University of Virginia Library

5. CHAPTER V.
TESTIMONY OF WATER.

THE atmosphere, as you will remember, consists mainly of two permanent and elementary gases; and having discussed the functions of its active element, oxygen, it would seem natural to consider next the offices of nitrogen, that most singularly inert gas, which constitutes no less than four-fifths of its whole mass; but we shall understand more clearly the complicated relations of this truly wonderful substance, associated as it is with all the higher forms of corporeal vitality, after we are acquainted with two of the remarkable cycles in nature, in which the water and carbonic dioxide of the atmosphere play a conspicuous part. It is true that these two substances are very variable constituents, and make up at best only an exceedingly small fraction of the whole mass of the air; but nevertheless, they discharge functions no less important than those of oxygen and nitrogen, and we shall find that they are equally rich in illustrations of the wisdom and power of God.

I have already alluded to the fact that the most striking illustrations of creative wisdom have been

discovered in those substances which are the most abundantly distributed through nature, and which are the most intimately associated with man, and of no substance is this principle more remarkably true than it is of water. As you well know, water is the liquid of the globe, and, if we except certain transient products of volcanic action, it is the only liquid which exists naturally on its surface. Moreover, it is in constant circulation, and, like the blood in our bodies, is the medium through which nourishment is conveyed to all parts of organized nature, and its life sustained. We should naturally expect that a substance filling so important a place in the scheme of creation would furnish undoubted evidences of design, and it will be my object in the present lecture to illustrate a few of the more striking examples of adaptation which its qualities present, beginning with the aeriform condition of water as it exists in the atmosphere.

The condition of the atmosphere of aqueous vapor, which surrounds the globe, differs essentially from that of the more permanent gases which are simultaneously present. Oxygen and nitrogen cannot be reduced to liquids even by the intense cold at the poles. It is very different with aqueous vapor. The slightest reduction of temperature, when the air is saturated with moisture, is sufficient to condense a portion of the vapor to water, and to shower it on the earth in drops of rain. On the other hand, when the temperature rises, the heat converts more water into vapor, and the aqueous atmosphere is replenished. Thus it is that the

atmosphere of aqueous vapor on the earth is liable to very great fluctuations, from which the Creator has protected the great mass of the air by endowing oxygen and nitrogen with the power of retaining the aeriform condition under all circumstances; and we shall find that the fluctuation in the one case is as important as the stability in the other.

I stated in the last lecture that our atmosphere may be regarded as made up of three partial atmospheres, simultaneously surrounding the globe, and as was the case with the atmosphere of oxygen, we shall best understand the fluctuations of the aqueous atmosphere if we begin by eliminating, for a moment, from our thoughts the other two. In order to make the subject clear, it will be necessary for me to dwell very briefly on a few well established facts in meteorology, which, although not very interesting in themselves, will unfold to us some of the beautiful provisions of nature by which the aqueous circulation of the globe is maintained.

If there were no free oxygen or nitrogen gas, the earth would still be surrounded with an atmosphere of aqueous vapor, and we are able to foresee, in some small measure, what the conditions of such an atmosphere would be. Its density at the sea level would depend chiefly on the temperature, and would therefore vary very rapidly with the latitude, and would be constantly changing at the same locality with the alternations of the climate. We are able to determine approximately what the density would be at any given temperature, and a few of the results are included in the following table:

Weight at the Sea Level of one Cubic Foot of Vapor.

                       

Temperature.	Weight.
Fahrenheit.	Grains.
0°	0.78
10°	1.11
20°	1.58
30°	2.21
40°	3.09
50°	4.28
60°	5.87
70°	8.00
80°	10.81
90°	14.50

It is evident from these numbers, that a very small change of temperature would cause immense fluctuation in such an atmosphere. At 0° one cubic foot of the aqueous atmosphere could contain only about three-fourths of a grain of vapor, while at 80° it could contain fifteen times as much, and hence, although under the tropics the density of our assumed atmosphere would be comparatively large, there would be almost a complete vacuum at the poles. Into this vacuum the vapor would flow from the equator, and thus in either hemisphere there would result a perfect torrent of vapor rushing towards the North or South. But it is also evident that, as this current became chilled in passing through the cooler climate of the temperate zone, the vapor would gradually condense to water, which, falling on the land or on the ocean, would return in time to the equator, ready to begin again the same succession of ceaseless changes.

Although the presence of the air materially modifies, it does not essentially change, the aqueous circulation. The air retards the formation of vapor, but does not prevent it, and at any given temperature the same amount of water will evaporate into

a given space, whether it be a perfect vacuum or filled with air. Thus, for example, when air at 80° is saturated with moisture, it contains, as before, exactly 10.81 grains of vapor, and the table just given applies equally well to the actual condition of the globe, covered with its dense atmosphere of oxygen and nitrogen, as to the case just assumed. There is, however, a most important difference between the two conditions,—a difference on which the adaptation of the system of aqueous circulation in the order of nature entirely rests.

Were there no air on the globe, the quantity of vapor would adjust itself almost instantaneously to any variation of temperature, and the maximum amount possible would always be present at any given place. An elevation of temperature would be attended by rapid evaporation, and the amount of water required to fill the space would suddenly flash into vapor; while, on the other hand, a corresponding depression of temperature would be accompanied with an equally sudden precipitation of the excess of water which the air could no longer contain, not in genial showers or diffusive rain, but in terrific torrents, of which the deluging showers of the tropics can give us only a feeble conception; for the drops, falling without resistance, would be as destructive in their effects as volleys of leaden shot.

In the actual condition of the atmosphere, the presence of a dense medium very greatly retards these changes, and although it does not alter their essential nature, it moderates their action and mitigates the violence of their effects. An elevation of

temperature is followed by an evaporation of water into the air; but the process is comparatively slow, and it is a long time before the air is fully saturated. So, also, when the air is saturated, a depression of temperature is followed by the condensation of a portion of the vapor into rain; but here, again, the mass of the atmosphere tempers the abruptness of the transition, and allays its violence. The vapor condenses first into a fine dust consisting of repellent particles of water, which are so minute, and, consequently, fall so slowly against the resistance of the air, that they seem to float in the atmosphere; and when, in consequence, probably, of some electrical discharge, these particles, losing repulsive energy, unite to form drops of rain, they again are wafted down so slowly through the resisting medium, and alight so softly, that the "soft falling snow and the diffusive rain'' have become fit emblems of the beneficence of God, as they give the strongest evidences of his wisdom and skill. Moreover, the glorious clouds, which add so much to the beauty of the landscape, and typify in their virgin whiteness the purity of heaven, are only collections of water dust floating [*] in the upper atmosphere, and mark the stage of transition between vapor and rain; and, further still, it is probable, as I stated in a previous lecture, that it is these same minute liquid drops which tint the morning and evening sky with their gorgeous hues, and cover our earthly dwelling-place with its canopy of blue.

