. The chief inhabitant of the earth is man, and man was created for +something higher than bare existence. He was created for civilization and +culture. The savage state is not, as some self-styled philosophers dream, +the natural state of man. Nothing is so much against Nature. The natural +state is that condition in which he attains the fullest development. Let a +brute be placed in so unfavorable conditions that his growth is dwarfed +and his natural instincts are not called into exercise, and no one would +look upon that as a natural state. But man, wild, uncultured, undeveloped, +is spoken of as being in his natural state. There could be no greater +mistake. Culture and civilization are according to Nature, but culture and +civilization require that man should get the mastery of Nature and subdue +her forces. Till man gets the victory over the forces of this rough world, +he spends a precarious existence in a hard struggle to gain a meagre +support for his animal life. But when once science brings art, and the +mastery of Nature is gained, man can rise into culture and beauty. +Opportunity is given for development. He blossoms into greatness and +strength. Ideal and spiritual ends take the place of mere subsistence. + +"But by what agency does man achieve the mastery of Nature? By the agency +of heat. By the aid of heat man subdues the world. Heat brings the +lustrous metal from its native ore; heat fashions the metal into a +thousand shapes for the use of men; heat reigns as king in the curious +processes of the chemist's laboratory, and the laboratory is the mother of +all those modern arts which bless and beautify human life. By heat man +prepares his food; by heat he drives his machinery; by heat he outstrips +the flight of the winds; by heat he turns winter into summer and in his +own dwelling makes for himself a perpetual springtime. For these purposes +of human comfort and culture, God has provided generous stores of heat and +placed them under man's control. He has placed in man's hands the means by +which he can generate a heat which devours the hardest metals like stubble +and a cold greater by far than Nature ever produces. We see that the +Creator has provided for man as a being susceptible of culture and +development, as a being of soul and sentiment, of spirit and aspiration. +God has fitted the world to be the dwelling-place of spiritual beings like +man." + +"I beg your pardon," said Mr. Hume at this point, "that the first word I +speak in your class should be a question which amounts to an objection." + +"I shall be glad," said Mr. Wilton, "to hear your question, even though it +be an objection. I will also answer it if I can." + +"I wished to ask why it is, if God designed to provide for man's wants, +that man can supply his wants, especially his higher wants--the wants of +his intellectual and spiritual nature--only with the greatest difficulty +and toil? The brutes supply their need with comparative ease, but man with +boundless thought and labor." + +"Your question is an important one, and deserves an answer. For myself, I +look upon the fact to which you refer as one of the many points in which +this world is adapted to human needs. Man is put in a condition which +requires boundless thought and toil for the supply of his higher wants +just because he possesses a nobler nature and such thought and exertion +are needed for its development. Which is the more desirable condition for +a young man to be placed in--one in which his every wish is anticipated +and his every aspiration is gratified without exertion on his own part, or +one in which opportunity and means are furnished for self-help, one in +which he can supply his wants and satisfy his aspirations only by the +exercise of his best abilities? Which will encourage the larger manliness +and nurture the higher culture and strength? He who has no need for +exertion rises at best only to a soft and feeble luxury, without mental +vigor or moral force. What does man need besides scope and reward for +exertion? Effort and struggle are necessities of our nature. This is +especially true of man's higher faculties. Human greatness and goodness +are not created by a word: they must be developed by exertion. For this +reason God has made exertion necessary, and as much more necessary with +man than with the brutes as his culture is more the result of voluntary, +intelligent exertion. Does this explanation seem to you satisfactory, Mr. +Hume?" + +"I have no fault to find with it; I must think of it." + +"Very well, then; if no other one has a question to ask, we will look at +another subject. We will survey the storehouses of heat which God has +prepared for warming the earth. Samuel, you may name the first great +source of heat." + +"I think, sir, that the sun is the chief source of heat." + +"We certainly receive the larger part of our heat from the sun. No one can +doubt this. So much of our heat comes from the sun that the temperature of +the earth varies according to the sun's heat, as if that were the only +supply. If but a fleecy cloud pass between the sun and the earth, we feel +a decided change of temperature. A few hours less of sunshine each day, +and a few degrees more of inclination to the sun's rays, change summer to +winter and make the difference between the torrid and the frigid zones. +Withdraw the heat of the sun altogether, and the whole world would become +a desert of frozen death." + +"What is the cause of the sun's heat?" asked Peter. + +"You have asked a question which I cannot answer, and which no man can +answer. The most careful and patient observations have been made to +discover if possible the constitution of the sun; learned and curious +conjectures have been brought forward to explain the source of its heat; +but the positive results have not been very large. It is certain that the +sun is a globe revolving upon its axis in a period of twenty-five days, +nine hours, and thirty-six minutes. This is known by the motion of dark +spots upon its surface. The appearance of the sun as seen through a +telescope is that of a globe of fire, its surface often in a state of +violent agitation and flecked here and there with dark, irregular, +changeable spots. These spots are sometimes of enormous dimensions--thirty +thousand or fifty thousand miles in diameter. They present a dark centre +with a narrow border or penumbra of lighter shade. To account for these +spots, it has been conjectured that the body of the sun is dark, but +surrounded by a double envelope of clouds, the outer layer of which is +intensely luminous. Openings in such enveloping clouds would present an +appearance like the spots upon the sun. According to this supposition, the +heat and light of the sun proceed, not from the body of the sun, but from +this luminous enveloping cloud. But granting that this supposition is +true, it gives no explanation of the origin of the sun's heat. Laplace +conjectured that the sun is a globe of fire in a state of violent, +explosive conflagration, and that the spots are enormous crater-like +caverns in its surface. Newton conjectured that comets falling into the +sun and being consumed feed the solar fires and maintain its temperature. +The reception of the dynamic theory of heat has led to the revival, in a +modified form, of this conjecture of Newton. It is suggested that meteors +or meteoric matter falling into the sun generates its heat by the force of +concussion. To show that the intense heat of the sun might be thus +generated, elaborate calculations have been made. It has been demonstrated +that if the sun were a solid mass of anthracite coal, its combustion would +maintain its heat at its present rate of emission only five thousand +years, while the falling of the planet Jupiter into the sun would generate +an equal amount of heat for thirty-five thousand years. A lump of coal +falling from the earth to the sun would produce three thousand times more +heat by the concussion than by its combustion. + +"The nearest approach that has been made, of an exact and scientific kind, +toward determining the constitution of the sun's surface has resulted from +an examination of the _solar spectrum_. A ray of light, by passing through +a triangular prism of glass, is, as you know, divided into its elements, +or constituent colors. The ray of light is spread out like a half-open +fan. This divided and expanded ray, thrown upon a screen, is called the +spectrum. An examination of the solar spectrum by a microscope shows +certain fine dark lines across it. The lines are invariably the same in +their position and grouping. The spectrum of the stellar light is found to +differ from that of the solar light, and the light of one star differs +from that of another star. Light from incandescent metallic vapors gives +bright lines across the spectrum. Each metal has its own number, position, +grouping, and color of these spectral lines. By comparing the solar +spectrum with the spectra of the various metals--the processes are curious +and the explanation difficult to be understood--corresponding lines are +discovered, and the conclusion is reached that the sun's atmosphere +contains the vapors of several of our well-known metals, as iron, nickel, +sodium, potassium, and others. This is a most curious and marvelous +scientific feat, to make an approximate chemical analysis of the sun and +stars by means of their light. The conclusions, however, seem +trustworthy. + +"Can you tell us, Ansel, whether the earth receives heat from the moon and +stars?" + +"I cannot, sir." + +"I should be glad, Mr. Hume, to have you instruct us upon this point." + +"In regard to the fixed stars," answered Mr. Hume, "counting them as the +remote suns of other planetary systems, we must believe that they radiate +more or less heat upon the earth; some indeed have extravagantly +maintained that we receive from them nearly as much heat as from the sun. +The heat received from them is so small that we perceive no difference +whether they be hidden, or shine with their utmost brilliancy. I do not +know that investigations have been made to determine scientifically their +exact thermal influence upon the earth. But little more can be said about +the heat of the moon. The light of the full moon, concentrated by a +two-foot burning-glass and thrown upon the bulb of the most delicate +thermometer, produces no perceptible effect. By means of the electroscope +or galvanometer, it is said, however, that the moon's heat has been +detected. At a late scientific convention held in Chicago, Prof. Elias +Loomis read a paper, in which he stated that Mr. Harrison of England, by +a comparison of observations made for sixteen years at Greenwich, nine +years at Oxford, and sixteen years at Berlin, has discovered that the moon +exerts a sensible influence upon the temperature of the earth, the highest +temperature occurring from six to nine days after the new moon and the +lowest about four days after the full moon. The conclusion, the opposite +of what we should naturally expect--the higher temperature occurring when +the enlightened face of the moon is turned from the earth--was explained +by supposing the moon's heat to be dark heat which would be absorbed by +the vapors and the clouds, and thus tend to warm and dissipate them. By +the dispersion of the clouds, the radiation of heat from the earth's +surface would go on more rapidly and the temperature would fall. According +to this explanation, the lunar heat reduces instead of raising the +temperature of the earth. The difference of temperature due to the moon's +influence Mr. Harrison believed to be two and a half degrees. Upon +extending his calculations through forty-three years of observations made +at Greenwich, he found the difference reduced to about one degree. As for +myself, I confess myself still a skeptic touching the supposed influence +of the moon upon temperature." + +"Upon that subject, I think," said Mr. Wilton, "that we must wait +patiently for more light. The popular superstitions which refer sickness +and health, and every kind of good or evil fortune, to the benign or +malignant influence of the moon, we, of course, must reject. Samuel, will +you name the second chief source of heat?" + +"I am obliged to answer as Ansel answered just now--I cannot tell. The +enormous amount of wood and coal burned amounts to something, but this can +have very little effect upon the temperature of the earth." + +"The second great store of heat is the internal heat of the earth," said +Mr. Wilton. "The importance of this store of heat we can easily understand +by considering that the earth is a mass of molten mineral matter cooled +and hardened upon the surface. The crust upon which we live is warmed from +beneath by an ocean, or rather a globe, a world, of glowing molten rock. +Deep excavations have been made in mining operations, and artesian wells +have been bored to still greater depths--as deep as two thousand, three +thousand, or thirty-five hundred feet. The heat of the sun penetrates not +more than seventy-five or a hundred feet; below that depth the temperature +of the earth remains the same throughout the year. Below the point of +constant temperature the heat of the earth is found to increase regularly +and constantly. The rate of increase varies in different regions, but the +average rate is about one degree of temperature for each fifty or sixty +feet of descent. From this rate of increase it is easy to calculate the +temperature at any given depth. At a depth of less than two miles water +would boil. At twelve miles in depth the rock becomes incandescent. At +twenty-two miles silver melts, at twenty-four miles gold melts, and at +thirty-five miles cast iron becomes liquid. Volcanic eruptions also +demonstrate the existence of immense masses of molten rock in the interior +of the earth; and we can account for the existence of volcanoes only by +supposing that they now communicate or once communicated with the deep +interior heat of the earth. The thickness of the earth's crust is, +however, a matter of conjecture. The melting point of different substances +rises as the pressure upon them increases, and as the density of the rock +increases its conducting power becomes greater. The crust of the earth, +therefore, may be fifty miles in thickness, or it may be one hundred miles +or two hundred or three hundred miles. The effect of this internal heat in +maintaining the temperature of the earth must be very great." + +"I want to ask," said Peter, "how this internal heat came to exist, and +how it is maintained?" + +"This, like your former question, is altogether beyond our knowledge. All +that we certainly know is that God made it thus. The process of creation, +if indeed God did not create the earth by a word, without a process, is a +matter of sublimest and most venturesome conjecture. According to the +opinion of some, the elements of which the earth is composed were created +separate and uncombined, and were suffered afterward to unite by their +chemical affinities. This chemical combination would be nothing else than +a tremendous conflagration, and the result would be the most intense heat +of which we can form a conception. Others have dreamed of a 'fire-mist' +created of God and by some means condensed into worlds. The temperature of +the earth is maintained, so far as we know, only by the poor conducting +quality of the enveloping crust preventing its cooling. At the present +rate of radiation, millions of years would be required to render the +change of temperature perceptible. + +"What is the third great natural source of heat? I will ask Mr. Hume." + +"Mechanical action, or force transmuted to heat." + +"Will you please explain this?" + +"Strictly speaking," said Mr. Hume, "this is not to be counted an original +source of heat. But heat is used in the production of winds and waves, the +flow of rivers, and all the ceaseless activities of the world, and this +force reappears from time to time transmuted again to heat. Whenever in +the friction of air and of water, in the dashing of matter against matter +and force against force, motion and force seem to be lost, heat is +produced. The water of the sea after long storms is said to be sensibly +warmed. We can appreciate the amount of heat generated in this manner only +by considering in how many thousand ways force is meeting force and motion +is destroyed. All this lost motion--lost as sensible motion--reappears as +atomic motion, that is, as heat. Such heat has been applied to artificial +uses. Heat generated by the friction of iron plates ground together has +been used for heating buildings." + +"And this transmutation of living force and heat," added Mr. Wilton, "is +but one of many illustrations of God's economy in the management of heat. +Nothing is wasted. The voices of Nature all echo the words of Jesus: +'Gather up the fragments, that nothing be lost.' + +"The fourth source of heat is chemical action. What is the chief form of +this which is used for the production of heat? Samuel may tell us." + +"Combustion, I think, sir." + +"That is right; and the most common form of combustion is the combination +of carbon with oxygen. This is commonly employed, not because it generates +the most intense heat, but because carbon exists so abundantly, and is the +most available and the cheapest. The most common form of carbon is wood +and coal. This is that storehouse of heat which God has placed in man's +keeping. Without this the larger part of the earth's surface would be +uninhabitable. This renders culture and civilization possible. Without it +the arts could have no existence. The key of this storehouse of heat God +has given to man, so that he may enter in and use its treasures at his +pleasure. In the finer arts where very great heat is required, hydrogen is +used in place of carbon. Jets of oxygen and hydrogen gas thrown together +constitute what is called the oxy-hydrogen blowpipe, and generate the +intensest heat which can be produced by man. + +"Another source of heat not often mentioned is electrical force. This, +like mechanical force, may be transmuted into heat. An electric current +sent through an insufficient or poor conductor heats it, and, if the +current be sufficiently strong, consumes it. Thus lightning-rods are +sometimes melted and buildings set on fire. + +"These, then, are the natural reservoirs of heat: 1, the sun and other +heavenly bodies; 2, the internal heat of the earth; 3, living force, or +motion; 4, chemical action; 5, electric force. + +"We can hardly over-estimate the abundance of these natural supplies of +heat. The world is warmed on the most munificent scale. The earth receives +from the sun heat sufficient to boil three hundred cubic miles of ice +water per hour, and the whole sum of the sun's heat would boil +700,000,000,000 cubic miles of ice water in the same time, that is, the +heat radiated by the sun would boil a mass of ice water of the size of our +globe in twenty-five minutes. + +"The amount of carbon provided by the Creator is enormous beyond +conception. Vast regions of country are covered with dense forests, but +the fuel from the forests is but a handful in comparison with the fuel +stored up in coal-beds below the surface of the earth. Mr. Mitchel +estimated the extent of the coal-beds of a portion of Europe as follows: +Great Britain, 12,000 square miles; Spain, 3500; France, 1700; Belgium, +5180. Mr. R. C. Taylor has made a like estimate for North America, giving +to British America 18,000 and to the United States 134,000 square miles. + +"These estimates, you will notice, say nothing of Asia, Africa, South +America, or the islands of the sea, and include only the smaller part of +Europe. In the United States, also, new coal-fields are constantly +discovered. The supply of carbon for fuel seems exhaustless. In the +British islands about 100,000,000 tons of coal are mined annually. At this +rate the known supply would last for a thousand years. In the United +States the supply has no known limit. + +"You will keep in mind that this supply of heat is also a supply of +mechanical force. The coal-fields are an exhaustless storehouse of heat +and power. They warm the dwellings of man and drive millions of engines +working with the strength of Titans for human welfare. + +"In this bountiful supply of heat to warm the earth and serve human needs +must we not see a kind design on the part of the Creator? God has provided +that which the world needs. He has provided without stint or limit. The +general heating of the globe he accomplishes by his own power. He has +provided for human culture, development, and happiness by placing stores +of heat under man's control. He has furnished scope and means and +encouragement for achieving greatness and goodness. He has put man in the +condition which a wise father would desire for his son. + +"In our next lesson we will look at the preservation and distribution of +heat, some of the primary elements and arrangements upon which the +temperature of the earth depends." + + + + +CHAPTER VII. + +PRESERVATION AND DISTRIBUTION OF HEAT. + + +Another Lord's Day comes, and the members of the class are, as usual, all +in their places. They find the subject increasing in interest after +leaving the review of the laws and principles of heat. + +"A week ago," said Mr. Wilton, "we looked at the chief sources of heat. +These are the sun, the internal heat of the earth, chemical action, in +which combustion is most important, electrical action, and mechanical +action, or 'living force.' The amount of heat furnished from these sources +is above all comprehension. The Creator seems bountiful even to +prodigality in supplying heat for the needs of the world and the uses of +man. But with all this largeness of supply the provision would prove +wholly inadequate if it were not prudently husbanded and all the avenues +of waste carefully closed. Men of ample incomes sometimes come to want +from too free expenditure. Their incomes are large, but their expenses are +larger. So it would prove in respect to heat if Nature were not as prudent +in saving as she is bountiful in providing. Will some one mention some of +the general methods by which the waste of heat is prevented?" + +No one answered. Mr. Hume did not think it best to put himself forward in +answering questions, and therefore answered only when personally +addressed. The others were silent because they had nothing to say. + +"I see that I shall have to suggest the answer. Ansel, what part of the +atmosphere is warmest?" + +"The bottom, I suppose, for the higher a man goes up upon the lofty +mountains or in a balloon, the colder he finds the air." + +"That is right; and we need to ascend only about three miles, even in the +tropics, to reach the region of perpetual snow, while in the polar regions +the line of perpetual freezing comes down to the sea level. What would be +the effect, Ansel, if the atmosphere were as warm, or warmer, at the top +than at the surface of the earth? How would that affect the rate of +radiation from the earth?" + +"It must, of course, increase the radiation very much. With the +temperature twenty or fifty or seventy degrees below zero, the radiation +must be very little." + +"By some means, then, the atmosphere is kept warm at the surface of the +earth and cold in the higher regions, and in this manner the radiation of +heat into open space is prevented. This is accomplished notwithstanding +that the top of the atmosphere is nearer the chief source of heat, the +sun. This would be no very easy problem if its solution were left to human +ingenuity. The explanation is very simple, however, when once suggested. +The atmosphere is diathermic, that is, it permits the luminous heat from +the sun to pass directly through it without heating the air, but the solid +earth stops the heat by absorption, and is warmed by it. The warm surface +of the earth imparts, in turn, its heat to the atmosphere resting upon it. +This warm air, being expanded by the heat received, becomes lighter than +the cold air around, and rises, or rather is forced, upward by the +greater weight of the colder air. But as it rises and the pressure of the +air is diminished it expands still further. By this expansion its sensible +heat becomes latent, that is, the heat is transmuted into force, and, as +force, is incapable of being radiated. In this manner radiation from the +upper surface of the atmosphere is greatly hindered and waste of heat is +in a good degree prevented. + +"In respect to this heating of the atmosphere from the surface of the +earth, a layer of clouds sometimes forms a kind of second surface which +receives the sun's rays and warms the air above. A few years ago I saw a +balloon ascension in Providence, R. I. The day was bleak and chilly, and +the sky entirely covered with clouds. The aeronauts were expecting a +chilly voyage. The balloon shot like an arrow toward the zenith, and in +five minutes was completely hidden by the clouds. But to the surprise of +the voyagers of the sky, on passing through the clouds their thermometer +rose ten degrees. This, doubtless, must very often be the case. The air +above the clouds must often be warmer than that below. + +"I think you all must have noticed illustrations of this principle on a +small scale. Have you not seen that snow and ice often melt around straws +and sticks, the snow or ice remaining still frozen at a little distance, +as if the sticks and straws were warm and had melted them? Have you not +seen a dark-colored board covered with ice, and the ice remain firm till +the sun shone upon it, and then the ice melt upon the under surface, +leaving the upper surface unaffected?" + +"I have seen such things a great many times," said Peter, "and wondered +what the reason was." + +"The reason is that ice is _diathermic_. Heat passes through the ice +without warming; but when the rays of heat fall upon the stick or stone or +board, the heat is absorbed, the dark body is heated and in turn warms and +melts the ice. In the same manner the atmosphere is warmed. The heat-rays +of the sun pass through the atmosphere and fall upon the surface of the +earth; the earth is warmed, and in turn warms the air resting upon it. + +"The gases and watery vapor contained in the air also hinder the radiation +of heat from the earth. Pure atmospheric air is perfectly diathermic to +both luminous and dark heat, and vapors and gases are also diathermic to +luminous heat. But to dark heat some of the gases are almost impenetrable. +Ammonia stops dark heat almost completely. In a smaller degree watery +vapor does the same. Gases and vapors thus serve as blankets to keep the +earth warm. The heat of the sun, being luminous heat, penetrates the +atmosphere with its vapors and foreign gases, and falls upon the earth +almost without loss, but, being absorbed by the earth, it becomes dark +heat, and cannot be radiated back through the same gases and vapors. Vapor +serves thus as a valve: it admits the heat of the sun to the surface of +the earth, but prevents its escape. Prof. Youmans calls watery vapor the +barb of heat; it catches the heat of the sun and holds it fast. + +"Who can sufficiently admire the simplicity of these arrangements for +preventing the radiation of heat into the stellar regions?