66 



SCIENCE 



[N. S. Vol. XXXIII. No. 837 



pretty clear idea may be obtained of the char- 

 acter of the okapi itseK, the great lack being 

 detailed comparison of the okapi with other 

 ungulates, living and extinct, and conse- 

 quently, the absence of information regard- 

 ing the relationships of the animal. A 

 large number of illustrations are devoted to 

 variations in the striping of the fore and 

 hind legs, practically no two animals being 

 alike in this particular. Some of these figures 

 are from mounted specimens, and some from 

 bandoliers made of okapi skin, including the 

 first two obtained by Sir Harry Johnston, 

 which Dr. Sclater took to be from a zebra and 

 in this belief described the animal as Equus 

 johnstoni, on February 5, 1901, the generic 

 name Ohapia being given by Lankester later 

 in the same year. OJcapia Uebrechtsi was de- 

 scribed by Forsyth Major in 1902 and subse- 

 quently Lankester based a third species, 0. 

 erichsoni, on a peculiarity shovm in the frontal 

 hair whorls of an individual. There is, how- 

 ever, little doubt that there is but a single 

 valid species. 



It was a theory of Professor Marsh that 

 good illustrations were really more important 

 than text, since they showed facts that might 

 be used by any one while the text would con- 

 sist naturally more or less of the opinions of 

 the writer. From this viewpoint the volume 

 under consideration will be appreciated by all. 

 It is also valuable as a study in individual 

 variation, no two specimens of the okapi being 

 quite alike either in external appearance or 

 internal structure. And while Lankester 

 qualifies his remarks on these points by say- 

 ing that he has not had the opportunity of 

 examining a similar amount of material of 

 any other species of large wild animal there 

 can be little doubt but what the okapi is really 

 exceptional in the amount of individual varia- 

 tion it presents. 



F. A. Lucas 



Reproduction artificielle de mineraux auXIXe 

 siecle. By P. N. TcHrawmsKY. Kief, 

 1903-1906. 8vo. Pp. Ixxxviii + 638 ; 117 

 figures and 11 portraits. 

 A very comprehensive work on the artificial 



production of minerals has recently been pub- 

 lished in Eussia by Professor Tchirwinsky. 

 The work contains 177 figures of various 

 crystals, some fifty of which were produced by 

 the author himself, and also eleven portraits 

 of scientists who have worked on synthetical 

 minerals. 



While covering the same ground as the ear- 

 lier treatises on the subject by Fuchs (1872), 

 Fouque and Michel Levy (1882), Bourgeois 

 (1882) and Meunier (1884), as well as the 

 chapters devoted to this subject in the works 

 on mineralogy by Doelter (1890) and Brauns 

 (1896), the writer has not only added a very 

 complete record of the rich and important re- 

 sults of scientific research in this department 

 during the last two decades of the past cen- 

 tury, but has revised and rearranged the 

 earlier material, and corrected several errors 

 in the references. The critical remarks with 

 which he accompanies his resumes are to a 

 considerable extent based upon his own experi- 

 ments. 



The work falls into two parts, a general 

 and a special part. At the outset the writer 

 explains that he uses the term " artificially 

 produced minerals " only in regard to those 

 which are produced in the laboratory, and not 

 in reference to such as may be fortuitously 

 produced, as for example, the diamonds which 

 have been found in steel, or minerals formed 

 upon metal ornaments, etc., that have been 

 long buried (pp. 13-15). In this connection 

 the author cites the words of St. Meunier, that 

 the convalescent who two thousand years ago 

 cast a coin into a mineral spring whose waters 

 had cured him, little knew that he was initia- 

 ting a geological experiment.' 



The writer then proceeds to describe the 

 more important kinds of apparatus employed 

 in the laboratories for the artificial production 

 of minerals; many of these are figured (pp. 

 15-24). He next passes to the consideration 

 of the methods used for measuring artificial 

 crystals (pp. 25-27). The fact that in a large 

 number of cases these crystals are exceedingly 

 small and can only be viewed through the 



'Page 14, note: St. Meunier, " Mgtiiodes de syu- 

 thfese en mineral ogie," Paris, 1891, p. 55. 



