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,[pg 273] 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[pg 274] 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[pg 275] 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[pg 276] 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[pg 277] 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[pg 278] 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[pg 279] 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[pg 280] 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[pg 281] 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[pg 282] 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[pg 283] 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[pg 284] 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[pg 285] 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 [pg 286]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[pg 287] 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[pg 288] 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 [pg 289]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.
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 [pg 290]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[pg 291] 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.”