--and their +efficiency is no less admirable than their simplicity. Arrangements like +these show that the Creator had a definite object in view, and that object +is benevolent. For the advantage and enjoyment of the inhabitants of this +world these arrangements were made. + +"We ought at this point to look at those adjustments by which the earth +receives just the amount of heat needed to maintain the requisite +temperature. The importance of maintaining some certain average +temperature cannot be over-estimated. Every animal and plant has its own +_habitat_--that is, its natural dwelling-place or location--outside of +which it perishes or maintains a stunted and precarious life. The habitat +of animals and plants depends in a very great degree upon temperature. +What a panorama would be seen if we could fly like a bird from the equator +to the poles, and look down upon the ever-changing animal and vegetable +life as we pass! How the luxuriant vegetation and flaunting colors of the +tropics would shade off into the scantier vegetable life and more sober +hues of the temperate zones, and these in turn die out and disappear in +polar barrenness! We should see the lion and tiger give place to the bear +and the wolf, the elephant and camel to the ox and horse, and these to the +white bear and reindeer. This sublime panorama we see, in miniature, in +ascending lofty mountains in the tropics. Around the base of the mountain +flourish the rich and various productions of the torrid zone; a few +thousand feet of elevation bring us among the productions of the temperate +zones. The most valuable fruits and grains thrive. Then vegetation becomes +scanty and stunted, and at last disappears. The top of Mt. Washington, +6234 feet high, in latitude forty-four degrees, is as bare of trees and +plants and every form of vegetation as the north pole. + +"The fitting temperature is almost as necessary to the animal tribes as to +vegetable life. Animals which are native to the tropics do not thrive in +colder countries, or if the difference of temperature be very great, they +perish. A change from a cold to a warm region is equally disastrous. Man +indeed transfers animals from their natural habitat by protecting them +from the extremes of temperature, but this is, of course, no exception to +the general principle of which I am speaking. A change of only a few +degrees in the mean annual temperature would render this earth a hard +place for even the human race to subsist. But the temperature of the earth +depends upon many a wise adjustment--how many, we cannot tell. Will you +tell us, Samuel, the first adjustment or arrangement upon which the +temperature of the earth depends?" + +"It must depend chiefly I think upon the intensity of the sun's heat." + +"Whether or not that be the chief adjustment by which the right +temperature is secured, it is at least a very important item. The +intensity of the sun's heat must, of course, be considered in connection +with its distance from the earth. The distance of the sun is no less +important than the power of his rays; indeed, in one sense, it is more +important, for if the intensity of the sun's heat were doubled, the +temperature of the earth would be increased only twofold; whereas, if the +earth were brought to one-half its present distance from the sun, the heat +would be increased four times. Heat being one of the radiant forces, its +intensity diminishes in proportion to the square of the distance through +which it acts. If the earth were 190,000,000 of miles from the sun instead +of 95,000,000, as it now is, the force of the sun's rays would be +diminished fourfold. The Creator has so fixed the distance of the earth +and sun, and the power of the sun's heat, as to give to this world a +temperature suited to its various inhabitants. + +"The temperature of the earth has also some dependence upon our +atmosphere. Can you tell us, Ansel, how the temperature of the earth is +affected by the atmosphere?" + +"You have already told us that the atmosphere is _diathermic_, allowing +the heat of the sun to fall upon the earth almost undiminished in force. +If the air were so constituted as to intercept the sun's rays, it is plain +that the earth would receive less heat." + +"This adaptation of our atmosphere to transmit the sun's rays," said Mr. +Wilton, "is more subtle than it appears at first sight. It is not merely a +matter of depth and density, though those are important considerations, +nor is it merely a question of the elements of which the atmosphere is +composed. Simple gases are _diathermic_. The atmosphere is therefore made +up of two simple gases, oxygen and nitrogen, not chemically combined, but +mixed together. Compound gases intercept the passage of heat. Ammonia, +composed of hydrogen and nitrogen chemically united, almost wholly stops +it. Even ozone, which is nothing but oxygen in a changed or _allotropic_ +state, is not _diathermic_. The _diathermic_ quality of the air depends, +then, not only upon the fact that it is composed of simple elements +mingled, but not chemically joined, but also upon the _state_, or +_condition_, of those simple elements. + +"Another point deserves attention. Oxygen is an element having a wide +range of very strong and active affinities. It is ready to unite with +every known substance, fluorine excepted. What if some other equally +active element were mingled with oxygen to form the atmosphere? What if, +in place of nitrogen, vapor of sulphur were substituted? What if hydrogen +were put in the place of nitrogen? The two elements would combine in +sudden combustion or explosion, and the atmosphere itself would perish. +But nitrogen is a substance so sluggish and inert that it can be brought +into union with oxygen only by indirect processes. Because the air is +composed of one so inert element as nitrogen, the atmosphere is preserved, +and, what is almost as important, it is kept, as it now is, composed of +simple elements, and hence _diathermic_. If our atmosphere were a compound +gas, the world would perish with cold. + +"The temperature of the earth depends also upon certain qualities of the +earth's surface. I should be glad to have Mr. Hume explain this." + +"I suppose," answered Mr. Hume, "that you refer to the qualities of the +earth as an absorbent and conductor of heat. The earth must needs have the +capacity of receiving and retaining the heat which falls upon it from the +sun. If the earth's surface were polished and brilliant, the heat of the +sun would be reflected into space as from the surface of a mirror, and +very small advantage would the earth receive from the solar heat. A dark +soil absorbs heat more readily than a soil of lighter color, and a wet +soil, on account of the high specific heat of water, requires more heat to +raise its temperature than a dry soil. The mineral elements of the soil +and its compactness or porosity also help to make up its capacity for +receiving and retaining heat. The color and constitution of the soil +sometimes go far toward making the climate of a region. The conducting +qualities of the earth's crust in its profoundest depths also must be +taken into account. If the crust of the earth were composed of silver, or +any other substance of like conducting quality, and the interior of the +earth were molten rock, as it now is, the interior heat would be so +rapidly conducted to the surface that everything upon the earth would be +consumed." + +"Upon so many circumstances wisely adjusted and nicely blended," said Mr. +Wilton, "does the temperature of the earth depend. The intensity of the +sun's heat, the dimensions of the earth's orbit, the constitution of our +atmosphere in the subtlest qualities and relations of its elements, and +the material, structure, and color of the earth's crust,--on all these and +many other things which I cannot stop to mention depends the temperature +needful for the well-being of the inhabitants of this globe. I beg your +pardon, Mr. Hume, but allow me to ask whether such a combination of +agencies and conditions, uniting to work out good for man, does not seem +to you quite superhuman and worthy of a wise and good Creator?" + +"I cannot deny it, sir," he replied; "I am not prepared to make any +objections. There are many things painful to man in the vicissitudes of +heat and cold, and if I were to make a world, I suppose I should leave +them out, or perhaps make the world upon a very different plan. But I am +not prepared to affirm that any changes which I could make would be +improvements, though I have thought until recently that more of knowledge +and power, and perhaps more of chance, too, than of wisdom and goodness, +were displayed in the works of Nature. But I must confess my opinion has +been much modified." + +"I think your change of mind is in the right direction, and I am glad that +it is so. We learn the secrets of Nature and appreciate her spirit much +better when we come as reverent questioners than when we come with +preconceived notions and a patronizing air. I can well understand your +feelings and state, for I myself have traveled over the same ground. My +eyes were once dazzled with the glories of science; I worshiped at the +shrine of natural laws. But I have learned that God is greater than +Nature, the Creator is mightier than the creation. Nature has no mind or +purpose apart from the plan and will of the supreme Architect and Ruler, +and this inner plan and purpose of Nature is seen only in the government +and discipline of our sinful race. I shall greatly rejoice for you and +with you if you shall go on to the same end which I have reached." + +"I shall much rejoice if I reach some satisfactory and peaceful +conclusion." + +"To understand the management of heat," said Mr. Wilton, "we must take +note of the differences and fluctuations of terrestrial temperature. The +sources of heat are constant. The sun sends out its flood of heat +uninterrupted and changeless for ever. The internal fires of the earth +give an even inward heat. Mechanical and chemical agencies are active +everywhere. These sources of heat do not fluctuate, flaming up and dying +away, yet temperature is the most variable of all inconstant things. In +passing from equator to pole we go from torrid to frigid, from everlasting +summer to everlasting winter. And not only this, but in the same region +the temperature never remains the same for even twenty-four hours. The +thermometer may pass from forty degrees above to thirty below zero in a +very few hours. We must first consider the agencies by which these +inequalities are produced. Ansel may mention the first of these." + +"The shape of the earth," said Ansel. + +"How does the form of the earth operate to produce inequality of +temperature?" + +"The earth is a sphere, and the rays of the sun fall upon it in nearly +parallel lines. Upon the centre of the hemisphere which is turned toward +the sun the rays fall perpendicularly, the sun is directly over head, +while toward the edges of the hemisphere, on account of the curvature of +the earth's surface, the rays fall more and more slanting, as if the sun +were sinking toward the horizon." + +"What is that inequality of temperature which is produced by the shape of +the earth?" + +"The five zones," answered Peter. + +"This subject is so well understood," said Mr. Wilton, "that I need not +spend time in explaining it. Every boy knows the difference between +setting his wet slate before the fire to dry so that the heat will fall +squarely and perpendicularly upon it and placing it edgewise to the fire. +Upon the torrid zone the sun shines perpendicularly, upon the temperate +zones obliquely, and upon the frigid zones still more obliquely, and +during a part of the year the sun is entirely hidden. In proportion as the +rays of heat fall obliquely, any given amount of heat is spread, so to +speak, over a larger surface, and the larger the space over which it is +spread, the feebler it becomes. What is another cause of inequality of +temperature?" No one answered. "Samuel, what is the cause of day and +night?" + +"The turning of the earth upon its axis." + +"And the rotation of the earth upon its axis," continued Mr. Wilton, +"brings not only an alternation of light and darkness, but also of heat +and cold. The heat of the sun is withdrawn along with the light. The heat +of the sun is not withdrawn from the earth, but one-half of the earth's +surface is constantly turned away from its influence. This must produce a +daily change of temperature. This diurnal fluctuation of temperature may +be very small or it may amount to seventy or eighty degrees. Samuel, what +is a third cause of unequal temperature?" + +"The inclined position of the earth's axis and the revolution of the earth +around the sun cause the change of seasons." + +"If it were not for this, the earth would still have her zones of seasons; +a part of the earth would have endless summer, a part endless spring, and +the rest unbroken winter, but the alternation of seasons at the same place +would be unknown. The axis of the earth is now inclined about twenty-three +degrees, twenty-seven minutes, twenty-three seconds to the plane of the +earth's orbit, and as this axis maintains constantly the same position, +being parallel in one part of the earth's orbit to its position in any +other part of its orbit, during one part of the year the north pole is +turned twenty-three and a half degrees toward the sun, while in the +opposite part of the year the south pole is in like manner brought into +the light and heat. This causes the sun to appear to move to and fro, +north and south, twenty-three degrees, twenty-seven minutes, and +twenty-three seconds from the equator in either direction. The tropics, or +turning-places, mark the limits of the sun's northern and southern +journey. Everywhere between the tropics the sun, at some period of the +year, passes through the zenith, that is, exactly overhead at noon. North +and south of the tropics the sun seems to rise higher in summer and to +sink lower in winter. In summer the sun at midday is about forty-seven +degrees nearer the zenith than in winter. Within the polar circles, which +are the same distance from the poles as the tropics from the equator, the +heat of the sun is entirely withdrawn during a portion of the year, and +during another portion of about equal length the sun does not set. The +extremes of temperature, caused by the inclination of the earth's axis and +its revolution around the sun, are very great. In the northern part of +Minnesota, the temperature rises in summer to one hundred degrees, and in +winter sinks to fifty degrees below zero, giving thus an alternation of +one hundred and fifty degrees. + +"In this connection you may also remember that the sun is nearer the earth +in one part of its orbit than in another part. This difference amounts to +about 3,000,000 miles. The sun also remains eight days longer north of the +equator than south of it. Our summer, therefore, is eight days longer than +the summer of the southern hemispheres, and our winters are +correspondingly shorter. These differences tend, however, to balance each +other, for while the southern summer is shorter, the sun at that time is +nearer, and while our summer is longer, the sun is more distant. Peter, +you may explain to us the effect upon temperature caused by the division +of the earth's surface into land and water." + +"I learned while studying physical geography that the temperature is more +even upon the sea than upon the land. But why, I do not know." + +"The smooth surface of the sea reflects heat better than the rough land: +for this reason, a larger proportion of the heat which falls upon the sea +is not absorbed, but reflected and lost, so far as the temperature of this +world is concerned. Water is also a very poor conductor of heat, and has +withal a very high specific heat. For these reasons the sea receives and +parts with heat more slowly than the land, and its absorption or radiation +causes a smaller variation of temperature. The result is, therefore, that +the sea is cooler in summer and warmer in winter than the land, and the +average ocean temperature is lower than the mean continental temperature. +The land receives heat more readily and parts with it more rapidly; the +fluctuations of temperature must therefore be greater. Hence, the +interiors of the continents have much greater extremes of temperature than +the sea-board. But of the influence of water in equalizing temperature I +shall have occasion to speak again more at length, and will pass it by for +the present. What effect, Peter, has the unevenness of the earth's surface +upon temperature?" + +"The higher we ascend upon mountains, the colder we find it." + +"That is, Peter, the greater the elevation of any place or country above +the sea level, the lower the temperature. Almost the whole surface of the +earth is an alternation of mountain and hill, valley and plain. One +continent has a very much greater mean elevation than another. One region +or tract of country lies sloping toward the sun, another is inclined from +it. The effect in the one case is the same as if the sun were brought more +nearly overhead; in the other case, the sun is depressed toward the +horizon. It is all the same as if the region of country were brought +nearer the equator or removed farther from it. The effects of the +curvature of the earth are obviated or exaggerated. Do clouds tend to +produce inequalities of temperature?" + +"I think they must do this," answered Samuel. "Clouds cover one portion of +the earth's surface and shut out the heat of the sun, while other portions +are well exposed to the sun's rays." + +"That is right, Samuel. Does any one think of another cause of inequality +of temperature?" + +There was a pause. Then Mr. Hume answered: "Considering the unmeasured +cycles of the past, the gradual cooling of the earth has brought a great +change of temperature." + +"And this change," continued Mr. Wilton, "has been very important for the +welfare of the human race. At the present temperature of the earth, the +coal-beds, so necessary for the culture and progress of the race, could +hardly have been formed, and at the temperature of the carboniferous +periods, when the coal-beds were deposited, the human race could with +difficulty have survived. The high temperature required to prepare the +earth for man is now no longer needed, but would prove destructive. And +this great change of temperature was doubtless caused by the cooling of +the earth. + +"The result of all these agencies--the shape of the earth, its daily and +yearly motions, the inclination of its axis, the eccentricity of its +orbit, the division of its surface into land and water, the varying +elevation of its surface, and the clouds and storms that hide the sun--is +that we have great extremes and rapid transitions of heat and cold, and +every variety of climate. These changes of temperature are often painful +and, unless guarded against, dangerous. Yet, taken as a whole, can one +doubt that variety of climate and change of temperature are of advantage +to man? What weariness and lassitude a changeless temperature would +bring! How the cooler air of the night comes as a tonic after the +relaxation of the heated noonday! Who can estimate the value of our +northern winters, not alone in building up a vigorous and nervous physical +frame, but in helping the culture of men and nurturing the domestic +virtues? We might almost say that her winter evenings have been the making +of New England. But periods of heat are needed for bringing fruit and +grain to ripeness. What variety and richness of productions for the use of +man the different zones furnish! The supply of man's wants would be +comparatively meagre if we had but one zone, even though we had our choice +of the zones. But every zone is necessary for the perfection of the +temperate zones. That we may have the warmth of summer in the temperate +zones we must have the torrid zone. That we may have the tonic cold of the +temperate zones we must needs have the severity of polar winters. I do not +mean that the Creator could not devise a world that should not have these +painful extremes, yet enjoy the advantages of the temperate regions. But +that would plainly require a world constituted upon principles very unlike +those which now prevail. With God this is doubtless possible, but the +mode is to us inconceivable. But we can easily see that by the present +arrangement of things God has secured many great advantages for man--how +many and how great, we can hardly understand--and the apparent +disadvantages we cannot positively affirm to be real evils. We can safely +declare that this world is well adapted to man's necessities. But these +inequalities of temperature are modified and softened by a most +comprehensive and beneficent system of agencies by which the extremes are +prevented from becoming destructive. In this system of compensating +agencies two great divine ideas are clearly developed, economy in the +expenditure of heat and benevolence toward man. Upon this subject we are +now prepared to enter." + + + + +CHAPTER VIII. + +MODIFICATION OF TEMPERATURE. + + +Resuming the subject where it was left the previous Lord's Day, Mr. Wilton +said: + +"We saw at our last session that the most prominent and permanent features +of the earth tend to produce differences and great extremes of +temperature. These variations of temperature within due limits must be +regarded as beneficial, if not absolutely essential, to the well-being of +the human race. The different zones give the world a richer and more +varied supply of food, and finer and more varied plants and animals. The +change of seasons gives variety in the experience of life; the warmth of +summer ripens the fruit and grain, and the cold of winter tones up the +physical strength; nay, the winter's frost is a natural subsoiler, +loosening up the hard earth and promoting vegetable growth. As for man's +higher interests, no one can tell how much the world is indebted to winter +evenings, to a period of darkness longer than is needed for sleep, and a +period of cold during which the work of husbandry may largely cease. +Learning, the domestic virtues, and religion are greatly indebted to our +winters. But were these agencies which tend to produce inequality of +temperature suffered to operate without counteracting influences, the +extremes of heat and cold would cease to be genial and healthful, and +become destructive. We are now to begin the consideration of those +counteracting agencies by which the extremes of temperature are moderated. + +"Let us look first at the daily fluctuation of temperature caused by the +revolution of the earth upon its axis. The rotation of the earth brings +every place by turns under the influence of the sun's rays, and in turn +withdraws it from the heat of the sun, thus producing a daily change of +temperature. How is this diurnal change of temperature alleviated?" + +This was addressed to all, but no one answered. "Mr. Hume, I should be +glad to have you suggest the answer." + +"There are two chief agencies," Mr. Hume replied--"first, the absorption +of heat during the day and the radiation of that heat during the night; +and, secondly, the formation of watery vapor during the day and the +deposition of dew by night." + +"The first of these agencies," said Mr. Wilton, "is so plain that very +little explanation need be made. During the day, while the sun is shining +and the temperature is rising, the surface of the earth, the rocks, the +trees, and all things are absorbing heat. This heat is, so to speak, laid +up in store, ready for use in time of need. In due time the sun sinks low +and sets behind the horizon; the supply of heat is cut off and the +temperature begins to fall. Then all those objects which during the day +were laying up heat in store begin to radiate heat into the air, and by +their contact with it keep up its warmth. Commonly, the temperature falls +so low that bodies radiate more heat than they absorb before the setting +of the sun. In this process water plays a very conspicuous part. You will +call to mind what was said before about the large specific heat of water. +By means of this, water is able to store up heat in large amounts--larger +in proportion to its weight than any other substance except hydrogen gas. +The heat that is stored up during the day is given off by contact with the +air and by radiation during the night. + +"But water plays a still more important part in moderating the daily +fluctuations of temperature by the process of evaporation and the +formation of dew. Call to mind what was said of the formation of vapor +when we were speaking of latent heat. Heat water to two hundred and twelve +degrees--the boiling point: it must still be heated a long time before it +evaporates. Boiling water must receive five and a half times more heat to +give it the form of vapor than to raise it from the freezing to the +boiling point; that is, about one thousand degrees of heat are required to +turn boiling hot water to vapor. The same amount of heat is required for +the formation of vapor whatever the temperature of the water from which +the vapor rises. There is only this difference--vapor from cold water is +cold, while vapor from hot water is hot. Evaporation goes on more rapidly +in proportion as the temperature rises, but vapor is formed at all +temperatures. Evaporation goes on from ice. The Alpine glaciers, or rivers +of ice, sink away several feet by evaporation from their surface during +their slow course of many years down the mountain ravines. This process of +evaporation goes on, I say, during the day, and in the formation of vapor +an amount of heat which would raise an equal weight of water through one +thousand degrees of temperature is used up. + +"This vapor which is formed is not supported _by the_ air, as men commonly +suppose. It is true that clouds are held up by the atmosphere, but clouds +are condensed vapor--minute globules of water floating in the air. Vapor +is invisible. You must have noticed that steam is invisible till it is +condensed by contact with the colder air. Vapor rests upon the earth and +supports itself by its own elastic force, just as the atmosphere supports +itself. The presence of air makes no difference with the formation of +vapor, except that in a vacuum vapor forms very much more rapidly, because +no air stands in its way. But at any given temperature, in the air or in a +vacuum, the same amount of vapor rises in due time, and the same amount +can support itself. Vapor seems to circulate between the atoms of air, as +sand fills the spaces between marbles. At the temperature of four degrees +below zero vapor equal to two-thirds of an inch of water can be formed and +support itself by its elasticity; that is, the elastic force of vapor at +four degrees below zero is equal to two-fifths of an ounce per square +inch; at thirty-six degrees vapor equal to two and two-thirds inches of +water can support itself; at eighty degrees vapor equal to thirteen inches +of water can exist; at one hundred and seventy-nine degrees, seventeen +feet; and at two hundred and twelve degrees nearly thirty-four feet; that +is, vapor at two hundred and twelve degrees has an elastic force of +fifteen pounds to the square inch. Let us suppose that at sunrise the air +has a temperature of thirty-six degrees, and that as much vapor is already +formed as can sustain itself at that temperature. As the sun sheds down +his rays the temperature rises and more vapor is formed. We will suppose +that half an inch of water is evaporated. Some of this vapor will be +carried by ascending currents of air into the higher regions and condensed +into clouds, some will be carried by winds into drier and warmer regions, +yet the amount of vapor will increase during the day. We will suppose that +during the night the temperature falls again to thirty-six degrees; all +the excess of vapor above two inches and two-thirds of water will be +condensed and become dew or fog, and in this condensation the thousand +degrees of heat absorbed in the formation of the vapor will be given out +again. If vapor equal to one inch of water be condensed, heat is set free +sufficient to boil a sheet of ice water, five and a half inches in +thickness, extending over the whole region; that is, it would be all the +same as if a fire were kindled on every square rod of land hot enough to +boil during the night more than twenty barrels of ice water. In this +illustration I have supposed a larger condensation than commonly takes +place, but very much less than is conceivable. Suppose that the +temperature is eighty degrees, and that, as is possible, more than one +foot of water exists in the state of vapor. Let the temperature fall to +thirty-six degrees, and full ten inches of water must be condensed, +setting free heat which would boil four and a half feet of ice water. So +large a condensation as this never takes place in twelve hours, partly +because the full amount of vapor which might be formed is never actually +produced, and partly because the condensation of but a small part of this +vapor would check the fall of temperature and prevent farther +condensation. The supposition that I have made shows the possibilities of +this method of moderating extremes of heat and cold. Were it not for these +processes, our days would be much warmer and our nights much cooler than +they now are. By the formation of vapor the excess of heat during the day +is stored up in a latent form; that is, it is used, not as heat, but as +force, and is employed in bringing the atoms of water into new +relationship; during the night the vapor returns to its former state as +water, and the heat-force again becomes sensible heat. Thus the day is +cooled and the night made warmer. + +"Ansel, have you ever heard the 'dew point' spoken of?" + +"Yes, sir, I have." + +"Do you know what is meant by it?" + +"That point or degree of temperature at which dew begins to be formed." + +"Upon what does the dew point depend?" + +"Upon the amount of vapor in the air." + +"That is right, Ansel. If at any time the full possible