Again, the presence of the air very greatly retards the aqueous circulation above described, without altering its essential character. There is now the same great difference between the density of the atmosphere of vapor at different latitudes, as if it were the only atmosphere on the globe, and the dense vapor of the tropics tends constantly to flow towards either pole; but as it cannot move without carrying with it the whole mass of the atmosphere, this tendency merely increases the velocity of those great aerial currents, already described in a previous lecture. Still the general fact remains the same. From the whole surface of the globe water is constantly evaporating into the aqueous atmosphere which surrounds it. The heated air from the tropics, heavily charged with moisture, is continually moving towards the colder regions, both of the North and of the South; and as the current thus becomes chilled, the vapor is slowly condensed, and the water showered down in fertilizing rains on the land. Thus it is that those beautiful provisions which we see in the rain all depend on the presence of the air, and result from a careful adjustment of the properties of aqueous vapor to the exact density of our atmosphere. "Hath the rain a Father?'' Science, by discovering these evidences of skilful adaptation,

has most conclusively answered this question, and the answer is the same now as in the days of Job. "Behold, God is great. . . . He maketh small the drops of water: they pour down rain according to the vapor thereof.''

But what becomes of the rain? Would that I could answer this question satisfactorily. We all understand the general theory of the aqueous circulation, but the deepest philosophy and the keenest science are not able to fathom its details, or to comprehend in their fulness the world of wonderful adaptations which the question unfolds. We all know that the drops of rain percolate through the soil, and collect in natural reservoirs formed between the layers of rock, and that these reservoirs supply the springs. The rills from numerous adjacent springs unite to form a brook, which increases as it flows, until it finally becomes the majestic river, rolling silently on its course. Every drop of that water has been an incessant wanderer since the dawn of creation, and it will soon be merged again in the vast ocean, only to begin anew its familiar journey. If you would gain an idea of the magnitude and extent of this wonderful circulation, you must bring together, in imagination, all the rivers of the world, the Amazon and the Orinoco, the Nile and the Ganges, the Mississippi and the St. Lawrence, and, adding to these the ten thousands of lesser streams, endeavor to form a conception of the incalculable amount of water which during twenty-four hours they pour into the vast basin of the world, and then remember that during the same period at least four times as much

water must have been raised in vapor, and scattered in rain over the surface of the globe. Would you form an idea of the importance of this circulation, you must not limit your appreciation to its economical value, as a great source of power, working the mills and the forges of civilized man, and building up vast marts of manufacturing industry, nor must you regard alone its commercial value, bearing as it does on its bosom to the ocean the freights of empires. These applications of power, however important in themselves, are insignificant in extent compared with those mighty agencies which the aqueous circulation is constantly exerting in nature. It has been the great agent of geological changes: here washing away continents, and there building them up; here gullying out valleys, and there smoothing away inequalities of surface; here dissolving out the particles of metals from the solid rocks, and there collecting them together in beds of useful ores. It has covered the earth with verdure and animal life, by conveying nourishment to the plant and food to the animal. It sustains our own bodies, for it is a portion of this very circulation which ebbs and flows in our veins, and whose pulsations beat out the moments of our lives; and could I bring together in one picture the infinite number of beneficent ends which it has been made by Providence to subserve, I am sure that you would agree with me that there is not in nature stronger evidence of design than in the adaptations of this simple and familiar liquid.

In order that we may appreciate, in some humble measure, the force of this evidence, let us consider

some of the qualities of water; but, at the same time, let us not forget that the strength of our argument lies not so much in the fact that each property has been skilfully adjusted to some specific end, as it does in the harmonious working of all the separate details. Had man creative power, the first would fall within the range of his intelligence; but to adapt the same substance to a thousand different ends, and to adjust each of its properties to a thousand different conditions, covering with their complex network all the known universe, implies a power nothing less than infinite, and an intelligence nothing lower than divine. It is evident, however, that we can gain a knowledge of the general plan only by studying the details, and unfortunately it is to these details that our accurate knowledge is almost entirely confined. We can see, for example, that each property of water has been designed for some specific purpose. We can also recognize the evident fact, that all the properties work harmoniously together in the general scheme of nature; but, in the present state of knowledge, to trace the intimate relations of these properties is frequently as impossible as it is to form a clear conception of the coexistenee and harmonious action of all. Yet in these very facts lies the whole force of the argument from design, and it is only the limitations of our knowledge and faculties which weaken the impression on our minds. But were these limitations removed, all argument would become unnecessary, for then, reasoning would be exchanged for vision, and in the refulgence of the Divine Presence we should know even as we are known.

It is a familiar fact, that water is an essential condition of organic life; but few persons, I suspect, are aware that this familiar liquid constitutes the greater part of all organized beings. The physical man has been described by one writer as consisting of merely a few pounds of solid matter distributed through six pailfuls of water, and it is a fact that no less than four-fifths of these bodies of ours are made up of water. Yet this is a small proportion compared with the amount which enters into the structure of most of the lower animals. Some of these, such as the medusæ,—sunfishes,—are little else than organized water. Professor Agassiz obtained from one of the large sunfishes found on our coast, weighing thirty pounds, only two hundred and forty grains of solid matter; and we may safely say that at least nine hundred and ninety-nine parts in a thousand of these singular animals consist of water. Water constitutes, to almost as great an extent, most of the vegetable products which are articles of food, as will be seen by the accompanying table.

             

Plums	contain 75 per cent. of water.
Potatoes	" 75 " " "
Apples	" 80 " " "
Carrots	" 83 " " "
Turnips	" 90 " " "
Watermelons	" 94 " " "
Cucumbers	" 97 " " "

It is evident from these facts that water is the

chief material of which all organized structures are formed, and in studying the aqueous circulation we have already become acquainted with the beautiful provisions of nature by which this life-giving liquid is distributed over the earth, and showered down upon the meadow and forest alike. Without water organic life cannot exist, and where, from any local causes, the supply fails, there we find a barren wilderness; while, on the other hand, the genial influences of the rain will soon make even "the desert blossom as the rose.'' It is a remarkable fact of physical geography, that the distribution of water by the aqueous circulation is rendered more effective by the peculiar structure of the continents, and the position of the great mountain chains.

