PRESERVATION OF THE COPPER SHEATHING OF SHIPS. THERE is scarcely any single de- per, and that the rapid decay of copper on partment of practical science so pregnant with interest to a maritime nation like Great Britain, as the recent discoveries made by that illustrious chemist Sir Humphrey Davy, applicable to the preservation of the copper-sheathing of vessels from corrosion. The expenditure, occasioned by the rapid destruction of the sheathing of his Majesty's ships, alone forms a very considerable item in the naval depart ment of the public service. But the loss to the country from their decay bears but a small proportion, during time of peace, to the aggregate loss sustained by the mercantile interests, from similar causes. Indeed the very considerable expense of copper sheathing, added to its rapid decay, serves to prohibit its use in numerous instances, notwithstanding the additional security it gives to a ship, by preventing the opening of her planks, and consequent leakage, in bad weather. But in spite of this expense and sacrifice, every ship destined for navigating the tropiif not protected by sheathing, in a very short period becomes perforated through the bottom by the innumerable marine animalcula which abound in the warmer latitudes. It would perhaps be an interesting inquiry to many persons concerned, to compute the annual loss which the shipowners of this great maritime nation sustain, from the corrosion and destruction of copper-sheathing; but although the amount must be obviously very great, it would encroach too much upon your miscellaneous columns to enter into such investigation. I shall therefore proceed to give your readers an abstract of the valuable researches of Sir H. Davy, which promise to lead to the most important results in the preservation of shipping. The president, in the communication of his important researches on this subject, to the Royal Society, after alluding to the rapid decay of the sheathing of the ships in his Majesty's service, ob cal seas, serves: It has been generally supposed that seawater had little or no action on pure cop more certain ships was owing to its impurity. some of which had been considered as re must have depended upon other causes than the absolute quality of the metal. Sir Humphrey then describes the chemical between sea-water agency and a sheet of copper as follows: When a piece of polished copper is suffered to remain in sea-water, the first effects observed are a yellow tarnish upon the which takes place in a few hours. The hue copper, and a cloudiness in the water, of the cloudiness is at first white, it then changes to green. Within a day a blueish green precipitate appears at the bottom of the vessel, which constantly accumulates, at the same time the surface of the copper corrodes, appearing red in the water, and grass-green where it is in contact with the air. Carbonate of soda gradually forms upon this grass-green matter, and these changes continue until the water becomes much less saline. The green precipitate, when examined by the action of the solution of ammonia and other tests, appears to consist of an insoluble compound of copper (which may be called a hydrated sub-muriate) and hydrate of magnesia. According to the views which I developed fourteen years ago, of the nature of the compound of chlorine, and which are now generally adopted, it is evident that soda and magnesia cannot appear in sea-water by the action of a metal, unless in consequence of an absorption or transfer of oxygen. It was therefore necessary, in order to produce these changes, that water should be decomposed, or that oxygen should be absorbed from the atmosphere. I found that no hydrogen was disengaged, and consequently no water was decomposed; the oxygen of the air must therefore have been quently by numerous experiments. the agent concerned, as appeared subse Copper placed in sea-water, deprived of air by boiling or exhaustion, and exposed in an exhausted receiver, or in an atmosphere of hydrogen gas, underwent no change whatever. But an absorption of atmospheric air was shown, when copper and sea-water were exposed to its agency in close vessels. Sir Humphrey, after referring to the principles of chemical and electrical agency, which he developed twelve or fourteen years ago by his beautiful experiments on the alkalis, farther ob serves: Copper is a metal only weakly positive in the electro-chemical scale, and, according to my ideas, it could only act upon seawater when in a positive state, and consequently, if it could be rendered slightly negative, the corroding action of sea-water would be null; and whatever might be the differences of the kinds of copper sheathing and their electrical action on each other, still every effect of chemical action must be prevented, if the whole surface were rendered negative.. .....I began with an extreme case. I rendered sea-water slight ly acidulous by sulphuric acid, and plunged into it a polished piece of copper, to which a piece of tin was soldered equal to about one-twentieth of the copper. Examined after three days, the copper remained perfectly clean, whilst the tin was rapidly corroded. No