When two opposite currents of air meet, of different temperatures, the vapors are sometimes condensed thereby, and rain ensues. It may be remarked, that if the temperature of our atmosphere had been 212, or upwards, rain could never have fallen on the earth; for the water taken up by evaporation would have been converted into a permanently elastic fluid. Such is the necessity of rain, that it alone not only affords a proper degree of moisture to the vegetable creation, but is of service in bringing the soils into a fit state to perform their office. Dry earth of itself is ineffective; but when moistened it has the property of decomposing atmospheric air, and of conveying its oxygen to the roots of those plants which vegetate within it. We are indebted to Humboldt for the knowledge of this fact. It is impossible ever to contemplate the various ways in which the different operations of nature are made to correct and balance each other, without being struck with the infinite comprehension of the Divine Mind, which could thus foresee the tendency of every law which it was about to establish. How many cases are there in which the slightest oversight would have produced the destruction of the world!
The effects of vapor have furnished a new moving force to mechanics, says Haüy, which it required no ordinary genius to have created, and to have measured its energy. This science, during a long time, had only employed water as a moving force, by availing itself of its natural course, or by judiciously managing its fall, so as to subject it to the operation of machines which is regulated by an impulsion continually renewed. The experiments made upon the force of water reduced to vapor, gave birth to the idea of applying that vapor so much the more advantageously to the same purpose, because independently of its great energy, it may be transported wherever it is called for by the interests of commerce and industry.
The execution of steam-engines has had, like that of all other machines, its different epochs, to which successively corresponded new degrees of perfection. To diminish, as far as possible, the quantity of vaporisation requisite for the effect in contemplation, and to make a moderate use of the combustible; to combine with this chief economy that of substance and of workmanship, by contracting the dimensions of the pieces without diminishing their utility; to prevent explosions, by the wisest precautions adopted in the management of an agent whose power becomes destructive when it is not limited: these are in general the objects which have fixed the attention of engineers, and have excited among them a laudable kind of rivalship.[94]
In no invention, either for ingenuity or utility, has modern genius been more conspicuous than in the invention of the steam-engine. The amazing power wielded by man, by this means, is just matter of astonishment and wonder. In no part of the kingdom have these stupendous machines been brought to greater perfection, either in size or principle, than in the mining counties of Cornwall and Devon. The largest ever built has lately been erected at Chacewater mine, in the county of Cornwall, by Mr. S. Moyle, of that place, and is for size and efficiency, as well as neatness, without a parallel. This stupendous machine is equal to 1,010 horses; it works day and night in pumping dry a mine of 100 fathoms deep, and of a large extent: and the quantity of water pumped out in one minute, and the column consequently lifted, is greater than any other machine of the kind ever erected. The whole reflects the greatest credit on the abilities of the engineer, and forms an interesting object to all those who are curious in mechanism, or who may visit the mines of Cornwall.[95]
A very ingenious naturalist suggests the idea, that subterraneous fire, and steam generated from it, are the true and real causes of earthquakes. And he thinks the elasticity of steam and its expansive force, are every way capable of producing the stupendous effects attributed to earthquakes, when it is considered that this expansive force of steam is to that of gunpowder as 140 to 5. He also apprehends that subterraneous fire must, at different times, have existed universally in the bowels of the earth, and that in union with water, or by the expansive power of steam, it has produced the immense continents, as well as the mountains of our globe.[96] There are, in the Memoirs of the Paris Academy of Sciences for the year 1707, some observations communicated by Vauban, from which it results that 140 pounds of water converted into vapor, would produce an explosion capable of blowing up a mass of 77,000 pounds, while 140 pounds of powder could only produce a similar effect upon a mass of 30,000.
