May 1 6, 1890.] 



SCIENCE. 



305 



A REMARKABLE meteor, or meteoric shower, paSsed over this 

 State at 5.30 p.m., Friday, May 2. In spite of the brightness of 

 the sun, shining at the time in a nearly cloudless sky, the light of 

 the meteor was very noticeable. Its great size, powerful illumi- 

 nation, discharge of sparks, comet-like tail three to five degrees 

 in length, and the great train of smoke which maiked its course 

 for a full ten minutes after its passage, made a strong and lasting 

 impression on the minds of all who saw it. Unfortunately the 

 clamor over an exciting game of ball prevented the many mem- 

 bers of the college who saw it from making as careful observa- 

 tions as they would otherwise have done: so it was impossible to 

 tell whether its passage was accompanied by sound or not, al- 

 though farmers near here report a faint hissing noise. It ap- 

 peared to enter the atmosphere about twenty to thirty degrees 

 south of the zenilb, and, descending at an angle of about fifty to 

 sixty degrees, passed below the horizon north- north- west of this 

 place. By telegraphing, one small meteorite weighing one-fifth 

 of a pound, and several fragments from a 70-pound one, were se- 

 cured, and analyses and microscopic sections at once made. They 

 contain a large amount of metal for the " stone " class of meteor- 

 ites. 



Following is the analysis of the matrix of the 70-pound mete- 

 orite: silica, 47,03; iron oxide, 29.48; oxide aluminium, 2.94; 

 lime, 17,58: magnesia, 3.96; total, 99.94. 



The specitic gravity is 2.63. The shower covered an area at 

 least two and a half miles long by one wide, near Forest City, lo. 

 There the meteorites are said to have fallen in great numbers ; 

 and already many have been found, varying from a few ounces 

 to sixty or seventy pounds in weight. 



It seems worthy of mention, that, in accordance with theories 

 entertained here, a 100-pound aerolite has just been found in Kos- 

 suth County, some thirty or forty miles farther north. These 

 meteorites all have the characteristic burned, blackened surfaces. 

 Within they are light gray, interspersed with innumerable irreg- 

 ular spots of iron. The many exaggerated and excited reports 

 make it difficult to get at facts: so it seems best for the present to 

 make only a preliminary statement and analysis, until we can 

 make a full and accurate report on this last and highly inlerest- 

 ing Iowa meteor. Joseph Toreey, Jr. 



Erwin H. Barbour. 



Iowa College, GrinneU, May 9. 



BOOK-REVIEWS. 



Die Entslelning der Arten durch raumliche Sonderung. Von 

 Moritz Wagner. Basel, 1889. 8"^. 



MORITZ Wagner, traveller and journalist, was born Oct. 8, 

 1813, at Bayreuth, and died at Munich, May 30, 1887, by his own 

 hand. He regarded the principal achievement of his life to have 

 bean the enunciation of his theory of the origin of species by 

 geographical separation. He wished, toward the close of his life, 

 to publish a comi^rehensive work on this theory; but an accident 

 having crippled bim. and illness interfering, he never carried out 

 his purpose. His nephew and namesake. Dr. Moritz Wagner, 2d, 

 of Baden by Zurich, has collected most of the elder Moritz' essays 

 ill a single bulky volume, to which he has added his own "rider" 

 m the shape of a speculative dissertation on the origin of life and 

 the evolution of species, and prefixed a memoir by Von Scherzer. 

 In judging of Wagner, we have to remember always that journal- 

 ism was his profession and means of support, and that natural 

 history, though his favorite study, always occupied a second place 

 until tlie latter part of his life. His father was a school-teacher 

 in poor circumstancf s, and with six children. Young Moritz 

 showed his master passion by keeping animals and making large 

 collections. When only fifteen years, he contributed editorial 

 articles to some of the local newspapers of Augsburg, where his 

 family were then living. In 1836. when twenty -three years old, 

 he undertook his first journey, going to northern Africa, where 

 he secured an appointment to accompany the French Army in 

 Algiers. The necessary preliminary outlay was covered by ad- 

 vances made by his brothers and friends, and all the expenses 

 were finally met by the sale of his collections and the earnings of 



his pen. He sent frequent letters to the Augsburger Allgememe 

 Zeitung, then as now a leading journal. These letters were 

 eminently successful; and from this time on, Wagner undertook 

 one journey after another, earning the means by his writing. 