blueness appeared in the liquor: though in a comparative experiment, when copper alone and the same fluid mixture were used, there was a considerable corrosion of the copper and a distinct blue tint in the liquor. If one-twentieth part of the surface of tin prevented the action of sea-water, rendered slightly acidulous by sulphuric acid, I had no doubt a much smaller quantity would neutralize the action of sea-water, when depending only on the oxygen contained in common air. And on trial, I found that one two-hundreth part of tin in proportion to the copper was sufficient to prevent the corrosion of the latter... In pursuing these experiments, and applying them in every possible form and connexion, the results were of the most satisfactory kind. A piece of zinc as large as a pea, or the point of a small iron nail, was found fully adequate to preserve forty or fifty square inches of copper; and the result was equally as satisfactory, in whatever part of the sheet of copper the other metal was placed. And even when the connexion between different sheets of copper was completed by wires or thin filaments of the fiftieth of an inch diameter, the effect was the same; every side, every surface or particle of the copper remained perfectly bright after being placed in sea-water for many weeks; while the iron or zinc was slightly corroded. A piece of thick sheet-copper was cut in such a manner as to form seven divisions, connected only by the smallest filaments that could be left; and a slip of zinc, one. fifth of an inch wide, was soldered to the upper edge. The whole, after being immersed for a month in sea-water, left the copper in a bright polished state, as at first. The same experiment succeeded with a slip of iron, soldered to the copper; whilst similar pieces of copper, undefended, were considerably corroded by the salt water. The importance of this discovery in the preservation of our shipping can at present scarcely be appreciated; for there appears to be not a shade of doubt as to its complete efficacy when reduced to practice. Sir Humphrey is still pursuing his researches on a large scale; but his observations on a comparative experiment, made for the purpose of demonstrating its practical effects, is all I shall venture to extract from his late communication to the Royal Society, As the ocean may be considered, in its relation to the quantity of copper in a ship, as an infinitely extended conductor, I endeavoured to ascertain whether this circumstance would influence the results. By placing two very fine copper wires, one undefended, the other defended by a particle of zinc, in a very large vessel of sea-water, which water may be considered as having the same relation to so minute a portion of metal, as the sea to the copper-sheathing of a ship. The result of this experiment was equally satisfactory with that of all the preceding. The defended copper underwent no change whatever; whilst the undefended wire tarnished, corroded, and deposited a green powder. These electro-chemical researches bid fair to open a most extensive field for investigation, and to prove of infinite value to the arts: for it seems not improbable that means will speedily be found, in almost every case, to prevent that destruction, or at least injury, to which all metallic surfaces are liable. from what is termed oxidation by the atmospheric air. I shall not fail to communicate to your readers, in the ensuing numbers, such new facts as become developed in this very interesting department of science. MY DEAR SIR, WASHINGTON IRVING'S NEW WORK. NEED not tell you how much your request flatters me, nor how will ing I am to comply with it. Having reflected a good deal on the character of Washington Irving's writings, a very few hours have enabled me to adjust my ideas with respect to his last work. I have looked forward to the publication of Geoffrey Crayon's new work with much greater anxiety than to that of a new novel from the indefatigable pen of the Great Unknown. Geoffrey (said I), does not write against time, as the novelist does. He pays his readers more respect and does himself more justice. He loves fame as well as money. Besides, even when the G. U. was chary of his reputation, and leaned but lightly on his feather, I do not know that so much value (taking the utile and the dulce together) was derivable from any of his works as from those of our transatlantic brother, Geoffrey. At least, speaking for myself, who always wish to combine in my read ing profit with pleasure, the perpetual insinuation of stories or passages where the strain of reflection is so deep as to amount almost to philosophy, the insinuation of such stories or passages amongst those of a more purely amusive kind, will ever render such works as the Sketch Book much more acceptable to me than novels like those of the Author of Waverley, which are wholly devoted to enter tainment. I read the latter, as it were, against my conscience. When I have finished one, and another, the question inevitably recurs-What have I gained by such an expense of time and eyesight? Am I wiser? Very little. Or better? Not much. What have I gained, then? Why, so many hours' amusement. And is this all? All: what would you more?