the impeller and the impelled of the automaton machinery by which commerce moves. Let us consider another metallurgic process. A furnace is constructed to throw all its heat by reverberation on a mass of lead, and as the metal melts, a current of air is made to play on its surface. Soon that surface becomes covered with a molten floating liquid, which flows off from it continually, and will flow so long as any lead remains. The last portions of the lead, however, are preserved for the silver they contain; the rest has all disappeared. This floating dross into which the air has converted the lead, hardens as it cools, and forms then a beautiful yellow-orange, unmetallic, highly-crystalline, soft, solid substance-litharge. It is the "oxyd of lead." It is the air that here, reversing the dictum of Anaximenes, is the destroyer. Its oxygen has combined with the melted metal. It needs not to melt iron to produce an analogous effect. If the bar of refined iron be but left in neglect to the rude influences of the weather, to air and moisture, it will soon be seen that the metal, with all its stern qualities, is, like man himself, dependent on certain conditions and circumstances, which must be ever supplied and preserved around it, or the bright shall tarnish, the strong fret away into weakness, and the lustrous and the elastic, the stern to labor and the patient to endure, shall suffer corrosion, and become a dull insipid earth, a mere heap of rust.. Yet from this earth, this oxyd of iron, no less than from the dross of lead, the metal may be again recovered. The earth or calx is in either instance formed by a union of the metal with the oxygen of the air, and any substance with a stronger tendency to combine with that oxygen will free the metal of it, and the iron or the lead may be restored to their metallic form of existence. Carbon, that is coal or charcoal, effects this, and the operation is similar in result whether it be performed in the blast furnace whose weekly product is above a hundred tons of iron, or in the reverberatory furnace wherein lead is reduced to the form in which we use it. ments, from the days of Geber to those of Beccher. Was there, in fact, anything contradictory or absurd in the belief that the crucibles of Albert the Great, of Raymond Lulle, or of Arnold, had yielded gold when gold had been absent as an ingredient from the conditions of the experiment? Did not a mere calx, when mixed with charcoal, yield lead? Did not the very metal of silver, Luna herself, emerge from ores in which no silver could be seen? nay, did not even the Saturnine ores-did not the stones which yielded lead, yield, too, their small quota of this queenly silver? If Luna could thus emerge from the region of Saturn; if the ores of copper when mingled with calamine produced not copper, the Venus of the metal-firmament, but brass; if bronze sprang from the conjunction of Venus and Jupiter, and the copper and the tin lost each their characters in the bronze they formed, why should not the addition of some subtile, redder mercury give to tin the properties of gold, or teach the alchemist to transmute the dross of Saturn or the charms of Venus into the glories of Sol, the golden metal-king? | But the alchemist passed from the earth, leaving to an age of less inflated hopes and of a sounder philosophy—an age that had learned something by the failures of the past—this metallurgic problem for its heritage. To those who have loved to linger over the gradual dawnings of human knowledge in past time, who have felt a delight in tracing the growth of some single idea in the mind of man through all its doubts, misapprehensions, aspirations rebuffs, successes, on to its final triumphto these, that will ever be an interesting history which tells of the progress of the first grand idea of chemical philosophy, the idea of the individuality, so to say, of the elements; of the elemental character of the metals; of the non-elemental, the compound character of the combinations of these with the vital element, the oxygen of the air. To them the erroneous dream of Stahl, "the phlogistic theory," will carry with it an unceasing interest, albeit that the balance of Lavoisier banished that theory from the laboratory, and showed its fundamental error by proving that the calx, or earth, weighed more than the metal which it yielded-weighed more by a precise amount, which was the exact weight of oxygen gas that the metal had taken from the air and fixed in solid com It was this singular conversion of a metal into an earthy calx, and this inversion of the phenomenon by the reconversion of the earth into the metal, that incited the alchemist to perpetual experi | bination with itself to form this earthy controversy"-received a new significance oxyd. He taught that the metal might in the decomposition which the voltaic be won from this its earthy calx or oxyd, pile effected in it, under the hands of but only by some stronger affinity than the Nicholson and Carlisle, in the year 1800. metal's own for the oxygen the earth con- They found the oxygen given off at the tained. Carbon has this stronger affinity, positive, the hydrogen at the negative, and hence the flow of molten iron from the pole; the water being gradually separated vast furnace in which its oxyd meets in by the voltaic agency into its component fiery contest with the coal that feeds its elements, oxygen and hydrogen. Davy, flames, meets it only to surrender to that who soon afterward appeared on the scene, coal its oxygen, and to set the iron free to saw at a glance the vast results to be deenter on its life of constant labor and trial veloped by this divellent action of the batin the service of man. tery upon chemical compounds. There is no one who cannot feel a sympathizing This doctrine, then, of the compound