July o, 1885.] 



SCIENCE. 



17 



mineralogy to the various arts — is not an 

 easy one. Tiie two branches of the subject 

 are too distinct to be easily fused together. 

 The methods of crystallography and the pro- 

 cess of making bricks are not very closely 

 related. About one-half of the volume is de- 

 voted to the preliminary discussion of the 

 general characters of minerals, physical and 

 chemical, and to the description of species. 

 This portion of the work is not only in no 

 sense an original contribution, but it is not 

 even a satisfactority competent presentation 

 of the present condition of the science. The 

 author is evidently a faithful student of Haiiy 

 and Dufrenoy, but hardly seems to be aware 

 of any thing that has been done, even in 

 his own country, in the last twenty-five or 

 thirty years. The chapters on crystallography 

 and the optical characters of minerals, the clas- 

 sification and description of species, are all 

 consistent in being what Dufrenoj- would have 

 given us in 1856. Even in minor points, mod- 

 ern innovations have been resisted : silica still 

 appears in all the formulas as SiOs, water as 

 HO ; and so on. 



The portion of the work which is devoted to 

 the practical side of the subject contains, how- 

 ever, much. that is interesting and valuable, if 

 not alwaj's original. In the preparation of it 

 the author states that he has A'isited personally 

 many manufactories and technical works, as 

 well as consulted numerous standard books 

 upon the subject. Some of the topics discussed 

 in greatest detail are the coal industr}', the man- 

 ufacture of glass, of powder, of bricks, of por- 

 celain, the treatment of various ores, and so on. 

 The descriptions here are minute rather than 

 profound, many trivial points receiving more 

 attention than they deserve. The frequent 

 long quotations from other authors, too, give 

 the whole treatment rather a jjatchwork char- 

 acter. The reader looks in vain in this part 

 of the work, as in the other, for evidence that 

 the author is thoroughly acquainted with the 

 progress that recent years have brought, espe- 

 cially outside of his own country. However, 

 it must be allowed that a large amount of inter- 

 esting matter has been brought together, par- 

 ticularly in regard to some of the leading 

 French industries ; and for this the book should 

 have all the credit that it deserves. That the 

 author had only a French audience in mind, is 

 shown by the fact that the bibliography at the 

 close of the volume contains (with the excep- 

 tion of two translations) only titles of French 

 works ; but while no fault need necessarily be 

 found with this, we can but regret that he has 

 not made more use of such admirable works 



as those of Des Cloizeaux and Mallard, which 

 are mentioned in his list. 



GEOLOGY OF THE VIRGINIAS. 



In publishing this compilation of Professor 

 Rogers 's contributions to the geology of the 

 Virginias, Mrs. Rogers has conferred a sub- 

 stantial benefit upon the science ; for Profes- 

 sor Rogers's investigations still remain the 

 most important and the only systematic or 

 comprehensive attempt to elucidate the geol- 

 ogy of these great states, which are not ex- 

 celled in structural complexity, or the interest 

 of the problems which they present, b}' any 

 district in eastern North America. But his re- 

 ports were printed from forty to fifty years ago ; 

 and copies of them are now so extremely rare, 

 that many geologists of the present genera- 

 tion have probably not seen them, and are not 

 aware of the vast amount of careful and endur- 

 ing work which they represent. Hence this re- 

 print is in many respects as fresh and timely 

 as the original publications, with the great ad- 

 vantage of combining in one convenient vol- 

 ume all of the annual reports and the widely 

 scattered separate papers, and thus forming 

 a handbook of Virginian geology which will 

 be indispensable to the student of the Appa- 

 lachiap sj'stem, and constitute a necessary 

 starting-point for all future investigations in 

 the Old Dominion. 



The geological survey of Virginia was in- 

 stituted in 1835, and Professor Rogers's annual 

 reports to the legislature for the first seven 

 years make up the principal part of this vol- 

 ume. These reports were ver}^ properly de- 

 signed for popular instruction, and are models 

 of clearness and simplicit}" of style, without 

 evident sacrifice of scientific accurac}^ and de- 

 tail ; while the general absence, in both termi- 

 nology and theory, of indications that the\' 

 were written nearly half a century ago, is a 

 matter of constant surprise. 



The difificulties attending geological explo- 

 rations in Virginia were much greater at that 

 time than now ; but Professor Rogers's energy 

 and industry had brought the survey of the 

 largest area ever at that time subjected to 

 sj^stematic geological examination within one 

 year of completion, according to his original 

 plan, when it was abruptl}^ terminated b}^ the 

 failure of the legislature to continue the appro- 

 priation. No provision was made for the 

 final report, which was to embod}' in a digest- 



A re2)rint of geological reporU and other papers on the geol- 

 ogif of the Virginian. By the late William B. Rogers, LL.]~).. 

 etc. New York, Appleton, 1884. 