amount of vapor +should exist, any diminution of the temperature must, of course, cause +dew to be deposited. Do you know, Ansel, how to ascertain the dew point at +any time?" + +"No, sir, I do not." + +"There is a beautiful instrument known as Daniell's Hygrometer which shows +the dew point as a thermometer shows the temperature. But any one can +easily determine the dew point without a special instrument for that +purpose. Pour warm water into a glass pitcher or goblet whose outer +surface has been wiped perfectly dry, and polished. Into this set a common +thermometer. Cool down this warm water by dropping into it small pieces of +ice, and notice carefully when the polished glass begins to be dimmed as +if it had been breathed upon. When that begins to take place the +thermometer will show the dew point. In this manner we can determine the +amount of vapor in the air, and by estimating the probable temperature of +the night judge of the probability that dew will fall." + +"I have noticed some things," said Peter, "about the formation of dew +which I do not understand, and I wish very much to ask about them." + +"I should be glad to hear your questions, and will answer them if I can." + +"I have noticed that dew falls on clear nights, but not very often on +cloudy nights. I don't see why that is so." + +"Have you ever noticed whether cloudy nights or clear nights are the +warmer?" + +"Cloudy nights are commonly warmer, I think, but I never could see the +reason for that, either." + +"Can you tell why a newspaper spread over a tomato vine keeps the frost +from the vine?" + +"Because the frost comes upon the paper instead of the vine, of course." + +"But why do you say, of course? Why does not the dew--for frost is nothing +but dew frozen as it forms--come upon the under side of the paper?" + +"How could the dew fall upon the under side?" + +"That is just the point which we need first of all to understand. Men +commonly speak of dew as if it fell. I don't know but I have spoken of the +falling of dew in this lesson. But dew does not fall at all. The vapor +simply touches some cold object, and is condensed upon it. The vapor by +its elasticity presses against the cold body, and the process of +condensation continues until either the body is warmed by the heat set +free so that its temperature rises above the dew point, or till the vapor +is so far exhausted that the dew point falls below the existing +temperature. Dew is formed upon the upper surface and not upon the under, +because the upper surface is cool and the under surface is warmer. Beneath +the paper spread over the tomato vine, the earth is radiating heat and the +paper is radiating it back again. If the paper were not there, the heat +would be radiated into space and not returned again. The vine would soon +radiate away its little store of heat, its temperature would sink, below +the dew point, and dew or frost would be deposited upon it. The under +surfaces of objects are kept warm by the radiation from the earth. In the +same manner clouds are wrapped around the earth and keep it warm by +radiating back its radiant heat. Dew is not formed on cloudy nights, +because they are warmer: the clouds throw back the heat which otherwise +would be lost in open space." + +"I never knew before," said Peter, "that clouds were of any great use +except to send down rain." + +"We shall see in the course of our lessons that clouds are of very great +use in warming the earth in other ways, as well as by serving as blankets +and radiating back the heat which otherwise would escape." + +"I wanted also to ask why dew falls--I mean, is formed--on grass and +leaves of plants while stones are dry." + +"I will answer your question by asking another. Did you ever see barefoot +boys running in the cold dew stop and stand upon a stone or rock to get +their feet warm?" + +"Oh yes, sir; I have done it myself." + +"Why did you stand upon a rock?" + +"Because I had learned that the rocks would be warm." + +"I think that answers your question. The rocks and stones are warmer than +the grass and the leaves. The blades of grass and the leaves are thin and +pointed and rough, and have a very large radiating surface. They have but +little heat, and that little they part with rapidly. The rocks and stones, +on the other hand, are bulky, and contain a much larger store of heat, +their radiating surface is comparatively small; only one side is exposed, +the other being covered by the warm earth, from which they are drinking in +heat almost as rapidly as they lose it. They therefore do not lose heat +enough to sink their temperature to the dew point. + +"So much, then, for the means employed to moderate the changes of +temperature from day to night and from night to day. But upon the +sea-coast and upon certain islands of the sea another agency is employed. +Will some one suggest what this agency is?" + +No one else answered, and finally Mr. Hume said: "I suppose, of course, +that you refer to the land and sea breezes?" + +"This is what I had in mind. During the day the land is warmer than the +sea, and the breeze from the sea blowing upon the land cools the air. +During the night the land radiates its heat more rapidly than the water, +and soon the sea becomes the warmer. Then a breeze springs up in the +opposite direction; the cooler air of the land flows out upon the sea. By +this means the air upon the land and the air upon the sea are daily +commingled, thus securing a more even temperature upon the land. This +softens the extremes of daily temperature. I make only this brief +reference to the land and sea breezes, because in another connection we +shall examine the general subject of winds and their influence in the +equalization of temperature. + +"The result of all these influences is that the changes of temperature +from day to night and from night to day, while not inconsiderable, are by +no means destructive, and in many cases are no greater than is refreshing +and agreeable. These agencies remind us every day of the wise provision of +the Creator for the well-being of his creatures. 'Day unto day uttereth +speech and night unto night showeth knowledge. There is no speech nor +language where their voice is not heard.' This care for the earthly +well-being of men is but a type of his care for their spiritual happiness. +The plan of salvation, and the ways of divine providence working in +accordance therewith, are more wonderful both in their means and their end +than the greatest of the works of Nature. If while we study the natural we +forget the supernatural, we commit the greatest mistake: we pass by the +greater to examine the less. The natural is valuable only as it leads to +the spiritual." + + + + +CHAPTER IX. + +THE MINISTRY OF SUFFERING. + + +"You must know, Mr. Wilton," said Mr. Hume, "that my mind is full of +objections, whether I speak them out or keep silence. I have looked so +long upon one side only that I find it hard to look upon other sides also; +and if there be a Satan, as the Bible teaches, I think he must be +marshaling all his legions to overwhelm me by the force of his impetuous +assaults. I cannot disguise the fact--I do not attempt to disguise +it--that my mind is not at ease. It used to be at rest, at least +comparatively so--not happy, yet not agitated and distressed. My heart was +not satisfied, but I believed that my position of unbelief was logically +impregnable. But I confess it, my unbelief has of late been shaken. I am +no longer contented. How I came into this state, I do not know. I am +certain that my present unrest was not produced by the force of arguments +which I had heard. It seems to me as if it sprang up uncaused. The old +arguments which I have thought impregnable do not now satisfy me. Why, I +cannot tell. I think this statement is due to you to explain my position +in your Bible class, and also to prepare the way for a question which I +wish very much to propose. I have no objections to make to the marks of +wisdom and benevolent design seen in the works of creation which I cannot +myself answer and remove. Good-will and goodness to the inhabitants of the +earth lie on the very surface of things; or, if I go beneath the surface, +I find them no less manifest in the profoundest and subtlest arrangements +of the universe. If I say, 'This is all the work of chance,' my very +language is self-contradictory and looks me out of countenance, for the +very idea of chance is the opposite of wise and orderly arrangement. The +difference between design and chance is that the one works by orderly +arrangements adapted to the accomplishment of a foreseen end, while the +other shows itself in chaotic disorder, with no adaptation to the +accomplishment of a purpose. To say that a universe like this, filled in +every part with order and beauty, with subtle and unseen elements and +agencies working out into the boldest relief in the accomplishment of +beneficent ends, all minute elements blending in the sublime sweep of the +universal plan,--to say that such a universe is the work of chance is to +use language without meaning. + +"If I deny a providential plan in the creation and government of the +world, and attribute to brute matter a nature that, by its own inherent +force, spontaneously develops into all these contrivances of use and +beauty, I see that the wisdom of the whole universe is concentrated in the +nature of matter, and, if it be possible, infinite subtlety of design is +doubly manifest. To create a machine which, upon its elements being thrown +into an indiscriminate pile, shall arrange itself, adapt part to part, and +set itself in motion; which shall repair all its breaks, produce other +machines as curious as itself, and thus reproduce itself and perpetuate +its existence for ever--that would certainly be the acme of intelligent +design. + +"Or if I go farther and deny a Creator, ascribing to the universe an +eternal, uncreated existence, I see that I only entangle myself in a +complication of difficulties. I find myself standing face to face with the +best-established facts of geology. If the fact that the animal tribes +which inhabit the earth, and especially the human race, had a beginning be +not well established, then no fact in geological science can be reckoned +as fixed. Geology has overturned the idea of an infinite series of +generations of animals and men. Nor do I see that I gain any advantage or +give any explanation of the universe by attributing to matter everything +which others refer to an intelligent and almighty Creator. The distinction +between mind and matter is that mind is endowed with intelligence and +will, while matter has neither intelligence nor will, but only blind +forces, blind attractions and repulsions. If I attribute the order, +beauty, design, and benevolence of the universe to mere matter, I clothe +matter with the attributes of spirit. In fact, I only set up another God +and ascribe to the universe a true divinity. I make myself a kind of +pantheist, investing all matter with the attributes of mind and spirit. +All this I have pondered over for many a day, and I cannot deny that a +belief in an intelligent Creator of the universe is logically more +satisfactory. But there is one question which confronts me at every turn. +I suppose that I might at length work out an answer for myself and that I +should now see the explanation if all my thinking for so many years had +not been upon the other side." + +"I am afraid that I shall not be able to give you satisfaction," replied +Mr. Wilton, "but I shall be glad to hear your question. I can at least +appreciate your state, and sympathize with you in your groping and +struggling. I am glad that you are walking the road you have just +described. You say that you do not know what has brought you to your +present state. I can easily tell you: your experience at this point is not +singular; I think the Holy Spirit of God has been leading you and has +brought you to your present position. I trust in God that he will lead you +still farther. You have great cause for thankfulness and great cause for +trembling. Let me caution you: be careful how you treat the divine Spirit; +walk softly; be honest, sincere, and simple-hearted as a little child. +'Except a man become as a little child, he cannot see the kingdom of +God.' Above all things, be sincere and straightforward. Deal truly and +frankly with the Spirit. If you will only be honest and frank,--honest and +frank to yourself, honest and frank to all men, honest and frank with +God,--God will soon give you cause to praise him and love him for ever and +ever. But what is the question which you wished to propose?" + +"My difficulty is this: Along with the many arrangements for conferring +enjoyment and promoting the well-being of man are other arrangements for +suffering. Man is made as capable of suffering as of enjoyment, and there +are appliances provided which are certain to inflict that pain of which +man is capable. How is this provision for suffering in man and in all +sentient creatures consistent with the benevolence elsewhere shown? How +are we to combine these two sets of arrangements in our thinking?" + +"A full unfolding of the ministry of pain in the good providence of God +would lead us entirely aside from our course of study." + +"But for me," said Mr. Hume, earnestly, "it would be not at all aside; for +if I can once see that the provision for suffering made in the +constitution of man and of Nature is not repugnant to the idea of a wise +and good Creator and Disposer of human affairs, I will admit whatever you +shall have to say afterward, and I shall feel that the gospel of Christ +comes to man and comes to me with a moral force which ought not to be +resisted. I know that I have no right to come into your class and ask you +to turn aside from your course of study, and the gospel certainly owes +nothing to me, yet I do hope you will give the opinions which you hold +upon this subject, if you have formed any positive opinions." + +"I am sure," exclaimed Peter, "that we shall all be very glad to have you +spend the time of this lesson in speaking of this subject." + +"But how would it please you if my talk upon the ministry of pain should +prove to be very much like a sermon?" + +"I think we like your sermons. I know that we were never so much +interested in them as now." + +"Very well, then; I will give you, as Mr. Hume says, some of my +conclusions touching this matter of pain and suffering; and if my opinions +are not satisfactory or do not cover the facts in the case, it will not +be because I have given the subject little thought or have had little +experience of suffering. The Lord has led me by a rugged road; he has +given me tears to drink and mingled my cup with weeping. But for this I +thank him, and I expect, when I shall look back from the life to come upon +my earthly course, to see my days of pain and grief shining more brightly +than the hours of radiant sunshine. + +"First of all, then, I believe that with the clear exhibition of +benevolent design which we see in this world we ought not to doubt the +goodness of the Creator, even if we can give no rational explanation of +the suffering which abounds. We ought not to believe, we cannot believe, +that the Creator's own attributes are self-contradictory and antagonistic, +that the same infinite Being is both good and evil, partly benevolent and +partly malignant. If God is good at all, he is wholly good. Nor can we +believe that a good being and an evil being--God and Satan--hold joint +sway over the universe and co-operated in the work of creation, and that +the good is to be ascribed to the one, and the pain and suffering to the +other. Whether we can explain it or not, we must believe that there is a +good reason for the existence of suffering; unless, indeed, we count the +infliction of pain the chief end of the creation, and refer the happiness +which men enjoy to some incidental arrangements not contemplated as +important in the work of creation. But no sane man can think that this +world is the work of a demon seeking to fill the earth with groans and +wretchedness. Our consciences and our reason alike require us to believe +in the supremacy of goodness. + +"In presenting my views, I of course cannot attempt to prove everything +from the beginning: I must take some things for granted between us. We +must start with the admission that there is a God, and that he is a +righteous, moral governor. We must at least believe what Paul declares to +be needful: 'He that cometh to God must believe that he is, and that he is +a rewarder of them that diligently seek him.' We must also believe our own +consciences when they testify that men are responsible, free moral actors, +and that sin and guilt are not false notions arising from diseased and +morbid mental conditions, but realities, true ideas which arise in the +mind when it works as God designed. Do you freely admit these points of +belief, Mr. Hume?" + +"Yes, sir; I could not ask you to prove every point touched upon in the +argument, for that would require half a score of volumes, nor will I deny +the testimony of my own conscience that there is a God, and that men are +rightly responsible to him." + +"Starting, then, with these fundamental principles, we will look first at +the provision made for physical pain. Men and, I suppose, all living +creatures are created with the capacity of suffering. The same nerves of +sensation which if excited naturally give rise to pleasure may be excited +unnaturally and inflict pain. But why not endow living creatures with +nerves of sensation which could experience pleasure, but could not feel +pain? Is this possible? Perhaps so, but no man can affirm it with +certainty. I do not think that any man can clearly conceive such a thing. +To us the capacity of enjoying and that of suffering seem inseparable. But +there is no need of insisting upon this point, for the capacity of feeling +pain is a most benevolent provision of the Creator for the benefit of +living creatures. It is designed to save life and limb. Pain is the +sentinel set to guard the outposts of the citadel of life. If there were +no pain, men would thrust their hands into flames without knowing it. They +would indulge in all manner of destructive excesses, and no sufferings +would warn them of danger. They would drink poison, and no pain would bid +them make haste to take the antidote. Tear men limb from limb, hew them in +pieces with the sword, and no painful sensations would rouse them to +self-defence. Without this benevolent provision of pain the race of man +could hardly be saved from extinction. How much more would this be true of +the animal tribes, which are wholly dependent on instinct for guidance and +impulse to action! We accordingly find pain possible in those parts of the +body where pain can subserve the purpose of protection; elsewhere no +provision is made for pain. Nerves of sensation abound in those parts +which require especial care or are especially exposed. The skin is +exposed, therefore the skin is well supplied with nerves. The parts +beneath the skin are less exposed, and are injured only by first wounding +the skin; they are therefore less sensitive. The heart, though so very +important, is almost insensible to pain, because the capacity of +suffering at that point would confer no protection. The eye is delicate +and requires the greatest care, and to secure that needed care the Creator +has made it delicately susceptible of pain. The sole of the foot, as its +work demanded, was made capable of bearing the roughest usage, and hence +the sole of the foot is but little supplied with nerves of sensation. +Still farther, when on account of injury any part of the body requires +unwonted care, provision is made that the injured part shall become +especially sensitive. A bone when well and sound may be cut or sawed +almost without pain, but when the bone is injured it becomes inflamed and +feels pain most keenly. When a limb for the sake of its own safety ought +to be kept quiet, Nature makes it painful to move it. For the benevolent +object of preserving life and guarding the well-being of living creatures +pain is given. The provision for pain shows the presence of danger, the +liability of receiving injury, and the kind design of putting men on their +guard. It is the automatic guardian of our happiness. This is all that I +have to say about bodily pain. + +"Mental suffering and pain of conscience are designed, first of all, to +subserve the same purpose. The sense of guilt when a man commits a wicked +act is designed, first, to lead him to repentance. It is the divine alarum +placed within the soul to remind men that they have done evil and received +moral damage which must be repaired. It is the moral goad which pricks men +to warn them to turn from wickedness. If evil-doing were as pleasant as +well-doing, men would see no difference between right and wrong; all moral +ideas would be subverted and the glory and beauty of man would be trailed +in the dust. + +"But a guilty conscience continues to trouble wicked men after the day of +repentance has passed; Remorse indeed seems to rise up with preternatural +power when Mercy has withdrawn for ever from the sight of Hope. What is +the meaning of this? It means that which we admitted in the beginning, +that sinners are guilty in God's sight, that guilt is a real thing and +deserves punishment, and that God, the holy and righteous King of men, +does actually punish the guilty. God is holy and abhors sin. Remorse of +conscience is the shadow of the Creator's frown, the voice of his eternal +indignation echoing and re-echoing in the soul of man. It is the divine +wrath penetrating the human spirit and making itself felt. As the holy God +abhors sin for ever, the wicked must expect to feel that abhorrence for +ever. He who puts himself into a rebellious position toward his Creator +must stand in that unnatural attitude guilty and suffering. We can +conceive that this should be otherwise only by subverting the foundations +of the moral world. Beings created in the image of God, created with a +conscience and moral affections, created with moral freedom, can attain +blessedness only by aspiring to heavenly things and becoming God-like. If +they break away from the divine will and order, they must suffer the +divine frown, they must feel that frown. How can God make his frown felt +except by looking pain, so to speak, into the sinner's conscience? + +"But this whole subject of pain and suffering derives a double +significance from the fact that the human race is a fallen race, alienated +from God by wicked works, yet under a merciful dispensation in which they +are called to return to obedience. There is no moral quality good and +beautiful to our eyes or pleasing to God in which men are not altogether +lacking, and what is still worse, men grow in evil; their last state is +worse than the first. There is no healing power in the man which can +renovate his heart and bring him back to holiness. It would seem as if +some satanic power were hurrying the human race along the road to ruin. If +men are to be saved, it must be by a force of renovation outside of +themselves, which shall reverse the evil bias of their nature. You say +that the world seems fitted to develop man's capacity for suffering, and +that this appears to be as much a part of the divine plan as the +impartation of happiness. What, think you, would be the result if the +human race were planted in a world where nothing could give pain, where +everything would afford gratification? What, Mr. Hume, do you think the +effect would be upon creatures such as we all know men to be?" + +"I hardly dare answer with the little thought I have given to the subject. +I would rather listen than speak." + +"I have noticed," exclaimed Ansel, "that those boys who have everything +done to suit them at home are the most unmanageable in school and the +most disagreeable to play with." + +"Picture to yourselves," continued Mr. Wilton, "a man who from childhood +should have nothing to suffer, no pain or weariness or hardness to bear. +From childhood he has no bodily pain, and the comforts of life are so +carefully and bountifully provided that he receives no unpleasant +sensation. Winter never chills him, summer never heats him. His slightest +wants are all anticipated. All his sensations are pleasure. Let the same +be true of his mind. His will is never crossed; whatever he wishes is +given him; there is no call for self-denial or self-control or abstinence +or patience. He feels no pressure of need spurring him to exertion. His +whole life is enjoyment. His very body would grow up, not strengthened and +compacted for exertion, but fitted only for the softness of indolence and +ease. His will would be the selfishness of self-will rather than an +intelligent, reasonable self-control. There would be no tenderness and +power of love, no endurance and patience in labor, no strength of moral +purpose under temptation, no self-denial and self-sacrifice of love for +the good of others or for the attainment of a higher blessedness, no +faith in God nurtured in darkness and trial. We should have a mushroom +growth of luxurious tastes and indolent ease, impulsiveness and +impatience, strength only in selfish, passionate self-will and rampant, +luxuriant vices. No other result would be possible with creatures like us. +Strength is developed only under circumstances which call for the exercise +of strength. A certain hardness and hardihood of living is needed to +develop a manly body. Resolute intellectual exertion in the face of +difficulties is demanded to educate the mental faculties. An earthly life +not wholly satisfactory is needed to awaken in faithless men a longing for +a better land. We may look upon the sufferings of this world, taken as a +whole, as an expression of God's displeasure at sin. How very much is such +an expression needed! If life were nothing but pleasure, how completely +men would forget sin and duty and God and heaven! All the varied +experiences of joy and sorrow, of good and ill, of trial and triumph, are +needed for man's spiritual discipline. I think you will bear me witness +that the noblest, sweetest, most beautiful characters are found in those +who have drunk the cup of sorrow to the dregs." + +"I cannot deny it, Mr. Wilton. There is old Deacon Smith. We all know +something of his history, I suppose. He was a poor boy; when he was twelve +years of age his father died, and his mother died four years later. But he +worked his way, first to a good education, and then to an honorable +position and ample fortune. Then the dishonesty of a partner brought him +back to poverty too late in life for him to recover himself. Now in his +old age he works for a small salary in the office of another. But he is as +cheerful and as grateful as if he had all that heart could wish, and had +never in his life suffered a pang. I think he verily believes that +everything which has befallen him has been an expression of God's love for +him. He sheds no tears except for the griefs of others. I think he truly +rejoices with those that rejoice and weeps with those that weep. As for +faith in God, I suppose he would go into a lion's den as calmly as did +Daniel. If every professor of religion were like him, I am sure that +nobody could say a word against the gospel. I freely confess that Deacon +Smith's character has affected me more than all the arguments I have +heard in favor of Christianity." + +"As to that, Mr. Hume," replied Mr. Wilton, "we have both of us, +doubtless, seen men who would hate a man the more bitterly in proportion +as he should show himself Christlike. And as to every church-member being +like Deacon Smith, we could hardly expect such a character to be nurtured +in a day or a year. Deacon Smith has become what he is by a lifetime of +severest spiritual discipline and patient endeavor. Such characters are +wrought out only by a discipline of every form of trial. This world is +constituted as it is for the purpose of giving just such a discipline of +effort and patience. + +"This explanation brings us, however, only to the vestibule of the great +mystery of suffering in the work of recovering man from the Fall. The +Captain of our salvation, who put himself in man's place and took upon +himself all human conditions, was made perfect through suffering. The full +preparation for his work as the Saviour of man called for a discipline of +pain. I shall not attempt to explain this experience of Christ, but +salvation brings the believer into a state of profoundest and most +mysterious union with Christ. The believer must walk in the footsteps of +Jesus. As Christ first came into a condition of sympathy with man, so must +man come into a condition of sympathy with him. The believer must share +and repeat, in a feebler way, of course, the experiences of the Lord +Jesus. He must fill up that which is behind of the sufferings of his +Saviour. By this union with Christ in the discipline of pain the Christian +is prepared for a union of blessedness. 