October 4, 1912] 



SCIENCE 



439 



ment of the subject embraces the molecular 

 properties of liquids. The kinematics of har- 

 monic motion is reproduced by an extensive 

 collection of typical eases, after which follows 

 a very full treatment of the graphics of 

 acoustics. The information which is here 

 brought together is extraordinarily rich. 



Thermal phenomena are now so extensively 

 known that the graphic method seems almost 

 necessary for their classification. Particu- 

 larly in the broad subject of solution such a 

 method seems to be the only one adequately 

 available and Auerbach has made full use 

 of it. 



The diagrams in electricity are as a rule 

 more familiar, though Auerbach has not failed 

 to introduce much of the recent progress, as 

 in radiology, for instance. Finally, in the 

 section of optics he has had the advantage of 

 long residence in Jena. Throughout the book, 

 in fact, the charts relating to the properties 

 of the Jena glasses are very satisfactory. At 

 the same time the progress there made in 

 optical theory is fully recorded. 



The book contains 213 pages and on the 

 average three or four graphs to the page. It 

 •concludes with a brief description of the 

 charts together with the necessary biblio- 

 graphical notes and an index. The charts are 

 throughout up to date, both in their theoret- 

 ical and experimental references. In looking 

 them over one obtains, perhaps, a more vivid 

 impression of the noble accomplishments of 

 modern physics than can be given by any 

 other method. 



Carl Barus 



Beown University, 

 Providence, E. I. 



Sow io Use the Microscope, a Guide for the 



Novice. By the Eev. Charles A. Hall. 



25 text-figures and 20 full-page plates. 



London, Adam & Charles Black; New York, 



The Macmillan Company. T5 cents net. 



The purpose of this book is well expressed 



by the author when he says : " It is a guide 



for the novice, and I have not presumed to 



offer advice to the expert microscopist." The 



seven chapters of the book lirnit themselves 



to what the novice can really do to start with 

 in microscopic work. Once fairly started, the 

 world is all before him. 



In Chapter I. the simple microscope, its 

 advantages and use, are described, and what 

 is said is wholly commendable. In the second 

 chapter there is a discussion of the compound 

 microscope, and the author tells from his own 

 experience how any one can construct a com- 

 pound microscope. In the third chapter is a 

 general discussion of the use of the compound 

 microscope and the excellent advice given to 

 learn the advantages of low powers. The 

 fourth chapter tells of some important acces- 

 sories like the substage condenser and the 

 polariscope and the stage micrometer. Com- 

 ing to the fifth chapter, the real work begins 

 with some common objects for microscopic 

 study. The student is shown where to find 

 them in ponds and ditches, in rook pools of 

 the sea, in the flower pots of the home, in the 

 garden and fields and in the great insect 

 world. He is directed how to prepare and 

 study the things collected, and good books are 

 mentioned which will give fuller information. 



In the sixth chapter directions are given 

 for preparing objects and mounting them 

 permanently. This includes mounting objects 

 dry, mounting insects whole in balsam, ma- 

 king sections of plant tissues, staining and 

 mounting them; and finally the making and 

 mounting of rock sections. The seventh and 

 last chapter deals with the method of making 

 photographs of microscopic objects, and the 

 examples of photomicrographs by the author 

 which illustrate his book furnish excellent 

 models. 



A critical reading of the book shows that it 

 is unusually free from errors. Its advice is 

 good and one feels sure that it comes from one 

 who has been over the ground many times 

 and has learned the good ways. It seems ad- 

 mirably adapted for the beginner in England. 

 For the beginner in any other country it is not 

 so well adapted, as it tells only of the optical 

 goods, etc., to be had of the London opticians, 

 and the beginner would naturally suppose 

 that he must have the identical things men- 

 tioned, at any rate he would know of no 