nature of the metal-yielding earths or ox-pleasure as he imagines the young Davy yds, and of the elemental character of the metals and of the oxygen they contained, was the grand doctrine of Lavoisier, and resolved the difficulty, of which the alchemists, and at last, after them, the phlogistic chemists, had sought in vain for the solution through so many centuries. But chemistry knew of other earths besides these that yielded metals when heated with charcoal --earths to all intents like these, notwithstanding that they had resisted all efforts to extract metals from them. with the wires of his enormous battery brought into contact through the medium of the alkali potash, until that moment undecomposed, and sees him watching a beautiful phenomenon. Little globules of a brilliant metal continually are presenting themselves at the negative wire, and lingering for a moment to show him their true metallic character, then cease to shine, and become again converted into the potash out of which they sprung, too powerfully assailed by the oxydizing air, of which the corrosive action is too strong for a metal of such eager affinities to exist in its presence. Davy soon contrived means of fostering his new-born metal, and exhibiting it to the world under the name of potassium; and soda soon yielded its sodium to the pole of his gigantic voltaic pile. Both of them are metals which, to be preserved, must be retained out of contact with the air; metals, the latter white as silver, and as lustrous, the former with something of the tint of tin or platinum; both lighter than water, and therefore floating on it, but also instantaneously decomposing it to absorb its oxygen, and disappear in it themselves as potash or as soda. To decompose magnesia, lime, (calx,) baryta, into oxygen and the metals " magima-nesium," "calcium," and "barium," respectively, was but a work of the few hours requisite to plan the experiment. And thus an antagonistic force had been found whereby to invert, as it were, the combining force of chemical affinity, so that now, With rod reversed, And backward mutterings of dissevering power, Of these other earths there were several besides magnesia, lime, and the earth of clay, alumina; and nearly akin to them, though more easily dissolved in water, and therefore lacking one of the prominent characteristics of an earth, comparative insolubility, were the alkalies, potash and soda. It needed, therefore, after Lavoisier's time, no great profundity in the chemist who should assert that it was a fair object of search, and that there was a fair ground for hope, that some means should be found, some more potent affinity than even that of carbon should be discovered, by the agency of which these earths too should yield up bright metals under the torturing inquisition of crucible and furnace. Lavoisier himself had proclaimed this before, and almost in Lavoisier's time it was gined by some sanguine experimentalists in Hungary that the anticipation had been realized. But that realization was not yet ripe for accomplishment, and time had to bring in other ideas and other men to contribute to the development of it. Galvani and Volta (the greatest name, perhaps, in the history of physics) had introduced a new force to the experimentalist. By its agency the compound nature of water -already proved by the illustrious men whose names now figure in the "water the master of this new necromancy freed from several of these earths beautiful metals, till then truly In stony fetters fixed and motionless. But some of the earths refused the solicitations of even Davy's voltaic magic. Among these was one of a very remarkable kind, named by the chemists alumina, from its occurrence as one of the ingredients in alum. In the sapphire and ruby this extraordinary body yields only to the diamond in hardness, while it far surpasses it as a gem in the beauty, if not in the variety of its color-suite. As the lux-sapphire, it rivals the diamond itself in colorless purity and exquisite luster. As the ruby, it demands a higher price than it, when above a few carats in weight; as the sapphire, there is no stone with which it can be confounded, when of the true azure blue; while as Oriental topaz, Oriental emerald, aquamarine, peridot, amethyst, it surpasses in beauty of color and luster, and far surpasses in value, the several gems from which it thus condescends to borrow its names. In all of these the alumina is pure, and crystallized in perfect transparency, the colors being due to minutest traces of other metallic oxyds, such as iron, chrome, or manganese. Then, again, in its less brilliant forms, as corundum and as emery powder, its uses are almost the same as those of the indomitable diamond | dust while in its softer moods, combined with water, it helps to form the plastic element of clay; and at one moment is seen assuming shapes and wearing tints, as vase and bowl, that give it more than the value of sapphire or ruby; at another, ministering in every shape to satisfy the wants of man. : From the nature of this earth, it was difficult to bring it within the sphere of action of the battery. But Davy recognized in his new metal, potassium, a substance whose avidity for oxygen might be utilized for the decomposition of the refractory earth which he could not subdue by his voltaic wires. And so he heated alumina white hot, and passed his new metal in the form of a metallic gas over it, and obtained thereby small globules of a metal which had its source in the alumina employed. This new member of the metal family, aluminum, he did not, however, succeed in effectually isolating, and he could not, therefore, announce its properties. Later it was produced by Wöhler by an analogous but better process, but then not in sufficient quantity, nor in advantageous form for