manifestly exhibited the same tint, though judging from certain extrinsic evidence it ought to have been painted green. Had not the parties concerned been amicably disposed, the mistake of a color-blind clerk might thus have given rise to a su perb amount of litigation. Imagine, too, a young painter madly in love, endeavoring to portray the idol of his heart. What would be her consternation on discovering that her soft blue eyes were a flaming red; that her nose was of the greenest tint, and that her locks hung in rich purple ringlets upon a neck of spotless drab ? can There are three or four points connected with color-blindness which we barely note. First, it is frequently hereditary in families. A Dr. Earle, of the United States, ascertained that amongst his own relatives there were at least twenty individuals who suffered from this oddity of vision. Secondly, ladies are said to be comparatively exempt. Professor Wilson states that in his researches he never heard of more than six feminine instances of color-blindness in this country, and of these he only succeeded in capturing a single decided specimen. Ĉases There is one very serious form, how- however have turned up which show that ever, in which color-blindness might be the men do not bear the exclusive burden, productive of disastrous results. You are as all polite individuals would doubtless traveling by railway; you observe in the wish the sex to do. Thirdly, it has been distance a man waving a flag. If that alleged that the number of color-blind flag is red it indicates danger; if green, persons amongst the Society of Friends it simply denotes caution. By night the is inordinately large, and an attempt has same purpose is answered by the employ-been made to explain this inference upon ment of lamps of corresponding hue. The philosophical grounds, for it has been said train goes rushing on. There happens to that the practice of wearing apparel from be some obstruction in the road. Then which all gay tints are excluded, must follows a crash; and in an instant scores ultimately tell upon the eye, and in the of men who, but a moment before, were course of several generations the consefull of life and perfect of limb, lie mang-quences will mount up until they appear led beneath the shattered vehicles. How as a decided physical imperfection. Unis this? The person whose duty it was to hoist the signal of danger is color-blind, and has seized the wrong flag, or the driver, whose business it was to interpret it, is dead to the difference between red and green. It may be true that catastrophes clearly traceable to this cause may never have occurred on our iron highways; but considering that red and green are the hues which are most frequently confounded in color-blindness-that red is especially treacherous during twilight because it soonest disappears and that until recently signal - men were never subjected to any practical examination to test the integrity of their vision, we may well shudder at the thought that our lives have repeatedly been staked upon the chance-sufficiency of an official's sight. fortunately for this theory Quakers are not always looking at their clothes, nor are they shut out from the varied hues of nature and art, nor does their defect bear any distinct relationship, complimentary or otherwise, to the prevalent drab of their denomination. The fact that Dalton was a member of their persuasion, and that consequently minuter researches may have been instituted amongst the body, will explain why they have furnished so large a contingent of patients. Lastly, it has been calculated that one individual in every fifty is decidedly color-blind, and taking milder cases into account, it is conjectured that one in every twenty may be more or less affected. MR. JOBARD, of Brussels, has invented an artificial statuary marble, which is to bo prepared for sculpture in a liquid state, and can be molded with the plaster figure. It is said to be puro and spotless as Carrara; transparent, polished, and hard as the real substance taken from the quarry. VOL. XLVIII.-NO. IV. a MADAME JENNY LIND GOLDSCHMIDT performed at miscellaneous concert, in Dublin, on Monday evening. The Freeman's Journal says that the appearance of the fair singer created quite a scene, all the vast assemblage seeming to bend forward whilst peal after peal of welcome greeted her. 34 SIR ISAAC NEWTON observes in his Optics, "that, as telescopes can not be so formed as to take away that confusion of rays which arises from the tremors of the atmosphere, the only remedy is a most serene and quiet air, such as may perhaps be found on the tops of the highest mountains, above the grosser clouds." The second edition of the Optics, in which this suggestion first occurs, was published in the year 1718. In 1852 Mr. Piazzi Smyth, the Astronomer Royal for Scotland, submitted to the Board of Visitors of the Edinburgh Observatory a scheme for carrying out Newton's suggestion by a summer expedition to the Peak of Teneriffe. On the second of May, 1856, Sir Charles Wood, then First Lord of the Admiralty, consented, on behalf of the Government, to the proposed experiment, and notified to Mr. Smyth that for this purpose the Treasury would place five hundred pounds at his disposal. On the fourteenth of July Mr. Smyth had commenced his work, on the rim of the great crater, at an elevation of eight thousand nine hundred and three feet above the level of the sea. On the twentieth of August he transferred his observatory to a loftier position, at a hight of ten thousand seven hundred and two feet, on the central cone itself-the renowned Peak; whence he was driven down by the weather on the nineteenth of September. These dates show how long a valuable suggestion may be in fructifying. They may also enable those of our readers who will bear them in mind while perusing the following pages to form some estimate of the astonishing amount and variety of work which a properly qualified and zealous observer may accomplish in a few weeks on such a station. Indeed, Mr. Smyth spent his two months on the Peak * Peport of the Teneriffe Astronomical Experiment of 1856, addressed to the Lords Commissioners of the Admiralty. London and Edinburgh, 1859. Teneriffe; an Astronomer's Experiment. 