'If we suffer, we shall also reign +with him.' How broad and deep this union of the believer with Christ may +be, I cannot tell. I am not able to measure this idea. It seems to me like +one of God's infinite thoughts, revealed in its dimness to overawe the +souls of men by its shadowy sublimity--seen only enough to suggest how +much vaster is that which remains unseen--an iceberg, one part standing +out and nine parts sunk in the unfathomed sea. It is a thought to be felt +and experienced rather than weighed and measured by human logic. This is +all that I have to say upon this subject. Do these views commend +themselves to you, Mr. Hume?" + +"I do not know," was the reply; "I want to revolve the subject in my own +mind. I have received some new ideas, but I judge that a man needs +experience in this matter as well as thinking. If I had Deacon Smith's +experience of life, I could form a better opinion. As much as this I can +see to be true--that provision for bodily pain is a safeguard to the +happiness and life of men, and that a world which should anticipate every +human want, leaving nothing to be struggled after and nothing to be +endured, would have a disastrous influence upon human character. I will +admit that the provision for pain is wise and good." + +"One other point," continued Mr. Wilton, "we ought to notice before +leaving this subject. The word of God says, 'We know that all things work +together for good to them which love God,' but it says no such thing of +those who do not love him. The afflictions of this life work out for the +righteous 'a far more exceeding and eternal weight of glory.' The ministry +of pain is a ministry of love only to those who submit to Christ. To those +who kick at God's mercies the best blessings turn to evils and curses; to +the faithful in Christ the greatest griefs and calamities become choice +blessings. A submissive heart and the agency of the Holy Spirit are +needed to sanctify pain. It is a great mistake to think that all men are +made better by afflictions. Only the few get good from the discipline of +life. With many persons troubles only stir up the worst passions till they +rage like caged tigers." + +"This last remark, Mr. Wilton, has thrown a flood of light upon this +subject. But it seems strange to me to find myself saying this. I see how +it is that so large a part of the pains of life is found in the end to +accomplish no good. The evil remains evil. Do you think that my long trial +of doubt and unrest and pain of heart can ever be blessed to my good?" + +"That it can be so blessed to your good and to the good of many others I +have no doubt; but whether it will be, I cannot tell. That depends upon +yourself, upon your coming through Christ to God as your heavenly Father. +It is my earnest prayer that from your unrest of spirit deep peace in +Christ may break forth; and many others unite in the same." + +"I certainly hope," said Mr. Hume, "that my life may not come to nothing. +It seems as if something better than a few years of mingled pain and +pleasure, overshadowed by most painful doubt and darkness and followed by +a plunge into nothingness, must be possible for me." + +"God give you grace," said Mr. Wilton, earnestly, "to forget the things +which are behind, and reach out your hands toward the worthiest destiny! +But remember that there is a destiny more terrible than to cease to be, +there is a death deeper and darker than the grave. + + 'There is a death whose pang + Outlasts the fleeting breath; + Oh, what eternal terrors hang + Around the second death!'" + +Mr. Wilton did not think it best to attempt to draw out Mr. Hume farther +at that time. He saw that he appeared to be under the guidance of the Holy +Spirit, and hoped that he would soon experience the new birth by which old +things pass away and all things become new. He knew that time is an +element even in the operations of the Spirit, and he feared to shake the +bough too roughly lest the fruit should fall untimely only to wither in +his hand. Happily, the superintendent's bell brought the conversation at +that point to a natural conclusion. + + + + +CHAPTER X. + +TRANSPORTATION OF HEAT. + + +"To-day we come to that subject which we should have looked at a week ago, +if that I hope not unprofitable discussion of the uses of trials and the +ministry of pain had not prevented. We must now examine the arrangement +for softening the rigors of winter and toning down the heat of summer. The +general principle is that in summer the earth receives an excess of heat, +while in winter the opposite is true. These extremes are mitigated by +transferring heat from summer to winter. How is this accomplished? Any one +who has thoughts upon this subject may answer." + +"I have some thoughts," said Ansel, "but whether right or wrong, I cannot +tell. I should think heat might be carried from summer to winter in the +same way as from day to night." + +"What are some of those means for transferring heat which seem to you to +operate the same in the annual as in the daily changes of temperature?" + +"One is the absorption and radiation of heat, and another is the +evaporation of water and the condensation of vapor." + +"You are right," said Mr. Wilton. "The effect of these operations in the +equalization of the annual extremes of heat is in no wise different from +their effect upon the temperature of day and night, but from summer to +winter their effect is vaster and more impressive. During the summer, sea +and land, and 'all that in them is,' are receiving heat and rising in +temperature. The heat of summer penetrates and warms the earth nearly a +hundred feet in depth. Into the sea heat penetrates still deeper. How vast +the amount of heat required to warm the whole surface of the earth and sea +to such depths! By withdrawing so much heat from active use the intensity +of the summer temperature is softened. During the colder months the land +and sea slowly radiate their heat. We can hardly over-estimate the effect +of this alternate absorption and radiation of heat. So great is the +effect of this stored up heat that the sea and the great lakes never +freeze even in the coldest winter weather, except in the polar regions, +and the temperature must fall far below freezing and continue for a long +time below the freezing point before the earth begins to freeze. The great +bodies of water, remaining always at a temperature above thirty-two +degrees, are especially important in warming the wintry air. In the +coldest weather they seem like steaming caldrons throwing up their warm +vapor. It is the absorption and radiation of heat alone which prevent the +temperature of the atmosphere from rising or falling suddenly to the +highest or lowest point possible. The sun breaks forth in all its splendor +at noonday in summer: what if the sun were to remain stationary, shining +thus in his strength for days and months? Everything would be consumed +with heat. But why do not the glowing rays of the sun raise the +temperature at once to the highest possible point? Because the earth and +sea and every object upon the earth absorb the heat, storing it up and +holding it in reserve. On the other hand, when the sun sets and his heat +is withdrawn, why does not the temperature fall suddenly to the lowest +possible point? Because the heat held in store is slowly radiated and the +change of temperature rendered gradual. + +"In this work of absorbing and radiating heat every object, earth, air, +and sea, does its appropriate share. But water stands chief, and performs +the largest service. Its high specific heat enables it to hold in store +the largest calorific treasure, and causes it to change its temperature +more slowly. + +"The formation and condensation of vapor also operate in the same manner +as in the transitions of day and night. During the summer the higher +average temperature makes it possible for a much larger amount of vapor to +be formed than in winter. You remember that at eighty degrees vapor equal +to thirteen inches of water can sustain itself, while at thirty-six +degrees the elastic force of vapor is equal to the pressure of only two +inches and two-fifths of water, and at four degrees to three-fifths of an +inch. If the mean summer temperature at any place were eighty degrees, it +would be possible for more than one foot of water to be held in the form +of vapor. In the formation of this vapor heat would be consumed +sufficient to boil more than five and a half feet of ice water. If the +mean winter temperature at the same place be thirty-six degrees, more than +three-fourths of this vapor must be condensed and give out its latent heat +to warm the air. It is not to be supposed that the full amount of vapor +which can support itself does commonly exist, but the difference between +the average amount of vapor in summer and in winter must be very great. I +suppose this difference often amounts to four or six inches of water. If +we suppose it to be four inches, an amount of heat is transferred from +summer to winter sufficient to boil twenty-two inches of ice water. In +estimating the effect of this we must consider that this heat is not given +out gradually and regularly for three months, but whenever there is a +sudden fall of temperature vapor is condensed, latent heat becomes +sensible, and the suddenness and intensity of the fall are diminished. We +need also to bear in mind that every open body of water is sending up its +clouds of vapor constantly. The open lakes, and especially the sea, are +like a seething caldron; and thus immensely more vapor is condensed during +the winter months than is brought over from summer to winter. Much of the +vapor formed in winter is to be set to the account of summer, for it is +the summer's heat absorbed by the water, which maintains its temperature +and enables it to throw up such clouds of vapor, even in midwinter. But +this comes in more properly at another place, and we will leave it for the +present. + +"There is another transition experienced by water by which heat treasured +up in summer is made available for softening the rigors of winter. Who +will suggest it?" + +"It is the freezing of water," said Mr. Hume. "In the process of +crystallization one hundred and forty degrees of latent heat become +sensible." + +"And this," continued Mr. Wilton, "is no inconsiderable matter. Every +pound of water frozen upon the surface of our lakes and rivers, every +pound of water frozen in the wet earth, every pound of water frozen as +snow or sleet in the air, gives out as much heat as would boil an equal +amount of water at seventy-two degrees. Have you never heard of setting +tubs of water in cellars to keep vegetables from freezing?" + +"I have," replied Peter. "I visited my grandfather two years ago, and his +cellar sometimes froze. I asked him why he put tubs of water in his +cellar, but he could not tell me, only he said that he knew that tubs of +water in his cellar did keep his vegetables from being nipped with the +frost." + +"Can you tell us, Peter, why tubs of water set in a cellar should have +this effect?" + +"I suppose that when the water begins to freeze it begins to give out its +latent heat." + +"That is one part of the reason. The water is drawn from the well at +perhaps fifty degrees; it must lose eighteen degrees of heat before it +begins to freeze, and all the heat which the water loses the air of the +cellar gains. And then, as you said, as soon as the water begins to freeze +latent heat begins to become sensible. Every pound of water frozen sets +free heat enough to raise a pound of water through one hundred and forty +degrees. But why do not the vegetables begin to freeze as soon as the +water?" + +"I don't know." + +"Water holding salt or other minerals in solution freezes at a lower +temperature than pure water. For this reason the juices of vegetables and +fruits and the sap of trees may be cooled below thirty-two degrees +without freezing. On this account the water set in cellars tends to +prevent vegetables from freezing; the water begins to freeze at thirty-two +degrees, while potatoes and turnips may be cooled a little lower than +thirty-two degrees without harm. In this manner the buds of trees are +sometimes warmed and protected by the coating of ice which forms around +them. The drops of water, falling through the sleety air, touch upon the +twigs of trees and freeze upon them, an icy coat embracing them all +around. In freezing, the water gives out one hundred and forty degrees of +heat, a part of which goes to the air and a part to the twig." + +"This reminds me," said Ansel, "of what the Irishman said on being told +that snow contains heat, that 'it would be a blessed thing for the poor if +one could tell how many snowballs it would take to boil a tea-kettle.'" + +"It might be difficult to use snowballs to boil the tea-kettle, but the +heat given out in the formation of the snowflakes is doubtless employed +quite as usefully for the poor as if used in preparing their tea. You have +all noticed that before a snow-storm, or perhaps during the early part of +the storm, the temperature generally becomes milder, and you have often +heard the remark, 'It is too cold to snow.' Men have learned that the +coming of a snow-storm is attended by a warming of the air. This popular +impression is philosophical, yet few understand its philosophy. A foot of +snow falls, equal to two or three inches of water. In the condensation of +the vapor which formed this snow one thousand degrees of latent heat +become sensible, and then in the congelation of the clouds into snowflakes +one hundred and forty degrees of heat are evolved. This softening of the +rigors of winter is, I think, as great a blessing to the poor as the +heating of the tea-kettle. Let us make an estimate of the amount of heat +set free in the production of one great snow-storm. Two feet of snow +falls, equal, we will suppose, to five inches of water. In the +condensation of the watery vapor one thousand degrees of heat are evolved, +and in the congelation one hundred and forty degrees--an amount of heat +which would boil three feet of cold spring water. In every square mile +there are 27,878,400 square feet, and a square mile of water three feet in +depth would contain 83,625,200 cubic feet. The production of such a +snow-storm sets free for every square mile of surface heat which would +boil more than 80,000,000 of cubic feet of spring water. Such a storm +sometimes extends over a region of country a thousand miles square, that +is, over a million of square miles. In the production of one such storm--a +very heavy and extensive storm, I have supposed--heat is generated which +would boil eighty millions of millions (80,000,000,000,000) of cubic feet +of spring water--an amount altogether too vast for our comprehension. To +accomplish this result by combustion would require more than 500,000,000 +of tons of anthracite coal--an amount at least three times as great as the +yearly product of all the coal-mines of the world. And this is but one +heavy storm. The amount of rainfall in the United States may be thirty-six +inches or forty or forty-five inches. Supposing the average rainfall of +the whole earth to be twenty-four inches--an estimate very far below the +truth--we have this result: There are, in round numbers, two hundred +millions of square miles of surface, more than five and a half +quadrillions (5,575,680,000,000,000) of square feet and more than eleven +quadrillions of cubic feet of water. The condensation of this amount of +vapor would boil more than sixty quadrillions of cubic feet of ice water. +One pound of anthracite coal burned under the most favorable circumstances +will boil sixty pounds of ice water. To boil sixty quadrillions of cubic +feet of ice water would require sixty quadrillions of pounds of +coal--thirty billions of tons--not less than twenty-five tons to every +inhabitant of the globe. At this rate a very few years would exhaust the +coal-fields of the world. Calculations like these are useful in showing +upon how stupendous a scale the Creator carries on his operations. But we +must remember that these works are carried on, not to amaze men, but to +benefit them. The works go on silently and unseen, challenging no +attention from fools, receiving no thought except from the patient student +of Nature, and eliciting no thankful recognition save from a few reverent +worshipers. + +"But I have been led away from a point which I had in mind. While +considering the effect of heat in expanding bodies, I reminded you that +water presents a marked peculiarity, and promised to speak of it more +fully. This is the place for us to look at this singular and beautiful +peculiarity of water. What is the general principle touching the effect of +heat upon bodies?" + +"Heat expands bodies and cold contracts them," answered Ansel. + +"Water both illustrates this rule and presents some very interesting +apparent exceptions. It contracts by cold like other bodies till it +reaches the temperature of thirty-nine and a half degrees; it then begins +to expand, and expands regularly till it falls to thirty-two degrees; at +that point it freezes, and in freezing it expands at once about one-ninth +of its bulk. If the cooling process be continued, the ice produced +contracts like any other solid. This peculiarity of the interrupted and +unequal expansion of water is of the utmost importance in the affairs of +our world. Consider the result if the water were to contract by cold as do +other bodies down to the freezing point and below it. Water is cooled from +the top by contact with the cold air. As the upper film of water cooled it +would sink and a new stratum be brought to the surface; that in turn would +be cooled and sink, and thus the cooling process would go on with the +utmost rapidity till the whole body of water should be reduced to the +freezing temperature. Then congelation would begin, and the first +particles of ice formed would sink to the bottom, and as fast as the water +became frozen at the top the ice would sink. In this manner a solid body +of ice would be formed at the bottom of our lakes and rivers, while the +surface would remain unfrozen in contact with the cold air till the whole +body of water became a compact mass of ice. Great lakes turned to solid +ice would not be thawed during the whole of the summer, for the water +warmed from the top would not sink, but would form a warm stratum of water +upon the surface, while, below, the solid ice would lie hardly feeling the +summer heat. Nay, more; in the higher latitudes it would seem as if the +very ocean must be turned to solid ice, never to be melted till the end of +time. By the singular expansion of water below thirty-nine and half +degrees and its great expansion in congelation, these disastrous +consequences are prevented. Our lakes are cooled even in winter only to +thirty-nine and a half degrees; below this temperature the colder water is +lighter and remains upon the surface; ice floats upon the surface. The top +becomes ice, but the great mass of the water remains at thirty-nine +degrees, and the inhabitants of the waters live on unharmed. Spring comes, +and the ice, being upon the surface, is soon melted, and the unbound waves +begin again to ripple forth their unconscious joy." + +"Do you look upon this irregular expansion and contraction of water," +asked Mr. Hume, "as a real exception to the rule that heat expands +bodies?" + +"Not at all. In freezing, a new force comes in and asserts itself--the +force of crystallization; or, more exactly, as the force of heat +diminishes the force of crystallization becomes predominant, and throws +the atoms into new positions and new relationships. To this new +arrangement of atoms is due the expansion in freezing. Ice contracts and +expands by cold and heat the same as any other solid. The attraction of +crystallization begins, doubtless, to throw the atoms into their new and +crystalline arrangement at the temperature of thirty-nine and a half +degrees. + +"We must remember that the heat which is set free in the condensation of +vapor and in the freezing of water is absorbed in the formation of vapor +and the melting of water. As much heat is taken from summer as is +conferred upon winter. The summer is cooled as much as winter is warmed. +The formation of vapor is a cooling process. Water is prevented from +rising above the boiling point by the formation of vapor. Perspiration +cools us by the evaporation to which it gives rise from the whole surface +of our bodies. And the higher the temperature, the more rapid the +evaporation, and the more vigorous the cooling process. + +"We might look at other appliances for transferring heat from summer to +winter, but they belong in principle to another department. We have now +looked at some of the means for transferring heat in time. The heat is +treasured up at the heated noonday, to be brought out for use during the +cool hours of night; it is garnered from the excessive heats of summer to +supply the deficiencies of winter. It is laid up in store to-day to be +expended at any future time when needed. The transfer is a transfer not in +space, but in time. We must hereafter examine those arrangements by which +heat is transported through space. Some of these arrangements exert an +influence upon day and night and upon summer and winter, and thus throw +further light upon the subjects already discussed. Already more than once +topics have been suggested and their full consideration put off till some +more fitting time. In our next lesson we must begin the examination of +these new principles. We have before spoken of the vicissitudes of days +and seasons and years. We shall now have to do with the vicissitudes of +zones and lands and seas, of deserts and mountain ranges. The elements +become vaster, the stage is broader, and the movements more sublime. + +"I am glad that you are so well interested in these great and beautiful +works of God's wisdom and power, but I hope that you do not forget that +the crucified Christ is pre-eminently the power of God and the wisdom of +God. These natural works are but the husk of which salvation from sin by +Christ is the kernel. These outward things are wonderful and beautiful for +the setting, but the gem, the royal precious stone, the Koh-i-noor, the +'mountain of light,' for which the setting was made, is the true knowledge +of the true God and of his Son Jesus Christ. During the past few weeks you +have heard others asking, 'What shall we do to be saved?' I should be +greatly guilty if I allowed you to think earth, air, and sea, with all +their silent and solemn movements, more important than our spiritual +attitude toward God the Father and Christ the Saviour. Are you, Samuel, in +your interest in studying Nature, forgetting Christ and the souls of men?" + +"I hope not, and I think not. During the three years since my baptism I +have never felt so much my obligation to Christ as now. I never felt +before so deep a desire that my friends should repent and believe in +Jesus. I think the love of Christ constrains me. I have not felt before +that my work was very important; I have been expecting to work more +earnestly by and by; but lately I have felt that Christ gives me something +to do now for which he holds me responsible." + +"What have you tried to do for Christ?" + +"I have been praying for some of my young friends, and especially for +Ansel and Peter. And then I felt that I must talk with them as well as +pray for them." + +"And can you, my young friends, be careless about your own salvation while +Samuel is so anxious for you? Are you contented to live 'having no hope +and without God in the world'? Is your happiness here and hereafter more +important to Samuel than to yourselves?" + +"We are interested," said Ansel. "We have been talking together about +being Christians, but we don't know what to do." + +"They said," broke in Samuel, "that they wished I would ask you to preach +a sermon and tell them what they must do to be saved. They wished to go on +with these lessons, but they thought that perhaps you would be willing to +preach a sermon just upon that subject." + +"You know that I often speak of that subject, and when persons have come +to the inquiry-meeting I have told them what they must do. But I know that +there must needs be 'line upon line.' If Ansel and Peter wish it, I will +devote a sermon to the subject, and make it as plain as I can. Hardly +anything gives me more pleasure than to explain the way of salvation when +I know that my hearers are interested." + +"We do wish to have you preach upon that subject, and I am sure that you +will have a great many interested hearers besides Ansel and myself." + +"But, Samuel, did you not pray for Mr. Hume also, and talk with him?" + +"I prayed for him, but I was afraid to speak with him. I have tried to +pray for him a double portion because I could not speak with him." + +Tears gathered in Mr. Hume's eyes; the thought came to him that his +unbelief had raised a barrier between himself and both God and his people. +This pious young man was afraid to come to him lest he should meet the +scornful arguments and cold derision of a proud unbeliever. He felt +humbled--he, a subtle, well-read unbeliever, and Samuel a pious lad +yearning for the salvation of his soul, but daring only to pray in secret +for him. + +"Have not you, Mr. Hume, been treating Christ and the Holy Spirit as +Samuel feared that you would treat him?" + +"Perhaps so," he answered. "I am sorry that Samuel did not come to me +freely. I think he need not be afraid of me now. I also hope you will +preach the sermon which Ansel and Peter wish to hear." + +Mr. Wilton assured them that he would do as they wished unless the Spirit +clearly drew him to some other subject. "I always look," he said, "to the +Holy Spirit for direction in my preaching. 'When he, the Spirit of truth, +is come,' said Jesus, 'he will lead you into all truth.' This was +fulfilled pre-eminently, I suppose, in the inspired men who laid the +foundation of the Church, but the Spirit still dwells in believers and +leads those who love and follow Christ. The preacher of the gospel can do +nothing without the power of the Spirit of God." + +And I, kind reader, will give you the outline of the sermon if the Spirit +bids him preach it. + + + + +CHAPTER XI. + +AN EFFECTIVE SERMON. + + +Mr. Wilton preached the sermon spoken of at the close of the last chapter +the next Lord's Day morning. The more he thought upon the matter and +inquired the mind of the Spirit, the more he felt that for a purpose the +Spirit was calling him to unfold again the authority of God and the +conditions of salvation. He gave notice of his subject, and invited all +good men to pray that he might be able, like a good and wise steward of +the mysteries of grace, to bring forth out of the treasure-house things +new and old, and that the word might prove as a nail fastened in a sure +place by the Master of assemblies. Much prayer was offered, and the people +came together in a spirit of unwonted solemnity and earnestness. + +Mr. Wilton prayed to the glorified Redeemer for his blessing: "O thou +exalted Christ, we assemble in thy name and by thine authority. Thou hast +bidden us not forsake the assembling of ourselves together for thy worship +and the preaching of thy gospel. By thy grace we enjoy another of these +sacred days. By thy death thou didst purchase for thy people eternal +redemption. Thou hast wrought out for them a great and glorious salvation. +For thy great love wherewith thou hast loved us thou didst empty thyself +of divine glories, and madest thyself a servant among servants, and didst +suffer in the garden, and die upon the cross, and enter the grave. Now +thou art exalted at the right hand of the Father, a Prince and a Saviour, +to give repentance and remission of sins. O thou that judgest men, thy +justice is great and glorious as thy mercies. Years ago we tested thy +love, years ago we felt the shadow of thy wrath; our guilt made us afraid +and we cried unto thee, and thou forgavest our sins, and didst shed abroad +thy peace in our hearts. In these recent days thou hast brought other +sinners to feel their guilt. They have seen thee upon the cross, and have +been smitten with anguish, and have repented, and thou hast received +them. Others are bowed down; they mourn; they feel themselves poor and +needy; they confess thy justice; they feel the need of thy salvation; they +walk in darkness; they grope and find no light; they look unto thee from a +distance; but they do not come to thee, they do not follow thee. Wilt thou +not draw them to thyself? Wilt thou not bow their pride of heart and turn +their wills and make their hearts tender, gentle, and believing? Wilt thou +not smite the rock, and cause the waters of penitent grief to flow? Lay +thy cross, O Jesus, upon their shoulders and upon their hearts, that they +may bear it after thee and share thy glory. Open thou their eyes that they +may see eternal destinies and look upon thy divine glories, thy beauty, +and thy tenderness. Let them follow thee and trust in thee, strengthened +and comforted by thy rod and thy staff. O Christ, for thine eternal love +with which thou hast loved us, reach down thine arm mighty to save and +lift us up. Lord, save or we perish. And speak thou by thy servant to-day, +and cause all that hear to recognize the message not as his, but as +thine." + +He read as his text Acts xvi. 30: "Sirs, what must I do to be saved?" + +He briefly recited the arrest, imprisonment, and release of Paul and +Silas. "The salvation for which the jailer cried out was not deliverance +from the dangers of the earthquake, nor from the displeasure of the Roman +governor. This was the bitter cry of a soul sinking under a load of guilt +and trembling at the thought of God's impending wrath. Some of you can +appreciate his feelings and his fears. Your sins against God and Christ +and the Holy Spirit have risen up before you; they stare you in the face; +they condemn you. You feel your guilt--not a light and trifling fault, but +guilt deep and dark, such as creatures made in the image of God incur by +rebellion against the blessed and holy Creator. The Holy Spirit has +recited the divine law in your ears. Your consciences have heard that +voice and echoed its condemnation. You desire to escape that divine +displeasure; you desire to have the fires of guilt that burn in your +consciences quenched. You cry out, 'Men and brethren, what shall we do?' +The answer must be drawn from many parts of the Holy Scriptures. + +"Understand, in the first place, that you are not to be saved by searching +out some plan of salvation for yourselves. Ask for the old paths. 