"To our meetings," said Bache in concluding, "each member brings his contribu tion; gathered from the land or the sea, the earth, the air, the heavens, the spirit, each one lays his offering on the altar of truth. How little, when under the influence of this spirit, seem contentions for special lines of research, the interference in special pursuits, the covetous desire to enter a particular path, and the determination to jostle the votary who is following it, rather than not occupy it exclusively. The realm is boundless; the paths are numerous; each one is wide.

"Let there be no contention, brother, between thee and me! Let there be rather a generous and eager urging forward, each of the other to the good which we all seek. Warmed by the glow of generous sympathy, let us find our zeal kept alive by association, and show that the bond of scientific brotherhood is worthy of Christian men, in a Christian land, of the faith which we profess in time, and of our hope in eternity."

At this session of the Association, one hundred and thirtyfour papers were read, and one hundred and twenty-one new members added. An invitation to hold the next meeting at Cleveland, O., was received from the corporation of that city, through the Mayor, and accepted. But as the time of this meeting approached, the prevalence of cholera throughout the West led the local committee to intimate their fears, that were a meeting to be held there at that time, and under the exist ing circumstances, it would certainly be small, and might be attended with disastrous results. The officers of the Association assumed therefore the responsibility of postponing the session for a year. The time selected for the meeting of 1853 was unfortunate, falling as it did upon the Commencement week of a number of the Eastern colleges, but the attendance was nevertheless very good.

Prof. PEIRCE presided. His opening address breathed the same spirit as that of Bache at New-Haven, and, like that, animated and urged the members to a chivalric devotion to the crusade for truth, rather than unworthy contests for personal distinction. Scientific men are but mortals, and though the tendency of all their studies, rightly pursued, is to exalt the mind above the turbulence of daily out-door life, still they have their peculiar trials and temptations. And, apart from these, the righteous indignation which every true lover of science must experience at the presumptuous arrogance of charlatanism, is in constant danger of being confounded with the very different, courteous and friendly regards, which it is our duty to entertain toward well-intentioned mediocrity. Peirce's address is well worth quoting:

"Gentlemen of the American Association for the Advancement of Science:

"We are again met in the service of our high cause; after the unusual interval of two years, we have again come together at our appointed rendezvous, to make each other glad with the tidings of truth which we bring from the Heavens and the Earth;

and to reänimate our fainting zeal by the story of the successful search for the philosopher's stone, the true elixir vita, the fruit of the tree of knowledge, and the footprint of Him, of whom the earth is the footstool.

"Gentlemen, from such an assembly egotism shrinks abashed, and you will not reprove your President that he does not intrude his feelings of grateful pride at the honor which you have conferred upon him, and his profound sense of his incapacity to wear the robes of Redfield, and Henry, and Bache, and Agassiz. His hopes of success in the discharge of his duties do not arise from the vigor of his own energy, or the readiness of his own wisdom, but from the manly hearts which surround him on all sides-hearty friends, whose generous sympathy will easily forgive and correct the errors of an honest purpose.

"Gentlemen, we are not convened for a light duty—our self-imposed task is not an amusing child's play; and we have not accepted the liberally-offered hospitalities of this beautiful city for the enjoyment of a social festival. We have come to give and receive instruction and inspiration. We have come to the shores of this great lake to admire and study the pebbles which our brethren may have picked up here and there with much labor, and to learn where or how they are to be found. We have brought our freights of knowledge to distribute them to the world that they may do good.

