August 12, 1892.] 



SCIENCE. 



95 



repository for the national collections, these reports touched but 

 lightly upon the vast amount of material stored away. Within 

 the past five years, however, and since the National Museum has 

 become recognized as the place where all government expeditions 

 shall deposit the material collected by them, a large volume has 

 been annually devoted to this branch alone. Those which have 

 been issued are filled with information upon a great variety of 

 subjects, although special attention seems to have been devoted 

 to ethnology. Naturally, other matters are treated of, and it is 

 likely that, in the future, place will be given to all departments as 

 fast as the several curators find time or see fit to devote their at- 

 tention to making the collections under their charge known to the 

 outside world. 



The article under review, for it is merely an e.xcerpt issued un- 

 der a separate cover from the Report of the Museum for 1890, and 

 covering pages 503-591 of that report, is one which, while designed 

 to be a handbook for the collections, is in reality a condensed ac- 

 count of the rocks forming the earth's crust. In it one will find 

 concise descriptions of the sixteen principal elements that go to 

 make up rock masses; a list of the original and secondary minerals 

 of these rocks; an account of the macroscopic and microscopic 

 structure of rocks; the chemical composition (in brief) and the 

 color. The most extensive portion of the handbook, however, is 

 that which deals with the kinds of rocks. Under this head we 

 have described the four varieties of (1) aqueous, those formed 

 through the agency of water either as chemical precipitates or as 

 sediments; (3) molian, those formed from wind-drifted materials; 

 (3) metamorphic, those changed by dynamical or chemical agents 

 from an original aqueous or igneous origin ; and (4) igneous (erup- 

 tive), those brought up from beneath the surface in a molten con- 

 dition. It is not necessary to go into details as to all these classes, 

 or to mention the various divisions made of them; an extract or 

 two will serve to show the character of the remarks For exam- 

 ple, under Chlorides we read : — 



" Sodium chloride, or common salt, is one of the most common 

 constituents of the earth's crust. From an economic standpoint 

 it is also a most important constituent. It occurs in greater or less 

 abundance in all natural waters, and, as a product of evaporation 

 of ancient seas and lakes, it occurs in beds of varying extent and 

 thickness among rocks of all ages wherever suitable circumstances 

 have existed for their formation and preservation. Salt-beds from 

 upwards of a few inches to thirty feet in thickness occur in New 

 York State and Canada, while others abound in Pennsylvania, 

 Vu-ginia, Ohio, Michigan, and Louisiana. There are also numer- 

 ous surface deposits, of great extent, in the arid regions of the 

 West" (p. 533). 



Under tbe head of Siliceous group, infusorial or diatomaceous 

 earth, we find the following: — 



"This is a fine white or pulverulent rock composed mainly of 

 the minute shells, or teats, of diatoms, and often so soft and friable 

 as to crumble readily between tbe thumb and finger. It occurs 

 in beds which, when compared with other rocks of the earth's 

 crust, are of comparatively insignificant proportions, but which 

 are nevertheless of considei-able geological importance. Though 

 deposits of this material are still forming, e.g., in the marshes of 

 Yellowstone Park, and have been formed in times past at various 

 periods of the earth's history, they appear most abundantly asso- 

 ciated with rocks belonging to the Tertiary formations. 



" The celebrated Bohemian deposit is some fourteen feet in 

 thickness, and is estimated by Ehrenberg to contain 40,000,000 

 sheUs to every cubic inch. The Australian specimen exhibited is 

 from a deposit four feet in thickness. In the United States, beds 

 are known at Lake Umbagog, New Hampshire; Morris County, 

 New Jersey; near Richmond, Virginia ; Calvert and Charles Coun- 

 ties, Maryland; in New Mexico; Graham County, Arizona; 

 Nevada; California; and Oregon. The New Jersey deposit covers 

 about three acres, and varies from one to three feet in thickness; 

 the Richmond bed extends from Herring Bay, on the Chesapeake, 

 to Petersburg, Virginia, and is in some places 80 feet in thickness; 

 the New Mexico deposit is some six feet in thickness and has been 

 traced some 1,500 feet; Professor LeConte states that near Monte- 

 rey, in California, is a bed some 50 feet in thickness; while the 

 geologists of the fortieth-parallel survey report beds not less than 



300 feet in thickness of a pure white, palebuff, or canary-yellow 

 color as occurring near Hunter's Station, west of Reno, Nevada. 