8vo. London, 1858. so profitably, as almost to atone, on behalf of his countrymen, for their having, for nearly a century and a half, treated with such unaccountable neglect the proposal of a great philosopher, upon whose fame their intellectual rank among civilized na tions so largely rests. We have now before us that part of Mr. Smyth's Official Report which has just been issued from the press, together with a popular narrative of the expedition he published last year. As we have now used the word "expedition," we must at once inform our readers, that in this case it means Mr. Smyth alone; for throughout he had no assistance, excepting that of his brave, enduring, and not unlearned wife: this we collect from the pages of the popular narrative just mentioned. The part of the Report now published contains only three of the ten books of the entire manuscript. In these three we have the astronomical, the physical and meteorological, and the botanical results of the expedition. The first six, still unpublished, comprise the journals of the work done in the different departments of observation. The tenth is composed of seventy-four photographic illustrations of the geology and botany of the mountain. Really we are bewildered at the variety of objects to which Mr. Smyth's attention was unremittingly directed, and of the scientific instruments by the aid of which his observations were made. We find him noting the phenomena of light, heat, radiation, wind, magnetism, clouds, and rain, and collecting geological and botanical facts as carefully and scientifically as he observes the heavenly bodies themselves. Nothing worth noting in the heaven above, and on or within the mountain beneath, was forgotten. Such an amount of valuable facts was, we believe, never before amassed in so short a space of time by a single observer. to bear in mind, that this expedition, And here we must request our readers though called an astronomical one, was, however, undertaken for astronomical | Greenwich, in a letter prefixed to the Repurposes of so novel a description, that port, the object of the expedition was not many other matters than astronomy pur so much to observe with the hope of diset simple necessarily engaged our ob- covering, in so short a space of time, any server's attention; while not one of the new celestial phenomena, as of determinappliances for observing could be supplied ing the physical qualities of the place of by the locality itself. On the contrary, observation, and of ascertaining for what not only had every instrument to be taken scientific purposes it was adapted, and out from this country, and carried up the what might be probably discovered heremountain, but an observatory also to after, if, in consequence of what Mr. receive them had to be built by the as- Smyth might report, it were thought detronomer himself after his ascent, and at sirable to erect a regular observatory on a hight where no materials for building the spot. Of course the physical qualities could be found, excepting an abundance were mostly meteorological. And as it of loose stones; and it was requisite that was generally believed among scientific this structure should be not merely wind men, up to the very time when the exand water-proof to a certain extent, but periment was tried, that the mountain-top also such as would admit of the proper would be found always enveloped in mist, employment of a variety of scientific in- drenched with rain, and swept with wind, struments. Now here, at home, with all and that, therefore, to go to such a place, the advantages of architects and skilled for astronomical purposes would be only workmen, and in close proximity to our a waste of money and time, a very conlargest cities, the mere erection of the siderable part of our observer's attention walls of an observatory, in the building of was most properly, and indeed necessariwhich many precautions must be taken, ly, devoted to ascertaining the meteorolois generally a work of some years, and gy of the site. It was a good augury of the correct establishment of the instru- success that the first day upon the mounments a work of as many more. We find tain presented a transcendently pure and Mr. Smyth, however, without any assist- clear sky, and so was directly at variance ance, excepting that of a native servant with the confident predictions of exuberand two British tars, who had accompa- ant moisture. But was this sky of the nied him up the mountain, constructing in first day the rule or the exception? It a few days, we may almost say in a few was found to be the rule. The despondhours, sufficient shelter for himself, and a ing prophets would, however, have delocus standi et operandi for his instru- sponded still, supported by the general, ments, out of the loose stones already but hitherto indiscriminate, experience of mentioned, together with some canvas the atmospheric