"The mountain chains,'' writes Professor Guyot, in his excellent work Earth and Man, "are great condensers, placed here and there along the continents to rob the winds of their treasures, and to serve as reservoirs for the rain-waters, and to distribute them afterwards as they are needed over the surrounding plains. Their wet and cloudy summits are untiringly occupied with this important work, and from their sides flow numberless torrents and rivers, carrying in all directions wealth and life.''

Thus the mountains, whose majestic forms affect so powerfully the human soul, and which have exerted such an influence on the history of the race, are also among the most beneficent means in the Divine Providence by which the earth has been fertilized and rendered a fit abode for man. Moreover, these mountain chains have been evidently so distributed

as to give the greatest efficiency to the aqueous circulation, and to irrigate the continents most effectively with their fertilizing floods. We cannot, therefore, suppose that even these ridges on the earth's surface, which are the lasting records of ancient geological changes, were fixed by chance, for they also bear traces of His intelligence who seeth the end from the beginning, and every part of whose works is adapted to every other. "Lord, thou hast been our dwelling-place in all generations. Before the mountains were brought forth, or ever thou hadst formed the earth and the world, even from everlasting to everlasting, thou art God.''

But it is not the mountains alone which condense the vapor of the atmosphere; for, under certain conditions, the level plains act in a similar way, and distil the precious drops of dew upon field and meadow, distributing it among the plants with discriminating care for the necessities of each. The dew is simply another phase of the great aqueous circulation, and, like the rain, it is a persuasive witness of the Divine Disposer, who has adjusted its amount to the wants of the vegetable world. Every one has noticed the deposition of moisture on a pitcher of ice-cold water during a summer's day, and in this familiar fact, we have at once an example and an illustration of the simple provision by which, during even the long droughts of summer, the plants receive a partial supply of water, sufficient, at least, to sustain their life until the later rains bring the autumn fruits to maturity, and stimulate a more vigorous growth.

The explanation of the dew upon the pitcher is very simple. The layer of air in contact with its cold mass is rapidly cooled, and when it can no longer hold all the moisture it contains, the excess is deposited in drops on the surface. Exchange now the pitcher for the earth, and you have at once an explanation of the proximate cause of the dew. After sunset the earth, like the pitcher, cools down the layer of atmosphere immediately in contact with it to such a degree that the whole of the vapor can no longer retain its aeriform condition. As a necessary result, a portion is condensed and deposited upon the surface, and this is what we call dew. But it will be asked, What cools the earth so suddenly after the setting of the sun? For this is not so evident as the cause of the coldness of the pitcher. Certainly not, and the question will lead us to a study of those relations in which the adaptations to be discovered in this natural phenomenon are chiefly to be found.

The earth, as I stated in the second lecture, is moving with immense rapidity through a space whose temperature is at least 270 degrees below the zero of Fahrenheit's thermometer, and, like a heated cannon-ball hung in the middle of a cold room, it is continually losing heat by radiation. The dense atmosphere with which it is enveloped, acting, as we have seen, like a blanket, protects the earth from the intense cold of space to a certain extent; but still the constant loss of heat is so great, that, were the sun's rays withheld for a few days, the temperature of the surface-land, even in the tropics, would fall as low as it is now at the poles during the long night

of the arctic winter. In the daytime the earth receives from the sun more heat than it loses; but when this great thermal source is temporarily withdrawn, the loss of heat continuing as rapidly as before, the surface becomes quickly cooled, and the deposition of dew follows, as just explained; or, if the temperature falls below the freezing-point, the dew is changed to frost.

You must all have noticed that the most copious deposition both of dew and frost takes place on clear nights, and that during cloudy weather this supply of moisture is entirely withheld. The reason is obvious. The earth loses heat by radiation, and the clouds, intercepting the rays, reflect them back to the earth. A shed or any other protection spread over the ground acts in the same way, and it is well known that a covering, however slight, is sufficient to protect tender plants from the blight of the early frosts. Can it then be an accident, a mere result of chance, that the dew is deposited most abundantly where it is needed most, and that this supply of moisture fails only when the clouds promise a more copious draught of liquid nourishment from the rain?

There is still another fact presented by the dew which is equally suggestive. The heavens do not distil their liquid treasures upon all objects alike, but the dew is deposited much more abundantly on the herbage, the shrubs, and the trees, which need the refreshing moisture, than on fallow land, the sandy plain, or the beaten road; and here again the cause has been discovered. It is evident from the general theory of the subject, that the

largest amount of dew will fall on the coldest surface, and it is equally obvious that, other things being equal, those objects will cool most rapidly which have the smallest supply of heat to lose, and which radiate it with the greatest freedom. Now it has been ascertained by experiment, that the facility of radiating heat depends entirely on the nature of the surface, and the surfaces of leaves have such a remarkable power in this respect, that it would seem as if they were especially designed for the purpose. If next you consider how small a quantity of matter the leaves contain, compared with their large radiating surfaces, you will see that there are all the conditions present of rapid cooling. When, therefore, under a clear evening sky, the rays of heat are escaping from all objects into the celestial space, the green foliage soon becomes colder than the barren rocks or the inanimate clod, and receives, in consequence, a greater supply of dew.

It will be remembered, as I stated in the second lecture of this course, that the points of leaves have the power of silently discharging the thunderbolts of heaven, and that, in consequence, every tree acts far more efficiently to avert the stroke of this destructive agent than the best constructed lightning-rod. Is not, now, the force of this evidence of adaptation very greatly enhanced, when we find that the surfaces of these same leaves have been endowed with an equally remarkable power of radiating heat, by which they are insured a daily supply of moisture when they need it most? Could the adaptation of the structure of the leaf to these two entirely distinct

physical conditions of the atmosphere be the result of anything but intelligence? Admitting, with the modern advocates of the development theory, that under the pressure of circumstances a plant may change its structure so as to adapt it to the external conditions, still I think no one will be so bold as to maintain that there can be any brute agency in vegetation endowed with such foresight as to have adapted the material and structure of each leaf, from the very first, to the physical conditions of the globe, and this, moreover, for the purpose of effecting ends so remotely connected with its own organization as the discharge of electricity or the radiation of heat. If this can result from chance, under its modern name of natural selection then chance is but a counterfeit name of God. Gideon believed that God would save Israel, because the dew fell on the fleece, but not on the ground, and afterwards on the ground, but not on the fleece; and shall we doubt the reality of the Divine Providence, before whom a similar miracle is repeated every evening, with such beneficent results? If it be the mark of intelligence to be able to fathom and comprehend this wonder of Nature, can it be anything below Infinite Intelligence "who hath begotten the drops of dew''?