"Gentlemen, we have come to study our duty as scientific men, and especially as American scientific men. We are to learn the apparent, and not very pleasant paradox, that America cannot keep pace with Europe in science except by going ahead of her. The New World must begin to build upon a level above that of the Old World, and it must build from its own materials. This is not asking too much. It is no more than was accomplished by the American Ship and the American ReapingMachine. The Yankee who picked the hardest lock of England, and contrived a lock which all England could not pick, is but a type of American intellect. This was a work of mind, and we have a right to expect equal excellence in the higher and more abstract efforts of American genius. But, above all things, it is not to be forgotten that the Temple of Science, by whomsoever built, belongs to no country or clime. It is the World's Temple, and all men are free of its communion. Let us not mar its beauty by writing our names upon its walls. The stone which we have inserted is not ours, it is not thine, it is not mine, but it is part of the Temple. The child picks up a shell, innocently admires its form and coloring, and listens, without a thought of self, to the singing of the angels within it. It is the unconsciousness of the attitude which gives it grace and beauty, and makes the child and the shell part of the same divine thought, each for ever belonging to the other, and both immortalized in the marble of the artist.

"Gentlemen, let us stand here reverently. This is holy ground. Let us not presume to make these walls resound with the bickerings of angry contention for superior distinction, and the foul complaints of mortified vanity. Let us not raise the money-changer's cry of mine and thine, lest the Purifier come, and, taking the royal jewel into his own possession, thrust us out into the ditch, and turn our fame into infamy.

"It has been observed by others, not of our number, that the meetings of the Association have been characterized by a generous appreciation of each other's labors, and it has naturally contributed to the influence and power of our Society. May we continue this honorable harmony so fitting to our sublime studies, and be always open to the reception of new discoveries and new discoverers. But mutual admiration is not our only, or our most necessary office. Mutual criticism is equally conducive to the best interests of the Association. We should exert ourselves to restrain vagueness and uncertainty of thought and expression, and to prevent the concealment of old truths under new forms. We must not permit erroneous statements to pass unchallenged. It is our stern and solemn duty to criticise and expose all false developments, whether they are intended, or the unintentional results of carelessness or ignorance. The task may and should be performed with delicacy and generosity, and the mode of performance will clearly manifest the spirit of the operator, and mainly determine the success of the operation. The knife, wielded with unsparing rudeness, is less effective than the touch of Ithuriel's spear.

"For no falsehood can endure
Touch of celestial temper; but returned
Of force to its own likeness, up it starts
Discovered and exposed."

"Gentlemen, let us learn wisdom from the poet."

Harmony and unanimity prevailed throughout the meeting, and while errors and misapprehensions, false deductions and incorrect reasonings were exposed with an unsparing hand, yet this was done in every instance, we believe, with courtesy and with magnanimity.

The departments of natural history were not so fully represented as usual, but the students of the exact sciences were present in large numbers, and those of astronomy and physics in special force.

Such is a comparatively brief description and history of the American Association for the Advancement of Science. Its field is large, its laborers are few. Should it continue to prompt to the detection of new truths; should it reänimate the weary, or encourage the faltering devotee of science; draw closer the bonds of union between laborers in kindred fields; paralyze error, expose assumption, or elevate the standard of scientific excellence, it will have accomplished a glorious mission.

Should it, on the contrary-and the warning is not without its need-afford an arena for the strife of combatants for distinction which they can win in no more honorable way; should it become a stand whence the charlatan may blow his penny trumpet, without fear of exposure and punishment; or serve, like some of its prototypes, but to afford a medium of publication for papers which would find no admission where rigid censorship is exercised, it would offer a most dangerous obstacle to the extension of true science in America; it would exert a most baneful influence upon the community, and disgrace the reputation and name of our country.

To attain the objects desired; to guard against the threatened dangers, the labors and continual efforts of the lovers of science are indispensable. Thus far they have been eminently successful, and the rainbow of hope spans the dark cloud behind it.

TREES.

The North American Sylva: or, A Description of the Forest Trees of the United States, Canada and Nova Scotia. 3 vols. Illustrated with colored Plates. By F. A. MICHAUX.

