November ii, 1887.] 



SCIENCE. 



237 



or mechanical skill. Besides, it will generally be admitted that the 

 construction of the simpler apparatus by the student himself is a 

 most valuable and useful exercise, giving him a firm and lasting 

 hold upon fundamental principles which he can attain in no other 

 way. But this attention to detail does not stop with the instrument 

 itself. All of various steps to be gone over in its use, its proper 

 adjustments, the errors to be looked out for, etc., are carefully con- 

 sidered ; and in nearly every instance a numerical example is pro- 

 vided, generally taken from real laboratory note-books, and the 

 solution and reduction are gone through with. 



In short, in this respect, as many others, the book comes as near 

 taking the place of the living instructor as can well be imagined. 

 It must not be understood that the book is for the beginner in the 

 study of electricity. It must at least be taken in connection with, 

 and better after, a course in some elementary text-book on the sub- 

 ject, and, in addition, may go along with a course of lectures upon 

 fundamental theories. The recognition of this fact is shown in 

 the plan of the book itself, in which, in the first three chapters, 

 the student is introduced to the leading principles of the science, 

 its nomenclature, units of measure, etc., that the less elementary 

 chapters which follow may ofifer less difficulty. 



The chapter on resistance measurement is naturally full and 

 complete, nearly all important and useful methods being given. A 

 full discussion of the tangent galvanometer is given, together with 

 the methods of determining its constants. Related to this is the 

 determination of the magnetic elements', and a good deal of space is 

 devoted to a very complete description of the Kew magnetometer : its 

 use is described, and a series of observations is completely worked 

 out. Other parts of the work are equally worthy of commendation, 

 especially the series of appendices at the end, containing among 

 other things a number of valuable hints as to the manipulation of 

 material used in the construction of apparatus. 



Nearly all of the formulas used in the reduction of observations 

 are derived from elementary propositions, but the mathematical 

 treatment of the subject is elementary, and well suited to the char- 

 acter of the work. In addition to its adaptability to class-room 

 work, the book can be highly recommended to private students of 

 electricity and magnetism. 



Introduction to a Historical Geography of the British Colonies 

 By C.P.Lucas. Oxford, Clarendon Pr. 12°. 



This little book is the first instalment of a larger work, to be 

 published in parts, and dealing separately with the various depend- 

 encies of the British Empire. It gives not only a brief history of 

 the founding of the British colonies, but treats of colonization gen- 

 erally, ancient and modern, and gives some chapters to what may 

 be called the philosophy of colonization. Mr. Lucas defines a col- 

 ony as a body of persons who have left their native country and 

 permanently settled in another, and who in their new home form 

 the bulk of the inhabitants. He then proceeds to consider the mo- 

 tives of colonization, the chief of which he finds to be these four : 

 " love of enterprise, desire of wealth, social or political discontent, 

 and religion." He does not attribute so exclusive an influence to 

 over-population in the mother-country as some writers do, but 

 thinks that the other motives have in many cases been more im- 

 portant than this. He gives a brief but interesting account of the 

 influence of religion in the founding of colonies and the conquest 

 of dependencies, and also of the effects of climate and race. A col- 

 onizing race should be not only enterprising and inclined to emi- 

 grate, but also endowed with an aptitude for commerce, and 

 especially for law and government. Of these characteristics the 

 last named is the most important : " Colonizing on any large scale 

 must imply dealing with subject races, and the past has shown, 

 that, in spite of other defects, the people which can govern will in 

 the end prevail" (p. 27). 



The brief history of colonization, ancient and modern, which the 

 book contains, and the special account of the English colonies 

 with which it closes, contain a large amount of information in a 

 small compass, and, though treating of matters that are familiar 

 to most readers of history, will be useful for reference. If the pro- 

 jected historical geography of England's colonies is carried out as 

 well as it is begun, it will ^prove a valuable addition to historical 

 literature. 