'He that +entereth not by the door, but climbeth up some other way, the same is a +thief and a robber.' 'Other foundation can no man lay than that is laid.' +'There is but one name given under heaven among men by which we must be +saved.' + +"Understand also that it is useless to attempt to save yourselves by +making yourselves righteous. You have tried, I doubt not, to make +yourselves better. Perhaps you have resolved that you would not come to +Christ till you can present yourselves in some degree worthy of his care. +Have you succeeded in getting rid of your sins? Can you blot out your past +sins? Can you erase the record which stands written in the book of +remembrance on high? The law of God written in this Bible condemns you; +God condemns you; you are condemned already for not believing in the name +of God's only begotten Son, the Lord Jesus from heaven. Can you change +that condemnation by your feeble, fickle resolutions to reform? 'Can the +Ethiopian change his skin or the leopard his spots? then may ye also do +good that are accustomed to do evil.' + +"Be assured also that it does not belong to you to change your own hearts. +'Ye must be born again;' 'except a man be born again he cannot see the +kingdom of God.' But that second birth comes not of blood, nor of the will +of the flesh, nor of the will of man, but of God. 'Ye must be born again, +but ye must be born of the Spirit.' Notice that the word _saved_ is in the +passive voice. Sinners do not save themselves; they must be saved by +another; they must be saved by one able to save, by one almighty to save, +from the wrath of God and from sin, by one able to do for those who trust +in him all that they need to have done in order to make their salvation +complete and glorious. Christ is able to do this. The crucified and risen +Christ is exalted a Prince and Saviour, to give repentance and remission +of sins. The word of God says, 'To give,' and he rejoices to give. + +"On one point we must pause and dwell with special clearness. Every +anxious sinner must not only feel his guilty and lost condition, but he +should also thoroughly understand what he means when he asks what he must +do to be saved. He should see to it that he wants that salvation which +Jesus gives. + +"In the Scriptures the sinner who would be saved is called upon to return +to God. He has gone astray. He must retrace his steps. What is meant by +this? I mean that man's sin consisted at first and consists to-day in +saying, 'I will,' and 'I will not,' in opposition to the will and command +of God. God said, 'Thou shalt not;' man said, 'I will.' God says, 'Thou +shalt;' sinners say, 'I will not.' If a sinner is to be saved from sin, +this opposition must cease. When God says, 'Thou shalt not,' the sinner +must reply, 'I will not,' and when God says, 'Thou shalt,' the sinner must +answer, 'I will.' The sinner's 'will' and 'will not' must agree with God's +'shall' and 'shall not.' In place of your self-will you must put God's +will; that is, repentance, a turning about, a returning to God. But +remember, salvation, if it be real and thorough, is not submission for an +hour, a day, or a year, but submission for ever and ever. It is submission +without condition and without limits. + +"The sinner says, 'This is a hard saying,' this utter and boundless denial +of self-will and selfishness. But is it hard that the creature should +yield to the Creator, that ignorance should yield to wisdom, that +selfishness should yield to love, that sin should yield to holiness, that +poor, lost, wretched, fallen man should yield to the eternal and +ever-blessed God? It is only by yielding that his will is brought into +sweet harmony with the will of God, and that he can be a sharer of the +divine blessedness. + +"Your views on this point should be clear and distinct. If you wish only +to be saved from the penalty of your sins, you do not desire the salvation +which Jesus gives. He saves his people, not in their sins, but from their +sins. If, however, you really wish for his full and glorious salvation, +you will desire that your will may be wholly subdued to the will of God. +You will be found ready to unite in the memorable prayer of the Lord +Jesus, 'Not my will but thine be done.' Salvation implies the giving up of +self-will and a reverent submission to the will of God. + +"Other sinful passions oppose the grace of God, but chiefly as helpers and +supporters of self-will. Pride and vanity strengthen self-will. Turbulent +fleshly lusts urge on and back up self-will. Fear of man, fear of danger, +and unbelief are but props of self-will. When 'my Lord Will-be-will' +submits, the town of Mansoul returns to her rightful allegiance. + +"The question at issue between God and the sinner, the question of +self-will or submission, is often contested around the performance of some +single definite duty. The Holy Spirit often presents to the convicted +sinner's conscience some single duty and presses its performance. That +duty is a test of the feelings and desires of the sinner's heart. So the +Spirit understands it, so the sinner often understands it. As, in the +garden of Eden, God gave to Adam a test command, so does he now press upon +the conscience of convicted sinners test duties to show them what they +are. That which is required may be important, exceedingly important, in +and of itself, or it may be in itself of very little consequence, but in +every case the duty is all-important and its performance absolutely +essential, because the Spirit has laid it upon the sinner's conscience. It +will show whether he wishes for salvation from sin or not. + +"I used to hear a Christian relate an experience like this. While the +Spirit of God was striving with him and conviction of sin was heavy upon +him, he felt a clear impression that he ought to go to his barn, and there +at one certain place upon the hay-mow kneel and pray. His self-will rose +in rebellion, chiefly, it would seem, because it was laid upon his +conscience as a duty. But his distress grew upon him. He went to his barn +and stood at another place and tried to pray, but no light or peace came; +his sense of his sins grew heavier. How could it be otherwise? He went to +the spot where he thought that he ought to go, and stood and prayed. Still +no peace came, but increasing sense of sin. At length he thought, 'Why +should I not? Why not give up my own will? Why not pray that God's will +may be done?' He yielded, he kneeled at the place where he had thought he +ought to kneel, and there he first felt peace before God. This was a +singular experience. Perhaps a man more intelligent and better taught in +the Sacred Scriptures would never have such a thing pressed upon his +conscience. But the battle of self-will is commonly fought around some +single definite duty. That duty may be a confession of wrong done to a +neighbor, or conversation with an impenitent associate, or a public +confession of sin before the great congregation. Whatever it may be, it +shows the sinner his heart and leads him to decide to follow his own will +just as he had always been accustomed to do, or it will lead him to pray +earnestly that he may be enabled in everything to bow his will to the will +of God. He will want the full salvation which Jesus in his grace brings +men--salvation from the penalty of sin and deliverance from its power. + +"I draw no bow at a venture and speak not doubtfully when I say some of +you are standing face to face with duties pressed upon you by the Holy +Spirit. Your self-will, supported by pride, and fear of man, and unbelief, +and Satanic temptation, refuses to yield. The yoke of Christ seems to you +like bondage. The cross is supremely heavy. You draw back from it, and +refuse to bear it. I cannot take away the cross which the Spirit bids you +bear. I dare not do it; I will not do it. As the messenger of Christ, I +repeat the voice of the Spirit and lay the duty, whatsoever it may be, +upon your consciences. Do you really and honestly wish to be saved from +sin? Then you will yield to the Spirit's kind and gracious movings; you +will yield humbly but heartily. If, however, you want something else than +the salvation which Jesus gives, what can you expect but perplexity, +difficulty, darkness? I beseech of you, deal truly and faithfully with +yourselves on this point. + +"To those who wish really to be saved I have good news to proclaim. There +is a Saviour such as you need. Trust in Jesus as your Saviour. Place the +whole work of your salvation in his gracious hands. Christ saves sinners +just such as you are. The faith which you are but to exercise is nothing +else than your confidence, by which you entrust yourselves to him. Faith +has no saving virtue in itself, but it is the hand by which the sinner +takes hold of Christ. With this duty few of you will have any great +difficulty. When once you wish to be saved from sin and are ready to +submit to the will of Christ, you will have no reluctance to take him for +your Saviour. You believe that Christ is a divine Saviour. If saved at +all, you expect to be saved by him who died on Calvary. Hardly for the +world would you resign your opportunity of coming to Christ and receiving +his grace. You believe that Jesus is the Christ, the Son of the living +God, the great sacrifice for sin. It remains that you should gladly accept +what he offers and follow him as loving, trusting disciples. + +"Follow the Spirit, and you will be led to Jesus and will come speedily to +the joy of salvation; resist the Spirit, and you grope in boundless +darkness and fall upon the dark mountains. + +"In the Holy Scriptures the question of the text is asked and answered +many times. Hardly any two answers are alike. Are there different +conditions and different duties required of different men? By no means. +But the Holy Spirit adapted the answer to the different spiritual states +of the various inquirers. The answer is made to each questioner's heart. A +self-righteous young man came to Jesus asking, 'Good Master, what good +thing shall I do that I may inherit everlasting life?' Jesus answered, +'Keep the commandments: thou shalt do no murder; thou shalt not commit +adultery; thou shalt not steal; thou shalt not bear false witness; honor +thy father and thy mother; and thou shalt love thy neighbor as thyself.' +The young man answered, 'All these have I kept from my youth up; what lack +I yet?' Jesus said, 'If thou wilt be perfect, go sell that thou hast, and +give to the poor, and thou shalt have treasure in heaven, and come, +follow me.' The young man went away sorrowful. Jesus knew his +self-righteousness, and gave him answers which opened that young man's +eyes to see himself. He gave him a test command, and the young man's +revulsion from that duty showed that, notwithstanding his self-confident +claim to righteousness, his riches filled all his heart. If your hearts +are filled with the love of the world, you must put your possessions out +of your hearts and follow Jesus. + +"Nicodemus also came making the same inquiry. He must have asked something +like this, for Jesus answered such a question. 'Ye must be born again; ye +must be born of the Spirit,' said Jesus. Nicodemus was looking for a legal +salvation by outward formal services, but Christ gave him to understand +that salvation involves a great spiritual renovation wrought by the Holy +Spirit, by which men old in sin become new creatures and enter the kingdom +of God as little children. He taught him thus that salvation was only from +God. If any of you are looking for a cloak of self-righteous religious +duties which you can put on, be assured that true religion springs from a +work of God wrought in the heart. You must be born again by the power of +the Holy Spirit. You must become new creatures in Christ Jesus. + +"On the day of Pentecost the great company of men 'out of every country +under the whole heaven,' while listening to Peter's pungent address, cried +out, 'Men and brethren, what shall we do?' 'Repent and be baptized, every +one of you, in the name of the Lord Jesus, for the remission of sins,' +answered Peter. Here were men who had a hand in crucifying Christ, or if +they had no active share in that deed of darkness, they had consented to +his death; they were partakers of the crime; very likely they had cried, +'Crucify him, crucify him.' They saw their sin, and were pricked in the +heart. Well might they repent of their rejection and crucifixion of their +promised Saviour, the Son of God, from heaven. Others were devout men who +had come to Jerusalem to worship. Like Simeon they may have waited long +for the consolation of Israel. How easy for them to enroll themselves +among the followers of Christ! All alike are commanded after repentance to +put on Christ by baptism. That burial with Christ was the symbol of their +dying and living again--of their dying unto sin and living again unto God. +The same duties are enjoined upon you. Repent of your long rejection of +the grace of God and his Son Jesus Christ, and before God and men devote +yourselves to his service by a public confession of Christ in baptism. + +"The jailer of Philippi was taken in the midst of his sins. He was holding +the servants of Christ in his dungeon. He knew for what offence they had +been seized, and he made himself a partner in the crime of persecuting +them by the zest with which he thrust them into the inner prison and made +their feet fast in the stocks. His conscience was ill at ease. Then came +the earthquake's shock, and he felt as if called to stand face to face +with his Judge. His soul was pierced through and through with a sense of +guilt. 'What must I do to be saved?' he cried in the bitterness of his +conviction. 'Believe on the Lord Jesus Christ, and thou shalt be saved,' +answered Paul. This is the answer to all of you who are well convicted of +sin and have given up all self-righteous hopes. Christ saves you. Look to +Christ, ask Christ; whosoever comes to him he will in no wise cast out. +Will you not come to him? Will you not trust his promises and commit +yourselves to his hands to be saved? He waits to bless you. He delights +to be gracious. To save sinners he lived among men, and died and has +ascended. His hands are full of gifts. He comes to you, and stands and +knocks at the door of your hearts. Will you bolt the door? There is joy in +heaven over repenting sinners. This alone of all earthly transactions +carries joy to Christ and the angels. Accept of Christ, and earth and +heaven will throb with a common joy." + +These words were listened to with most earnest attention, for at that time +Christ and heaven were realities in the minds of men, and salvation was a +living issue. Mr. Wilton spoke as an earnest man, without cant or +circumlocution, pressing upon men of thought and conscience the great +concerns of eternity. The full result of this discourse will be known only +when the opening of the books at the last day shall reveal it, but the +beginning of the result was seen in the evening prayer-meeting. When the +invitation was given for anxious persons to make known their feelings, +both Ansel and Peter arose, and confessing in few words that the Spirit of +God had been striving with them, and that they had been resisting the +Spirit, said that now they were determined to resist no more, and asked +Christians to pray for them that they might be able to submit fully to the +Lord Jesus and trust entirely in him. Then there was a pause. Mr. Wilton +was just on the point of rising to close the meeting when Mr. Hume rose to +his feet. After a sudden start of surprise, a deep hush passed over the +congregation, and in the midst of deepest silence Mr. Hume said: + +"I have been more than merely an impenitent man: I have been an +unbeliever; I have been an infidel. I have not only tried to disbelieve +the Holy Scripture, but I have actually disbelieved. I have thought myself +wiser than the word of God. I do not mean that I have enjoyed peace, that +my conscience has been at rest, and that I have been happy in my unbelief. +Three months ago I began to grow more than usually discontented with +myself. Questions which I counted settled and put to rest for ever came +back to trouble me. A hundred times a day the questions came, What if +there be a God who holds me responsible? What if there be a future life +and a judgment day? What if Christ be the Son of God? Why such questions +should haunt me day and night I could not tell. I have learned to believe +that the Spirit of God was speaking to me. This restlessness brought me to +the church for half a day. If my object was to gain rest in unbelief, I +could not have done worse. My old arguments were unavailing to break the +force of the truths preached. The questions which had been sounding in my +ears and echoing in my heart began to change to solemn affirmations: +'There is a God;' 'There is a day of judgment;' 'Appointed unto man once +to die, and after that the judgment;' 'Christ is risen.' Texts of +Scripture learned in my boyhood and forgotten long years ago came back +fresh to my memory. But I will not stop to rehearse to you all my +struggles of mind for two months past. For a few weeks you have seen me +here. I determined that I would try to find Christ if he manifests himself +to men in these latter days. For two weeks I have tried to pray, but I +have found no satisfaction. Christ has not manifested himself. My darkness +has grown deeper and deeper. I have sometimes almost determined to abandon +all thought of Christ and throw myself back again upon my former +unbelief. But I could not lay down the subject. + +"Since I began to try to pray I have felt, faintly at first, like the +whisper of a suggestion, but becoming clearer and stronger, like a voice +from heaven, that I must in this congregation confess my former state and +the feelings which I have had. It seemed to me that I could not do this. +It seemed easier to die than to stand up here and confess that my belief, +which I had pressed upon others and had boasted of as better than the +gospel, had given me no peace. To-day I have been made to understand that +the Spirit of God has set me face to face with this confession. I have +seen what it means to be saved--that my self-will must die or I must bid +adieu to Christ and hope. I cannot live and die hopeless. I cannot rest my +head upon unbelief. I confess to you that all my thoughts have been wrong. +My beliefs and my unbelief have done me no good. My whole life has been +enmity and opposition to the Holy Spirit. I will try to oppose the Spirit +no more. I know not what the Spirit may lay upon me, I know not how soon I +may break my resolution, but I now feel that I want to be saved from sin, +and cannot do otherwise than follow the Spirit though I dwell in darkness +for ever. If Christ reject me I cannot complain, but if you think there is +hope for one who has so despised the grace of God, I entreat you to pray +for me." + +It is needless to say that from scores of family altars and closets +supplications went up to God that night for the salvation of Mr. Hume and +Ansel and Peter, and men prayed especially that Mr. Hume, who for years +had been such a tower of strength to the ungodly and the dread of +Christians, might be saved for the glory of Christ and the confounding of +unbelievers. Those prayers were heard. When the report of that meeting and +that confession went out through the community, unbelievers were silent. +It was as if the God of battles had emptied his quiver into the hearts of +his enemies. + + + + +CHAPTER XII. + +TRANSFER OF HEAT IN SPACE. + + +"We now turn our attention," said Mr. Wilton, "to a new theme. In the +vicissitudes of day and night and of summer and winter heat is transferred +_in time_. We now are to look at the arrangements by which heat is +transferred _in space_. But since the transfer of heat in space requires +more or less of time, the means employed are such as suffice to accomplish +both objects. Heat is treasured up and carried away to distant regions, +and delivered up for use as occasion demands. + +"In a previous lesson the inclination of the earth's axis was spoken of. +By this means the northern hemisphere of the earth is turned somewhat +toward the sun during one half of the year, and receives a correspondingly +larger portion of heat, while during the other half of the year the +southern hemisphere is turned toward the sun and is warmed. This +inclination of the earth's axis to the plane of its orbit gives us the +change of seasons. + +"The change of seasons is manifestly designed for the welfare of man. +Along with the genial warmth of summer, fruits and grains and the comforts +of life are carried far toward the poles, into regions which otherwise +would be desolate with perpetual frost. But these extremes need to be +softened; otherwise, the violence of the changes would prove destructive +rather than beneficent. The severity of these annual changes of +temperature is ameliorated by some of the grandest movements and +arrangements upon our globe. These arrangements we have in a very +imperfect way already examined. + +"But there are other inequalities of temperature besides those of day and +night, summer and winter. Passing from the equator toward the poles, every +degree of the earth's surface passed over causes the sun to sink one +degree from the zenith toward the horizon, and gives a corresponding lower +temperature, till within the polar circles for a part of the year the sun +is entirely hidden and winter reigns without a rival. The temperature of +the sea differs from the temperature of the land; the sun comes nearer to +one hemisphere than the other, and remains longer north of the equator +than south. These and many other differences upon the earth give to +different parts of the world every possible variety of temperature and +climate. These differences of temperature upon sea and land, from zone to +zone and from hemisphere to hemisphere, are equalized or ameliorated by +many agencies, but chiefly by a transfer of heat in space, a transfer of +heat from place to place. + +"I do not need to tell you that while we in the northern hemisphere are +enjoying the warmth of summer the southern hemisphere is enduring the +severities of winter, and in turn, when winter comes to us, summer smiles +upon the nations that live south of the equator. You also remember that +the orbit of the earth is not an exact circle, but an ellipse, that is, +what is sometimes called in common language a long circle. For this reason +the earth is three millions of miles nearer the sun in one part of its +orbit than when in another part. Can you tell us, Peter, at what season of +year the earth is nearer the sun?" + +"In midwinter, or about the first of January. I have always remembered it +because it seemed so strange to me, when I learned it, that the sun should +be nearest the earth at the coldest season of the year." + +"Yes, one is reminded by it of the humorous argument that the sun must +emit cold instead of heat, because when we are at the point of the earth's +orbit which is nearest the sun it is winter, and the higher one ascends +upon mountains toward the sun, the colder he finds it. But this nearness +of the sun while south of the equator would naturally give the southern +hemisphere a warmer summer than the northern. For this there is a +beautiful compensation. The earth passes through her orbit more rapidly +when nearer the sun, and that half of her orbit is also smaller, so that, +as the result of this, the sun remains north of the equator about eight +days longer than in the southern hemisphere. The sun is nearer while in +the southern hemisphere, but the summer is shorter. That which the +southern hemisphere gains in distance it loses in time, and that which the +northern loses in distance it gains in time. + +"The nearness of the sun while south of the equator, the shortness of the +summer, and the corresponding distance of the sun and length of the +winter would tend to give the southern hemisphere great extremes of heat +and cold, a short and hot summer and a long and cold winter. For this also +there is a most interesting compensation in the comparative amount of land +and water north and south of the equator. Much more than one-half of the +dry land lies in the northern hemisphere. This would tend to give the +northern hemisphere extremes of heat and cold. South of the equator there +is comparatively little land and much water, which tends to give the +southern hemisphere evenness of temperature. The inequalities of the +earth's orbit and the earth's motion in its orbit we find counterbalanced +by the arrangement of land and water upon the earth's surface. + +"In connection with this we may notice still another compensation in the +elevation of the lands by which the burning heat of the torrid zone and +the rigors of the colder zones are more or less diminished. The greater +the elevation of any region of country, the cooler must be its climate. +Physical geographers like Baron von Humboldt and Guyot have made +calculations which show that those grand divisions of the earth which lie +in the hot regions of the earth are most elevated above the sea level. +South America lies higher than North America, Asia is more elevated than +Europe, and Africa is more elevated than Asia. The continents rise as they +approach the equator and sink toward the sea level as they come nearer the +poles. As these colder lands approach the water level their valleys sink +beneath the sea, their coast lines become deeply indented with bays and +gulfs, and lakes abound. Thus the warmer waters of the sea are +interspersed among the cooler lands, and the temperature of the lands is +raised. The very elevation of the continents and the configuration of the +lands have a providential relation to the temperature and climate of the +world. We cannot suppose that arrangements like these, so aptly fitted to +the needs of man, came by chance. In the unmeasured ages past, while this +earth was in preparation for man, God had the beneficent _end_ in view; +nay, in the very beginning, the whole plan and its beautiful completion +was had clearly in mind. Millions of ages ago the great Creator tenderly +considered the comfort and well-being of the human race, the latest born +of his creatures, in these last ages. + +"As a general statement, the torrid zone receives an excess