-Instruction. I do not ask a sermon, or a philosophical essay; but instruction of some kind or other, an accession to my previous stock of knowledge, something which I can chew upon, digest, and turn to my own aggran35 ATHENEUM VOL. 2. 2d series.. dizement, I must have, or I would nearly as soon spend my time at a billiard table. Indeed altogether as soon; for a good game of billiards invigorates the body, whilst a novel, such as I speak of, debilitates the mind. The imagination being pam pered, we have no energy of appetite for the simple fare of reason and wisdom which other books set before us. That is a higher kind of writing which, in however small a degree, addresses the heart or the understanding as well as the fancy. I do not, however, mean to be taken as one who condemns romantic or imaginative works; I merely say that those not wholly so are better. It would be hard upon readers as well as writers to prohibit (were that possible in effect) all works of mere entertainment ; there are many who can read only such works, and some who can write none other. Yet perhaps it is unjust to say so: there are probably few readers who would not willingly imbibe the lessons of wisdom if they were sufficiently few and concise, if they were agreeably displayed and happily illustrated; there are probably few writers who could not impart such lessons, if they took half the pains to deserve their own approbation that they do to merit the applause of others. To instruct by delighting is a power seldom enjoyed by man, and still seldomer exercised. It is in this respect that Homer may be called the second of men, and Shakspeare the first. The wisdom of the Greek was not so universal as that of the Briton, nor his genius so omnipotent in setting it forth attractively. From the several works of the latter, a single work might be compiled little less worthy of divine sanction than any other extant, and by the beauty of its nature, far more secure of human attention. But Shakspeare has done so much in this way, so nearly all that is sufficient,-he has made the laws of the decalogue and all their corollaries so familiar, he has exhibited the passions and propensi ties, the feelings and emotions, incident to humanity, so freely, and as I might say, graphically, that another such artist would be superfluous. Nature might create a second Shakspeare, but it would be bad economy. What the first has left undone, may be completed by a much less expense of Promethean fire than would go to the creation of a second. We are therefore not to look for a similar being, at least until we acquire new attributes, or are under a new moral dispensation. Spirits of an inferior order, a Milton, a Pope, or a Cowper, are potent enough to disseminate the remaining or minor truths of natural morality amongst the people, or rather to repeat, illustrate, and impress them on our hearts and memories. Writers of this class whom we may call the lay ministers of the Deity, to teach from the press instead of the pulpit, in the closet instead of the church, we may expect; and with them should we be satisfied. Though we cannot reasonably hope for another high prophet of profane inspiration to re-communicate to us the lessons of divine wisdom which are already to be found in Shakspeare, it is no presumption to hope that the spirit of illumination will descend upon humbler poets, and make them our secular guides in morality. This is the office which should be sought by every writer, and for which he ought to prepare himself, as the will to become is (independent of genius) one and the same with the power to be. In this case it is not God who chooses what priests shall serve him, but the priests who choose whether they will serve him or not. The preceding exaltation of the poetic character into something of a sacred nature, the designating poets, as it were, a temporal order of moral teachers, may astonish those who have been accustomed to degrade poetry into a mere collection of sounding words and glittering images. But a great poet is always a philosopher and a moralist; such also, in some degree, is every poet who is worthy of that name. The moral state of a nation may be judged of by its poetry, and it is its poetry which chiefly influences its morals. For one man on whom a moral lesson is impressed by a sermon, there are at least an hundred on whom it is much more deeply impressed by a poem. No one who ever read can forget I dare do all that may become a man, But we hear every Sabbath many more maxims than we care to remember. A nation's poetry is then its immediate Scripture, and the digest of its practical wisdom and morality. A nation's poets are the best moral teachers of its people. In ancient times, when the priesthood was not so separate an order as at present, the task of instructing the people devolved almost wholly on the poets; especially on the dramatic writers. And hence we find the Greek and Roman dramas so replete with maxims, precepts, pious exhortations, and moral sentiments. But to combine the poet and the philosopher is not given to