I might, with advantage, enter more into detail in regard to the laws of the distribution both of the rain and of the dew, but time and space forbid. I have been able only to open the subject; yet if I have succeeded in impressing you with the extent of the field which these beautiful phenomena present

to your inquiry, it is all that I could expect. We have seen that it is through these familiar channels that liquid nourishment is conveyed to the organic world, and the reservoirs supplied which feed the great river-system of the globe. But we should form a very imperfect idea of the resources of nature were we to limit our regards of the aqueous circulation to this important use. The life-blood of our bodies, which conveys to each muscle the nourishment it requires, when it returns again through the veins, this errand well done, is no less usefully employed in carrying away the portions of the tissues which have been worn out in the processes of life; and where from any cause this last function is not faithfully discharged, and the wasted muscles are allowed to remain in the system, disease and death are the inevitable results. So also is it with the life-liquid of nature, which in the rain and the dew carries food to the whole organic world. When this office has been fulfilled, it returns again to the ocean, washing away those waste products of organic life, which, if they remained, would cause pestilence and death. It is true that we cannot trace all the details of this cleansing process; but you need not the aid of science to assure you of the general facts. Let the free flowing of the rain-water be interrupted, and you well know that stagnant pools, breeding pestilence, or deadly swamps, exhaling malaria, are the immediate results. I cannot overstate the importance of this function of the aqueous circulation, or too strongly insist on the evidence of wisdom which the adaptation of the properties of water to this beneficent end implies. It is the great cleansing agent of the world. Wherever it flows, there it purifies, and its limpid streams, clear as crystal, are fit emblems of the purity of heaven. Hence the significance of this liquid in all religious systems. The ancient Egyptians worshipped the water of the Nile, and the Hindoo idolaters of the present day reverence with equal devotion the water of the Ganges. Passing to Judaism, we find the washing with water enjoined as a sacred duty by the Hebrew law; and lastly, in the Christian dispensation the pure liquid has become the medium of its most sacred rite, and the outward washing of baptism typifies that inward "washing of regeneration,'' by which alone man is saved.

Glancing now, for a single moment, at the æsthetic aspects of the subject, consider what sources of pleasure the varied phases of the aqueous circulation furnish, and what an influence on the soul of man they are calculated to exert. The bubbling spring, the purling rill, the murmuring brook, the sparkling cascade, the roaring torrent, the majestically flowing river, are familiar images of poetry, and the occasions of mental emotions which all have experienced and none can fully describe; while the mighty cataract and the ocean-storm are among the sublimest aspects of nature, and inspire the beholder with reverence and awe. When, now, you reflect that the chords of the human soul have been so strung as to vibrate in sympathy with these emotions of the material creation, and that thus the aqueous circulation has been made a means of instructing

and elevating the human race, can you refuse to accept the evidence of wisdom and goodness which a system, so far-seeing in its design, and so beneficent in its results, affords?

The mechanism of nature differs, as we have seen, from the creations of human ingenuity, in the fertility of its resources. Man combines numerous means in order to produce a single end; but in nature the most varied and apparently incompatible results flow from a single design. In God's works the means are employed, not as we use them in the poverty of our resources, but from the exuberance of riches. To use the language of another: "All the means are ends, and all the ends are means;'' and the grand result is an harmonious system, in which every part is a whole, and where the whole that is known is felt to be only a very insignificant part. Such is the character of the aqueous circulation, which we are now studying, and assuredly the numerous results we have already seen flowing from this simple mechanism are sufficient to mark the system as Divine; but we have not as yet exhausted its resources. Indeed, we have been all the time looking at only one side of the design, and there is a whole set of adaptations yet unnoticed, which are no less important in the scheme of organic nature than the one we have chiefly considered. And when we have become acquainted with these, we shall find still other phases of this boundless plan presented to our view, and not until man ceases to learn by study, or the waters cease to roll, will the subject be exhausted.

We have thus far only considered the agency of the aqueous circulation in distributing over the earth the chief constituent of all organic matter, together with some of the secondary ends which the river-system of the globe subserves. But there is another condition of organic life no less essential than moisture. The animal kingdom is absolutely dependent on the vegetable, and plants cannot grow except within a limited range of temperature. Therefore, unless during at least a portion of the year the amount of heat supplied is sufficient to maintain the temperature of the climate within the required limits, organic life cannot exist in that region. Now this familiar substance, water, has been endowed with most remarkable and unusual properties, by which the aqueous circulation has been made a great means of distributing heat, and thus of sustaining organic life in vast tracts of country where otherwise it could not exist; and it is to this class of its adaptations that I wish next to call your attention.

One of the prominent inventions of modern times is the method of heating large buildings by steam. You must all have seen the apparatus. There is first the boiler, where the steam is generated by the combustion of fuel; then pipes, by which it is distributed to the different rooms; next the iron radiators, in which the steam is condensed to water, and during this change gives out heat, which is radiated from the corrugated surface of the iron; and, lastly, the return pipes, through which the condensed water flows back to the boiler, ready to start again on the same journey. Every one is familiar with these

external aspects of the apparatus; but all may not know that the efficiency of the method depends entirely upon a remarkable quality of water, a quality which is not possessed to the same degree by any other known liquid. Were you to test with a thermometer the temperature of the water in the boiler and that of the steam rising from it, you would be surprised to find,—if you were not forewarned of the fact,—that they were precisely at the same point; and yet in order to change one pound of boiling water into one pound of steam it is necessary to burn up sufficient coal to raise the temperature of ten pounds of ice-cold water to the boiling-point. The coal which is burning under the boiler does not raise the temperature of the water. Press the fire ever so hard, you cannot increase the temperature either of the water or of the steam by a single degree. The effect of increasing the fire will be only to generate steam more rapidly, for the whole of the immense amount of heat set free by the burning fuel is absorbed by the boiling water in changing into steam. But this heat is not lost. It remains latent in the steam, is carried by it into the different rooms, and there, when the steam changes back again into water, it is all given up, without the slightest diminution, diffusing its genial warmth through the house. The steam, therefore, is merely the vehicle by which heat is carried over the building. The heat comes from the burning fuel in the cellar, and originally it came from the sun; for the coals burning under the boiler are merely fagots, as it were, of condensed sunbeams, gathered by the plants of some ancient geological epoch, subsequently fossilized and preserved in the earth for our use. The steam merely acts the part of a common carrier; but what I wish you to notice is the fact that steam is peculiarly fitted for the work, because it has been made capable of holding so large a quantity of heat.