of heat, while +the frigid zones receive too little, and the temperate zones, lying +between, receive, at different times and places, sometimes too little and +sometimes too much. The providential arrangements for equalizing +temperature are, then, chiefly arrangements for conveying heat from the +overheated tropical regions and scattering it over the temperate and polar +regions. First among these means we will notice the _trade-winds_, or, as +for the sake of brevity they are often called, 'the trades.' Will you tell +us, Samuel, how winds are caused?" + +"The air is heated at some place and expands; it becomes lighter and +rises, while the colder air around rushes in to fill its place." + +"You use the words which are commonly employed in explaining the origin of +winds, and very likely your idea is right, but the language needs a little +correction. The warm air does not rise of its own accord, so to speak, but +is pressed upward. The warm air is expanded; it presses outward and +upward; the same weight of warm air occupies more space than cold air; +the warm air rises and overtops the surrounding air, and then flows off in +order to reach the common level. The column of warm air is lighter than +the cooler air, and cannot balance it; consequently, the cold air sinks +down, pressing the warm air upward. In this manner an ascending current of +warm air is formed, and also currents of cold air flowing from every +direction toward the warm centre. These currents continue until the +temperature of the air is equalized. + +"The atmosphere is commonly believed to be forty-five or fifty miles in +height, though some men have estimated its height as very much less than +this, while others believe it to be six or seven hundred miles in height. +Are we to suppose that the column of heated air reaches to the top of the +atmosphere?" + +"I think not," answered Mr. Hume. "The rarefaction of the lower part of +the column renders the whole column lighter than the air around, and the +warm air, as we know by the movements of the clouds, after rising a little +way, spreads off in every direction, forming upper currents corresponding +to the currents below, but moving in the opposite direction." + +"Only a few days ago," remarked Peter, "I saw in the same part of the sky +clouds moving in exactly opposite directions, and others which seemed to +be standing still. I knew how one layer of clouds might be moving north +and another layer moving south, but I did not understand why some should +be standing still." + +"Do you imagine, Peter, that the upper and lower currents of air, moving +in opposite directions, come sharply together, the one sliding against the +other?" + +"I think not," said Peter. + +"Supposing, then, as is certainly true, that a stratum of still air lies +between the upper and lower winds, does not that explain how certain +clouds might be standing still while the others were moving?" + +"I might have thought of that myself." + +"But how does this carry heat from the warmer region to the colder regions +around?" asked Ansel. "I see how the colder air coming in would cool the +warm region, and how the warm ascending air would carry away the excess of +heat, but how do the cooler regions get the advantage of this heat?" + +"That is just what I was on the point of explaining. Do you remember what +was said about the production of cold by expansion and of heat by +compression?" + +"I remember that if air be rarefied by removing pressure from it, its +temperature falls: I think you said that a part of its sensible heat +becomes latent; and if air be compressed, its temperature rises. I have +seen experiments with the air pump and condenser to prove this." + +"That principle explains the transfer of heat by winds. If the heated air +rose to the upper regions, and there radiated its heat, nothing would be +gained; the heat would be simply radiated into space. But as the warm air +rises pressure is more and more removed from it; it expands; its sensible +heat becomes latent and is thus kept from radiation; its temperature +falls, but not from loss of heat. This rarefied air forms the upper +current flowing away from the heated centre. In due time this air must +come to the surface of the earth again. Whenever this takes place the air +is brought again under pressure; it is compressed, and its latent heat +becomes again sensible. Heat is thus transferred from the warmer region to +the colder in a latent condition, so that it cannot be lost. We must now +apply this to the trade-winds. What are the trade-winds, Mr. Hume?" + +"They are regular winds blowing from a little north and south of the +tropics of Cancer and Capricorn south-west and north-west toward the +equator." + +"These winds are called _trade-winds_," continued Mr. Wilton, "on account +of their great advantage to trade or commerce. The regular and steady +sweep of these winds bears the merchantmen rapidly and safely on their +way. The formation of 'the trades' is easily explained. By the intense +heat of the sun under the equator the air is greatly expanded and +rarefied; the heated air rises along the whole line of the equator; from +both sides the cooler air presses in, is heated, and rises; thus steady +winds are formed from the tropics, or a little beyond the tropics, toward +the equator. If the earth had no rotation upon its axis, these winds would +blow directly toward the equator, exactly south and north. The rotation of +the earth gives the trade-winds their oblique, south-west and north-west +direction. Suppose that a single particle of air at the tropic of Cancer +starts upon its journey toward the equator. At its starting it has the +same motion eastward as the surface of the earth at that place, that is, +about nine hundred and fifty miles per hour. But as it moves on southward +the degrees of longitude become longer and the motion of the earth's +surface becomes more rapid, till at the equator its motion is one thousand +and forty miles per hour. But the particle of air we are watching is not +fastened to the earth's surface, and as the earth moves more rapidly the +nearer we come to the equator, the particle of air falls behind, that is, +the air moves southward and eastward, but the earth moves eastward more +rapidly than the air, so that the air falls behind and seems to be moving +westward. The result is that the air upon the earth's surface moves +south-west. That which takes place with a single particle takes place with +the whole body of the air, and that which takes place north of the equator +takes place south of it also, producing north-west winds. On reaching the +equator the winds from the north and the south meet and stop, forming the +equatorial calms, and mingling together, they rise into the higher +regions. In rising, the air bears away heat from the torrid zone, and this +heat, rendered latent by the expansion of the air, is carried north and +south by the upper currents as far as the limits of 'the trades.' In due +time these upper currents descend and their latent becomes sensible heat, +and is used in raising the temperature. Mr. Hume, can you suggest any +method by which we can estimate the amount of heat which is carried north +and south by the return trades?" + +"I know of no method, except to estimate the amount of heat necessary to +raise that flood of air which pours in from the temperate zones to the +equatorial heat. That immense amount of heat must, nearly all of it, be +carried away to the temperate regions." + +"This is the general explanation of the trade-winds. You must understand, +however, that, in certain regions and under certain conditions, the trades +are liable to interruption or change of direction. Desert regions within +or near the tropics give rise to local winds which overpower the trades. +In Southern Asia, while the sun is north of the equator, the land becomes +so much hotter than the sea under the equator that the trade-wind is +overpowered and reversed, forming a wind which blows to the north-east +instead of the south-west. But this is only a beautiful flexure, so to +speak, of a general arrangement for the greater advantage of a particular +region. By this means the summer winds of Southern Asia come from the sea. +Northern winds would have been dry. Prevailing northern winds would have +made the whole of Southern Asia a desert; but the south-west monsoons come +from the Indian Ocean laden with vapor, and render Southern Asia a very +garden for fertility. + +"The next great agency for equalizing temperature between the torrid and +temperature zones is the formation and condensation of vapor. This comes +in here, because it depends for its efficiency upon the agency of winds. +More than once this method of conveying heat from place to place has been +hinted at, but deferred till we came to the proper place to speak of +winds. + +"The trade-winds, passing over from a colder to a warmer climate, are +constantly accumulating vapor. Under the equator the annual evaporation +from the surface of the ocean is set down at fifteen feet, or half an inch +daily. The formation of this vapor consumes heat which would boil more +than eighty feet of ice water. The vapor thus formed is borne upward by +the ascending current of heated air. On reaching the higher regions a +portion of it is condensed and forms a belt of clouds around the earth. +This belt of clouds along the equator is known as the 'cloud-ring.' This +cloud-ring shields the belt of calms from the burning rays of the sun and +sends down almost incessant rains. But does not that condensation which +forms the cloud-ring set free latent heat, and thus intensify the great +heat of the equator? Latent heat becomes sensible, but it is given out +into the ascending current of air, and serves only to give it another lift +till by expansion of the air it again becomes latent. The heat is simply +transferred from the vapor to the air. The vapor which remains uncondensed +is borne away on the wings of the return 'trades' to the south and to the +north, and in due time is condensed and returns to the earth as rain; the +heat which is given out by its condensation, wherever and whenever it is +condensed, is given over as latent heat to the keeping of the air, and is +passed back for use whenever the air descends to the earth. + +"Vapor gathered from sea or land is everywhere exerting this equalizing +influence upon temperature. Does the temperature rise in any place? Vapor +is formed. Every moist body begins to give up its moisture, and the excess +of heat is employed in turning this water into vapor. This is the method +by which perspiration cools man or beast; whether it be insensible +perspiration from the invisible pores of the skin, or perspiration +standing in beady drops upon the face of the toiling laborer, vapor is +formed and heat is carried away. Have you not noticed on close, muggy days +when nothing dries, showing that very little vapor is forming, that +perspiration seems to have no cooling effect? It oozes from the skin, but +does not evaporate, and hence does not carry off the surplus heat. Animals +like dogs and oxen, that do not become wet with perspiration, do not bear +heat well; they soon pant and loll, attempting to get rid of the excessive +heat through the moist breath and open mouth. + +"The sum-total of heat transferred by this agency is too great for +comprehension. Look at the Amazon rolling to the ocean a flood broad as an +arm of the sea. That great river is brought from the Atlantic Ocean on the +shoulders of the trade-wind. As the vapor is slowly lifted by the rise of +the land from the sea level to the summits of the Andes, it is condensed, +and falls as rain. Well is it for South America that the Andes were thrown +up on the western coast, for the winds west of the mountains are dry as a +pressed sponge, and the most of that narrow slope is barren and desolate. +South America would be a desert if the Andes ran along the eastern coast. +Look at the Mississippi, and the great rivers of Europe, and the matchless +rivers of Southern Asia. All the rivers of the world represent only the +_wastage_ of the rain which falls upon the land after supplying the wants +of the vegetable kingdom and keeping the lands moist. All this water is +lifted into the air by heat, and every movement of vapor is a movement of +heat. Every particle of vapor goes freighted with heat. Every cloud driven +across the sky represents the transfer of heat, and every transfer is in +the direction of equalization. Everywhere the tendency is to equilibrium. +Nature has no processes for transferring heat from colder to warmer +regions. + +"We may form a conception of the amount of heat transferred by the agency +of vapor by estimating the amount of heat-force required to evaporate the +water which forms our rain-clouds and lift them into the upper regions. +According to a calculation of Mr. Allen, late of Providence, to evaporate +one-eighth of an inch of water daily from that belt of the surface of the +earth lying within the tropics, and raise it five thousand feet high, +requires 4,700,000,000 horse-power, or one hundred and thirty times the +effective force of the whole human race, reckoning it at 250,000,000 +able-bodied men. But the actual evaporation from the sea within the +tropics is believed to be about half an inch daily--four times as great as +Mr. Allen's supposition. + +"I see, however, that our time is nearly exhausted, and I wish before +closing to revert to that more important theme upon which I spoke this +forenoon. I do not know how the truths preached interested or affected +you, nor do I now wish to have you tell me. I wish only to say that, as +the sermon was preached at your request, I hope it proved applicable to +you, and that you will give the truths presented earnest attention. +Consider them well, and make your conclusions known this evening." + +The conclusion which the evening made known, you, reader, have already +learned. + + + + +CHAPTER XIII. + +OCEAN CURRENTS AND ICEBERGS. + + +A week has passed since Mr. Hume made his frank confession. He went home +no lighter of heart than before, yet he felt in some respects different, +for he had attempted to do what was right in the sight of God. But he did +not feel the joy of sins forgiven. He had not looked upon Christ as a +Saviour for himself. He felt that God had distinctly set life and death +before him. His doubts were gone; the spiritual world was a reality; +Christ stood at his right hand and Satan at his left; he stood where the +path of destiny divided, the one path leading up to heavenly seats with +Christ, the other leading down to darkness and despair. A voice seemed to +be whispering in his ears, "This is the last call." He went to his chamber +determined, if possible, to settle the question of life or death before +he left the place and before he slept. He took his Bible, and on his knees +turned and read the Psalms at random. But the cloud of darkness only +gathered deeper. The words of David's penitential Psalm caught his eye: +"Against thee, thee only, have I sinned, and done this evil in thy sight." +He felt that these words of David were true in his case also. All his long +impenitence and bold unbelief had been against God. By night and by day, +for many a long year, before the sleepless eye of God, he had lifted up +his hand, almost defying the holy One, yet the lightning of God had not +smitten him. He wondered as much at the long-suffering of God as at his +own dreadful daring of the divine wrath. He had been taught better things; +he was trained to know the Scriptures and to go reverently to the house of +God, but he had turned from Christ and hope. He read on: "Deliver me from +blood-guiltiness, O God, thou God of my salvation." He felt that this +belonged to himself more than to David. David had shed the blood of +natural life, but he had destroyed the souls of men. He had stood chief +among unbelievers. He had led young men into infidelity. He had seen them +drink in his unbelief like water, throw off all restraint, and rush +headlong to ruin. He had wrought a work of evil which he could never undo, +and for which he could make no atonement. What was a confession in +comparison with the ruin he had caused? What could his confession do for +the young men already, perhaps, among the lost through his influence? +Could his late repentance call them back to life and hope? Would God +forgive and raise to heavenly heights a man who had dragged others down to +hell? Would it be possible that Christ should fill his soul with +blessedness while his victims were drinking the wine of the wrath of God? +A deep horror seized him. The darkness of eternal death seemed to enfold +him. Must he, then, after having caught a glimpse of life and joy, be cut +off from hope and be driven from God for ever? This would be just, but he +felt that he could not endure it. "O thou great and holy God," he prayed, +"I will ascribe righteousness to thee though thy righteous wrath shall +sink me to hell; but, O thou merciful God, my soul cannot endure thy +justice. The foretaste of thy wrath fills me with the pangs of eternal +death. O God, have mercy upon me. O God, blot out my transgressions. +Create in me a clean heart, and renew a right spirit within me. O Christ, +whom I have despised, cast me not from thy presence. Help me to submit to +thee. Help me to follow thee. Spare me that I may undo something of that +which I have done against thy glory and the souls of men. O Jesus, I can +do nothing to save myself. O Lord, have mercy on me, the chief of +sinners." + +He read the invitations and promises of Christ, and prayed again. Again he +read and again he prayed. Little by little the promises of Christ stirred +a feeble faith in his heart; he felt that there was still hope for him, +and with the determination to cast himself upon the sure mercies of Christ +and to devote himself to his service, he threw himself upon his bed, and +being wearied almost to exhaustion, soon fell asleep. When he awoke it was +broad daylight. He had slept a sweet, refreshing sleep. But he was +refreshed not merely in body. He woke to a new world. His heart was filled +with sweet thankfulness. "How beautiful," he said, "is God's world! I +never saw it so before, but the earth and sky seem clothed in glory. But +most wonderful of all is God's goodness to me. I have rebelled against him +all my life, yet he has loved me and sought for my salvation, and now the +sunlight of his love has broken through the thick clouds of my sin, and a +day of hope and joy has dawned upon my life. Christ has indeed revealed +himself. Blessed be his holy name for ever and ever! What shall I render +unto the Lord for all his benefits? I will take the cup of salvation and +call upon the name of the Lord. I will pay my vows now in presence of all +his people. I will teach transgressors thy ways, and sinners shall be +converted unto thee." + +All this was known to the people, for during the week Mr. Hume had spoken +of it in private and in public. He had told it to Mr. Wilton, and they had +rejoiced together. + +Ansel and Peter had also regularly presented themselves at every meeting +as anxious inquirers desiring the grace of God. Peter had also on his +knees said from the heart, "Here, Lord, I give myself away," and had +received the assurance that his sins were forgiven. The Spirit of God +witnessed with his spirit that he was born of God. He began at once to +use all his influence to bring his young friends to Jesus. The addition of +two such workers as Mr. Hume and Peter, each moving in his own circle of +acquaintances, gave a fresh impulse to the religious interest, which was +now becoming deep and pervasive. Especially had Mr. Hume's conversion, so +clear and positive, confounded those who had sat "in the seat of the +scornful," and many came in now for the first time to see for themselves +what it could be that had mastered their cold, clear-headed leader in +unbelief. + +But Ansel still walked in darkness. He had talked with Mr. Wilton, but no +light had entered his mind. He said that he thought he had submitted in +all things to the will of God. He was becoming impatient that Christ had +not come to him as to others. This was their condition as they came +together upon the Lord's Day. They all understood each other, and had no +need now to ask questions or make explanations. Mr. Wilton believed that +the study of God's works would not interrupt the working of the Holy +Spirit, and therefore went on with his lesson as usual. + +"We have already spoken of the transfer of heat from the torrid to the +temperate and frigid zones by the agency of winds and watery vapor. These +carry heat chiefly in a latent condition. But great movements of heat take +place in a sensible state. In this transfer of heat, also, water is the +great carrier. The winds and vapor go freighted with latent heat above, +and the waters and wind go freighted with sensible heat below. We will +first examine the operation of the ocean currents. + +"Not only do rivers run through the lands and hasten to the sea, but in +the midst of the oceans rivers are flowing in comparison with which the +Mississippi, the Amazon, and the Yang-tse-kiang are rippling brooklets. +The earth is belted by these ocean streams traversing the seas. An ocean +current, called the Gulf Stream, issues from the Gulf of Mexico between +the Florida coast and the Bahama islands. It flows northward off the coast +of the United States, gradually increasing in breadth and spreading over +the Atlantic Ocean. It is deflected by the New England coast and the great +shoals off Newfoundland, called the Grand Banks, or else by another +current flowing southward from Baffin's Bay, and strikes across the North +Atlantic, bathing the shores of the British islands and reaching even to +Iceland. + +"The general outline of the ocean currents is this: issuing from the South +Pacific, a current flowing eastward splits upon Cape Horn. The western +portion, called Humboldt's current, flows northward along the western +coast of South America, and is swallowed up and lost in the great +equatorial current of the Pacific. This is a broad current flowing +westward and covering the entire space between the tropics. Striking upon +the eastern shores of Asia, this equatorial current divides, one part +flowing northward along the coast of Asia, the other finding its way +through the many islands, sweeping across the Indian Ocean, and flowing +down the eastern shore of Africa on each side of Madagascar. Doubling the +Cape of Good Hope, the current continues in a north-westerly direction +across the Atlantic. Striking upon Cape St. Roque, this current again +divides; a part flows south and a part pours into the Caribbean Sea. From +the Caribbean Sea it issues as the Gulf Stream, of which I have already +spoken. This Gulf Stream impinges upon the western coast of Europe, and +pours partly into the North Sea and partly flows south off the western +coast of Africa, completing thus the circuit of the Atlantic. The currents +of the Indian and of the great Southern Oceans are as yet very imperfectly +understood. Of all the ocean streams the Gulf Stream is most famous and +best understood. I shall therefore use this as an illustration of the +agency of ocean currents in conveying heat and modifying climate. + +"The waters of the Caribbean Sea are heated by the tropic sun to +eighty-eight degrees. From these heated waters the Gulf Stream issues +salter and warmer, and of a deeper blue, than the waters of the +surrounding sea. Its greatest velocity as it issues from the gulf is a +little more than three miles per hour. As it flows northward its velocity +diminishes, its breadth becomes greater, and its depth less. It covers +thus with its warm waters a broad belt of the Atlantic Ocean, and extends +its influence to the most northern part of Europe. You can judge of the +amount of heat which is removed from the tropics when I tell you that the +unmeasured flood of the Gulf Stream would swallow up three thousand rivers +like the Mississippi. This one ocean stream is many times greater than +all the rivers of the world. We feel the warmth of the Gulf Stream with +every wind that blows from the sea. To this the British isles owe their +mild, moist climate and perennial greenness, and by its influence a winter +in Iceland, upon the Arctic circle, is no more rigorous than a winter in +Montreal, twenty-one degrees nearer the equator. But what is the Gulf +Stream, though it be fifty fold greater than all the rivers of the world, +in comparison with the whole sum of the ocean streams? Upper currents and +under currents fill the sea. They meet the explorers of the sea +everywhere. The navigator drops his measuring line, and finds it swept +away and drawn out by unseen currents. All these movements of the waters +are in favor of the equalization of temperature. The cooler waters of the +frigid and temperate zones are mingled with the heated waters of the +tropics and exchanged for the equatorial waters. The transfer of heat +would not be greater if broad rivers of molten lava were flowing from the +equator to the poles. + +"Another agency for the transfer of heat is the movement of ice, and +especially of icebergs." + +"Will you not tell us," said Samuel, "how these ocean currents are +produced? I can understand how winds are formed, but I do not see that +these streams in the sea could be formed in the same way." + +"I designed to speak of this, but for the moment it had slipped from my +mind: I am glad that you called my attention to it. I do not expect, +however, to give a full and satisfactory account of their origin. If I +should do this, I should succeed where every other man has failed. I shall +not attempt a full explanation. By some means or other, the waters of the +ocean are thrown out of equilibrium, and these currents are plainly an +effort to restore the balance or equilibrium of the waters. Many +influences and agencies conspire to disturb the equilibrium of the sea. +The attractions of the sun and moon are constantly counteracting the +attraction of the earth and lifting the waters, so to speak, above their +natural level. The tides produced by these attractions of the sun and moon +are the immediate cause of some of the minor local currents. The winds set +the waters in motion, tending to pile them up in one place and leave the +sea below its natural level at another. The effect of strong winds in +piling up the waters, even upon our great lakes, is very considerable. A +heavy east wind upon Lake Erie has been known to drive the waters toward +the western end of the lake so much as to leave Niagara River above the +falls almost dry. On the other hand, a heavy west wind drives the waters +eastward, and produces almost a flood in the river. The influence of +constant winds like the 'trades' acting upon an immense expanse of water +must be very much greater. Unequal evaporation tends to destroy the +balance of the waters. In the colder regions the evaporation is very +little, while within the tropics it amounts to about half an inch daily, +or fifteen feet per annum. The head of the Red Sea is two feet lower than +its mouth on account of evaporation. This unequal evaporation causes also +an unequal saltness, and consequently an unequal weight. The fresher and +lighter water cannot balance an equal bulk of salter and heavier water. +When once currents are started the revolution of the earth upon its axis +would affect them, just as the rotation of the earth affects the +trade-winds. Now, all these various agencies, and perhaps many others, +combine their influence to destroy the equilibrium of the waters of the +ocean. They unite and interweave their influence in a thousand ways beyond +all human calculation. The result is the ocean currents. But how much is +due to one cause and how much to another in the present state of knowledge +no man can tell. Only for a few years have the phenomena of ocean currents +been made the object of scientific observation and research. But the +effect of ocean currents in modifying climate is well understood, and the +modification of climate means nothing else than the transfer of heat. This +is all that I have to say of the rivers of the sea, and if there are no +more questions, we will now look at the movement of heat caused by +icebergs." + +No question was asked, and Mr. Wilton continued: + +"In polar regions there must be an immense formation of ice. Except in the +oceans, the movements of water are chiefly movements of water in the +condition of ice. Only for a small part of the year could water exist +unfrozen. Immense regions of the Antarctic continent seem to be covered +with one broad glacier. The ice pushes down into the