conditions of mountainand a few planks that had been providen- tops, had not Mr. Smyth, by a well-sustially brought up at the time of the ascent. tained series of careful observations, so We notice this, not merely as an instance thoroughly investigated the point as to be of considerable mechanical resource on the able to explain why that particular mounpart of our astronomer combined with a tain is enveloped differently to most thorough knowledge of the requirements others. of his instruments, but rather for the pur- This is a good instance of the way in pose of reminding those of our readers which scientific questions, like the rings who may have become familiar with the which spread over the surface of a lake orderly, but perhaps at times somewhat into which a pebble has been cast, expand ponderous, reports of our long-established and multiply around any object of inquiry, and thoroughly-furnished home institu- however narrowly defined at starting. tions, that they must not be displeased at And thus it came to pass in this so-called finding a great deal more variety, and not astronomical expedition, that not only quite so much minuteness, under every were there made uninterrupted series of head in the Report of a summer astro- observations of the barometer, thermomenomical expedition to a previously uninter, hygrometer, and other usual meteorvestigated and even uninhabited region, two thousand miles away in a tropical sea. In fact, as was anticipated by Mr. Smyth's brother Astronomer Royal at ological instruments, both at the top and bottom of the mountain, during the whole period of Mr. Smyth's sojourn on the island, but that much attention was also paid to the cumulative evidence as to climate to be gathered from noting the some of the physical observations which various features of the vegetation. found were made simultaneously with those we at different hights, and from the phenome- have just mentioned such as the obser na of physical geography. Nor was there vations connected with the radiation of any cessation from these labors until suffi- the sun, the heat of the moon- a longcient data had been collected to demon- disputed point at last satisfactorily setstrate that, for six months at least out of tled the black lines on the spectrum the twelve, there would always be found under varied optical conditions-all interon the upper parts of the Peak perfect esting in themselves, and possessing unusu immunity from cloud and moisture, asso-al importance from having been made at ciated with moderate breezes and pleasant temperature. us. But even to have ascertained all this was not enough. Every astronomer knows to his cost, that to insure the best performance of his telescopes, not only must there be an absence of actual cloud, but, furthermore, a certain rarely-obtained quiescent state of the whole atmosphere, for in this alone is good definition with high magnifying powers possible; and so extremely seldom are the conditions essential for this state of the air to be found at the sea level, that Lord Rosse assures that whole years have passed away without affording him, among an abundance of clear nights, one of such accurate defining quality as to enable him to use the higher magnifying powers of his great reflecting telescope to any advantage. And as this is a difficulty which continually increases with the size and excellence of the telescopes employed, its solution is becoming more important every day. Now with respect to the attempt made to resolve it on the Peak of Teneriffe, no testimony would have been accepted by the astronomical public as convincing unless procured by the actual use of an optic tube of very high caliber. This testimony our observer was enabled to supply from the recorded performance on the Peak of one of the most valuable equatorial instruments now in this country, (about which we shall have a word or two more to say before we conclude.) He thus succeeded in having satisfactorily ascertained the triple fact, of incalculable importance to practical astronomy, that on such a station the skies are often freer from haze, the stars always decidedly brighter, and the definition very much better, than near the level of the sea. Here we confine ourselves to the general results; but in the Report the statement of the circumstances connected with the numerical degree to which each of these advantages was obtained occupies considerable space. We might now proceed to describe such a hight in the atmosphere, that nearly a third part of its ordinary disturbing effects were practically eliminated; but we deem it better to leave these matters as they present themselves to us in the Report, bristling with hard numbers ar rayed in uninviting columns and tables, and pass on to a subject much more gener ally attractive and intelligible the use that was made during the expedition of photography and of the stereoscope. This method of illustration has such great and obvious advantages, that by adopting it, and in such a manner as to demonstrate both its advantages and its practicability, Mr. Smyth has laid the general public, as well as men of science, under a very great obligation. At all events, should it become universal, as we can not but think that it must, to him will belong the far from inconsiderable merit of having been the first to have had recourse to it. Of the seventy-four stereoscopic photographs appended to the Report, the twenty most generally interesting may also be found in our author's Teneriffe, accompanied, in a pocket formed in the cover of the volume, by a portable folding