THE POPULAR SCIENCE MONTHLY.
race is no such mere incident of humanity. It is a great thing, and its greatness is conditioned upon and attested by the serious sacrifice of other things. Woman is organized throughout her whole nature to the end of maternity, and, if treated in her youth like the opposite sex, which has not this organization, evils are liable to arise that are often numerous, lasting, and fatal. And that which reason says must be the result, experience says is the result, as Dr. Clarke's book abundantly proves. In his second chapter he makes a very clear statement of the physiological facts and principles involved in the question, and, in his third and main chapter, entitled "Chiefly Clinical," he traces the morbid consequences that have followed a false system of female education. This part of his book is full of startling facts, given in detail, that should arrest the attention of some of our headlong reformers. The book is one that ought to have a wide circulation, and to be issued in a cheaper form.
British Marine algæ: being a Popular Account of the Sea-weeds of Great Britain, their Collection and Preservation. Illustrated. By W. H. Grattann. London: "The Bazaar" office, 32 Wellington Street, Strand, W. C.
While the collecting of algæ at the sea-side has long been a graceful and favorite amusement, and many persons have very pretty collections of them, mounted on cards and papers, or arranged in fanciful designs, very few have attempted to learn their names or to study out their structure, fructification, and the principles of their classification. Thanks to the labors of the two Agardhs, Kützing, Thuret, Harvey, Greville, and other eminent phycologists, the scientific knowledge of these plants now rests on a satisfactory and logical basis, and while the study of algæ is difficult in the extreme, there are ample results to reward the patient and careful investigator. The purpose of the little book, the title of which is given above, is to afford to amateurs and to students an easy introduction to the knowledge of algae, and, if one may judge from the first four parts of the work, all yet received, the author has succeeded admirably in his purpose. The wonder is, that Mr. Grattann has been able to convey so much knowledge about the subject he treats of, and yet be so sparing in the use of technical expressions.
The fact that most of the sea-weeds of the Northern Atlantic coast of the United States occur also about the British Islands, renders this book nearly as available for use here as in Great Britain. The illustrations are very neatly prepared woodcuts, mostly on a black ground, and are inserted in the body of the work. For advanced students in American phycology the only special treatise is the "Nereis Boreali-Americana" of the late Dr. Harvey, of Trinity College, Dublin, a quarto with fifty colored plates, published by the Smithsonian Institution.
Physical Conditions of Inland Seas.—In the August number of the Contemporary Review is a paper of great interest by Dr. Carpenter, in which that scientist explains some curious phenomena of inland seas. It is well known that in the open ocean the depths are uniformly colder than near the surface, so that, while the surface-water in some cases approaches 80° Fahr., the temperature is near the freezing-point at depths of one or two miles. This appears to occur where the movement of water is unobstructed by inequalities of the ocean's bed. Where these are present, however, the temperature is more uniform throughout, as in the Sulu Sea, where the water is at 50° at the greatest depths, but in the contiguous but more open China Sea it is at 37° in deep soundings.
From the cause assigned, the inland seas show a uniformity of temperature as compared with the open oceans. While the surface-waters may be of equal temperature, the depths present great contrast. The Straits of Gibraltar are quite shallow, and a free interchange of waters between the Atlantic and the Mediterranean is impossible. From local causes there is frequently no current, or but a very slight one, either one way or the other. As a consequence of this, the cold waters of the deep Atlantic are prevented from flowing in, and a comparatively uniform temperature prevails in the depths of the Mediterranean.