346 



Notices respecting New Books. 



curves. The remaining chapters of this valuable Monograph are : 

 XIV. Sunspots and Terrestrial Magnetism ; XV. Wolfs Sunspot 

 Formula ; XVI. Nature of Sunspot Relationship ; XVII. General 

 Conclusions, — in which the contents of the preceding chapters 

 are shortly resumed. It is to he regretted that the author has 

 taken no notice of Zeeinan and "Winawer's researches in solar 

 magneto-optics in connexion with the spectroscopic properties 

 of sunspots. 



Edinburgh Mathematical Tracts. London : G. Bell & Sons, Ltd.? 

 1915 :— 



No. 1. A Course in Descriptive Geometry and Photogrammetry for 

 the mathematical laboratory, by E. Lindsay Ince, M.A., B.Sc, 

 Pp. viii + 79. 2s. 6d. 



No. 2. A Course in Interpolation and Numerical Integration 

 for the mathematical laboratory, by David Gibb, M.A., B.Sc. 

 Pp. viii + 90. 3s. 6d. 



No. 3. Relativity, by A. W. Conway, D.Sc, F.R.S. Pp. 43. 2s. 



No. 4. A Course in Fourier Analysis and Periodogram Analysis 

 for the mathematical laboratory, by G. A. Caese, M.A., D.Sc. 

 and G. Sheaeee, M.A., B.Sc. Pp. viii + 66. 3s. 6d. 



No. 5. A Course in the Solution of Spherical Triangles for 

 the mathematical laboratory, by Heebeet Bell, M.A., B.Sc. 

 Pp. viii+66. 2s. Qd. 



No. 6. An Introduction to the Theory of Automorphic Functions, 

 by Lestee E. Ford, M.A. Pp. viii+96. 3s. 6d. 



1. The first Tract of this carefully edited and beautifully 

 published series begins with a very clear and interesting expo- 

 sition of the purpose and the methods of Descriptive Geometry. 

 The subject is introduced by a plain description of Monge's 

 method, of the fundamental properties of projections, and of the 

 methods of " Contours " and of " Perspective." Some useful 

 hints concerning Laboratory Methods are given. The intro- 

 ductory chapter closes with an account of the evolution of 

 descriptive geometry, from Vitruvius up to Lambert. Chapter II. 

 treats of the straight line and the plane in orthogonal projection, 

 and contains a good number of fundamental problems with their 

 solutions, explained on clear diagrams. A few numerical examples 

 accompany each of these problems. The chapter closes with a 

 collection of appropriate exercises. Chapter III. is dedicated to 

 curved surfaces and space-curves, in orthogonal projection, the 

 subject being again developed chiefly upon a series of interesting 

 problems concerning cylindrical surfaces and solids of revolution. 

 In the two concluding sections, the method of contours is applied 

 to topographical surfaces. Chapter IV. initiates the reader in the 

 perspective representation of regular solids, of plane and of twisted 



