# Popular Science Monthly/Volume 1/June 1872/Literary Notices

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Corals and Coral Islands. By James D. Dana, LL. D. Dodd & Mead.
This book will be widely welcomed, not only for the interest of its matter and the elegance of its form, but because of the gratifying assurance it will afford to the numerous friends of its accomplished author that, although in shattered health, he still retains that wonderful power of versatile labor by which he has been distinguished in the world of science for the last 25 years. Prof. Dana went round the world, from 1838 to 1842, with the Wilkes Expedition, as geologist in the scientific corps. In this extended exploration, in addition to his geological work, he made a special and elaborate study of the zoophytes, and treated at length of corals, coral animals, and coral reefs. His reports upon these subjects were, of course, designed mainly for men of science, but in the present volume he has recast the statement, with the view to its more general usefulness. In his preface the author says: "The object in view, in the preparation of this work, has been to present a popular account of ‘corals and coral islands,’ without sacrifice of scientific precision, or, on the main topic, of fulness. Dry details and technicalities have been avoided as far as was compatible with this restriction; explanations in simple form have been freely added, and numerous illustrations introduced in order that the subject may have its natural attractiveness to both classes of readers." The object proposed has been very completely attained, and a volume produced which will be alike valuable to men of science and entertaining and instructive to general readers. Its illustrations are many and fine, and its manufacture is a credit to the publishers.
We have no room here to treat of the ​contents of Prof. Dana's volume, but mean to do so in a future number; yet we cannot forbear quoting a pleasant passage referring to a man of whom much is now vehemently said, both in praise and disparagement:
"Our cruise led us partly along the course followed by Mr. Charles Darwin during the years 1831 to 1836, in the voyage of the Beagle, under Captain Fitzroy; and, where it diverged from his route, it took us over scenes, similar to his, of coral and volcanic islands. Soon after reaching Sydney, Australia, in 1839, a brief statement was found in the papers of Mr. Darwin's theory with respect to the origin of the atoll and barrier forms of reefs. The paragraph threw a flood of light over the subject, and called forth feelings of peculiar satisfaction, and of gratefulness to Mr. Darwin, which still come up afresh whenever the subject of coral islands is mentioned. The Gambier Islands in the Paumotus, which gave him the key to the theory, I had not seen; but on reaching the Feejees, six months later, in 1840, I found there similar facts on a still grander scale and of more diversified character, so that I was afterward enabled to speak of his theory as established with more positiveness than he himself, in his philosophic caution, had been ready to adopt."
Spectrum Analysis, in its Application to Terrestrial Substances, and the Physical Constitution of the Heavenly Bodies. Familiarly explained by Dr. H. Schellen, Director der Realschule I. O. Cologne. Translated from the second enlarged and revised German edition, by Jane and Caroline Lassell. Edited, with Notes, by William Huggins, LL. D. With numerous Woodcuts, Colored Plates, and Portraits; also, Angström's and Kirchhoff's Maps. 455 pages, 8vo. D. Appleton & Company.
In his late work on the sun, Mr. R. A. Proctor, author of “Other Worlds than Ours,” says: “The reader is referred, for fuller details than there is here space for, to Dr. Schellen's work on ‘Spectrum Analysis,’ the English edition of which is now preparing for publication under the able supervision of Dr. Huggins. This work will be specially worthy of very careful study in all matters relating to the spectral Analysis of the sun.” This long-expected work, which has been so eagerly looked fo by those who desire a popular and authoritative exposition of this beautiful subject has now appeared, and is republished in this country at half the English price. An able writer in the London Spectator thus speaks of it:
In the whole history of science there is nothing more wonderful than the discovery or invention (it would be difficult to say which is the more correct term) of spectrum analysis, and the sudden advance of the new method of research into a foremost position, among all the modes of scientific inquiry. If we take up at random any recent scientific work, whether on astronomy, or chemistry, or meteorology—nay, even though it treat of subjects like entomology, botany, and conchology, which seem as far as possible removed from optical problems—we cannot turn over its pages without finding more or less copious reference to the prismatic analysis of light. Yet, thirteen years ago, spectrum analysis had no existence whatever as a mode of scientific inquiry. It was a subject for research, not a method of research, and there were not a few who regarded it as a subject altogether intractable, while scarcely any believed that it would become the means of advancing our knowledge to any important extent.
