August 12, 1898.] 



SCIENCE. 



193 



larger type have been used, and the work is in 

 every respect an improvement over the earlier 

 edition. The scope of the bools is limited to 

 coplauar kinematics and dynamics, and it seems 

 remarkable that so much of the groundwork of 

 the science is covered in spite of that restrict 

 tion. The author has also limited himself in 

 the use of the calculus, the book being so ar- 

 ranged as to form a consecutive elementary 

 course without resort to that branch of mathe- 

 matics which is still a mystery to many well 

 developed minds. On the other hand, by such 

 limited use of the calculus he seeks to prevent 

 the student ' from thinking, as is often the 

 case, that there is a kind of mechanics called 

 elementarjf, another analytical, a third theo- 

 retical, and so on.' For the average student, 

 it must be admitted, this type of book is more 

 readable than any other, and we can heartily 

 recommend Professor Wright's book as one of 

 the freshest, most interesting and most instruct- 

 ive of the type. In the old days, when all stu- 

 dents of some colleges were compelled to pursue 

 mechanics, it was commonly considered a ' dis- 

 mal science. ' Saxe, in his Reflective Eetrospect, 

 says : 



" 1 recollect those harsh affairs, 

 The morning hells that gave us panics. 



I recollect the formal prayers 

 That seemed like lessons in mechanics. ' ' 

 But no one can read Professor Wright's book 

 without being interested at least in the histor- 

 ical references and apt quotations he has worked 

 in along with the formal parts of the science. 

 Even the ponderous gravity of John Milton has 

 to submit to a sly dig from the wily mechanician. 

 Witness this conclusion from Milton's data : 



" Men called him Mulciber : and how he fell 

 From heaven they fabled, thrown by angry Jove 

 Sheer o'er the crystal battlement : from morn 

 To noon he fell, from noon to devrey eve, 

 A summer's day : and with the setting sun 

 Dropt from the zenith like a falling star, 

 On Lemnos th' JJgean isle." 



"Taking the summer's day fifteen hours, 

 show that the distance of Lemnos isle from 

 heaven is about one- fourth of the distance to the 

 moon." 



Of a radicallj' different type from any other 

 work noticed in our list is the text-book on 



applied mechanics of Professor Perry. It is 

 also quite different from the standard works on 

 the subject by Rankine, Weisbach and others. 

 In fact, it is a unique work, full of information 

 as an egg is full of meat, and written in a style 

 which is very lively in comparison with the 

 sedate models set by previous writers. As 

 stated on the title-page, the book is intended to 

 be 'A treatise for the use of students who have 

 time to work experimental, numerical and 

 graphical exercises illustrating the subject.' 

 As to the qualifications of a reader taking up the 

 work the author says in his preface : " I should 

 like to think that, before a student begins the 

 part in small type, he has worked through 

 Thomson and Tait's small book on Natural 

 Philosophy, and that he has read the early part 

 of my book on ' The Calculus for Engineers.' " 

 The vigorous way in which the views of the 

 author are set forth may be inferred from the 

 following quotations from the introductory 

 chapter : 



"When we think of what goes on under the 

 name of teaching we can almost forgive a man 

 who uses a method of his own, however unsci- 

 entific it may seem to be. Nevertheless, it is 

 not easy to forgive men who, because they have 

 found a study interesting themselves, make 

 their students waste a term upon it, when only 

 a few exercises are wanted — on what is some- 

 times called the scientific study of arithmetic, 

 for example, or of mensuration." 



" In our own subject of Applied Mechanics 

 there are teachers who spend most of the time 

 on graphical statics, or the graphing of func- 

 tions on squared paper, or the cursory exami- 

 nation of thousands of models of mechanical 

 contrivances. One teacher seems to think that 

 applied mechanics is simply the study of kine- 

 matics and mechanisms ; another, that it is the 

 simple exercise work on pure mechanics ; 

 another, that it is the breaking of specimens on 

 a large testing machine ; another, that it is try- 

 ing to do in a school or college what can only 

 be done in real engineering works ; another, 

 that it is mere graphics ; another, that it is all 

 calculus and no graphics ; another, that it is 

 all shading and coloring and the production of 

 pretty pictures without center lines or dimen- 

 sions. Probably the greatest mistake is that of 