Your attention, perhaps, has been called to the efficiency and economy of this method of heating; you have admired its neatness and absolute safety from fire, and have been delighted with the softness of the temperature which it diffuses through the rooms; or, if you have examined more closely the details of the apparatus, you must have been struck with the ingenuity of the adjustments by which it is self-regulated. Yet this is no new invention. A similar apparatus, on a vastly grander scale, working with far greater economy and efficiency, and provided with adjustments of wonderful delicacy, which perfectly regulate its action, and which never fail and never wear out, has been at work ever since the dawn of the creation, and is at this moment softening the inclemency of our northern winter.

The general aqueous circulation is a great steam-heating apparatus, with its boiler in the tropics and its condensers all over the globe. The sun's rays make the steam, and wherever dew, rain, or snow falls, there the heat, which came originally from the sun, and which has been brought from the tropics concealed in the folds of the vapor, is set free to warm the less favored regions of the earth. This apparatus of nature, although so much simpler, and

working without pipes, iron boiler, or radiators, is exactly the same in principle as the steam-heater, which may be seen at work in almost every large factory. It is true that the atmospheric vapor is a much better vehicle of heat than ordinary steam, and it is also true that this thermal application is but one of the hundred uses of the aqueous circulation; but still the general method is the same, and both systems owe their efficiency to the unique property with which water has been endowed. It is true that other liquids in changing into vapor absorb heat, but the heat stored up in these vapors is vastly less than that in steam, and it must be noticed that, of all created forms of matter, this familiar liquid, which fills the ocean, which distils upon us in the rain, and which flows in the rivers, is the only substance which has been thus especially endowed. Is this an accidental concurrence of circumstances? or is it, on the contrary, the work of Infinite Wisdom? We regard, and with reason, the beautiful invention of man, by which our dwellings are warmed, as an evidence of intelligence; and can we refuse to recognize the existence of that higher Intelligence, which not only adjusted the more perfect system of nature, but also created the properties of water, on which the efficiency of both depends?

Having considered that peculiar quality of vapor through which the aqueous circulation becomes an important means of distributing the sun's heat over the surface of the globe, we might next discuss more at length the extent of its influence, and examine in detail the ingenious system of checks and balances

by which the action of this great heating apparatus is regulated, and its constant working secured; but here, as before, having glanced at the main points, I must leave it to your study to fill the unavoidable blanks, and pass on to consider another special property of water by which a similar result is secured.

The amount of heat required to raise the temperature of a pound of water, or of any other substance, one degree, is capable of exact measurement, and the quantity has been determined experimentally for almost every known substance. These experiments have led to a remarkable result, to which I alluded in a former lecture. It appears that, when water is heated through a given number of degrees, it absorbs more than twice as much heat as any other substance (except one or two very closely related bodies), and more than ten times as much as iron and most of the metals. It is not probable that many of my audience have verified this striking result, but you all know how long it takes to boil a tea-kettle, even over a brisk fire, and have, therefore, some conception of the amount of heat which cold water is capable of absorbing. This familiar experience shows that water has a very great capacity of holding heat, and accurate experiment has proved, as just stated, that, with the exception just noticed, water contains, at the same temperature, more than twice as much heat as any other solid or liquid known.

The importance of this simple provision will appear if you reflect that it makes the ponds, the

lakes, and the oceans great reservoirs of heat. It not only requires a vast amount of heat to warm one of these large bodies of water, but when once warmed they cool very slowly. Hence the marked difference between the oceanic and the continental climate in the same latitude. During the summer the ocean eagerly absorbs the heat of the sun's rays, which are showered upon it in such profusion; but water has so great a capacity for heat, that the ocean, nevertheless, does not grow very warm, and, moreover, a large amount of the heat it receives is carried away by the vapor which is constantly rising from its surface. In winter, on the other hand, the water gives up its heat to warm the colder air; but it contains such an inexhaustible supply, that the loss does not materially lower its temperature. There results, in consequence, a great uniformity of temperature, in which the air, by its perpetual contact with the surface of the water, necessarily shares, and this uniformity extends, in a greater or less degree, to the climate of all islands and seaboard districts. It is quite different with the surface of continents. There the soil becomes rapidly heated under the vertical rays of a summer's sun, and, as its particles are immovable, the surface-layer soon rises to a high temperature; while, on the other hand, in winter it is cooled by radiation with equal rapidity; and this is the cause of those extremes of heat and cold which characterize all countries of the temperate zone removed from the influence of the ocean. The oceanic climate is moderate, while the continental climate is excessive. During the day, under the same circumstances, the land is warmer than the sea, and colder during the night, or, taking the different seasons, the land is warmer than the sea in summer and colder in winter. These general principles have been verified by the extensive series of meteorological observations which, during the last twenty-five years, have been made all over the civilized world. You will find an excellent abstract of the results in Professor Guyot's work on Earth and Man, before referred to. I have time only to cite a few familiar facts in illustration of my subject, which I will give nearly in his words.

"On the coast of Cornwall shrubs as delicate as the laurel or the camellia are green through the whole year, while under the same latitude in the interior of the continents, the most hardy trees can alone brave the rigor of the winter. But on the other hand, the mild climate of England cannot ripen the grape, although almost under the same parallel grow the delicious wines of the Rhine. At Astrachan, on the northern shore of the Caspian, as Humboldt tells us, the grapes and fruits of every kind are as beautiful and luscious as in the Canaries and in Italy; the wines have all the fire of those of the south of Europe, although in the same latitude, at the mouth of the Loire, on the Atlantic sea-coast, the vines hardly flourish at all. But while in the south of France the winter is a perpetual spring, the summers of the Caspian are succeeded by a winter of almost polar severity.''

I might multiply illustrations, but these are sufficient to show how the remarkable property of water

which we are considering tends to equalize the climate of the globe.