every one. To instruct and delight at the same time is, as I before observed, not within the power of every author; at least, in this respect, there is a great difference in different authors. In the single province of amusing they are more on a level both with each other, and with the professors of many less intellectual arts, the painter, the musician, the actor, and the buffoon. But he who can, at once, improve our hearts, expand our minds, and entertain our fancy, is a far superior genius to him who can do but one of these. It is in this general faculty that I think Washington Irving excels his cotemporaries. This is the age of "deep feeling," but of little else. Few authors endeavour to merit the reputation of being as wise as they are passionate. The author of Waverley is certainly a more powerful writer than the author of the Sketch Book; that is, his subjects are more lofty, his imagery is more daring, and his language is, if I may so express myself, much louder and more vehement. But though a more powerful, he is not a more effective writer. He agitates the heart more, but he does not more forcibly persuade it towards his object. And he would as soon think of putting happiest example. The subject is interesting to the most insensible reader; the language is some of the sweetest I have ever met with; and the sentiments are of that deeply impressive moral kind, pregnant with feeling, simple, yet full of thought,composing a master-piece of its kind, which it is almost vain for me to recommend to imitation; for it can scarcely be imitated with success, perhaps by the author himself. The last page or two where he speaks of "the sorrows for the dead," are worthy of perpetual study and eternal remembrance. They are at once beautiful and sublime; instructive and delightful. To them I would chiefly point my reader's attention, as exhibiting that degree of reflection, and that measure of instruction, which I am anxious to see all our general authors impart to some portions of their writings. I am not an admirer of didactic composition; but I confess it is not without some compunction that I sacrifice my time to the perusal of works where the imagination alone is pampered, and the reason altogether starved. Idle meditation would be a more profitable employment than such reading. on band and cassock as of addressing the reason instead of the fancy of his readers. I say not this to disparage the author of Waverley; by no means. His line of writing may not admit of such a proceeding. His talents may lie in another direction, and, powerful as they are, they may not be universal. I merely wish to point out in what I conceive Washington Irving's superiority to consist. He is certainly the only author I can now recollect, who, in the present day, largely intermingles moral reflection with the poetry of composition. This is the consummation devoutly to be wished by readers, and devotedly to be sought after by writers. The author of the Sketch Book is, in my opinion, a model for that class of writers to whose works the multitude chiefly resorts for its mental recreation, apprehensible by almost every age, sex, and condition, yet not beneath any. He unites much of the solid with more of the splendid; a certain degree of reflection with a greater degree of imagination; considerable power and will to instruct, still more considerable power and will to delight. But such unions are rare; unions by which Nature sometimes endeavours to make compensation for the myriads of fools whom she brings every day into the world. How beautifully, for instance, does the story of "The Widow and her Son," in the Sketch Book, intervene between "The Country Church," and "The Boar's Head Tavern!" How much sweet and unobtrusive wisdom is inculcated by the sketch of "Westminster Abbey" and several others in these volumes! How frequently does the author lead us unwarily into a train of reflection! and in the midst of his liveliest stories how often do we meet with sentences and passages of gentle admonition or instructive remark, a maxim or a moral, tending to make us better or wiser, disclosing a new truth, or impressing an old one!—but of this beautiful and most praiseworthy introduction of moral reflection into works of enterfainment, "Rural Funerals" is the With these pre-dispositions in Mr. Irving's favour, and with these expectations from his forthcoming work, you may judge, my dear sir, of my disappointment, when instead of the qualities I have mentioned as raising him so far above his cotemporaries, I found little in his Tales of a Traveller, but the style, to admire. Here is scarcely a gleam of his playful and Addisonian wit; nothing of his vivid delineation of character. But this is not the worst. The Tales of a Traveller are a number of short stories comprised in two volumes of about the same size as his former works. Not one of these stories is of the reflective character. In not one of them does the author indulge that fine strain of sentiment and moral feeling which makes his Sketch Book such a familytreasure,-even for the space of an ordinary paragraph. Some of the tales are to be sure of a serious na |