"The earth is used mainly as a polishing powder, and is some- 

 times designated as tripolite. It has also been used to some ex- 

 tent to mix with nitro-glycerine in the manufacture of dynamite. 

 Chemically the rock is impure opal"' (p. 540). 



It is in such books as these that the young student finds his best 

 helps. The information given is accurate; the paths are made 

 pleasant; the rough places are smoothed. It is greatly to be de- 

 sired that the other departments of the Museum may have as 

 u'eful descriptions of their contents. Joseph F. James. 



Washington, D.C., Aug. 8. 



Phases of Animal Life, Past and Present. By R. Lydekker. 

 London. Longmans, Green & Co. 8°. |1.50. 



This admirable series of essays, which was originally published 

 in Knowledge, has been reprinted in an attractive form both as re- 

 gards typography and illustrations. The essays are concisely 

 written, and reveal a wealth of knowledge on the jiart of the au- 

 thor. The explanations of scientific discoveries and conclusions 

 are neither too elementary nor too technical, and the essays will 

 be read with pleasure as well as profit by anyone interested in 

 zoological lore. 



The earlier and the closing chapters of the book are devoted to 

 the consideration of various morphological adaptations, such as 

 protective armor, the modifications of limbs for flying and swim- 

 ming, and tbe forms of teeth and horns. The author then takes 

 up the fossil reptiles, describing the characteristics of the ichthyo- 

 saurs, plesiosaurs, and dinosaurs, and explaining tbe differences 

 between them. Other chapters relate to the tortoises, the extinct 

 gigantic birds, the egg-laying and marsupial mammals, and other 

 animals whose structure and history are of special interest. There 

 is for the most part no close connection between the various 

 topics, but they are all important and worthy of attention. 



In the treatment of morphological subjects Mr. Lydekker makes 

 use of certain metaphorical expressions which may possibly mis- 

 lead the unwary reader. Various modifications are snoken of as 

 if they resulted from the conscious, intelligent action of the ani- 

 mals concerned. It is stated, for example, that the ancient maU- 

 clad fishes " appear to have come to the same conclusion as the 

 more advanced divisions of the human race, that a massive armor 

 for the protection of the body is an encumbrance " (p. 7). Again, 

 the reptiles " held divided opinions as to whether a bony coat of 

 mail was or was not a thing to be retained as a permanency." 

 Such expressions are calculated to induce a wrong way of looking 

 at things unless, indeed, the Lamarckian idea that modifications 

 result directly from the efforts of organisms is to be accepted. 



One is surprised to find in the writings of so good a naturalist 

 as Mr. Lydekker the statement, or insinuation, that the separation 

 of the amphibians from the reptiles is due to "that tendency to 

 multiply terms for which they (the naturalists) are so celebrated" 

 (p. 8). Mr. Lydekker, of course, well knows and, indeed, takes 

 pains to explain, that the separation was made on account of the 

 fact that the typical representatives, at least, of these two groups 

 are very different both in structure and mode of development. 

 There have undoubtedly been many instances in which naturalists 

 have coined new names unnecessarily, but this is certainly not a 

 case in point. 



These are small defects, however, and are entirely overbal- 

 anced by the excellencies of the book. It deserves and will re- 

 pay perusal. 



AMONG THE PUBLISHERS. 

 " The Delaware Indian as an Artist" is the subject of a fully 

 illustrated paper by Dr. Charles C. Abbott, to appear in The Popu- 

 lar Science Monthly for September. The objects of art which are 

 represented include carved-stone gorgets, a wooden spoon-h'andle, 

 wooden masks, and other carvings, many of them showing much 

 skill. Professor J. S. Kingsley will describe ''The Marine Bio- 

 logical Laboratory at Woods HoU,'' giving pictures of its build- 

 ing and interior arrangements. Something is told also of its 

 neighbor, the laboratory of the United States Fish Commission. 

 Surgeon George M. Sternberg, U.S.A., will have a paper on -'In- 