THE poets, and even men of science, when their views are elevated, as in the case of Humboldt, recognize a mysterious affinity between human consciousness and external nature; it is a relation modified by individual feeling,-in Byron having the character of intense sympathy, in Wordsworth of an abstract sentiment, and in our own descriptive poet welcomed as a serene and holy element, born of calmness, veneration, and the gentle affections. But however diverse in its influence, the relation between humanity and the universe, independent of material laws, is recognized more or less distinctly by all capable of reflection, or alive to natural impressions; and in persons of imagination and sensibility, like Rousseau, St. Pierre, Cowper, Petrarch and others, whose writings embalm in finished language their communion with the phenomena of earth, wave, and sky, the feeling is developed with emphasis, and acknowledged by those equally susceptible but less gifted in expression, as identical with their own. The general aspects and universal language of nature, however, are the medium through which her secret endearments reach the soul; it is while contemplating the entire landscape, its verdure and blue crystal water or golden sunset, and inhaling the freshness of the breeze, and listening to the cheerful or sad tones that mingle or succeed one another in rural scenes, that the spell is woven and the heart touched. In a word, it is what the painters call general effect, and not specific objects, that usually awaken the peculiar sympathy to which we refer. When, however, we turn from the unity of this picture and examine its details, attempting to grasp and realize a single feature with somewhat of the skill of the artist and the analytical power of the naturalist, and yet, at the same time, endeavor to gratify, in so doing, a personal and comprehensive interest, what object does nature afford more fit for the nucleus both of sentiment and science than a tree? Complete in itself, yet related most intimately to all the elements; having a distinct vitality, yet associated with the permanent scenery of still-life; massed into a vast phase of nature, and yet having the most individual traits; there is in the organization, the life, uses, aspect, and history of trees, a world of marvels and an enduring charm. They reveal processes, excite fancies

and attach feelings such as no other material product of the earth can boast. A mountain or a stream may become favorites, but with the one is blended an idea of grandeur and extent, incompatible with individual affection, and with the other the idea of movement and change, which assimilates the feeling it awakens with that indulged towards a sportive child. But the dignity, the grace, the fixed position and varied costume of a tree, its prominence in the landscape, the venerable familiarity of its presence, its nearness, its shelter, its whispering foliage, concentrate and render habitual the feeling which other objects in nature generalize. A flower is too dainty, a rock too sterile, a cloud too evanescent to awaken more than a passing admiration or a mere partiality; but a tree, so gradually matured, so exquisitely arrayed, so noble in proportion, so friendly in its very appearance, and often wreathed with associations of country, home, boyhood, meditation, and love, as vivid and luxuriant as its own summer foliage-a tree is, of all single inanimate objects in nature, the most picturesque and the most endeared.

We may find in the mere life of a tree adequate reason for this preference. Its vital economy is in many respects identical with our own: there is a similar process of circulation and respiration. The roots penetrate the soil in every direction in search of moisture; the new layers around the young tree carry sap to leaves, as blood is taken to the lungs; the net-work of the leaves is like nerves; and when the juice is prepared in these verdant receptacles to form wood, it is carried through vessels in the bark and distributed. The oxygen of the atmosphere is absorbed by the leaves, combines in the sap with carbon, and forms carbonic acid, which the light decomposes. While the carbon is deposited in the returning sap, oxygen is exhaled into the air. Thus trees breathe, and undergo a chemical process analogous to that which transforms blood into flesh and bone; they also secrete gum and other substances; their withered limbs must be amputated not less than the maimed soldier's; they are liable to disease, to decay with age, and are deformed by excrescences like goitres and warts; they are divided too, into sexes, possess family peculiarities, assert their individuality in development; they may be grafted like breeds of animals; live in communities and isolated; have their special affinities, and their sensation is only doubtful because they are inarticulate! Thus the organization of trees brings them nearer to humanity than any other product of the elements; and natural science reveals new facts which increase the mysterious analogy, by unfolding the most delicate resources and curious relations in the highest order of the vegetable kingdom.

Every species of tree is the distinctive feature of a landscape,