Water would be the purest of all drinks, says Sturm, were it as absolutely simple body; but on the other hand, its medicinal virtue would be reduced to nothing. If we consider the manner in which water nourishes plants, it is easy to presume that it communicates the nutritious juices which it contains, to men and animals in the same way. Water is not very nutritive by itself, but being very subtile, it dissolves the nutritious parts of aliments, is a vehicle for them, and carries them along into the minutest vessels. It is consequently the most wholesome drink; and is essentially necessary to men and animals; and its salutary effects are felt, where all other liquids are found hurtful to health. “The water of Egypt,” says the Abbé Mascrier, “is so delicious, that one would not wish the heat to be less, or to be delivered from the sensation of thirst. The Turks find it so exquisite, that they excite themselves to drink of it by eating salt. It is a common saying among them, that if Mahomed had drank of it, he would have besought God that he might never die, in order to have had this continual gratification. When the Egyptians undertake the pilgrimage of Mecca, or go out of their country on any other account, they speak of nothing but the pleasure they shall have, at their return, in drinking of the waters of the Nile. There is no gratification to be compared to this: it surpasses, in their esteem, that of seeing their relations and families. All those who have tasted of this water, allow that they never met with the like in any other place. When a person drinks of it for the first time, he can scarcely be persuaded that it is not a water prepared by art: for it has something in it inexpressibly agreeable and pleasing to the taste; and it should have the same rank among waters, that champaigne has among wines. But its most valuable quality is, that it is exceedingly salutary. It never incommodes, let it be drank in what quantity it may: this is so true, that it is no uncommon thing to see some persons drink three buckets full of it in a day, without the least inconvenience! When I pass such encomiums on the water of Egypt, it is right to observe, that I speak only of that of the Nile, which indeed is the only water, drinkable, for their well-water is detestable and unwholesome. Fountains are so rare, that they are a kind of prodigy in that country; and as to rain-water, that is out of the question, as scarcely any falls in Egypt.”
Having attended to the situation and properties of water in the world of nature, we shall now show that by this element is represented the blessings of Divine grace in the moral or spiritual world. God is the fountain of living waters, ever-living, all-sufficient, and incessantly flowing; like waters, arising and issuing from a spring, which continue during the whole year: not like waters that proceed only from some excess of rain, such as land-floods, or those flowing down from hills, which in the winter season run in torrents, but in the heat of summer are dried up and fail. Such uncertain waters are well expressed by Job—“My brethren have dealt deceitfully as a brook, and as the stream of brooks they pass away; which are blackish by reason of the ice, and wherein the snow is hid: what time they wax warm they vanish: when it is hot they are consumed out of their place. The paths of their way are turned aside; they go to nothing, and perish. The troops of Tema looked, the companies of Sheba waited for them. They are confounded because they had hoped; they came thither, and were ashamed.” He alludes to those merchants who travelled in companies or caravans, with beasts of burden, through the deserts of Arabia; who, having in the winter observed and marked out in certain places on the road great pools of water, or copious streams locked up in the valleys by severe frosts; so that, when travelling the same road in summer, they expected finding water there still to refresh themselves and their thirsty camels; but, to their great grief and consternation, instead of pools or brooks of water, found heaps of dry sand, occasioned by intense heat. But God is a fountain which sends forth streams of blessings in all seasons, and never fails. The living waters which proceed from him as their fountain, are not stagnant, or dead, but running, like those that issue from springs which are never dry, and possess the most refreshing and invigorating properties.
The element of water is used for washing and purifying the body; so the operation of Divine grace on the soul removes its moral defilement. All the purifications by water under the law, were outward expressions of this inward cleansing. Thus those important words by the prophet Ezekiel, “I will sprinkle clean water upon you, and ye shall be clean; from all your filthiness, and from all your idols, will I cleanse you: a new heart also will I give you, and a new spirit will I put within you.” Accordingly the Psalmist says, “Thou shalt wash me, and I shall be whiter than snow.” He also prays, “Create in me a clean heart, oh God; and renew a right spirit within me.” As purity is necessary for enjoying communion with God in all his instituted ordinances, he says, “I will wash mine hands in innocency: so will I compass thine altar, oh Lord.” Similar language is used in the New Testament. Our Lord said to Peter, “If I wash thee not, thou hast no part in me.” The apostle Paul, after mentioning several immoral characters to the Christians at Corinth, says, “And such were some of you: but ye are washed, but ye are sanctified, but ye are justified in the name of the Lord Jesus, and by the Spirit of our God.”
Our Lord gave himself for us, not only that he might redeem us from all iniquity, but also that he might purify us unto himself a peculiar people. This cleansing, washing, and purifying the soul from sin, is, in the Holy Scripture, attributed to the virtual efficacy of his blood. “The blood of Jesus Christ his Son cleanseth us from all sin.” “Unto him that loved us, and washed us from our sins in his own blood.” The primary effect of his blood is the expiation of sin; and, as a consequence thereof, the remission of it. “This is my blood which is shed for the remission of sins.” “In whom we have redemption through his blood, the forgiveness of sins.” Now by the blood of Christ in these places we are to understand his sufferings, which were completed in the shedding of his blood on the cross.