This influence of water is very greatly increased by the oceanic currents, which, like the winds, are set in motion by the heat of the sun, and are constantly carrying the warm waters of the tropics toward the poles. One of the most remarkable of these currents is the Gulf-Stream, which flows near our coast, and which diffuses the warm waters of the Caribbean Sea and the Gulf of Mexico over the Northern Atlantic, depositing on the shores of Scotland and Norway the plants and seeds of the tropics. It is solely the heat which these waters bring with them from the equator that has made the island of Great Britain so great a centre of commerce and civilization; for it must be remembered that the latitude of England is the same as that of Labrador, and, were it not for the influence of this ocean current, her soil would be equally desolate and barren. If the configuration of our Western Continent were only so slightly changed as to give a passage to the equatorial current through the present Isthmus of Panama—a change insignificant in comparison with those which have heretofore taken place—"the mountains of Wales and Scotland would become again the abode of glaciers, and civilization would disappear before the invasion of arctic cold.'' [*] So also it is to the enormous mass of heated water which the Gulf-Stream pours into the seas surrounding

northern Europe that Sweden and Norway owe their temperate climate, while at the corresponding latitudes on our own continent the land is shrouded in eternal ice and snow.

But all these provisions for distributing heat over the earth's surface would have been insufficient to maintain organic life in our northern climate, were it not for still another remarkable property with which water has been endowed,—a property even more entirely unique than either of those we have studied, and one which seems to be an exception to the general laws of nature. The familiar cycles of organic life, both in animals and plants, are intimately associated with the succession of the seasons, and this, in its turn, depends on the inclination of the earth's axis to the plane of the ecliptic, and on the great primary laws by which this axis is constantly maintained in a position parallel to itself during the revolution of the planet around the sun. To these fundamental conditions in the formation of the solar system the whole constitution of organic life on the earth has been adjusted; and Dr. Whewell, in his excellent Bridgewater Treatise, has discussed at length the evidences of design which this circumstance affords. It would be foreign to my plan, to consider these evidences here; but, assuming the succession of the seasons as a part of the order of creation, and as a means of adapting a larger portion of the earth's surface to the habitation of organized beings, it is evident that the higher forms of organic life could be sustained in these northern regions only by furnishing

to the plants and animals an adequate protection against the intense cold of winter, and thus preserving the growth of one summer until the returning sun awakened new life in the succeeding spring.

The required protection has been provided by making a most marked exception to the general laws of expansion in the case of water. It is the general law of nature that all substances are expanded by heat and contracted by cold, and water forms no exception to the general rule, except within certain very narrow limits of temperature, shortly to be noticed. Indeed, were it not for the expansion, we could not readily either heat or cool a large mass of liquid matter. All liquids are very poor conductors of heat, and can be heated only by bringing their particles successively in contact with the source of heat. When you set a tea-kettle over a fire, the first effect of the heat is to expand the particles of water resting on the bottom of the kettle, which, being thus rendered specifically lighter, rise, and are succeeded by colder particles, which are heated and rise in their turn; and thus the circulation is established by which all the particles are successively brought in contact with the heated bottom of the kettle, and in the course of time the temperature of the whole mass is raised to the boiling-point. The case is similar when you add ice to a pitcher of water in order to cool it. The water at the top of the pitcher, in contact with the ice is, of course, cooled, and, being thus rendered specifically heavier than the water below, sinks

and gives place to the warmer water, which is cooled and sinks in its turn, and thus, as before, a circulation is established, which continues until the temperature of the whole water is reduced to 40°. But at this point the circulation is entirely arrested; for, in consequence of its singular constitution, water at 39° is lighter than water at 40°, and consequently remains at the top. And so it is as the temperature sinks toward the freezing-point. The colder the water, the lighter it becomes, and the more persistently it remains at the surface. Hence, although the upper layers of water may be readily cooled to the freezing-point, yet, in consequence of its poor conducting power, the great body of the liquid below will remain at the temperature of 40°.

The cold atmosphere of winter acts upon the ponds and lakes exactly as the ice on the water in the pitcher. They also are cooled from the surface, and a circulation is established by the constant sinking of the chilled water until the temperature falls to 40°. But at this point, still eight degrees above the freezing-point, the circulation stops. The surface-water, as it cools below this temperature, remains at the top, and in the end freezes; but then comes into play still another provision in the properties of water. Most substances are heavier in their solid than in their liquid state; but ice, on the contrary, is lighter than water, and therefore floats on its surface. Moreover, as ice is a very poor conductor of heat, it serves as a protection to the lake, so that at the depth of a few feet, at most, the temperature of the water during winter is never under

40°, although the atmosphere may continue for weeks below zero.

If water resembled other liquids, and continued to contract with cold to its freezing-point,—if this exception had not been made, the whole order of nature would have been reversed. The circulation just described would continue until the whole mass of water in the lake had fallen to the freezing-point. The ice would then first form at the bottom, and the congelation would continue until the whole lake had been changed into one mass of solid ice. Upon such a mass the hottest summer would produce but little effect; for the poor conducting power would then prevent its melting, and instead of ponds and lakes we should have large masses of ice, which during the summer would melt on the surface to the depth of only a few feet. It is unnecessary to state that this condition of things would be utterly inconsistent with the existence of aquatic plants or animals, and it would be almost as fatal to organic life everywhere; for not only are all parts of the creation so indissolubly bound together that, if one member suffers, all the other members suffer with it, but moreover, the soil itself would, to a certain extent, share in the fate of the ponds. The soil is always more or less saturated with water, and, under existing conditions in our temperate zone, the frost does not penetrate to a sufficient depth to kill the roots and seeds of plants which are buried under it. But were water constituted like other liquids, the soil would remain frozen to the depth of many feet, and the only effect of the summer's heat would be to

melt a few inches at the surface. It would be, perhaps, possible to cultivate some hardy annuals in such a climate, but this would be all. Trees and shrubs could not brave the severity of the winter. Thus, then, it appears that the very existence of life in these temperate regions of the earth depends on an apparent exception to a general law of nature, so slight and limited in its extent that it can only be detected by the most refined scientific observation.

Moreover, this exceptional property is united in water with another quality, which greatly aids in preserving vegetable life during the winter months. We shudder at the thought of snow, but nevertheless it affords a most effectual protection to the soil, forming as warm a covering as would the softest wool. Water in all its conditions has been made a very bad conductor of heat, and snow is ranked with wool among the poorest of conductors. Heat, therefore, cannot readily escape from a snow-covered soil, and thus its temperature is prevented from falling materially below the freezing-point, however great the severity of the season. Notice now, that, when winter sets in and the cold increases to such a degree as to endanger the tender plants, Nature promptly spreads her great frost-blanket over forest, prairie, meadow, and garden alike, so that all may slumber on in safety until the sun returns and melts away the downy covering, when the buds break forth again and the trees put on a new mantle of living green.