sea until, +undermined by the dashing of the waves, it breaks off, and enormous +fragments are launched upon the deep waters. Sir James Ross saw in the +southern ocean a chain of such icebergs extending as far as the eye could +reach from the mast-head, many of them from one hundred feet to one +hundred and eighty feet in height and miles across. Captain d'Urville saw +one thirteen miles long and one hundred feet high. Its bulk was so vast +that though the waves were dashing against it not a tremor was +perceptible. Astronomic observations could be made from it as if it were +solid rock rooted in the heart of the earth. In the same manner icebergs +are formed in the northern ocean also. How much heat is given out in the +freezing of water?" + +"About one hundred and forty degrees," answered Peter. + +"In the formation of icebergs, then, heat is given out nearly sufficient +to boil an equal quantity of cold water. The icebergs float away toward +the equator. They come down from Baffin's Bay till they meet the Gulf +Stream off Newfoundland. In the southern hemisphere they come ten degrees +nearer the equator. As they float toward the tropics they slowly melt, and +in their melting they exact from the air and the sea where they melt the +same amount of heat which they gave up in their freezing. If they melted +at the same place where they froze, there would be no transfer of heat. +But they are formed in the polar regions; they give out their heat in the +frigid zone, while they melt and absorb a like amount of heat from the +temperate zones. In this manner the polar regions are exchanging with the +temperate zones ice for water. They borrow water, rob it of its latent +heat, and send it back in the form of ice. The temperate zones supply the +needed heat and bring the ice back to the form of water, when the polar +regions again borrow it, seize upon its heat, and again send it back in +the form of ice mountains. The effect is the same as if thousands of +railroad trains were transporting water to the frigid zones, leaving it +there to freeze and give up its one hundred and forty degrees of latent +heat, and bringing it back in the form of ice. Let us estimate the bulk of +one such iceberg as that seen by Captain d'Urville. It was thirteen miles +long and one hundred feet high, and we will suppose that it was four miles +broad. Standing out from the water one hundred feet, it must have sunk at +least eight hundred feet below the surface. This would give us the +enormous bulk of (1,304,709,120,000) one trillion three hundred and four +billions seven hundred and nine millions one hundred and twenty thousand +cubic feet of ice. The burning of one pound of coal will generate heat +sufficient to melt about five and a half cubic feet of ice. To melt one +such iceberg would require more than one hundred and eighteen millions of +tons of anthracite coal. This is the amount of heat given out in the polar +region by its freezing. This is the amount of heat transported from the +warmer to the colder regions. But what is one iceberg to the thousands +which drift yearly from the frigid zones toward the tropics? + +"But even this hardly represents the entire transfer of heat by the agency +of icebergs. The icebergs are formed from the snows of polar storms, and +these are formed from the condensation and freezing of vapors. In the +process of condensation one thousand degrees of heat are given out. Every +iceberg _represents_ a transfer of heat sufficient to boil more than six +times its weight of ice water. + +"One marked illustration of the effect of icebergs we ought to notice. +Down through Baffin's Bay icebergs are constantly floating. They are borne +on southward till, in the still waters of the Grand Banks, between the +polar current and the Gulf Stream, they float around and melt and +disappear. To these melting icebergs the chilliness and unfailing fogs of +the Grand Banks are due; and not only this, but the very existence of the +Banks is supposed to be due to the deposit of sediment, sand, earth, and +stone brought by polar ice. + +"I have spoken only of the polar glaciers and the icebergs formed by their +pushing off into the sea. But the same transfer of heat is taking place, +on a very much smaller scale and within narrow limits, by the glaciers of +the Alps and every other mountain glacier. The glaciers are nothing else +than rivers of ice. Snow falls upon the mountain tops and valleys of the +mountain sides from age to age. The snow slowly changes to the structure +of ice, and by its enormous weight flows down through the gorges of the +mountain sides, till in the warmer vales below it melts and disappears. +We have not time to go into a full examination of all the interesting +phenomena of glaciers, but this one point you will notice and remember: +these rivers of ice--for they flow like rivers--cool the valleys and tend +to warm the mountain tops; of course upon the tops of the mountains there +can be no accumulation of heat, because, standing out into the eternal +coldness of space, and swept by winds for ever, and exposed by the +thinness of the air to a rapidity of evaporation unknown at the sea level, +heat is caught up and borne away in a moment. + + +[Illustration: TRANSPORTATION of HEAT. + +Page 288.] + + +"This closes this department of our theme. I might have gone much more +into details and given you great stores of particular facts and figures, +but they would have added nothing to your understanding of the subject, +and we can hardly afford to devote our Lord's Day to mastering the details +of the natural sciences. We have now looked at some of the methods by +which the extremes of heat and cold, in day and night, in summer and +winter, and in the tropics and polar regions, are mitigated. The same +principles operate upon the smallest and upon the largest scale. If there +is need for me to attempt in a formal way to awaken in you admiration for +the wisdom and goodness of God shown in all these beneficent arrangements +for equalizing temperature, our study has been largely in vain. We have +only to remember that all these contrivances are the Lord's designs. He +created the world; he endowed matter with its qualities and forces, and he +gave it these qualities and forces for the purpose of using it as he has +used it. He planned all those contrivances by which he secures the comfort +and the good of man, and the fact that these natural agencies are fitted +for moral uses in recovering sinners to holiness and blessedness is but +the culmination of its adaptation to the uses of man. + +"This, however, does not complete our course of study. A few other points +will demand our attention for two or three more lessons. But while we go +on with our studies of Nature, remember that the physical was created for +the sake of the spiritual; the spiritual is more important. Let us not +subvert the divine order and sink the high purpose of the creation to mere +material agencies and contrivances. To know God is greater and better than +to understand Nature. That we might know and enjoy and glorify the +Creator was the object of our creation. We cannot express it in better +language than that employed in the old catechism: 'The chief end of man is +to glorify God and enjoy him for ever.' That term 'for ever' includes the +present life as well as the future. We ought to know, enjoy, and glorify +God to-day. I hope that another week may find Ansel with some happy +experience in this matter." + + + + +CHAPTER XIV. + +COMBUSTION.--COAL-BEDS. + + +Another Lord's Day comes, and no change has taken place with the class +which calls for mention. Ansel still walks in darkness, ready indeed on +every occasion to manifest his concern for the salvation of his soul, +diligent in reading the Scriptures, frequent in prayer, and giving yet no +indication of a flagging of his avowed purpose to follow Christ, but he +receives no comfort and peace. A painful and distressed interest is +becoming more and more concentrated upon him. What will be the end of his +groping in darkness? This cannot last always. Unless the hindrance, +whatever it be, which prevents the exercise of faith, be seen and removed, +Ansel will probably soon go back to his former careless state, and, it may +be, become tenfold more obdurate than before. He will be likely, on the +one hand, to become self-righteous from his supposed effort to come to +Jesus, and, on the other, discouraged and despairing, feeling that for him +effort is vain and salvation unattainable. While he remains in this state +the very lapse of time is dangerous. All feel concerned for him, but no +questions are asked, and the lesson goes on as usual. + +"The method of transferring heat which we are now to examine is wholly +different in principle from any which we have as yet considered. I refer +to the production of heat by combustion. The transfer of heat by +combustion cannot be compared for vastness with those great movements of +heat which have before claimed our attention, yet for the comfort and +well-being of the human race combustion is exceedingly important. Without +that command of heat which combustion gives, man could not rise at best +above the savage state, and in fact could hardly exist upon the earth. We +smile at the Grecian myth that Prometheus stole fire from the gods and +brought it to men in his reed staff, but fire is certainly worthy of being +counted one of God's great gifts. But whence comes the heat of combustion? +Is it a new and original generation of heat, or is it merely a transfer? +Will some one explain this?" + +"I don't think that I can tell," said Samuel. "I remember the principles +you have given us about the nature and production of heat, but I do not +know how to apply them to combustion." + +"I did not suppose that you would be able to explain all the phenomena of +Nature at sight, yet the production of heat by combustion is not difficult +to be understood. The burning of wood and coal is chiefly the union of +oxygen with carbon. The oxygen of the air unites with the carbon of the +combustible. The attractive force between oxygen and carbon is very +strong. When they unite, the atoms of oxygen dash against the atoms of +carbon with great violence. As they dash one upon another their motion is +lost, but by the laws of transmutation of forces that lost motion +reappears as heat; that is, the motion of the atoms as they fall the one +against the other is changed to that vibration of the atoms which we call +heat. The atoms of carbon, in their separation from oxygen, may be +compared to weights suspended, ready to fall. Let once the cord be cut, +and the weight falls and dashes against the earth; its motion in falling +is lost, and reappears as heat. So carbon is suspended, so to speak, +waiting to unite with oxygen. But how is the weight raised? How is carbon +brought into this state of suspense, waiting to dash upon oxygen and +develop heat? That is not its natural state. + +"Carbonic acid is found everywhere mingled in small proportions with the +atmosphere. This carbonic acid is nothing else than carbon and oxygen +united in the proportion of one atom of carbon to two atoms of oxygen. +This is the natural state of carbon. This carbonic acid is the food of +plants; it is this which supports all vegetable growth. The carbonic acid +is absorbed by the leaves of plants and trees, and in the hidden +laboratory of the leaf, by what process is one of the undiscovered secrets +of Nature, the carbon is separated from the oxygen, the oxygen is +discharged through the pores of the leaf, and the carbon is carried into +the circulation to build up the fabric of the woody fibre. That which the +most skillful chemist in the world cannot do, except by indirect processes +and at a high temperature, the leaves are doing directly at the ordinary +temperature. Vegetable growth is a deoxidizing process. To accomplish this +an enormous force is requisite. To separate carbon and oxygen, a force is +demanded which is able to overcome their powerful attraction. How shall we +estimate the strength of this force? In order that they may unite, as in +the explosion of gunpowder, solid rocks are torn asunder. The attraction +of carbon and oxygen is strong enough to tear great rocks in twain. It is +this attraction which sends the cannon ball and the shell like meteors of +death upon their errands of destruction. This great force must be +overcome; carbon must be separated from oxygen and built into trees. This +is the lifting up of the weight. But whence comes the force necessary to +accomplish this? From the sunbeam. The heat of the summer's sun, employed +as force, is used to deoxidize carbonic acid. Heat is used, and used up, +in lifting the weight which in its fall shall generate again a like amount +of heat. The combustion of wood produces the same amount of heat as was +needful to separate its carbon from the carbonic acid of the air. +Vegetable growth is thus a cooling process; heat is withdrawn from use as +heat, and is employed as force. As force it has nothing to do with +temperature. The summer's heat, employed in vegetable growth, reappears +in the blazing billets of the kitchen fire. Heat is condensed and +solidified, so to speak, and placed under man's control. In this +solidified form heat may be laid up in store or transported at pleasure. + +"The grandest application of this principle is seen in the formation of +the coal-beds. At some early period in the unmeasured ages past, the +temperature of the earth must have been much higher than it now is; the +air was filled with moisture, and carbonic acid abounded. As a +consequence, there was an enormous vegetable growth. This, as we have +seen, is a heat-consuming process. The heat is withdrawn from the air and +employed in deoxidizing the carbonic acid. This vast vegetable +growth--enormous ferns and coniferous trees--fell, and was swept by rivers +or by floods into valleys, or the beds of lakes, or the sea; the sediment +of the waters covered it, and there, shut up from the air and subjected to +a heavy pressure, this vegetable mass underwent a slow transformation. +Peter, have you ever seen a coal-pit? I do not mean a coal _mine_, but +that which charcoal-burners call a coal-pit." + +"I have seen them many a time." + +"Tell us, then, how wood is burned to coal without being burned up." + +"The wood is set on end, closely packed in the shape of a mound, and then +covered with earth. Fire is kindled in the middle of the pile, and just +enough air admitted through air-holes at the bottom to keep up a slow +burning. It burns just fast enough to heat and dry the wood without +burning it up." + +"The same process," said Mr. Wilton, "went on in the formation of the +coal-beds, but very much more slowly. Under the pressure of earth and +water the vegetable deposits lie smouldering, not for a few days, but +probably for ages, till nothing but the carbon remains, and that pressed +into a solid mass heavy as stone. Veins of coal are found interspersed +with layers of earth and rock, layer above layer, and these layers are +commonly not level, but more or less inclined and sometimes broken. This +shows that a deposit of driftwood was made, then a deposit of sand or +clay, then another deposit of vegetable material and another layer of +earth. At length, by internal convulsions, the whole surface was raised +from beneath the waters, and in due time the coal-veins were laid open, +and the coal brought out for the use of man. Then the force so long pent +up and held in suspense is set free; the stored-up heat of the geologic +ages is brought out for use. The excess of heat in that ancient period is +handed down to these later times. How sublime this transfer of heat! It +carries us back, in imagination, to the 'heroic ages,' so to speak, of the +history of creation. By other methods heat is treasured up for a day or a +year: by this method it is kept in store for myriads of ages. We see that +the same natural forces were working in those early ages as to-day, and +the same benevolent Creator was arranging the affairs of the world for +man's advantage. The sunbeam which streamed upon the earth long ages +before man was created is to-day smelting ores, driving machinery, +dragging ponderous trains of loaded cars, and ploughing the seas with +freighted keels. This seems like a fairy-story or a dream, but instead of +that it is the soberest of philosophic and scientific truth. + +"We ought also to notice the internal heat of the earth. This has been +handed down from the day of creation, it would seem, till the present. No +new principle is seen in the earth's internal fires, but a sublime +illustration of the storing up of heat in a hot body and its slow +radiation. + +"The origin of the internal heat of the earth we can only conjecture. +Perhaps God created the various elements separate, uncombined, and allowed +them then to combine according to their natural affinities. This sublime +conflagration of all the elements of the earth would generate the highest +temperature which could be produced by combustion. The elements would melt +with fervent heat; everything which could be vaporized by heat would be +turned to vapor. Then radiation of heat would begin. Vapors would sink to +fluids and fluids turn to solids; a hard crust would be formed on the +surface of the globe through which the heat of the still molten mass +within would be slowly conducted and escape. Upon this internal heat the +earth depends in no small degree for its temperature. The heat generated +perhaps upon the day of creation helps now to render the earth habitable. + +"That the earth was once in a fluid state and has lost a portion of its +heat by radiation is indicated by several facts. It is one of the received +beliefs among geologists that at some period in the past the temperature +of the earth was much higher than it now is. The animals and plants which +flourished during the ages when the coal-fields were deposited show that +sea and land were warmer than at present. It is believed that the change +of temperature has taken place on account of the cooling of the earth from +radiation. The rate of radiation is so slow, however, that no farther +sensible change of temperature can take place for thousands of +generations. + +"The form of the earth also indicates that it was once fluid. The earth is +an oblate spheroid, a flattened sphere, and has that degree of flatness +which a fluid mass would assume if revolving at its present rate. The +earth swells at the equator and rises thirteen or fourteen miles above the +sea level at the poles. The waters of the ocean move freely and take the +same form as if the whole globe were fluid, and the solid parts of the +earth have the same degree of convexity, which shows that it took its form +from its own rotation upon its axis while in a fluid state. This would +also show that in the primal ages, when the earth was in a plastic or +fluid state, it had the same rate of rotation as at present. + +"The lifting up of the mountain ranges also is best explained by +supposing that the earth was once molten. The earth cooled, a crust was +formed, and by farther cooling and contraction of the molten mass within +the crust wrinkled and formed mountain chains. Thus the higher temperature +of the geologic ages, the form of the earth as if it were a revolving +fluid mass, and the corrugation of its surface--these, joined with its +present internal heat, point to the fact that it was once molten and fluid +to its surface. The benefits of this heat laid up in store on the day of +creation we still enjoy." + +"Before the class is dismissed," said Mr. Hume, "I should like to say a +few words." + +"I have nothing farther to say to-day," answered Mr. Wilton, "and we +should be glad to hear you now. Say on." + +"I wish only to say that these lessons have led me to such thoughts of +God's wisdom and goodness as I never had before. Of course it is not +strange that this should be the case with me. I now look at everything +with new eyes. It is not merely this one element of heat in Nature that +moves my admiration, but I have been led to consider a thousand things in +which the goodness of God is shown. My thoughts of the divine goodness +are as fresh and interesting to me as my impressions of his righteousness +and holiness are startling. For years I have tried with might and main to +look upon the dark side of the world and to exaggerate its physical evils. +I have searched for disorder and want of adaptation. As long as I +misunderstood the purpose of the creation, I thought I was successful in +impugning the wisdom of the arrangements of this physical world. While I +supposed that the earth must needs be the Creator's masterpiece in beauty +and pleasantness and all manner of perfections, designed just to give +sensual pleasure to its inhabitants, I could find, or thought I found, +many faults in the Creator's work. Now I withdraw all my former charges. +My eyes are opened. The rougher elements of man's life will henceforth +have a new meaning to me. I see that God seeks not so much present +pleasure for men as their holiness. He lays a solid foundation for their +happiness. He seeks to render men blessed by bringing them into likeness +and union with himself. These are new views to me, and I thank my heavenly +Father that this new light has dawned upon me. I feel now that I can bear +the ills of this life cheerfully, understanding that the Lord is using +them as a means of spiritual discipline. It seems to me as if this lower +world and man's lowly life were already glorified by a beam of light +falling from heaven. I hope that my young friends have been as much +profited as I have been." + +"I rejoice with you, Mr. Hume. 'We know that all things work together for +good to them that love God.' This light has shone upon me for many +years." + + + + +CHAPTER XV. + +ECONOMY OF HEAT. + + +"In this final lesson I wish," said Mr. Wilton, "to bring before you some +general views of the whole subject of the agency and management of heat. + +"When Jesus had fed the five thousand men upon the mountain side by the +Sea of Galilee, he said to his disciples, 'Gather up the fragments that +remain, that nothing be lost.' The Christ who spoke these words was the +same Christ by whom 'all things were created that are in heaven and that +are in the earth, visible and invisible.' These words inculcate the +propriety of saving, the very opposite of extravagance and wastefulness. +The same prudent economy we find in all God's works. Nothing is wasted. +God provides bountifully; he is not stinted in his works; we find nothing +narrow or mean; his resources are ample for all his undertakings. Perhaps +a careless observer might charge him with prodigality and wastefulness. +The wilderness rejoices in beauty and fertility upon which no human eye +gazes, and which supplies no human want. + + 'Full many a gem of purest ray serene + The dark unfathomed caves of ocean bear; + Full many a flower is born to blush unseen, + And waste its sweetness on the desert air.' + +Rich fruit grows ruddy and golden in the autumnal sun only to fall and +decay. How small a part of the seeds which might germinate and reproduce +the parent plant ever fulfill this their legitimate object! But this is +not waste. As for the beauty with which the unpeopled wastes are smiling, +we know not what other beings besides man 'grow glad at the sight.' Fruits +and grains and seeds were appointed as much to nourish the animal kingdom +as to reproduce plants and trees. And that which decays is not wasted. The +oak lifts high its leafy arms and does battle with the tempests for a +century, and then having served its purpose in Nature, if man does not +call it to the higher mission of serving his purposes, Nature begins to +pull down the structure she has reared and rebuild the elements in other +forms--such forms as man perchance may need. The fruit that falls and +decays is not wasted; it shall blush with golden tints in other forms and +in other years. God pulls down the old that he may build the new. The same +elements appear and reappear in a thousand shapes. There is endless +change, but no waste. This sentiment, 'Gather up the fragments, that +nothing be lost,' which is proclaimed throughout all Nature, is uttered +most emphatically in the management of heat. God has provided most +bountiful stores of heat, but has left no heat to go to waste. Will you, +Mr. Hume, suggest one of the general arrangements for the economical use +of heat?" + +"I think that the arrangement for economizing heat which ought to be +mentioned first is the confinement of heat to the locality where it is +needed." + +"Will you explain that a little farther, Mr. Hume?" + +"All living creatures are confined near the surface of the earth. They +penetrate only a few feet into the earth and soar a few hundred feet above +it. Heat is therefore confined to the region of the earth's surface. It +penetrates but a little way below the surface, and when warm air rises +into the higher regions, heat becomes latent. The higher parts of the +atmosphere are cold, and in the empty spaces of the heavens the +temperature is we know not how low. God has provided for heating only that +part of the world which needs to be heated. I think you spoke of this in +some one of the earlier lessons." + +"Perhaps I did. But I refer to it again to call especial attention to the +idea of the economical use of heat. Who will mention another method by +which heat is economized?" + +No one answered. + +"I asked the question, but did not expect an answer. God shows economy in +the use of heat by accomplishing many different results by its agency. I +do not mean that the same identical heat accomplishes different results at +the same time. The same force cannot accomplish two works. As man cannot +spend his money and at the same time keep it, no more can heat be used and +not used up in that form. The heat which raises the temperature can do +nothing else at the same time, and when it is employed as force it ceases +to affect temperature. But by this one agency of heat the Creator brings +very various works to pass. Heat expands bodies, relaxes cohesive +attraction, and brings the chemical affinities into activity. By this +means the elements of Nature are subdued to human uses, seeds germinate, +all the processes of vegetable life go on, and digestion and nutrition are +carried forward in the bodies of animals. By the agency of heat the winds +blow, the deep waters of the ocean circulate, clouds are formed, dew and +rain refresh the earth, rivers flow, and all the activities of life fill +the world. The employment of one agency for the accomplishment of so many +works indicates economy in the expenditure of force and means. Moreover, +the same heat appears and reappears again and again, passing from the +sensible to the latent form and back again, asserting itself alternately +in raising the temperature and as active force. A beam of heat falls upon +our world: it is partly absorbed by the earth, and warms it. A part of +that warmth is used in setting the chemical affinities in action in the +sprouting of seeds; a part warms the air by conduction; a part is +radiated, and being stopped by the vapor in the air, warms it; the heat +of the air is partly used in the evaporation of water: the vapor formed is +condensed and waters the earth, and gives out the heat by which it was +formed; that raises the temperature of the air; a part of it is used in +deoxidizing carbonic acid and building up the forests; the forest tree +falls by the woodman's axe, is burned for fuel, and gives out its heat +again, or if it falls and decays, the result is the same; the heat given +out by combustion cooks the laborer's dinner and warms his room, or it +goes out again, and is used in preparing food for the growing wheat; that +wheat is used for food, and by slow combustion in the blood the heat is +again evolved, the body is warmed, and the chemical operations of +digestion and nutrition are maintained; the heat is radiated or conducted +from the body into the atmosphere, and again raises the temperature and +goes to do other work. At last, so far as our earth is concerned, it +escapes into the stellar spaces, and goes to bless other worlds. In all +these operations no heat-force is frittered away and wasted and lost. This +is one of the accepted doctrines of physical science. Heat is used +bountifully, but economically and without waste. + +"Even the inequalities and variations of temperature must be counted +economy in the use of heat. The heat of midday is not needed at all hours, +and therefore it is not always provided; the heat of summer is not always +useful, and is therefore not given; a higher