Electricity for Public Schools and Colleges. By W. Larden. 

 London, Longmans, Green, & Co. 12°. 



The ceaseless activity in all matters pertaining to electricity is. 

 shown in the continued appearance of books relating to the subject^ 

 in all parts of the world and in all languages. 



This book is intended, as its title implies, to serve as a text- 

 book for high-class public schools, and for colleges in which a 

 thorough training in the fundamental principles of electricity and 

 magnetism is furnished, in the development of which the instructor 

 is restricted to elementary mathematics. 



Few institutions of learning in this country can offer to their stu- 

 dents more than this, and, in fact, not very many have found it pos- 

 sible to make use of a separate treatise upon the subject, except, of 

 course, in the way of special elective courses. 



Of the several books containing an elementary treatment of elec- 

 tricity and magnetism which have appeared within the last ten or 

 fifteen years, this by Larden has the advantage of being one of the 

 most recent, and in breadth of treatment, and thoroughness of 

 execution, one of the best. 



Only elementary mathematics is made use of, and it is therefore 

 necessary occasionally to state a proposition on authority. Frequent 

 references are given, however, to treatises in which such proposi- 

 tions will be found fully discussed. In some instances where 

 elementary demonstrations are presented, the author has not 

 selected the easiest and most simple. An illustration of this state- 

 ment is to be found in his proof of the condition under which a 

 battery gives a maximum current. Some of his discussions are 

 also open to the objection of an excessive conciseness and brevity 

 of statement, thus presenting difficulties which the average student 

 of the class for which the book is intended will have difficulty in 

 overcoming. The diagrammatic illustrations have been drawn 

 especially for the work, and are generally very clear. A number 

 of cuts of complete and well-known forms of apparatus are alsO' 

 furnished. 



Among the commendable features of the book may be mentioned 

 a very full discussion of induction machines (electro-static), includ- 

 ing the Voss machine, the Holtz machine, and others, the operation 

 of which is often very perplexing to students. 



The author is not fortunate in his chapter on atmospheric elec- 

 tricity, and especially where he attempts to account for the vary- 

 ing potential of the atmosphere. 



The treatment of electric measurements is tolerably full, suf- 

 ficiently so for a book of this kind, in which one ought not to expect 

 to find all of the now nearly innumerable methods and devices. 

 The chapter on Joule's law and the conservation of energy is es- 

 pecially complete, although not long ; and other chapters, on elec- 

 tro-dynamic induction, the dynamo, induction coils, etc., will be 

 found quite satisfactory. Many teachers and students of the science 

 will welcome the book, and find it useful in their work. 

 The Science of Politics. By WALTER THOMAS MILLS. New 

 York, Funk & Wagnalls. 12°. 



In taking up a book with the above title, we naturally expect to 

 find it treating of the duties and functions of the State, or of its or- 

 ganization or its history ; but these topics are scarcely touched upon 

 in the work before us. The author himself states his subject to be 

 the duties of citizenship and the means of performing them ; but he 

 confines himself mostly to the treatment of political parties. Mr. 

 Mills, as he tells us on his titlepage, is a journalist ; and the influ- 

 ence of his profession is a little too plainly visible in this work, the 

 style showing some of that offhand infallibility which many journal- 

 ists affect. As regards matter, the book is not specially profound 

 or original, yet it nevertheless contains much that is good. The 

 author has in the main very correct ideas as to the nature and 

 functions of parties and the rights and duties of the citizen with re- 

 gard to them. He sees clearly that a party without principles is 

 worthless, and that the fact that a party has done well in the past 

 is no guaranty that it will always do well in the future. He vigor- 

 ously maintains the right to bolt a bad nomination, and the right 

 and duty of leaving an old party and joining a new one in case the 

 old one proves recreant to its trust. Such views as these are not 

 yet so widely accepted in this country as they ought to be ; and, if 

 this book should be read by the right persons, it can hardly fail to 