This leads me to speak of still another remarkable property of the wonderful liquid we are studying;

for nature has provided in the constitution of water a most effectual means of tempering the transition of the seasons, and protecting vegetation against the early frosts of autumn or the first deceptive glow of returning spring. In order to freeze a liquid it is necessary to remove from it a certain quantity of heat called the heat of fusion, and the more of this heat a liquid contains, with the more difficulty, of course, it freezes, and when once frozen the less readily the solid melts. Now water contains a larger amount of heat of fusion than any other liquid yet examined, and in this respect, therefore, it is also peculiarly constituted. And mark how this property tends to produce the result just noticed. As the weather becomes cooler in autumn, our ponds and lakes gradually give up the stores of heat which they contain, until the temperature of the whole mass of water is reduced to 40°; then the surface water cools still further to the freezing-point; but before it can become any colder than this the water must freeze, and in freezing it will set free four times as much heat as it has already given out in cooling from the temperature of summer (63°) to the freezing-point. It is evident, therefore, that freezing must be a slow process. Moreover, it is also a warming process, and although the temperature of surrounding objects can never be thus raised above the freezing-point, nevertheless the immense amount of heat evolved greatly tends to retard the approach of severe cold, and prepares the way for the inclemency of winter. So also, when spring comes, vegetation is not awakened by her first touch to be exposed to the blights of the early frosts, and before the snow covering can be melted off the danger is mostly passed. Again, when we consider what devastating floods would sweep the earth were the icy bonds of winter suddenly dissolved, we shall discover still further evidence of the wisdom of that Being who has so adjusted the properties of water that both frost and freshet are the exception, not the rule.

I have said that water presents the only well established exception to the laws of expansion by heat, and some writers on natural theology have dwelt on this point as one of great importance to their argument. But I cannot think they are wise; for, to say the least, they rest their argument on our ignorance, and not on our knowledge. It is true that in the present state of science the anomalous expansion of water near the freezing-point seems to be an exception [*] to the general laws of nature; but hereafter this very anomaly may appear to be the natural result of a more general law not yet discovered, or, like the perturbations in the orbits of the planets, may prove to be the strongest confirmation of the very law it now seems to invalidate. Moreover, I do not share in that indefinite dread of natural laws which troubles so many religious minds. To me the laws of nature afford the strongest evidences of the existence of a God, and in their uniformity I see merely the constant action of an omnipresent Creator, who acts with perfect regularity

because he acts consistently and with infinite wisdom. I believe that all parts of nature are correlated by laws, and that the wider our knowledge becomes, the more universal these laws will appear. I do not, therefore, regard the constitution of water as something apart from law, and as the evidence of a power coming down, as it were, upon law to make an exception to it. This is making altogether too much of law. God is not bound by law. He acts wisely, beneficently, and with a definite plan, and the most we can claim for natural laws is, that they are our imperfect human expressions of this Divine plan. Moreover, that is a far nobler view of God's wisdom which supposes Him to be able to harmonize special adaptations with general laws. What I find so remarkable in the constitution of water is, not that it is an exception to the general laws of nature, but that, while filling its place in the general plan, it has been endowed with such extreme properties, and that in each case the peculiar property has special adaptations at once so complex and so important. Not only has water this exceptional property of expanding when other liquids contract, but, moreover, of all known substances it has the greatest capacity for heat; so also, when changing into vapor, it absorbs more heat than any other liquid; again, it is far lighter in the solid than in the liquid state; and lastly, it contains the largest amount of heat of fusion as yet observed in any substance. All this maybe in harmony with general laws. I have no doubt that it is; but the existence of the law does not in the least impair the significance of the fact, that in each of these respects water has been peculiarly constituted. This one liquid of the globe, which covers more than three-fourths of its surface, which circulates through all its channels, which percolates through all its pores, which constitutes three-fourths of all organized beings, has been endowed with these four pre-eminent qualities, on each of which the whole order of terrestrial nature may be said to depend. I cannot conceive of stronger evidence of design than this; and if these facts do not prove the existence of an intelligent Creator, then all nature is a deception and our own faculties a lie. Yet, my friends, this is only a small part of the evidence of design which science has discovered in this familiar liquid. I might occupy several lectures with this subject alone, but I have time only to glance at two more striking facts.

Water is the most universal solvent known, and there are but few substances which are not, to a greater or less degree, dissolved by it. Those which we call insoluble generally differ from the rest only in degree. Thus, all lime rocks dissolve to a limited extent in spring water, and the same is also true of almost all mineral substances. The magnificent crystals which we frequently find in the rocks are formed in almost every case by a deposition of the mineral substance from a state of solution in water. The feeble solvent power of the water for these substances is made up by the large volume of the solution, and the length of time occupied in the process of crystallization. Many of the large crystals which may be seen in cabinets of minerals have

been unquestionably thousands of years in formation. And not only does the solvent power of water stud the cavities of the rocks with gems, but it is also constantly producing most important changes in the rocky structures of the globe itself, here cementing together the loose sands, and there converting the soft clays into firm and solid rock.

Again, the solvent power of water extends to aeriform as well as to the solid substances, so that the gases composing the air pervade the lakes and the oceans as well as the atmosphere. Indeed, it is on the gases dissolved in the water that all the aquatic plants and animals live, and the members of the various finny tribes breathe the free oxygen dissolved in the water, as we breathe the oxygen of the air. Again, the process of respiration is essentially the same with these lower animals that it is with us, and the structure of their organs has been adjusted to the amount of this life-sustaining element which water is capable of dissolving. Moreover, the power which water possesses of dissolving oxygen is much greater than its power of dissolving nitrogen, and hence the air dissolved in the ocean is proportionally much richer in oxygen than our atmosphere. This is undoubtedly another quality with which water has been endowed in order to render the oceans, the lakes, and the rivers a fit habitation for that world of organic life which modern zoölogy has revealed. That we are unable to trace all its relations, is evidently owing to the imperfection of our knowledge. But here a new field of study opens before us, which, when fully explored,

will undoubtedly prove as rich in the evidence of design as the atmosphere itself.