investigating its physical characters. He obtained it as a powder, and in this finely divided form it is very difficult to ascertain the properties which a metal may assume when fused into a solid mass. Even lead, when in fine division, will burn spontaneously in the air, and it is therefore not to be wondered at, that in the pulverulent aluminum of Wöhler, that chemist did not recognize those remarkable characteristics which have thrown so much interest round the bars of this metal that have been produced by M. Deville, and exhibited so recently in Paris. Wöhler, indeed, had himself, previously to M. Deville, formed the metal in fused globules. But the method adopted by M. Deville, though in principle similar, was superior in details to Wöhler's process. The metal, as thus obtained, possesses most curious and unexpected properties. Tin-white in color, it is unaffected by the air, and is less disposed to tarnish than silver itself. It is unattacked by any ordinary acid, except muriatic acid, which, and the alkalies, seem to be its only natural chemical enemies. It is very malleable, and when rolled and hammered becomes as hard as iron, a most invaluable property, possessed by no other metal in use. It is an admirable conductor of electricity, and slightly magnetic, like iron. It melts at a lower temperature than silver, so that it possesses all the most valuable properties required of a metal by the artisan. But its most singular property is its lightness. In this respect it stands above all other bodies of the metallic class that are in use. The lightest of these is zinc, which is seven times heavier than water; iron is nearly eight times, silver is ten and a half times, and gold nearly twenty times heavier than water, whereas aluminum is little more than twice and a half as heavy as that fluid, and, consequently, about a quarter of the weight of silver. An ounce, therefore, of this metal will go as far as four ounces of silver, or eight of gold. Its price per ounce is, however, at present that of gold, and hence about four times as dear, bulk for bulk, as silver. Doubtless neither commerce nor chemistry will rest till aluminum can be used for household no less than for philosophical purposes, and doubtless, also, for what may prove a most important application of it, the formation of light, hard, useful, and beautiful alloys with other metals. A bell formed of it would possess singular novelty. Its ring is the sharp clear note of glass, not the fuller tone of metal; one's fancy already anticipates the music in which some instrument whose vibration shall ring from aluminum bars shall take its part. ST. PAUL'S SALUTATIONS. IT T has often been objected, that however we may admit the inspiration of other parts of Holy Scripture, the same cannot be affirmed of the "Salutations," and other seemingly minor matters, with which St. Paul frequently closes his Epistles. It is said they are too trivial to be the subject of inspiration, not worth the interference of the Holy Spirit either one way or another. There is no harmfulness in them, but it is absurd to apply to them the solemn words, "All Scripture is Godinspired." We do not purpose to answer this objection in detail by way of argument. We would rather see whether something may not be gleaned from these salutations which shall, on the one hand, show that there is nothing trivial in them, and, on the other, lead to the conclusion that there are no exceptions to the rule that St. Paul spake as he "was moved by the Holy Ghost." And we may mark by the way the internal evidence which such passages afford to the genuineness of St. Paul's Epistles. An impostor who wished to foist on the world a human composition as the revelation and very word of God, would never have endangered his scheme by inserting such passages as that wherein Paul bids Timothy bring his cloak which he had left behind at Troas, or as the salutations and greetings by name of many members of the Church at Rome. There is a naturalness about them which goes far in itself to forbid the thought of imposture. It is just what we should expect St. Paul to write. He is sending a letter to Rome by the hands of Phoebe. As he dictates its final sentences, associations and remembrances of all kinds spring up in his heart. Many were personally known to him. Some had been his companions as he went forth preaching "the Gospel of the blessed God," fellow-laborers in the work that was nearest his heart. Others had been diligent in the varied departments of Christian labor and ChrisThe transmutations wrought by modern tian benevolence. One was affectionately chemistry are as great in character, and, remembered as his first convert in Achaia. however different in kind, are far more Others had known Christ and His Gospel important and useful in their result, than at a time when he himself had been a perseall that alchemy ever dreamed of; they cutor and a blasphemer. All were the obare not the less complete because their jects of his Christian love, dear to his heart character has been so correctly explained. I in the bonds of the faith of Jesus Christ. Another metal not less curious than aluminum has followed in its wake. The emerald and the beryl are varieties of the same mineral, rivaling all except, perhaps, the sapphire family in beauty as gems. These contain an earth called by the Greekderived name of glucina, from the sweetness of its salts. The metal of this earth had also been isolated by Wöhler, but its properties are first described by M. Debray, a pupil of M. Deville. It appears as a beautiful white metal, nearly as unalterable as aluminum itself, but with the curious property of being one-fifth lighter, its specific gravity being twice that of water. Lime has also now surrendered its constituent metal, calcium, in pure form, and