536 Notices respecting New Books, 



may a. sufficiently" accurate result be obtained with the least 

 trouble? All experimenters ask themselves these questions,. and 

 often answer in an off-hand, unscientific way. Prof. Holm an is 

 impressed with the importance of establishing a course of proce- 

 dure easily understood and fairly general, and not too laborious in 

 its application. As he says in his preface : — " In venturing to 

 urge the importance of the subject as a course of study for 

 engineers and for students of physics, or other pure sciences, the 

 author would suggest the value of the attitude of mind produced 

 by it. One who has in any reasonable degree mastered its methods, 

 although he may never apply them directly, will not only have 

 increased his power to intelligently scrutinize experimental results, 

 but will have acquired a tendency to do so. And it is, perhaps, 

 not too much to hope that he may acquire a notion of a judicious 

 distribution of effort which, with the best of results to himself, he 

 may carry into quite other matters." The course of procedure 

 seems to us to be one which is practised by every experienced 

 laboratory worker, and whether one ought to adopt it instinctively 

 and because it is natural to exercise some common sense even in a 

 physical laboratory, or whether the inexperienced laboratory worker 

 should study it by listening to lectures on it as a new science are 

 -questions which Prof. Holman's old pupils can best answer. An 

 experienced man who already follows the course of procedure will, 

 we think, read the book with greater pleasure and benefit than the 

 students for whom it has been written. In the planning of direct 

 measurement the method of procedure is summarized as follows : — 



(a) Obtain a general idea of the proposed method, apparatus, 

 and conditions of work, or of several' methods, &c, from which 

 selection may be made. 



(6) Make a thorough study of all discoverable sources of error, 

 taking preliminary observations if necessary. 



(c) Plan the sufficient removal of all determinate sources of 

 error or determine corrections for them. 



(d) Take the final series of observations. 



Of course this summary gives only a one-sided view of the 

 teaching, but still the book is intended to be read by students who 

 need to be taught these things. We should have thought that 

 work in the laboratory and attendance at a few meetings of a 

 Scientific Society would have better effected the author's purpose. 

 We can hardly forgive the author for ignoring altogether the use 

 of squared paper by experimenters. 



Prof. Holman would, probably, deliver an interesting course of 

 lectures to babies to teach them how to walk ; but after all the 

 babies will learn better through falling and crawling and general 

 experience. So a student will learn more in a good laboratory, 

 under an experienced demonstrator, than from this course of 

 lectures. It is the experienced demonstrator who will enjoy 

 reading the book. 



