878 



SCIENCE. 



[N. S. A'OL. VIII. No. 207. 



that Desmodus (called Desmodon) is no larger 

 tlian our Little Red Bat and that bats do not 

 migrate. The use of the name Least Shrew 

 for Sorex personatus seems ill advised, since there 

 are at least two smaller species and several 

 which do not exceed it in size. Aside from 

 these minor criticisms, there is little but good 

 to be said of the book as a whole. Mr. Thomp- 

 son's illustrations are numerous and in the 

 majority of cases splendidly executed ; that 

 they are well up to his own standard is suffi- 

 cient commendation. 



W. H. Osgood. 



A Laboratory Guide in Qualitative Chemical Analy- 

 sis. By H. L. Wells, M.A., Professor of 

 Analytical Chemistry and Metallurgy in the 

 SheflBeld School of Yale University. New 

 York, John Wiley & Sons. Pp. 200. $1.50. 

 A Short Course in Inorganic Qualitative Analysis 

 for Engineering Students. By J. S. C. Wells, 

 Ph.D., Instructor in Analytical Chemistry, 

 Columbia University. New York, John 

 Wiley & Sons. 



Both of these books are new, and both are 

 worthy to be picked out from the innumerable 

 laboratory manuals as much above the average. 

 Professor H. L. Wells' laboratory guide is the 

 most original and one of the best works on the 

 subject, known to the reviewer. 



In a ' notice to the student ' in the first chap- 

 ter of the book, the author says : " The object 

 of this course is to introduce the subject of quali- 

 tative analj'sis in such a way as to develop the 

 powers of observation, inductive reasoning and 

 memory, and at the same time to give a knowl- 

 edge of chemical facts and methods which will 

 be of use in the future study of this and related 

 subjects." The author's method is to have the 

 student make and preserve a solution of a salt 

 of each of the common bases. The student is 

 then told to test the action of hydrochloric acid 

 on each of these solutions ; he finds that three 

 yield a precipitate. Five cc. of each of these 

 three is diluted with two volumes of water and 

 again tested with hydrochloric acid ; by further 

 dilution and testing with acid, calculating in 

 each case the amount of salt present, the quan- 

 titative limit of the reaction is studied. The 

 student then takes iu separate beakers a meas- 



ured amount of each of the three original solu- 

 tions, and in a fourth beaker a mixture of the 

 three ; all four are precipitated by the acid, 

 filtered, and washed with boiling water. By 

 addition of sulphuric acid to the filtrate from 

 the mixed chlorides a precipitate is formed ; by 

 adding sulphuric acid to the filtrate from each 

 of the other chlorides the student finds out 

 which of the three constituents of the mixture 

 caused the precipitation. The action of ammo- 

 nia on the residues in the filters is then studied, 

 and thus the student works out for himself the 

 common scheme of analysis of the first group. 



The other groups are worked out in a similar 

 way ; at every step the ingenuity of the author 

 in presenting the problem to the student in the 

 best way is worthy of notice. 



The reactions of acids are studied in a similar 

 manner. The book contains no tables, no ab- 

 breviated schemes, and everything is done to 

 avoid mechanical work and to lead the student 

 to iudepeudent thought. Fresenius' plan of an- 

 alysis is followed, though various new methods 

 are introduced. Constant references to Fre- 

 senius' ' Qualitative Analysis ' foster the habit 

 of consulting books of reference. 



It is the belief of the reviewer that Professor 

 Wells' method is admirable for students who 

 can devote time enough to the subject, and it is 

 to be hoped that teachers who have classes or 

 single students in this position will give his 

 book a trial. 



The book of Dr. J. C. S. Wells, of Columbia, 

 is quite different in character from that of the 

 Yale professor. It is a careful and thorough 

 work, designed for the use of those who can 

 give little time to the subject. It endeavors by 

 exceptionally full and clear descriptive test and 

 tables of scheme reactions to teach qualitative 

 analysis in the least time and with the least labor 

 on the part of the student. 



The advantages and disadvantages of the 

 scheme-table system are apparent and have 

 often been discussed. To those teachers who 

 prefer the use of tables Dr. Wells' book can be 

 recommended as one of the best of its kind. 

 Edward Renouf. 



A Text-Book of Mineralogy. With an extended 

 Treatise on Crystallography and Physical 



