REVIEWS 



MATHEMATICS 



Logarithms 



Improved Four-Figure Logarithm Table. Multiplication and Division made 

 Easy. Bv George C. McLaren, Fellow of the Faculty of Actuaries, 

 Scotland. [Pp. 27.] (Cambridge: at the University Press, 191 5. Price 

 1 s. 6d. net.) 



Interpolated Six-Place Tables of the Logarithms of Numbers and the 

 Natural and Logarithmic Trigonometric Functions. Edited by 

 Horace Wilmer Marsh, Head of Department of Mathematics, School 

 of Science and Technology, Pratt Institute. [Pp. xii + 155.] (New York, 

 John Wiley & Sons ; London : Chapman & Hall, Ltd., 1916. Price 5s. 6d. 

 net.) 



Five-Figure Mathematical Tables. Together with an Explanatory Introduction 

 and Numerous Examples. Compiled by E. Chappell, B.Sc, A.C.G.I., 

 Assoc.M.Inst.C.E. [Pp. xvi + 320.] (London: W. & R. Chambers, 191 5. 

 Price 5-r. net.) 



The first of these books was reviewed briefly in our Book List for July 191 5. 

 The little book contains only twenty-seven pages and is furnished with marginal 

 thumb index. As we stated, the principle is to simplify by leaving the determina- 

 tion of the characteristic to ordinary arithmetical consideration — and, indeed, this 

 is often the most troublesome part of a logarithmic computation. Another 

 innovation is to denote the remainder of the logarithm after the first four figures 

 by the use of the full stop for a fraction of about one-third and by a colon for 

 a fraction of about two-thirds. The pamphlet is of course limited only to 

 logarithms of numbers, but is so well arranged that the reader will find it useful 

 for small current calculations, such as may be used in classes, and other rough 

 statistical work. 



In the preface to Mr. Marsh's book he says, " Why a six-place table ? The 

 teacher of conventional mathematics who endeavours to impart a knowledge of 

 theory through the use of the artificial problem whose data are fictitious or 

 ' contrary to fact,' can have no answer to this question. In problems of this type 

 the results obtained by solution have no part in human industry, and it 

 immaterial whether they are expressed in three figures or in more. If interpo- 

 lated alike, a three-place table is therefore as good as a five or greater place for 

 such computation, and even better, because necessitating the use of fewer figures. 

 In industrial and technical problems, however, the result is of supreme importance 

 and the number of figures is fixed by standard practices of manufacture. In simple 



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