it proves to be yellow like gold, but, unfortunately, as evanescent as it is beautiful. The action of the air alone is sufficient to corrode it into its natural calx, the well known earth, lime. It is curious to see science thus working out, in its own way, and by lights of its own kindling, problems after the solution of which the alchemist groped so long in darkness, whose obscurity he increased and perpetuated, because he would retain for himself alone and for "the adepts," not for the world, the riches which he sought. Like the miner, and unlike the metal lurgist with whom we commenced, the alchemist delved in dark recesses after gold. He handled, indeed, metallic ores, but he touched not the living metal. It was only when that ore was brought into the light and into the furnace, that it assumed the real metallic shape; only when the fire of truth has tried it, and the advancement, intellectual no less than material, of the human race is the object to be won, is the transmutation of ignorance into knowledge effected, only then is the superstition of the miner corrected by the higher knowledge of the experienced and sagacious metallurgist. But let us observe in what way this portion of the Holy Book is profitable for instruction in righteousness. Not to dwell on the example of Christian courtesy which it affords, we may first notice the interesting insight which it gives us into the state of the early Church. By means of it we perceive how the Christians of that day delighted to labor in the service of Christ, sometimes by active effort in spreading the knowledge of the Gospel; sometimes by ministering to the wants of the afflicted, or the necessities of the evangelists and teachers. Several benefactors of this kind are mentioned in the last chapter of the Epistle to the Romans. Various were their positions in life. But one motive animated them all. Phoebe, who carried the apostle's letter to Rome, is specially commended. Her most Christian kindness had diffused itself like the refreshing stream, carrying sympathy and succor wherever they were needed. Aquila and Priscilla had helped the apostle much, periling their lives on his account at some time of personal danger, and thus had laid all the Churches under deep obligation. Others also were worthy of special remembrance, for one cause or another. Shall we say there is nothing profitable in Scriptures like these? Do they not, on the contrary, point out a path of duty and of love untrodden by a large majority of Christians? Do they not teach us that every Christian, however humble, should and may do something for the increase of the Redeemer's kingdom? By this we mean, not the mere attendance at the house of prayer, not the casting of a gift into the treasury of Christian charity, but active personal labor, and diligent painstaking effort. It would show an utter forgetfulness of the lessons of God's truth, it would curtail some of the highest Christian privileges, and dam up many a stream of piety and love, to shut out from these labors and efforts any Christian, however lowly their earthly position, or to say that none but the ordained minister, or the elevated in social position, should labor for the Lord, and be fellow-workers in the kingdom of God. All together make up the body of Christ, and each one is a member in particular. "The eye cannot say to the hand, I have no need of thee; nor the head to the foot, I have no need of thee." All Christians, then, of whatever rank in life, and whatever grade in society-whether moving in the polished circles of refinement and opulence, or in the lowly routine of artisanship and labor whether tradesman at the counter, or mechanics in the workshop-whether gaining their bread by the toil of the mind or the sweat of the brow-we would desire to see all enlisted in the ranks of Christian helpers. Would that every heart which has been touched and changed by the Gospel were ambitious to rival and excel in Christian exertion that Phoebe, who was a succorer of many; that Priscilla, and Aquila, and Urbane, who were the apostle's helpers in Christ Jesus; that Tryphena and Tryphosa, and the beloved Persis, who labored much in the Lord! Every walk of life affords a sphere, and every day an opportunity. These, doubtless, neglected no duty which had a prior claim; but combined together the Christian diligence, and the large-hearted sympathy and love, which enabled them to rule their own households well, and at the same time to strengthen the hands of the apostle, and minister to the wants of the necessitous and the feeble. Who shall say with how mighty an energy, with what increased power, the work of God would progress in the land, nay, in the world, if every Christian felt a personal interest and a call to personal effort? Who shall say what a sanctifying influence would pervade every department and relation in life, did each one determine to labor, not merely for his own salvation, but that of others? How many a seed of infidelity would be stifled in the germ, if the Christian laborer and mechanic made his religion a relative as well as a personal thing. Where is the faith that quickened to exertion those helpers of St. Paul of whose labors he had such an affectionate remembrance? Where the love which constrained the Christians, of whom this chapter tells, to gather proselytes from every circle in which they moved? Where the self-denying devotion which prompts to effort wherever there is a call for it and a place for its exercise, wherein a Christian needs sympathy or a sinner is ignorant of the great salvation? A second thought suggested by these salutations of St. Paul is worthy of special notice. They afford a striking example for Christian women. They prove them to have had an important place in the early Church. Of the names which this chap |