 After his first journey he felt the lack of scientific training, and 

 accordingly spent two years at Gottingen, studying geology prin- 

 cipally, maintaining all the while his newspaper activity. His 

 next enterprise was a journey to the Caucasus, Black Sea, and 

 Persia, and later followed his principal journey. In company 

 with Von Scherzer, he came to New York, May, 1853, travelled 

 over the United States for a year and in Central America for two 

 years, much of the time collecting archaeological material for the 

 British Museum. His reputation as a writer and traveller attracted 

 the favor of the King of Bavaria, who gave him liberal aid for 

 another long exploring journey to Central and South America. 



Except as regards the Australian and polar regions, Wagner 

 possessed an intimate acquaintance with all the principal faunas 

 and floras of the world, and the central interest of all his work 

 lies in the study of the geographical distribution of species. The 

 phenomenon which attracted his attention most was that of closely 

 allied species occupying separated areas of distribution. Thus 

 among rattlesnakes, all of which are American, Grotalus durissus 

 belongs to the Atlantic fauna; C. rhomibifer, to Central America; 

 C. miliarius, to the south-western United States ; O. ttrgeminus, 

 to the Rocky Mountains; C. horridus, to Brazil; and soon. Simi- 

 lar instances recur in all classes of plants and animals. The most 

 striking examples are furnished by the humming-birds, some of 

 which are widely distributed, like our own Trochilus eolubris, 

 which ranges from Mexico to Labrador, while others are exceed- 

 ingly restricted, there being a number of species which are limited 

 not merely to a single mountain, but also to certain altitudes. 

 There is, says Gould, a new species about every thousand feet. 

 The genus Oi-estrochihis occurs only at great heights, 10,000 feet 

 and more, and is represented by distinct species on Aconcagua, 

 Cotopaxi, Chimborazo, Cayambe, and other mountains. Orostro- 

 cliilus chimborazo lives up to 16,000 feet, and hunts for flies above 

 the snow limit. Wagner's writings give these examples and 

 many others. This class of facts acquired an immense importance 

 in his mind, and led him to think that species always are distin- 

 guished by separate areas of distribution ; and as a corollary from 

 this opinion he maintained that species arise by a common stock, 

 having two or moi'e areas of distribution, which become distinct 

 or separated by some physical barrier, and that the separation 

 causes the differentiation of the original single species into a cor- 

 responding number of new species. 



The first formal announcement of his theory was made by Wag- 

 ner in a brochure published at Leipzig in 1868, and entitled " Die 

 Darwin'sche Theorie und das Migrationsgesetz der Organismen." 

 He defended the theory in 1870 in a pamphlet on the influence of 

 geographical isolation, and also in three articles published in the 

 periodical Kosmos for 1880 All of these, and others bearing upon 

 the subject, are included in the volume before us. Wagner's essays 

 show the jom-nalisi. They are all discursive and pleasant, it is easy 

 to read along in them, but there is a complete absence of that for- 

 midable marshalling of facts and unconquerable logic which is 

 the stamp of Darwin's work. Wagner nowhere compiles all the 

 facts of geographical isolation, nor enumerates those which con- 

 flict with his theory, either to acknowledge their force or explain 

 them away. He leaves us, moreo^'er, completely in the dark as 

 to how geographical isolation causes new species. All that he has 

 done is to make the generalization that in a large class of cases 

 closely allied species have distinct areas of distribution, — a fact 

 which indicates that separation is a favorable condition for the 

 development of specie?, but does not prove it to be a cause. More- 

 over, the fact that often closely allied species have similar or even 

 identical areas of distribution shows that species arise from other 

 influences than mere separation. Nor can Wagner's theory ex- 

 plain the phenomena of mimicry. These objections have all been 

 urged against Wagner's theory of the origin of species,' and their 

 force has justly prevented the general accepiance of the theory ; at 

 the same time naturalists have recognized the value of the array 

 of facts presented by Wagner. 



1 See especially August Weismann's criticisms, published in 1872. 



