England, and the formation of dew is described. The account of liquid water is followed by that of solid water (Chap. IV.), and the principal physical properties of ice and snow receive full attention. A chapter on evaporation shows the connection between it and the rainfall.

The sixth chapter is devoted to the atmosphere, the chemical nature of which is fully discussed. This is followed by an account of its physical properties, and of the perturbations which arise owing to alterations in the pressure. "The Times" weather-chart is reproduced and described; also the barometercharts of the "Standard" and "Daily Telegraph." The chemical and physical history of the air is followed by a chapter in which the composition of pure water is demonstrated. The constituents of mineral waters and of sea-water are discussed, and analyses given.

The ninth chapter is of a more geological character: it treats of the work of rain and rivers, the power of running water, and processes of denudation. The Thames is said, on the authority of Prof. Geikie, to discharge annually 1,865,903 cubic feet of sediment, to which must, of course, be added the mineral matter carried away in solution, which brings up the amount to 14,000,000 cubic feet of solid matter. "Imagine a huge dieshaped mass of stone 100 feet in length, 100 feet in width, and 100 feet in height: this would contain one million cubic feet. No fewer, then, than fourteen of these gigantic cubes appear to be quietly stolen from the surface of the Thames basin by means of running water, and transported to the sea, in the course of a single year. But the Thames basin covers a very large area, and it will be found on calculation that, admitting the abstraction of this vast mass, the entire surface of the basin would be reduced in level by only 1-800th part of an inch every year. At the present rate of wear and tear, therefore, denudation can have lowered the surface of the Thames basin by hardly more than an inch since the Norman Conquest; and nearly a million years must elapse before the whole basin of the Thames will be worn down to the sea-level." Prof. Geikie has calculated that, at the present rate of denudation, it would require 5 million years to reduce the British Islands to a level with the surface of the sea. The tenth chapter is devoted to "Ice and its Work:"-the mechanical expanding work of water in the act of freezing, the motions of glaciers, and so on. A capital engraving of the glacier of Zermatt is given on page 156. It is shown that the passage of a glacier across a country produces peculiarities which are not caused by any other process of denudation, and it is thus possible to infer with certainty that ice has been at work in a district in which ice is now never seen. The flat-domed hillocks known as roches montonnées are thus produced, and they may be detected in Ireland, Cumberland, Scotland, and North Wales, together with bloce perchés, and vestiges of old moraines.

The chapter on the "Sea and its Work" is illustrated by a capital section of the Atlantic between Sandy Hook and Bermuda, in which the soundings are given at short intervals, the temperatures, and the position and dimensions of the Gulf Stream. Here, also (p. 182), we find a chart of the estuary of the Thames between the Nore and Margate. The account of volcanoes and earthquakes includes geysers, and is illustrated by a representation of the Beehim Geyser of Yellowstone Park, Colorado, which throws jets of hot water to a height of 200 feet. It is said that there are no less than 10,000 hot springs, geysers, and hot lakes within the area of Yellowstone Park.

The slow movements of the land (Chapter XIII.) are shown to be altogether more important than the sudden paroxysmal changes produced by earthquakes. The best-known example of such changes within the memory of man is perhaps to be found at Puzzuoli, where the land near the Temple of Serapis appears to be sinking at the rate of one inch in every four years. This occurs in the midst of a volcanic district; but in Scandinavia, a country peculiarly free from earthquakes, we have positive proof of similar slow changes. The northern part of the peninsula is rising, while the southern part appears to be undergoing depression. Evidences of similar changes are not wanting in some parts of Great Britain.

A long chapter (XIV.) is devoted to "Living Matter, and the Effects of its Activity on the Distribution of Terrestrial Solids, Fluids, and Gases. Deposits formed by the Remains of Plants." Herein it is shown that the gaseous and liquid constituents of the earth are being constantly reduced to the solid form, either temporarily or permanently, by living matter. Prof. Huxley objects to the term organic matter, "because all forms of living matter cannot be strictly said to be organised." Vegetable life is traced up from its most primitive beginnings, by a gradual process of evolution, until it attains full perfection, and then passes to decay. The same is done with animal life, commencing with the egg; and the analogy between the growth of the plant and of the animal is shown. Then the principal fossil vegetable forms are described, and the formation of the coalmeasures. The whole of this chapter is treated in an original and highly suggestive style. A natural continuation leads, in Chapter XV., to the formation of land by animai agencies, such as Coral Land," and (Chapter XVI.)" Foraminiferal Land." The latter embraces an account of some of the deep-sea soundings of the Challenger, the bed of the Atlantic, and globigerina

66

ooze.

Since at the commencement of the volume we find an account of the surface configuration of the Valley of the Thames-that river being chosen for the reason stated above-it is appropriate that now the geological structure of the Thames basin should be discussed (Chapter XVII.): this is accompanied by a geolo

gical map and section of the district. The history of one single river-basin leads to a more general account of the distribution of land and water over the surface of the globe (Chapter XVIII.)

The penultimate chapter treats of the figure of the earth and the construction of maps, and the final chapter of the sun.