It is not, however, merely as a solvent, that water is an important agent in the great laboratory of the world. I have already stated to what extent all animal and vegetable substances are composed of water, and that some, such as the jelly-fishes among animals, and the gourd family among plants, may be said to be living forms of water. But we should entertain a very erroneous conception of the condition of the water in these animal and vegetable structures, were we to regard it as so much dead material, building up the form like the bricks in an edifice. This water is in constant circulation, conveying nourishment to all the parts, and at the same time removing from the system those tissues which have fulfilled their functions and become effete. It is being constantly decomposed, and as rapidly again reformed, assuming the most protean conditions, and administering to the functions of the animal economy in a thousand ways.

As a constituent of inorganic matter, water is no less important than it is in organized being. A substance so bland as water, and apparently so entirely inactive, which fills the most delicate vegetable cells, and penetrates the finest capillaries of the body,—whose minuteness and delicacy no art can approach, nor imagination scarcely conceive,—yet without affecting either in the slightest degree, we should suppose would be endowed with no affinities, and capable of exerting no chemical force. Yet what is the fact? In attempting to classify

chemical compounds, I have studied with care the chemical history of water, and its relations to other substances, and it is still to me a perfect enigma in nature. For, so far from being that inert material which its bland exterior would seem to indicate, it is among the most important of chemical agents, forming some of the most stable compounds, and surprising the chemist by the strength of its affinities. Not only is water a common constituent of most crystalline salts, and an essential ingredient of many of the powerful acids which are used both in the arts and in the chemist's laboratory, but it makes, also, a not unimportant part of the rocky crust of the globe. Besides forming the immense deposits of ice which perpetually surround either pole, and the glaciers which creep down the high mountain slopes, we find that water enters as an essential ingredient into the composition of talcose and chlorite slate, gypsum, serpentine, soapstone, and other rocks. Moreover, water is the medium in which most chemical processes take place, and throughout all geological history it has been producing the most fundamental changes in the composition of the earth's crust, the extent of which geologists are only of late beginning to appreciate. It is now supposed that granite and similar rocks, which were formerly regarded as products of igneous fusion, have been really formed from loose beds of mud and clay, through the transforming power of this wonderful and powerful agent.

When, lastly, we consider the composition of water, our wonder is still further increased; for it

consists of two permanent gases, condensed by the force of chemical affinity to the liquid condition. With one of these, oxygen, you are already familiar. The other is a light, combustible gas, called hydrogen, fourteen and a half times lighter than air, and by far the lightest form of matter known. One cubic foot of water yields more than eighteen hundred cubic feet of a mixture of these two gases, and so persistently do they retain their aeriform condition, that not even a pressure of twenty tons on the square inch is sufficient to reduce them to liquids. Yet, immense as this pressure seems, requiring all the mechanical skill of man to apply it, that force must be still greater which is constantly acting in every drop of water to hold these highly elastic gases in the liquid state. It is difficult to estimate the magnitude of such power, as our only standard of measurement is the quantity of some other force, equally immeasurable, which is required to balance the first. Water is easily decomposed by electricity, and the amount of this agent required to force apart its constituents may perhaps give you some imperfect conception of the magnitude of that power by which they are so securely imprisoned. The statement may seem incredible, but yet it has been proved by Professor Faraday, that it requires more electricity to decompose a drop of water than to charge a thunder-cloud.

What a revelation of power we have here! In every drop of water there is a constant striving of the elements to escape; they are exerting a force to break the bonds that unite them, which can be

measured only by the power of concentrated thunder-bolts, and yet this immense force is kept in check by a force of equal power, and so exactly balanced that not the slightest disturbance can occur. When now I endeavor to estimate the value of this chemical force by our human standards, and find that in comparison with it all the mechanical energy which man can exert, even when aided by the appliances of modern art, is utterly insignificant; and when I reflect that in every particle of water the force is still acting, so that every rain-drop which falls is a silent monitor of human weakness, I am overwhelmed by that mystery in nature, which, here as elsewhere, ever points upward to the Infinite, and thus silently teaches that the mighty influence which binds the atoms of the rain-drop is merely the manifestation of His ceaseless power who holdeth "the waters in the hollow of His hand.''

It is a very common mistake to suppose that the grand in nature is to be seen only in its great water-falls and its lofty mountains; for, to the intellectual eye, there is more real grandeur, more evidence of omnipotence, in a single raindrop than in the rush of Niagara or in the magnitude of Mont Blanc. The more I study the evidence of design in this simple liquid, the more I find there is to learn, and I feel the utter inadequacy of any language to convey the full and complete idea. Review, for a moment, the examples of adaptation which have been so briefly noticed. Remember that water is the liquid of our globe, and the only liquid which exists in any abundance

on its surface. The total amount of all other liquids is in comparison but as "a drop of a bucket.'' Consider, next, that its specific gravity has been so adjusted that our ships float, and the oceans are made great highways for the nations; that it is easily converted into vapor, and as easily condensed to fertilizing rain and refreshing dew, which nourish the growing plants, fill the springs, and keep the rivers— the great arteries of the globe—in circulation; that at a comparatively low temperature it is changed into highly elastic steam, which, imprisoned by man in his iron boilers, has become the great civilizer of the world; that it has been so exceptionally constituted that the great mass cannot be cooled below forty degrees, and again has been made such a poor conductor of heat that, when the surface is frozen, the very ice becomes a protection against the cold; that to this same liquid there has been given a very great capacity for heat, and that thus it has been made the means of tempering materially the climates of the globe. Add to this that water has been made an almost universal solvent; that from the substances it holds in solution the crustacea form their shells and the coral polyps build their reefs; that it fills the cavities of the rocks with gems, and their fissures with useful ores. In connection with this host of wonderful mechanical adaptations, remember that water has been made a chemical agent of great energy and power; that there have been united in it the apparently incompatible qualities of blandness and great chemical force; that, although in the laboratory of nature it corrodes the most resisting rocks, it also circulates through the leaflets of the rose and the still more delicate human lungs; that it forms the greater part of all organized beings, from the lichen to the oak, and from the polyp to man. Reflect, now, that these are only a few of the grosser qualities and functions of this remarkable compound, gleaned here and there from many others no less wonderful, and you will form still but a very imperfect conception of the amount of design which has been crowded into it. Attempt to find a liquid, which, if in sufficient quantity, might supply its place, and you will be still further impressed by this evidence of intelligence and forethought. Of all the materials of our globe, water bears most conspicuously the stamp of the Great Designer, and as in the Book of Nature it teaches the most impressive lesson of His wisdom and power, so in the Book of Grace it has been made a token of God's eternal covenant with man, and still reflects His never-fading promise from the painted bow.