The history of the sudden advance of this great problem into the position of a great solver of problems is full of interest. Not five years had passed from the day when Kirchhoff announced the true meaning of the dark lines in the solar spectrum, before Huggins and Miller were telling astronomers of the terrestrial elements existing in the stars. Then the great secret of the gaseous nebulas was revealed by Huggins, and soon after the structure of comets began to be interpreted. Nor had chemists been idle in the mean time. In 1861, Bunsen and Crookes, by means of the new analysis, had detected three hitherto unknown elements, cæsium, rubidium, and thallium, and, in 1863, Reich and Richter had discovered a fourth new element, indium. The importance of the new mode, of research in all problems of chemical analysis, as a delicate test for determining the presence of poisons, as a means of ​proving many processes of manufacture, and as an aid in almost every branch of scientific inquiry, became each year more clearly recognized. We have seen Sorby analyzing by its means the coloring-matter of plants, and the entomologist comparing the spectrum of the glow-worm and the fire-fly, or discussing the absorption-bands peculiar to the fluids of insects. The microscopist employs the powers of the new analysis to solve problems which the magnifying powers of his instruments would be altogether unable to cope with. Nothing, in fine, seems too vast or too minute, too distant or too near at hand, for this wonderful instrument of research, which deals as readily with the mass of Sirius, a thousand times larger and a million times farther away than our sun, as with the ten-thousandth part of a grain of matter in a flame within a few inches of the spectroscopic tube. It is, perhaps, not the least wonderful circumstance about the new analysis that it has already been made the subject of many volumes of scientific lore. A goodly library might be filled with the printed matter which has been devoted to spectroscopic analysis, either in works definitely directed to the subject, or else in chapters set apart for its treatment in works on other subjects. But the general public has undoubtedly not had occasion to complain, as yet, that the analysis has been too fully expounded to them. It cannot be denied, indeed, that hitherto the vaguest possible ideas have been entertained by many respecting the most powerful mode of scientific research yet devised by man. The work of the telescope or of the microscope all men can at once understand, even though the principles on which these instruments are constructed may not be thoroughly understood save by a few. But the case is very different with the work of the spectroscope. When the astronomer says that with a telescope magnifying so many times he can see such and such features in Mars or Venus or Jupiter, every one knows what he means; but, when the spectroscopist says that his instrument shows certain bright lines in the spectrum of a nebula, or certain dark lines in the spectrum of a planet, the general reader has to accept on trust the interpretation placed on such results by the observer.
It was to remove this difficulty that the present volume was originally written. Of its value in this respect we can have no higher evidence than the fact that Dr. Huggins named it to the two ladies who have translated the present edition 'as the best elementary work on spectrum analysis.' The translators—the Misses Lassell (daughters of the eminent astronomer who has just vacated the presidential chair of the Astronomical Society)—remark that the interest they derived from the perusal of this work 'suggested the idea of undertaking its translation.' Dr. Huggins agreed to edit the volume; and, accordingly, we find appended to the valuable text of Dr. Schellen many important (in some cases absolutely indispensable) notes by the English master of the subject.
The work thus translated is from the second German edition, which is not only much larger than the first, but is improved by the correction or omission of several faulty passages. It consists of three parts. The first describes the various artificial sources of high degrees of heat and light. The second relates to the application of the analysis to terrestrial substances. These portions of the work are extremely important, and, on the whole, they are well arranged; but, to say the truth, they are rather dry. Fortunately for the general reader, they occupy together little more than one-third part of the work, the remainder being occupied by the description of the application of spectrum analysis to the heavenly bodies. In this, the third section of the book, we have four hundred pages full of the most interesting matter. The investigations of astronomers into the nature of the sun's globe, and of those wonderful envelopes which surround him, are described with great fulness of detail, and illustrated by a fine series of drawings. The colored plates, representing the prominences as seen by Zöllner, Respighi, and Young, are especially interesting and suggestive, more particularly when the reader's attention has been directed to the scale of miles—or rather of thousands of miles—placed under each. Respighi, indeed, rejects mile-measurement altogether, and can be satisfied only by a scale of terrestrial diameters; so that, instead of showing how many thousands of ​miles would correspond to the height of the colored prominences, his scale tells us how many globes as large as our earth could be placed one above another, so as barely to reach to the summit of the solar flames.
The sections on the stars and nebula? are full of interest, though Dr. Schellen is disposed to place somewhat more reliance on the researches of F. Secchi into the stellar spectra than is entertained by our leading spectroscopists. On dealing with meteors and their spectra Dr. Schellen lays a well-deserved stress on the labors of Schiaparelli, to whom science owes the recognition of the strange fact that meteoric rings are associated with comets. Nearly ten years have passed since Schiaparelli announced that 'the comet of 1862, No. III.' (a large and bright object) is no other than the remains of the comet out of which the meteoric ring of the 10th of August has been formed in the course of time. Received with doubt for many months, this bold assertion gradually commended itself more and more to the attention of those who studied meteoric phenomena, until in 1866 the recognition of a corresponding agreement between the November meteor-ring and Temple's comet of that year removed all doubt as to the reality of the relation. On February 9th of the present year, the gold medal of the Astronomical Society was awarded to Schiaparelli in recognition of this important contribution to our knowledge.