temperature for a part of the +year and a part of the day is necessary, and is bestowed. The smallest +amount of heat is so disposed as to accomplish the largest result. Keep in +mind, then, the economical aspect of God's management of heat. + +"I would also have you remember how few are the principles involved in all +the ways and means for transporting heat and equalizing temperature. All +the various phenomena which we have examined can be brought under two +general principles. The first principle or method is the heating and +cooling of bodies. Bodies absorb heat; they part with their heat by +conduction or radiation. If they are heated and cooled without change of +place, heat is transported in time, but not in place. If the body be +removed from one place to another between the heating and the cooling or +between the cooling and the heating, heat is transported in both time and +space. This applies alike to solids, liquids, and gases; each one is a +carrier of heat in proportion to its specific heat. + +"The second principle or method is the transportation of heat by the +change of sensible to latent heat and its restoration to a sensible state. +Under this principle there are four cases: + +"1. Heat is employed in the evaporation of liquids, and is restored again +to use as affecting temperature by the condensation of the vapor. + +"2. Heat is employed in liquifying solids, and becomes latent thereby, and +returns to the sensible state when the liquid solidifies. These two +principles find their grandest application in the changes of water: of +this application I have chiefly spoken; but they apply also to other +bodies--to metals as well as to liquids. + +"3. Heat is rendered latent in the expansion of gases from removal of +pressure, and latent heat becomes sensible by the compression of gases. + +"4. Heat is employed in the deoxidation of carbonic acid or other +combinations of oxygen, and is evolved in combustion. While in the latent +condition, heat may be kept without loss for an unlimited period of time +or transported from equator to pole. By the various applications of these +two general principles, all the different methods of equalizing +temperature are determined. + +"I would have you remember also that these processes for transporting heat +and modifying temperature are not confined to the regular changes of days +and seasons and the permanent differences of zones, but apply to every +possible difference of temperature. One minute the sun shines out in full +splendor; the next, a cloud hides his face and cuts off his fervent beams; +the methods employed to soften the heat of the one minute and the chill of +the next are the same which equalize the temperature of the seasons. +Evaporation carries off the heat from the seething tropics, evaporation +carries off the excess of heat from the bodies of animals and men. The +same methods are equally efficient upon the grandest and upon the smallest +scale. + +"In this connection let me give one or two illustrations of the delicacy +with which general principles adapt themselves to the minutest +circumstances. When the earth is wet, it is fitting that evaporation +should go on rapidly and remove the excess of water, but when the ground +is drier, it is fitting that evaporation should be checked and the +remaining moisture spared. This result is secured not merely by the lack +of moisture at the surface, but also by the decreased capacity of the +earth for absorbing heat. A dark color absorbs heat more readily than a +lighter color, and the earth becomes, as a general rule, darker when wet; +and lighter when dry. Moist earth, therefore, receives heat more readily +than dry earth, and the excessive moisture is the more rapidly carried off +by evaporation. + +"Another more interesting illustration is presented by the odor of +flowers. In its place I told you that watery vapor hinders the radiation +of heat from the earth. Dark heat is absorbed by it. The same is true of +other gases, and also of the odors of fragrant substances. A bed of +flowers fills the air around with odors. By these odors much of the heat +radiated by the earth is stopped. By this means the air around the +blooming flowers is warmed. The invisible fragrance raises the temperature +and secures for the blooming plants a more genial atmosphere. The Lord +provides for the flowers when most of all they need to be cherished by a +congenial warmth. + +"This completes what I have to say to you upon the subject of heat. I +might have gone far more into particulars, and extended these lessons over +six months instead of three. We started with the design of finding out +whether the works of Nature have anything to say about a wise and good +Creator. We could not examine the whole circle of God's works, and +therefore chose a single department--that of heat. I will leave yourselves +to decide whether we have found marks of divine wisdom and goodness, +whether Nature has had anything to say to _us_ about a Creator." + +"It seems to me," said Samuel, "that if the works of Nature do not show +God's goodness and wisdom, it would be hard to tell what works would show +them. I think I shall always, after this, look upon the earth and sky with +more interest than I have ever felt in them before; I shall always look +upon them as having something to do with God." + +"We certainly ought," said Mr. Wilton, "to study Nature in such a manner +and with such a spirit that we shall be led to reverence and worship the +Creator. Some very good men are afraid of scientific study, as if there +were something in it to draw men from belief in the Scriptures and the +Jehovah revealed in them; and it cannot be denied that not a few +unbelievers have tried to find a foundation and a defence for their +infidelity in scientific studies; but such men are not made skeptics by +earnest and reverent study of God's works: they were unbelievers before +and aside from physical studies, and they only try to glorify their +rejection of the Bible and Christ by deifying science and the creation and +holding them up in opposition to inspired revelations. If ever you find +the works of God separating you from God, you may know at once that you +misunderstand those works or come to them with a wrong spirit. 'The +undevout astronomer,' it has been said, 'is mad,' and the same might, with +good reason, be said of every undevout student of physical science. + +"In selecting heat for our examination, I did not take the only rich +department of Nature's works. The practical chemist would find a richer +and broader field of research, and so would the anatomist and animal +physiologist, the geologist, or the physical geographer. I purposely chose +a comparatively narrow field, in order that our course of study might not +become wearisome by its length. You will find ample scope in the fields of +natural science for your largest powers, and enough to carry your thoughts +reverently to the great Creator and Governor. + +"In one respect the study of Nature resembles the study of the Sacred +Scriptures. It is a revelation; it is an embodiment of God's thoughts; in +it God has expressed himself; and Nature, by most suggestive symbols and +types, teaches much more moral truth and spiritual sentiment than some men +think. In the brute creation it gives us, in pantomime, all the virtues +and graces and all repulsive vices and cruel passions. To this book of +Nature we ought to come without prejudice, reverently inquiring what is +written therein. We must study it thoroughly and interpret it as we +interpret the written word, comparing Scripture with Scripture. It is a +great attainment to be able to read and understand the thoughts of God +embodied in his works. + +"In another respect, the book of Nature and the Sacred Scriptures have +very little in common. The Bible is occupied pre-eminently with moral +duties and spiritual relationship. Its great themes are sin and salvation. +Christ is the great central truth. One might compare the Scriptures to a +picture in which one central figure seizes every eye, and by whose +radiance the whole picture is filled with light, and that central figure +is Christ; or we might compare the Bible to a sublime oratorio, the +glorious symphony of the ages; through it all is heard one strain, sweetly +exultant as angel voices, faintly heard at first amid the sadness of the +fall, but rising still above the terrific bass of Sinai and its +ever-repeating echoes, growing more clear and strong upon the harps of the +prophets, till its rapturous beauty pours itself triumphant along the +plains of Bethlehem. In this revelation of salvation from the guilt and +ruin of sin the Bible stands alone. Upon this subject Nature is silent. +Salvation by Christ is the gem enshrined in the Scriptures. But what is +the setting for this gem? The works of God on the earth and in the +heavens. The prophets were men in sympathy with Nature. How David sung the +praises of the divine handiwork!--'O Lord, how manifold are thy works; in +wisdom hast thou made them all.' 'The heavens declare the glory of God +and the firmament showeth his handiwork. Day unto day uttereth speech, and +night unto night showeth knowledge. There is no speech nor language where +their voice is not heard.' How Christ unfolded the deepest spiritual +truths by the symbols of Nature! But if the casket be so worthy, what +shall be said of the gem which is enshrined within? That is the pearl of +great price. To that book which speaks in no doubtful voice of deliverance +from sin let us turn with increasing reverence; and above all, let us come +to him who came to reveal our God, who came to be as well as to make a +revelation of God, being himself 'the brightness of his glory and the +express image of his person.' I am glad that you all now feel that you +know him whom to know is everlasting life." + +From these words of Mr. Wilton you will conclude that Ansel has at length +found rest in Christ. In another brief chapter I will tell you of his +experience, and then bid you adieu. + + + + +CHAPTER XVI. + +A DAY OF JOY AND GLADNESS. + + +The reader has already learned that after Ansel had confessed himself an +anxious inquirer and professed himself willing to obey Christ, he remained +three or four weeks still in darkness. Others found peace in believing, +but he felt no joyful confidence that Christ had received him and forgiven +his sins. He sometimes felt almost discouraged, and sometimes was tempted +to complain of God for not treating him as favorably as others, or to feel +chagrined because others were rejoicing, while he found no light. But he +fought against these evil thoughts and insinuations of Satan, and did not +flag in his private devotions or cease to confess himself, always and +everywhere, an anxious inquirer, still in darkness, but desiring to find +the grace of God. If ever he was tempted to push away all concern about +salvation and return by force to his former careless state, the words of +Christ would come to his mind: "Will ye also go away?" and Peter's answer, +"Lord, to whom shall we go? for thou hast the words of eternal life." The +alternative, salvation by Christ or the loss of his soul, stared him in +the face. + + "I can but perish if I go; + I am resolved to try; + For if I stay away, I know, + I must for ever die." + +Great interest was felt for him and much prayer was offered in his behalf, +but he seemed to make no progress toward a better state. Mr. Wilton had +talked with him, but had failed to discover what it was that hindered his +humble acceptance of the grace of Christ. After long and anxious musing +upon Ansel's character and surroundings and the previous conversations +which he had had with him, Mr. Wilton determined to probe him more fully. +For this reason he invited Ansel to his study, where the following +conversation transpired: + +"Good-morning, my young friend; how do you find yourself to-day?" + +"I am feeling, I think, very much as when I was here a week ago." + +"Are you becoming discouraged and almost ready to give up all effort to +follow Christ?" + +"I do sometimes feel very much discouraged, but I am not ready to give up +my interest in religion." + +"Have you no more enjoyment in reading the Scriptures and in your prayer +in secret than you had a week ago?" + +"I think that I am trying to do right in doing these things, and I enjoy +them better than I should if I felt that I was doing something wrong, but +I do not feel as I think a Christian ought to feel." + +"Are your thoughts and feelings and opinions about Christ and salvation +the same as they were six weeks ago?" + +"I think they are very different." + +"I am glad to hear that; but can you tell how they are different?" + +"At that time I felt that I was a sinner, but was fighting against that +feeling. I wished that Christ would let me alone, and that the Holy Spirit +would not trouble me. But now I very much wish that I may feel my sins, +and that Christ may come to me and save me. I wish to follow the Spirit." + +"Did you expect a month ago that at this time you would be feeling and +acting as you now feel and act?" + +"No, sir; I meant then to fight it through, and not let anybody know how I +felt." + +"Do you wish now that you had fought it through, as you proposed, and kept +all your feelings to yourself?" + +"I am very thankful that I did not keep on hiding my feelings. I almost +tremble to think what the result would have been." + +"You have said that you wish to spend your life in serving Christ. Does it +seem to you a hard and painful work--a work that you would get rid of if +you could--or does working for Christ and confessing Christ before men +seem attractive?" + +"I think his service seems pleasant; there is no other life that seems +half as pleasant." + +"Do you believe that Christ is able to save you?" + +"I suppose he is. If he cannot save me, there is no hope for me, for I +cannot save myself." + +"Do you believe that he is willing to save you?" + +"I think he is, if I come to him and trust in him. I suppose he is willing +to save all who come to him." + +"Are you unwilling to come to him--to trust him and submit to him?" + +"I don't know; I have tried to come to Christ, but I have met with no such +change as I have always supposed that a Christian ought to have." + +"What do you think it is that hinders your coming into light and joy as +others have done?" + +"I cannot tell. I suppose it must be something or other in myself, but I +cannot guess what it is." + +"I would like to ask you a few questions which you may think rather close +and personal, and which you may find it hard to answer frankly. You know +the spiritual adviser, as well as the physician, must first of all find +out the condition of the patient." + +"I am willing to have you ask any questions you please, and I will try to +answer them as well as I can." + +"Did you ever think, Ansel, that you were very ambitious?" + +"I knew that, like many others, I was a little ambitious, but I never +thought that I was very much so." + +"Perhaps you were more ambitious than you thought. You know that you would +work day and night rather than not stand at the head of every class you +were in. On the play-ground you asserted your position as leader in every +game. Did you not carry the same idea of being chief into your plans and +expectations for the future? You were ambitious of standing the very first +whatever course of life you might follow. Was not this so?" + +"I don't know: I can't deny it; I think it was." + +"It is possible, Ansel, that you are trying to carry the same ambition +into the kingdom of Christ. Perhaps you have wished in conversion some +brilliant experience which would draw attention to you. Tell me how this +is. Would you be satisfied to have a commonplace experience, such as +thousands of others have, which would attract no special notice? Have you +not formed an idea of the great and brilliant change you must pass +through, and are you not refusing to take anything else from the Lord's +hands?" + +Tears gathered in Ansel's eyes, and his face worked painfully. At length +he answered: "Your question is a hard one to answer, but I cannot deny it; +I am afraid it is so. I have heard persons tell of the great load of sin +like a pack on their shoulders, and of the earth seeming as if it would +open and swallow them up, of sleepless nights and unspeakable anguish, and +then of light and joy, so that they could never doubt that they were +converted. I have been expecting that I was to have such an experience, +but I have not seen it. Is it wrong to wish for such an experience?" + +"It is certainly wrong to _insist_ upon such an experience. God leads each +one to himself in his own chosen way. There was but one Saul, whom Christ +met and blinded with the dazzling light. As a general rule, when a sinner +makes up his mind in what way he will be converted, the Lord will +disappoint him. If he fixes in his mind that he will not come to an +anxious-seat, or will not confess his feelings till he can say that his +sins are pardoned, or will not do anything else, the Lord will very +likely bring him to do the very thing he resolved that he would not do. +If he attempts to bring his ambitious aspirations into Christ's kingdom, +he will be disappointed. 'The first shall be last and the last first.' Men +become great in Christian service by counting themselves the least of all, +and humbling themselves to become the servants of all. You need to examine +yourself in this matter. If you have looked for something great and +startling, be contented with something small and commonplace. It is an +unspeakable privilege to be brought into Christ's kingdom in any manner. +It is sometimes a great blessing to have a very unmarked and plain style +of conversion. Such a convert is compelled to look to the truly scriptural +evidences of a change of heart instead of resting upon the evidence, often +deceptive, of a great and sudden illumination or a fancied voice from +heaven. Some of the greatest and best of men have been unable to tell at +all the time of their conversion. Richard Baxter could not tell even the +year of his change. The best experiences I have known have been those +where the converts could tell very little about themselves; they had been +doing something else besides looking into themselves to watch the motions +of their own thoughts." + +"I will try to do as you say. But what kind of evidence am I to look for?" + +"The same kind of evidence which you now look for in me or any other +Christian. It is not one thing to come to Christ and another thing to +follow Christ. The best evidence that a sinner has come to Christ is that +he actually follows Christ and serves him. 'By their fruits ye shall know +them.' 'Bring forth fruits meet for repentance,' said John the Baptist. +Bring forth fruits that show that your thoughts about sin, and about +Christ, and about the service of Christ have been changed. Look for the +same kind of evidence in yourself that you would look for in any stranger +whom you should meet. But above all things take the words of Jesus as true +and rest on them; consecrate yourself to Jesus with all the heart; with +lowliness of mind hold yourself ready for any work or any sacrifice; you +will find that evidences will take care of themselves. When men come into +sympathy with Christ, when they believe his words, walk with him, and talk +with him, and bear the cross with him, when they enter into a partnership +of service and suffering with Christ,--the Spirit bears witness with their +spirits that they are born of God." + +"I will try to follow your advice, and am very thankful that you have +spoken about my ambitious spirit." + +"Another caution I wish to give you. Do not think that you, by any methods +or by cherishing any spirit, are to make yourself fit to be saved. If you +are saved at all, Christ must take you as a sinner, and a great sinner. If +you get rid of your spirit of pride, it will be by Christ's saving you +from it. Let me also suggest to you that which a consideration of your +associations suggested to me, that you may have stumbled at the idea of +baptism. You must have heard baptism spoken of very disrespectfully, and +it is possible that you may have learned to look upon it as a humiliation +and a reproach. You may have recoiled from the thought of submitting to +it." + +"That was my feeling once, but since I have been willing to have my +feelings known I have ceased to be afraid of what those who despise +religion may say." + +"Be careful now, since you feel that your sympathies are with the +Christian band, that your love of greatness does not lead you to resist +the Spirit. Be willing to be small. Be thankful for small gifts. I trust +that your present feelings will before long give place to a humble trust, +a childlike confidence, and a holy boldness in Christ, and that your +usefulness in the kingdom of God will be all the greater because he now +requires you in the beginning to trample under foot your budding pride and +die to all human ambitions." + +When Ansel gave up the idea of a wonderful conversion, a sudden +illumination which should bring with it something of éclat, he found that +he could understand the Scriptures better and have more enjoyment in his +religious duties. While he humbled himself, hoping for little, he found +his soul soon filled with a deep, quiet joy. + +The next Saturday afternoon was the regular time for the covenant-meeting, +and also, according to custom, for hearing the experiences of any who +wished to unite with the church by baptism. Ansel, Peter, and Mr. Hume +came, along with others, to present themselves to the church. In regard to +Mr. Hume there had been much speculation among his former comrades as to +what course he would take. Some said: "Mr. Hume will never wet the sole +of his foot in that river. Don't you remember how he used to laugh at the +idea of being plunged in the river in honor of a dead man? He may talk in +meeting, but it is a very different thing to go down into the river with +the whole hillside covered with people." Others said: "We can't tell what +has come over him, but he will not go back now. He has gone too far to +retreat." + +Some even ventured to approach Mr. Hume himself with their raillery: + +"What do you think now of being dipped in the river in honor of a dead +man?" + +"I think that I would be willing to be baptized a thousand times if I +could recall by that means what I have spoken against baptism." + +"And what, Mr. Hume, about the ice water?" + +"You know and I know," he answered, "that we always respected those who +did not shrink from cold water for Christ's sake. What effeminacy, what +more than effeminacy, for a resolute man to hesitate and tremble at +baptism! We should be ashamed of such weakness in any worldly matter. I +have given you occasion for all your raillery, but as I once was a leader +in evil, so I wish that I might lead you to better things." + +Ansel, Peter, and the rest gave an account of their religious experiences, +and last of all Mr. Hume. + +"What leads you," asked Mr. Wilton, "to present yourself to the church, +asking for baptism?" + +"I think that the love of Christ leads me. I have done a great deal +against Christ, and now I wish, if possible, to do something to show my +love for him. I come to obey the word and example of Christ by being +buried with him in baptism." + +They were received for baptism, and the time of administration fixed at +half-past twelve o'clock the next day. + +The Lord's Day was cold and blustering. Many were disappointed, for they +hoped that the day would prove warm and sunny. But the blustering day did +not prevent the gathering of a great company by the riverside. As the +congregations left the churches they turned their steps toward the place +of baptism. Ungodly men turned out, and those who never came to hear the +preaching of the gospel flocked together to see the gospel preached by +this symbolic service. The word had gone out that Mr. Hume was to be +baptized, and this drew together his former associates. At the place +chosen the river swept around in a gentle curve and the bank rose up like +a magnificent amphitheatre; while just above, the land put out into the +water and threw the current upon the opposite side. Here gathered almost +the entire population of the village to witness that simple and solemn +service which from the days of John the Baptist has thrilled so many +hearts. The candidates came warmly clad, brought from their own homes in a +close carriage. Gathered there, the little band of Christians, surrounded +by so great a cloud of witnesses, first sang the hymn commencing: + + "Thou hast said, exalted Jesus, + Take thy cross and follow me; + Shall the word with terror seize us? + Shall we from the burden flee? + Lord, I'll take it, + And rejoicing follow thee." + +Then Mr. Wilton read with a voice that reached all the company a few +passages from the New Testament which authorized and commanded that +service. After that he prayed that the joyful presence of Christ might +attend those about to follow him in baptism, that believers might be +encouraged, and careless sinners awakened. One by one the converts were +buried with Christ, and one by one they came up out of the water, +forgetting all else in the joy of obedience. They sang the words +consecrated by use at so many riversides: + + "Oh how happy are they + Who their Saviour obey, + And have laid up their treasure above! + Tongue can never express + The sweet comfort and peace + Of a soul in its earliest love." + +These words found a response in many hearts. + +High up upon the river bank were gathered a little knot of mocking +unbelievers. One among them, seven years before, had publicly professed +his faith in Christ. For a little time he seemed to be treading in the +Lord's ways, but falling among evil associates, he not only neglected +Christian duties, but became a professed unbeliever. He read infidel books +and loaned them to others. He sought to sow the seeds of unbelief wherever +he went. Upon this Lord's Day he stood with others profanely mocking at +the sacred service. With shivering, tremulous accents he exclaimed, "Poor +Harry Gill is very cold; I would not go into the water to please any +Christ for five hundred dollars." That young man went home with deep +conviction of sin upon him. Two days after, Mr. Wilton was called at ten +o'clock at night to visit him. He was trembling like an aspen leaf with +his deep anguish of conscience, and for two days and nights his body shook +under his fear. Then little by little faith took the place of fear, and +hope smiled upon him. He was the next person whom Mr. Wilton baptized. + +Look in upon the Christian band assembled that Lord's Day evening. Upon +the faces of those who had been baptized there was no sign that the +service of that day had been painful; if they had done the duty as a +cross, the cross must have been quickly followed by a crown of joy, for +every face was radiant with light. Among them was one little girl twelve +years of age whose face, as she rose from the water, shone like the face +of an angel, and the transfiguration of that moment had hardly begun to +fade away. Ansel was peacefully happy, and from the face of Mr. Hume the +old look of dissatisfaction was all gone; his soul had entered into rest, +and he felt at home. Every one of them testified that it had been the +happiest day of his life. They declared themselves willing for Christ's +sake to be baptized a hundred times if he commanded. They had already +found that "in keeping his commandments there is great reward." + +I should be glad, kind reader, to trace with you the Christian course of +these disciples through the years that follow. But we must leave them. I +am sure, however, that their course will be upward. Their experience was +not the mere effervescence of fickle feeling. The word of God germinated +in their hearts; they had root in themselves. They believed, they believed +the truths of the gospel, and therefore they felt, and therefore they +acted. "Whatsoever is born of God overcometh the world," and believing +that they were truly born of the Spirit, we are confident that "he which +hath begun a good work in them will perform it until the day of Jesus +Christ." + + + +***END OF THE PROJECT GUTENBERG EBOOK CURIOSITIES OF HEAT*** + + +******* This file should be named 39566-8.txt or 39566-8.zip ******* + + +This and all associated files of various formats will be found in: +http://www.gutenberg.org/dirs/3/9/5/6/39566 + + + +Updated editions will replace the previous one--the old editions +will be renamed. + +Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. 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