stereoscope, adapted to the photographs inserted in the work itself. In these illustrations the greatest gain is not the artistic attainment of solidity and distance, but the gratification of our instinctive longing for exact truth. We here see each object, not as a more or less clever sketcher might have been able to present it to us, or as he fancied that he saw it, but precisely as nature herself would have presented it to our own eyes. These stereoscopic photographs of Mr. Smyth produce in us quite a new sensation: we feel as if we were ourselves the actual observers of the plants, and of the forms and structure of the rocks of the Peak. With a good magnifier, or with our eyes applied to the stereoscope, we feel as sure of our facts and inferences as we should were the objects themselves before us. The advantages of this are so unquestionable, and the feelings which | The Professor next places on the summit accompany the perception of them so delightful, that we would fain hope that the day is not distant when the public will demand the adoption of this mode of illustration by every traveler who would have them purchase his work, and when, consequently, no publisher will entertain the question of offering to the public books of travel otherwise illustrated. of his solid trunk a large number of majestic branches: the Dragon-tree, however, as it belongs to the liliaceous order of plants, can have no true branches at all, but when young exhibits a single, almost palm-like, head of leaves, and when old, a congeries of these heads, each supported by a stem of nearly uniform thickness throughout. His imaginary branches he then clothes with a rich and abundant foliage, reminding us of that of our native elm; whereas the foliage of this Canarian vegetable giant consists of the long lanceolate leaves which constitute one of the features of the natural order to which it belongs. This particular spe: imen grows upon the rocky broken flank of the mountain, in such a position that its northern side is elevated five feet above its southern; but Mr. MacGillivray places The portraits of the great Dragon-tree of Orotava-the subject of some of Mr. Smyth's photographs exemplify in an amusing and instructive manner the scientific value of this application of the art of sun-painting. We must premise, however, that the interest which attaches to this celebrated tree is mainly due to the fact, that Humboldt, misled by a hasty view of its bulk, inferred that it must have commenced its vegetative career six thousand years ago; and then proceeded to de-it on the open level ground. He makes duce from this inference the existence at that remote date of commercial intercourse between the Guanches, or their unknown predecessors, and the contemporaneous occupants of the Indian peninsula; thus overturning, by the unexpected leverage of botanical evidence, the whole system of received chronology, and calling upon history to admit the unique and unaccountable fact of a highly-developed state of civilization having died out, without leaving the trace of a record excepting the strange one of the existence of a single tree; for when these islands were discovered, or rediscovered, in the fourteenth century, their simple inhabitants were even unacquainted with the use of iron. As might, then, have been expected, we have many portraits of a tree which thus became invested with so much historical, or even pre-historical, interest. One of the most recent of these is to be found in Professor MacGillivray's Epitome of Humboldt's Travels. It will be necessary for our purpose to point out some of the errors this contains. In the first place, it represents the tree as having a solid trunk, while, in fact, it has lost its true trunk, which died and rotted away ages ago; that which now supplies the place of the true trunk being a rough imperfect cylinder, composed of aerial and partially inosculating roots, which in the fashion of the Indian fig, support the numerous family of distinct though clustering plants which sprang from the crown of the old and long-since-perished stem. its hight, if we measure it by the hight of the man he represents as ascending a ladder applied to its trunk, a hundred and fifty feet; this, however, is more than double its actual hight, which on the north side is sixty-six feet, and on the south fifty-one. Now here are serious misrepresentations, though perhaps almost as unavoidable as serious, in every one of the main features of this famous tree. Mr. MacGillivray fell into them by endeavoring to copy the portrait he found in Humboldt's Atlas Pittoresque; and in so doing, just as might have been expectedfor, as was said of old, while truth is single and difficult of attainment, error is multiform and correspondingly easy-deviated from the small degree of truth contained in Humboldt: while the greatest of trav elers had himself erred, but only in a less degree, from the same cause; for he had taken his portrait, not from the tree itself, but second-hand from the sketch of M. Ozone, the artist who accompanied the Chevalier de Borda to Teneriffe towards the close of the last century. Here is a good instance of the way in which, under the only method of illustra tion hitherto possible, misrepresentations originated and were perpetuated, being magnified at every step. Mr. Smyth, in order to make this progression of error palpable to the eye, has supplied us with a photograph of the tree itself, accompanied by photographs of Ozone's, Humboldt's, and MacGillivray's portraits of it, appending to them the comment, "that the tree |