The editorial work of Dr. Huggins adds considerably to the value of Schellen's treatise. In places, the author apportions somewhat incorrectly the merit due to various workers in the field of spectroscopic research; so that some of the notes in which Dr. Huggins refers to these points are, in reality, very necessary. But the work of the editor is yet more important in removing errors and explaining difficulties relating to scientific details.
Ancient America: in Notes on American Archaeology. By John D. Baldwin, A. M. Harper & Brothers.
One of the great results of modern science is the power it confers of arriving at true interpretations of the past. Just in proportion as it discloses orderly relations in the events of Nature, and trains the human mind in the careful weighing of evidence, it enables investigators to turn backward and gather a knowledge, which was before impossible, of the ancient order of things. We owe to science, therefore, a history of man which is earlier than books—of civilizations which rose and passed away with no literature to preserve its memory. Fragmentary and most incomplete it assuredly is, and a host of questions arise in the inquirer's mind to which no answers can be given; yet a vast and constantly-increasing mass of facts is known, from which many valid conclusions are deduced of interest to the students of Nature and of Man.
Archæology, or the science of antiquities, searches for all the vestiges of human action in the distant past; the remains of architectural structures, of public works, carvings, inscriptions, coins, medals, heraldic symbols, workmen's tools, articles of use and ornament, and whatever can serve to throw light upon the state of man and society when they were produced. It matters nothing how apparently trivial are the relics of by-gone ages; they have interest for the archæologist because they are the results of art, industry, intelligence, and social organization, and become the measures of these conditions.
The book before us treats of the most interesting departments of American archæology. Its author published a volume in 1869 on the prehistoric nations, and now follows it with a popular compendious statement of what is known of the ancient monuments of North and South America, and the inferences they warrant as to the condition of the early inhabitants of our continent. For, whatever theory is adopted regarding the origin and career and relationship of the American races of men, one thing is certain: this continent was formerly the theatre of a people greatly superior to the Indian tribes. Many of the works that remain give evidence of high, though of course, indefinite antiquity.
One of the phases of ancient works which remain to us in great abundance is the mound-structures; the people who made them being known as the mound-builders. These are numerous in the Mississippi Valley—there being 10,000 of them in Ohio ​alone. One, in West Virginia, is 70 feet high, and 1,000 feet in circumference. They are truncated, and their summits are supposed to have been occupied by edifices—probably temples which have disappeared. Lines of artificial embankments remain which enclose from 100 to 400 acres, and evince a considerable degree of geometrical knowledge in their plans. Many articles, as vases, pottery, fragments of cloth, and copper implements, have been found in them, indicating considerable industrial skill. There is evidence that, since they were built, the rivers have changed their courses, and it is also a significant fact regarding their antiquity that the human skeletons found within them are in a state of decay so advanced that they crumble to pieces as soon as touched. Skeletons found elsewhere, and known to be 2,000 years old, are still compact, and comparatively well preserved. An interesting fact in regard to these aborigines is, that they knew something of mining. In the copper-mines of Lake Superior, old excavations for the extraction of the metal, 30 feet deep, have been discovered. Mining implements were found in the cavern, and trees 400 or 500 years old (as ascertained by counting their annual rings) stood upon the débris. Prof. Newberry, Geologist of the State of Ohio, informs us that he has found evidence of the ancient working of oil-wells and lead-mines.
The indications of civilization in Central America, Mexico, and Peru, are still more perfect. The author states that the great Peruvian roads of stone, lime, and cement, 25 feet wide, and with a strong wall on each side, and carried over rivers, marshes, and mountains, and as long as both our Pacific Railroads, make these boasted works of the nineteenth century dwindle into insignificance.
Mr. Baldwin's book is neatly and copiously illustrated, and it has the excellent defect of being too brief.
PROF. TYNDALL'S NEW BOOK.
The first volume of the "International Scientific Series" will be by Prof. Tyndall, on the "Forms of Water," and will treat of the mutations of this element in the great operations of Nature, especially in the phenomena of glaciers. We publish a short article from the advanced-sheets, which will give an idea of the lucid simplicity of the style in which it is written. Prof. Tyndall throws his statements into the direct colloquial form, as if he were talking to a young student beside him, and showing him the things he is talking about. There is true art here as well as science—the art of forcible, effective, vivid presentation by which words become pictorial to the imagination. Prof. Tyndall is as skilful in his manipulation of language as of his scientific apparatus, and he sets his successors in the International Series an example which it will be not easy for them to imitate.
While speaking of Prof. Tyndall, it may be proper to add that he intends visiting the United States in the autumn, perhaps early in October. He will come to see his friends (and he will find them numerous), and to get acquainted with our people; but it is not his purpose to exploit the country as a lecturer. He may probably give a few lectures, but he will embarrass himself by no previous engagements.