It will be seen from the above that no formal sequence of subject-matter has been attempted by the author. A book which commences with "The Thames" and ends with "The Sun," and discusses midway geology, paleontology, and physical geography, interlaced with chemistry and physics, cannot be regarded as an example of great continuity of structure and design. Only a most comprehensive and original mind, such as that of Prof. Huxley, could make such a work at once intensely interesting and highly instructive. The book will be welcomed alike by the general reader, the teacher, and the student. For the upper forms in our modern school divisions it is admirably suited. Its great value to every class of reader depends not only on the matter which it contains, but upon its suggestiveness and upon its excellent literary style.

An Elementary Treatise on Physics, Experimental and Applied. Translated from Ganot's" Eléments de Physique," by E. ATKINSON, Ph.D., F.C.S. Eighth Edition, Revised and Enlarged. London: Longmans. 1877.

THIS is a new edition of a very well-known work which has been reviewed at length in our columns. It is not often that a scientific book of this magnitude reaches an eighth edition in this country, and the fact speaks for itself without any further comment. The present edition contains sixty pages of new matter and sixty-two illustrations. All the most recent discoveries in Science have been introduced, and the work is a complete exponent of the present state of general elementary physics.

A Star Atlas for Students and Observers. Showing 6000 Stars and 1500 Double Stars, Nebulæ, &c., in Twelve Maps on the Equidistant Projection; with Index Maps on the Stereographic Projection. By RICHARD A. PROCTOR. Fourth Edition. London: Longmans. 1877.

THREE editions of this work having been sold rather rapidly, the author determined to bring out a cheaper edition, and this is the result. The maps are constructed in reference to the year 1880, and they will continue to be more and more correct than in the

year when first published, until 1890; moreover, it will not be as far from correctness, on account of precession, as existing Star Atlases, until the year 1927! The stars which are mapped include all down to the sixth magnitude inclusive, and are taken from the B. A. Catalogue and all other most available sources. The maps are drawn by Mr. Proctor himself. We predict a longcontinued career of usefulness to this laborious work.

Transits of Venus. A Popular Account of Past and Coming Transits. Third Edition.

The Universe of Stars, Presenting Researches into, and New Views respecting, the Constitution of the Heavens. Second Edition.

Other Worlds than Ours. The Plurality of Worlds Studied under the Light of Recent Scientific Researches. Fourth Edition.

By RICHARD A. PROCTOR. London: Longmans. 1878. THESE works are second, third, and fourth editions of well-known treatises on popular astronomy, by that most indefatigable and industrious writer Mr. R. A. Proctor. In each instance the former editions have been revised, and in some respects modified. New discoveries have also been introduced, and these have increased as much in astronomy as in any other science. Of recent matters we have Dr. H. Draper's discovery of oxygen in the sun by means of its bright lines; also the discovery of the two small moons of Mars, which revolve around him in respectively 30 and 7 hours, at distances of 14,000 and 5600 miles from his centre. A new star, which appeared in Cygnus, has faded into a planetary nebula, and it emits the monochromatic light of certain gaseous nebulæ whose spectrum is a single nitrogen line. The calculations regarding the distance of the sun from the earth, founded on the recent observations of the Transit of Venus, appear to be drawing to a close, and they give an approximate distance of 93,000,000 miles. Mr. Proctor unites much learning with an easy popular style: he thoroughly understands his subjects, and has carried out much observational research; moreover, he is an excellent draughtsman, and frequently gives us his own designs. Thus his books are at the same time popular and scientifically accurate, and they must always commend themselves to every class of reader.

Pocket Altitude Tables. Short and Simple Rules for Accurately Determining Altitudes Barometrically. By G. J. SYMONS. London: Stanford.

WE once heard of an amateur who fell to work to measure the height of one of the loftiest peaks of the Carpathian range. He made his observations with great precision, calculated out the results, and found-a height, or rather depth, considerably below the sea-level! Mr. Symons's little book will, we think, effectually prevent such an undesirable consummation. By following the author's instructions fairly accurate results may be obtained with a minimum of time and trouble, and without the necessity of employing two observers and two sets of instruments, which on an exploring expedition is not always practicable,

How to Work with the Spectroscope. A Manual of Practical Manipulation with Spectroscopes of all Kinds, &c. By JOHN BROWNING, F.R.A.S., &c. London: John Browning. 1878.

THIS little work, from the pen of our leading spectroscope maker, will be found useful to the student who is commencing the study of spectroscopy. It gives practical directions for working with spectroscopes of all descriptions, from the simple pocket form to the large compound prism apparatus. The various kinds of instruments at present in use are also figured and described, so that the beginner may gain an insight into the cost of an outfit before taking up this branch of scientific study. The paragraphs giving directions for mapping spectra might have been extended with advantage. The whole is illustrated with thirty woodcuts and diagrams of apparatus and spectra.

As an introduction to the more expensive works of Schellen, Roscoe, and others, Mr. Browning's little book may be safely recommended, especially if used in conjunction with Mr. Proctor's shilling manual of the Spectroscope.

Mineralogy. By J. H. COLLINS, F.G.S. Vol. I., The General Principles of Mineralogy. London and Glasgow: W. Collins, Sons, and Co.

1878.

THIS book, which forms part of Collins's Advanced Science Series, has been specially written to enable those practical working miners, quarrymen, field geologists, and students of the